# Main > General Discussion >  On hadron colliders, dark matter and black holes

## torstan

So, there is a job thread somewhere in here (looks like it got dropped off the bottom of the page) where I foolishly admitted to being a theoretical particle physicist working on predicting what might be seen at the new collider being built under CERN. If this has no interest to you, feel free to skip to other threads, this one will be unashamedly physicsy. I also promised to post here if there was any major news on the collider.

Well, the short version is this - there is a collider being built under the Swiss-French border. Here's a picture of where it sits and how big it is:


The big white circle shows the path of the tunnel the collider sits in - it's 100m or so beneath the ground and the tunnel has a length of 27km. Note Geneva airport on the right for scale.

The plan is that protons - the nucleus of a hydrogen atom - will be accelerated around the ring to very close to the speed of light in two beams going in opposite directions. Once they are up to speed these beams will then be crossed (with less dramatic consequences than in Ghostbusters - but this is actually what those beams where based on). The beams will collide at two points on either side of the ring and enormous (6 storey tall) detectors will catch the subatomic debris that comes out.

----------


## torstan

So, some facts and figures.

The LHC - Large Hadron Collider
(hadrons are composite particles - of which protons and neutrons are two examples. Always be careful when typing hadron not to get the d and r mixed by accident. Easy typo, completely different machine....)

26 659 m in circumference - the largest machine ever built
>10 years to build, and due to start this summer (first collisions predicted in August)
The magnets are kept at 1.9 degrees above absolute zero so they are colder than outer space. This is so they are superconducting.
This requires the world's largest fridge - >10,000 tonnes of liquid nitrogen.
This, combined with the detectors, will produce more than 800,000 GB of data every year and requires a whole new class of supercomputer to be designed to be able to handle it.

This of course is if it works as planned. We'll find that out later this summer.

----------


## RPMiller

So you aren't taking the warning to not cross the beams seriously then?  :Wink: 

I think this whole project is really interesting. I think my biggest question is what do the participants hope to learn from it? I think that is the one aspect that I still don't quite understand. Will this provide a new energy source? Unlock some important information to improving life? That sort of thing?

----------


## torstan

Okay, all very impressive, but didn't someone mention a black hole?

Well yes, one possible result is that the LHC will produce microscopic black holes the size of atoms. This, contrary to popular speculation, would be great. In fact, some theories predict that we should produce them. However, rather than sucking in the world, these would decay in the detector - exploding in a spectacular shower of subatomic particle that would light up the detector like a Christmas tree. I've seen experimental plots of an event like this. People take it very seriously and would be very excitied if it happened.

But, I hear you shout, what if it doesn't decay? What if the black hole sits there, getting larger and larger until it ate the world?

Well, this has been carefully studied. Though we have never created collisions at this energy in a laboratory on earth before, these type of interactions _do_ occur when cosmic rays hit the earth from outer space. So if this was going to happen, it would have done so already. Okay, so maybe we're just lucky that this hasn't happened to us yet? No. It hasn't happened to us, or to Mars, or to Jupiter, or the sun, or any other object we can see. This was addressed in a recent paper (out this week). I think the abstract (or at least the last line of the abstract) is worth a read:

http://arxiv.org/abs/0806.3381

So no, we will not be destroyed by black holes produced at the LHC. The same arguments (that such interactions have taken place in the earth's atmosphere for its entire lifetime and so any bad thing that can happen should have happened already) is a pretty solid argument against all 'LHC will destroy the earth/universe' theories.

On the other hand, humans are a pessimistic bunch and everyone likes to think the scientists will get it wrong, so I believe that there are a number of End of the World parties being organised for early August....

----------


## RPMiller

Wouldn't there also be a difference in that the naturally occurring ones do not occur inside of a container that could restrain the event? Does the article say anything about that?

For the record I absolutely do not believe anything bad will happen other than it maybe not working. I am curious about the conspiracy theories though. They always make great roleplaying fodder.  :Smile:

----------


## jfrazierjr

> So, some facts and figures.
> 
> The LHC - Large Hadron Collider
> (hadrons are composite particles - of which protons and neutrons are two examples. Always be careful when typing hadron not to get the d and r mixed by accident. Easy typo, completely different machine....)


And a totally different tool also.   :Razz: 




> 26 659 m in circumference - the largest machine ever built
> >10 years to build, and due to start this summer (first collisions predicted in August)
> The magnets are kept at 1.9 degrees above absolute zero so they are colder than outer space. This is so they are superconducting.
> This requires the world's largest fridge - >10,000 tonnes of liquid nitrogen.
> This, combined with the detectors, will produce more than 800,000 GB of data every year and requires a whole new class of supercomputer to be designed to be able to handle it.


Umm so how much energy is this thing supposed to give us?  If I got it all wrong, just let me know since I am not very physicy as you put it.




> This of course is if it works as planned. We'll find that out later this summer.


Yea... it's this bit that has be worried about the state of the universe after you guys turn this thing on...  Typically, anytime some one says "It's completely safe", or "There's no way anything can go wrong", or something like that, the worst possible thing happens.... of course, thats usually in movies, but art imitates life and once in a while life imitates art. :Very Happy: 

Besides, since RPMiller knows the world is going to end in 2012, something will happen to the project and you will have to delay for another 3 years before starting it up again... either that or it takes that long to blow us all to hell, take your pick.

Joe

----------


## RPMiller

> Besides, since RPMiller knows the world is going to end in 2012, something will happen to the project and you will have to delay for another 3 years before starting it up again... either that or it takes that long to blow us all to hell, take your pick.


ROFLMAO!! This is exactly how conspiracy theories get started.  :Laughing:  I love it!

You know the Illuminati are watching and have plans already in motion to make this a reality.

oh and...

FNORD

----------


## torstan

Oops, cross-post. Sorry RP.

There are lots of things we hope to learn from this. 

1. We expect to understand the origin of mass by finding a particle called the Higgs boson.
2. I personally want to know what dark matter is. There's 5 times more dark matter in the universe than atoms, molecules and all the other stuff we've been studying ever since we started asking questions. We foun out it was there only a few decades ago and there are good reasons to believe that the LHC will be able to produce it from scratch. That would be the first time ever that dark matter was created in the lab on earth. Incidentally, dark matter was the basis for 'dust' in the Dark Materials trilogy (though there's really no basis for thinking it is conscious  :Smile:  )
3. The LHC will test theories that differ on the number of dimensions we live in - the four we know about (3 space dimensions and one time or N/S, E/W and your heightmap for cartographers) or whether there are another 6 or even seven, and whether they are small or large.
4. It may start to shed light on how the universe began and how it may end, and also whether there are other universes.

These are ordered in degrees of speculation. The first we should definitely answer. The last is highly unlikely to be any more than a hint, if we get that much.

But of course, this doesn't answer your question. Neither of those things is likely to immediately lead to any new technologies that will improve your life. Technologies tend to come when we put research into a field where the theory is already known. Fusion has been understood theoretically for about 60 years, but we'll only get our first working fusion plant in 15 years or so. However the theoretical understanding of fusion came from particle physics experiments - and no-one knew when they started those experiments that fusion might come out the other end. The purpose of these experiments is to find out how the universe works. When we peel back another layer, sometimes we find something that can be turned to our own use, sometimes we don't. The point is that in particle physics, unlike many other sciences, we don't know the underlying theory until we look, so we can't say what use the discoveries may have until they have been made.

That said, the field has a pretty good track record. The straightforward results of the work are things like lasers, tvs, radiotherapy and so on. None of these would exist if we had not researched atomic and subatomic physics.

However more important perhaps are the spin off technologies. The LHC has funneled a huge amount of money into brand new research into superconductors, electronics, seismology, solid state physics and (of course) IT. All of the developments that have been made for the collider will be applied in the rest of the world. Without the collider, much of this research could not be done because it would be way too risky for a company to invest that amount of its own capital into R&D that may not work.

Past examples of spin offs are everywhere, but the most obvious is the Web. That was put in place so that the data from the previous collider at CERN could be shared between the international collaboration of scientists working on this. The LHC has a similar challenge - there will be more data produced than ever before and a computer infrastructure needs to be set up to deal with it, and to handle the processing tasks on this data sample. That requires a supercomputer and we've built something called the Grid (yes, we're no good at names) - a supercomputer that spans the globe that consists of networked computers in universities in countries on every continent. You can submit a job to the Grid and it will use the processing power of computers right across the Grid to do the job. It's the largest distributed computer resource in the world and will eventually be made available to everyone, just like the internet.

Hope that answers that question! Wow, that got a little longer than intended....

----------


## NeonKnight

Oooooooo Noooooooooz! Torstan is going to be responsible for creating *The Mist* in Geneva!

Ooooooo Noooooz!

----------


## jfrazierjr

> ROFLMAO!! This is exactly how conspiracy theories get started.  I love it!
> 
> You know the Illuminati are watching and have plans already in motion to make this a reality.
> 
> oh and...
> 
> FNORD


Which of course, just brings to mind one of my favorite sayings:   


> Just because I'm paranoid *doesn't* mean they're not out to get me.

----------


## torstan

@jfrazierjr - This won't give us any energy. Rather we pump energy in to get the particles up to speed and then study the results after they collide. It's like pumping a load of petrol into two trucks, watching the fireball when they collide and then measuring how far the bumper went.

@RP - the protons will collide in a vacuum - the center of the pipe is as empty as the engineers can get it to reduce the chance of them accidentally hitting something other than the proton that is coming the other way. Therefore the collision itself is almost identical to a collision in outer space. In fact, at the atomic scale, even gas is mostly empty, so it's functionally the same as collisions in the atmosphere too, which is where the cosmic ray interactions happen. What happens to the debris afterwards - when it flies off and hits the solid bit, the detectors, is essentially just garbage collection. We pick up the bits and see what happened. So the detector doesn't influence the collision itself. In this way, the collision should be as identical to a collision that occurs outside a detector as possible. Otherwise all we'd be studying was how physics works inside a detector - which wouldn't really help us to understand the wider world  :Smile:

----------


## jfrazierjr

> That requires a supercomputer and we've built something called the Grid (yes, we're no good at names) - a supercomputer that spans the globe that consists of networked computers in universities in countries on every continent. You can submit a job to the Grid and it will use the processing power of computers right across the Grid to do the job. It's the largest distributed computer resource in the world and will eventually be made available to everyone, just like the internet.


AHHH... soooo even if you don't directly blow stuff up in a hugh explosion that rips the fabric of space/time, you will be responsible for building a skynet like entity that will eventually destroy humankind....

Like I said, Torstan destroys the world... :Razz: 

Joe

----------


## torstan

Anyone read Angels and Demons? I'll support any conspiracy theory that says CERN should have a space plane. That would be cool.

(yes - they have antimatter, no - they could never use it to blow up the Vatican)

@Neon -The Mist? How did you hear about that. That's strictly..... definitely not something I've heard about....

----------


## RPMiller

> Which of course, just brings to mind one of my favorite sayings:


What are you referring to? That statement came completely out of the blue.  :Wink:

----------


## torstan

Well, at least Skynet would run linux (yep - Grid runs linux).

Incidentally there's another collider reference - last terminator had one I think....

----------


## jfrazierjr

> What are you referring to? That statement came completely out of the blue.



The conspiracy theory bit.  

Now... where did I leave my tinfoil hat????

Joe

----------


## RPMiller

> The conspiracy theory bit.  
> 
> Now... where did I leave my tinfoil hat????
> 
> Joe


Hm... It doesn't appear to be working... Trying again...

FNORD FNORD FNORD

Sir, I think we have someone that is immune. We need a memory erase team stat!

----------


## RPMiller

> @jfrazierjr - This won't give us any energy. Rather we pump energy in to get the particles up to speed and then study the results after they collide. It's like pumping a load of petrol into two trucks, watching the fireball when they collide and then measuring how far the bumper went.
> 
> @RP - the protons will collide in a vacuum - the center of the pipe is as empty as the engineers can get it to reduce the chance of them accidentally hitting something other than the proton that is coming the other way. Therefore the collision itself is almost identical to a collision in outer space. In fact, at the atomic scale, even gas is mostly empty, so it's functionally the same as collisions in the atmosphere too, which is where the cosmic ray interactions happen. What happens to the debris afterwards - when it flies off and hits the solid bit, the detectors, is essentially just garbage collection. We pick up the bits and see what happened. So the detector doesn't influence the collision itself. In this way, the collision should be as identical to a collision that occurs outside a detector as possible. Otherwise all we'd be studying was how physics works inside a detector - which wouldn't really help us to understand the wider world


Interesting. I'll be very intrigued to hear about the data collection and the results there of.

Have they given any percentages on chance of success for the whole experiment?

----------


## NeonKnight

> @Neon -The Mist? How did you hear about that. That's strictly..... definitely not something I've heard about....


When you started talking other dimensions.

OK, I know of the standard 4: length, height, width and time (basicially the previous 3, as in I am the same entity as I was last year but I appear different in the most basic of laymans' terms.)

The 5th dimension and upwards have been theorized as other realities that over lay our own but we just are not in sync with them. This of course then gets into the whole paranormal aspect of that is where the monsters and ghosts and UFOs and what not comefrom.


******WARNING SPOILER INFO BELOW******

In the Steven King novella/and movie *The Mist* a Military installation was able to open a portal to another dimension and of course that was were all the baddies came from. So, when you mentioned the collider could be used to study the existence of other dimensions beyound the 4 known....

----------


## töff

> What if the black hole sits there, getting larger and larger until it ate the world?


Larry Niven had a story based on the speculation that the Tunguska meteorite was in fact a black hole that went right through the Earth.

I've long been fascinated by particle physics, although I am an utter tyro. Cheers to everybody who's working to expand the collective knowledge of our species!

p.s. Yeh please don't suck the Earth into a black hole, kthnxbai.

----------


## Karro

Not having read Mist (or seen the resulting film), I just assumed Torstan was going to give us a map of the array so that others might be able to game out a scenario in which the unpredicted results of these experiments causes tiny tears into extradimensional space, allowing the unspeakable horrors that live beyond our consciousness to slowly leak into our world, which is slowly torn assunder by the unknowable forces at their disposal until, eventually, the entire planet is a ravaged, desiccated husk wherein all of humanity has been consumed by the otherwordly things except those scientists and sundry others still holed up at the CERN facility which, ironically, is the only surviving bastion of life and civilization.

Those last few survivors would be fighting for their lives, struggling to find a way to reverse the flow of extradimensional energy and parasitic intelligence.

I have not played Call of Cthulhu, but it might be best for this game.

I had hoped to include this all in one (maddening) sentence, but, alas, I failed.

----------


## torstan

@RPMiller: There's no real chance of the machine 'failing' as such. The Standard Model of particle physics predicts that there is a Higgs boson. If it finds it, Peter Higgs gets a Nobel along worth the experimentalists that find it. If there is no Higgs found, then the entire Model has been disproved - which would be a major result as it would mean that one of the best tested theories ever constructed would be disproved. Finally it could (and is widely expected to) produce a whole world of new matter that we've never seen before, in which case it is champagne all round and a lot of work for me.

The way it could fail is to not actually produce collisions of the energy required, at the rate we need. That would be an engineering failure and is possible, though, we hope, very unlikely. Nevertheless, the collider is scheduled to run for 10 years at least, so even if it doesn't work as expected when it starts, it should be fixed soon enough in that 10 year window. We'll have to wait and see what first runs this summer produce to know how well the machinery is working. Something this large, complex and unwieldy is guarranteed to have teething trouble when they flick the on switch. The question is how serious the problems are and whether they can be fixed before the first physics run next spring (it turns off during the winter because electricity is too expensive and the experimentalists need downtime to tinker).

@Neonknight - There are many theories with extra dimensions, all of which differ on their nature. Every one of them has a good reason why we haven't seen them yet. These generally fall into one of two categories - either atoms can't move in them, but more exotic matter such as gravitons (a hypothetical particle that transmits gravity) does. Or they are very small and circular. By circular I mean that if you travel far enough in that dimension you get back to where you started - like in the Meteors! or Maelstrom games where if you fly off the right of the screen you come back on the left. In the case of these dimensions, the width of the screen is of an atomic scale, so you would never notice the process of moving across it and coming back to where you started.

There are theories with other universes that are separated from us because of the way space-time might split in quantum mechanics (ala quantum leap and parallel universes) but that is a different use of the word 'dimension'.

----------


## torstan

@ toff: nprb

@ Karro: Now that there is a top plan for at Cthulhu game... Hmmm, sounds like a fun start to an adventure.

@RPMiller: Forgot to mention, I looked it up. The expected data output is around 15 petabytes a year. That will be written to tape on site and simultaneously sent out to two or three other storage facilities around the world to avoid problems from data corruption, or say a fire. Each of those will be accessible from the Grid.

----------


## Karro

> @ toff: nprb
> 
> @ Karro: Now that there is a top plan for at Cthulhu game... Hmmm, sounds like a fun start to an adventure.


It came to me all at once upon reading your first post... I'd have posted it sooner but was distracted by work...  :Frown: 

Is "NPRB" secret mad-scientist code?  :Wink:

----------


## NeonKnight

> @Neonknight - There are many theories with extra dimensions, all of which differ on their nature. *Every one of them has a good reason why we haven't seen them yet.* These generally fall into one of two categories - either atoms can't move in them, but more exotic matter such as gravitons (a hypothetical particle that transmits gravity) does. Or they are very small and circular. By circular I mean that if you travel far enough in that dimension you get back to where you started - like in the Meteors! or Maelstrom games where if you fly off the right of the screen you come back on the left. In the case of these dimensions, the width of the screen is of an atomic scale, so you would never notice the process of moving across it and coming back to where you started.
> 
> There are theories with other universes that are separated from us because of the way space-time might split in quantum mechanics (ala quantum leap and parallel universes) but that is a different use of the word 'dimension'.


Wow! I can be a theoritcal Physicist by publishing a third theory of why we don't see other dimensions:

Here it is:

*NeonKnight's Big Theory on the Reason we don;t see Dimensions beyond the 4 Known*

They don't exist.**




Thank You!

**Just being cheeky/ I couldn't resist  :Wink:

----------


## torstan

@Neon - actually if they find them I'll be ****ed, I work on theories in the standard 4  :Smile:  When they prove they don't, I'll split the winnings with you...

@Karro: Yes.

----------


## jfrazierjr

> @ Karro: Now that there is a top plan for at Cthulhu game... Hmmm, sounds like a fun start to an adventure.


See.. what you do here is get some players who know nothing about whats going on with your work... start the game... freak them out with some really off the wall crazy crap(and I mean WAY crazy) in the game.   Then tell then that the project you are working on is doing the same thing and try to convince them that the world "really" won't end like it did in the game.   

Heh.. that's where RPMillers suggestino about animated gifs and the whole "fog" doing the show/hide tokens for a fraction of a second while moving closer to the players would be just freaking awesome in Maptool!

Joe

----------


## Robbie

I had to do it...sorry...

May I now present to you the site of CERN LHC...August 2012.

----------


## jfrazierjr

> I had to do it...sorry...
> 
> May I now present to you the site of CERN LHC...August 2012.



heh.... you should have thrown in some of the world monuments being sucked toward the event horizon.....

----------


## RPMiller

> Heh.. that's where RPMillers suggestino about animated gifs and the whole "fog" doing the show/hide tokens for a fraction of a second while moving closer to the players would be just freaking awesome in Maptool!
> 
> Joe


Where/when did I post that idea? I have so many ideas that I often forget that I post them. LOL

----------


## töff

> CERN LHC...August 2012.


lulz!!!!!!

----------


## jfrazierjr

> Where/when did I post that idea? I have so many ideas that I often forget that I post them. LOL



Somewhere over on RPTools when talking animated gifs.   I found it cause I searched and asked a question about that feature in Maptools and thought your post was a good idea.   Your example was something like a partially translucent fog overlay stamp and have the GM turn the bad guy tokens on and off between moving them closer to the players tokens.   Kind of like a freaky strobe light horror movie effect.

----------


## RPMiller

Ah, I vaguely remember that. Thanks!

----------


## Karro

> See.. what you do here is get some players who know nothing about whats going on with your work... start the game... freak them out with some really off the wall crazy crap(and I mean WAY crazy) in the game.   Then tell then that the project you are working on is doing the same thing and try to convince them that the world "really" won't end like it did in the game.   
> 
> Heh.. that's where RPMillers suggestino about animated gifs and the whole "fog" doing the show/hide tokens for a fraction of a second while moving closer to the players would be just freaking awesome in Maptool!
> 
> Joe


See, now that's just mean  :Wink: 




> I had to do it...sorry...
> 
> May I now present to you the site of CERN LHC...August 2012.


I work in a cube farm, at least for today... This pic was incompatible with that fact.  I almost broke the code of silence...

----------


## NeonKnight

Am I the only one who keeps reading the title as *on HARDon colliders*, or am the only sicko here? :Question:

----------


## Midgardsormr

> (hadrons are composite particles - of which protons and neutrons are two examples. Always be careful when typing hadron not to get the d and r mixed by accident. Easy typo, completely different machine....)


Evidently not.

I have something of the opposite problem.  Imagine my chagrin when I clicked on a link to what I thought was going to be an enormous hadron.




Okay, that didn't really happen.

----------


## jfrazierjr

> The LHC - Large Hadron Collider
> (hadrons are composite particles - of which protons and neutrons are two examples. Always be careful when typing hadron not to get the d and r mixed by accident. Easy typo, completely different machine....)





> Am I the only one who keeps reading the title as *on HARDon colliders*, or am the only sicko here?



Which is why Torstan explicitly warns you to be careful... :Razz:

----------


## RPMiller

> Am I the only one who keeps reading the title as *on HARDon colliders*, or am the only sicko here?


Looks like you're the only one.  :Evil:   :Wink:

----------


## Robbie

I'm sporting quite a large Hadron right now...oh yeah!!!


Seriously though...Torstan, this thread was VERY enlightening, and I honor your work and look forward to the future through what you guys learn.

----------


## Ascension

A year ago I would not have had the foggiest idea about this whole thread, but thanks to the Science Channel I can actually follow this.  God love a couch potato...would that be dark matter wasting dark energy?

----------


## torstan

Happy to have such an interested audience. If there are any interesting developments I'll add them on to the end of this thread. Equally if people have questions I'm more than happy to pull together some answers. It'll be an interesting couple of years in this field.

----------


## jfrazierjr

> Happy to have such an interested audience. If there are any interesting developments I'll add them on to the end of this thread. Equally if people have questions I'm more than happy to pull together some answers. It'll be an interesting couple of years in this field.


Hehe.... yea, be sure to post here if the world blows up so I will know about it.... :Very Happy:   I would hate to walk out my door one morning and there not be anything out there.

Joe

----------


## RPMiller

Oh, I have a question. Most Grids allow anyone to connect so that their computer can be used for processing data. Does this project allow for that as well, and if so is there a link that we can go to to join the Grid?

----------


## torstan

Currently it is not a public Grid so unfortunately you can't link up to it from outside. I don't (and probably won't) have access to the Grid either as it - in its initial form - is almost entirely devoted to the experimentalists on the experiments for their data analysis. This will start soon after the LHC turns on, but the large data rates aren't expected until 2009 at the earliest.

They _do_ have a sort of mini distributed tool which is LHC@home which, like SETI@home runs a programme on your home computer as a screensaver. That's not really Grid computing, as it can run happily for hours and then sends back results when its done rather than being assigned tasks in real time as part of one larger calculation being done across a network of machines.

This side of stuff really isn't my area, but I'm enjoying flicking through the info on the CERN website about it and giving you my understanding of the information I can drag out.

I don't know - I draw a piddly map and someone reps me. I prove* that the universe isn't going to be destroyed in a couple of months and everyone just passes on regardless. Priorities people?  :Smile: 

*well, yes 'prove' is a little strong, but 'point people to a proof' is a little long winded.

----------


## jfrazierjr

> I don't know - I draw a piddly map and someone reps me. I prove* that the universe isn't going to be destroyed in a couple of months and everyone just passes on regardless. Priorities people? 
> 
> *well, yes 'prove' is a little strong, but 'point people to a proof' is a little long winded.



I am still not convinced.   What day did you say they are they going to turn it on?  I want to make sure I have all my affairs in order just in case... of course, if we will all be obliterated, I don't really guess theres that much to do to prepare as there will be no after(assuming we are not shunted to some strange new dimension, in which case, I think I should probably make sure I have some food, a gun, and a few big knives just in case)


Joe

----------


## Redrobes

> ...to prepare as there will be no after(assuming we are not shunted to some strange new dimension, in which case, I think I should probably make sure I have some food, a gun, and a few big knives just in case)


Ok you do that. Me, well i'll make sure I am stood near to a bus load of cheerleaders.  :Razz:

----------


## Karro

> I don't know - I draw a piddly map and someone reps me. I prove* that the universe isn't going to be destroyed in a couple of months and everyone just passes on regardless. Priorities people? 
> [/SIZE]


Ah, but you've only offered evidence that _you_* won't destroy the universe in a couple months.  It's everyone else that I'm worried about  :Wink: 

Besides, what if you change your mind?

*And ostensibly your colleagues.

----------


## RPMiller

Yea, what happens if a bad man sets off a bomb at the moment the collision occurs and releases the black hole and infuses it with enough power to grow in magnitude and it in turn absorbs the energy of the the collider itself and while still growing begins to suck in the very planet we call home? We are all doomed!

This message brought to you by the letter B and the number 6.

----------


## torstan

:Smile:  Yes we are, but only when the sun explodes in a few million(?) years. And no, that one isn't my fault either.

I heard that one physicist who was being interviewed about this said that it was far more statistically likely that a pink dragon would pop out of nothing and devour the earth than that the LHC would destroy it. To which the interviewer responded 'but it _could_ happen?'. You can't win.

----------


## Ascension

~5 billion...gives me plenty of time to finagle my way into getting Scarlett's cell phone number too.

----------


## Redrobes

A serious question for Torstan... I know break the habit etc...

If in due course they do find the Higgs Boson and get a handle on gravity and maybe even further flung know the recipe to make gravitons or gravity waves or whatever, would that mean that we could have anti-gravity, gravity propulsion and levitation devices ?

Also, given that there are companies about like, I think they called, American Anti gravity which are alleged to do military work do you think that this sort of stuff already exists ? or do you think that there are similar systems using another method - they go on about Hutchinson effect or charged particle thrusters, lifters etc.

I.e. do you have any inkling that some people know a lot more about the stuff thats about to happen with the LHC than is public.

I'll take my tin foil hat off now.

----------


## torstan

Having done a quick search on Hutchinson, it seems the only physics myth he doesn't claim to have created is cold fusion. As far as I can tell, he has admitted himself to being unable to replicate any of his effects after 1991 - which seems a bit bizarre given that they would be worth a fortune if they were true. He should know the physics behind it, and if he could replicate even a small example under test conditions then he would quickly become one of the richest men in the world. So no, as he is selling 'video evidence' for $100 a throw rather than drinking cocktails in the carribean, I don't think there is much to those stories.

However, the claims to have worked with the military are likely to be true. Military research budgets (as far as I understand it) do have room for blue skies research and something wildly unlikely but potentially of enormous use can still be a good investment for them. If someone claims to be able to do something remarkable, like create anti-gravity, then I believe that would be something that would be researched. I believe that such a project was looked into in the UK as well. I am unaware of any positive results from this stuff, but then I am as outside that circle of research as anyone else and so can't really say. What I can say is that there is no physical effect that I know of that can produce anti-gravity.

Now to the second part of your question. If we understand gravity at the LHC, will we be able to do something useful with it, like create anti-gravity. First off, a few qualifiers. The Higgs boson is the physical manifestation of the Higgs field, a field that gives particles mass. How that mass is then affected by gravity is a separate question. This separate question deals with gravitons, and the unification of quantum mechanics with relativity - through string theory, M-theory, loop quantum gravity or some other speculative theory. We will not break that problem at the LHC unfortunately. We may get some further hints how to proceed, but we won't get the answer.

However, we believe that gravitons exist. All forces have a particle that carry the force. Electromagnetism has the photon, the weak nuclear force has the W and Z bosons, the strong nuclear force has the gluon. All these have been experimentally proven. The graviton has not. f we were to be able to study a graviton then we would get some insight into the theory of gravity at the quantum scale which would be truly amazing. The unification of relativity and quantum mechanics is the holy grail of particle physics and one that Einstein died trying to achieve.

So that's all great, but how does it apply to anti-gravity. Well, the problem is that gravity is an attractive force. There are no negative gravitational fielsds around. This is unlike electromagnetism in which you get positive and negative forces. Just try to push two like sign magnets together and you'll see. We currently have no structure that gives a negative gravitational force. You can also think of it this way. Gravity comes from the warping of space and time (yes, I know, but stay with me). Space-time can be thought of as a rubber sheet (really, the maths is surprisingly close). Drop a hevy weight on a rubber sheet and you get a dip. Now if you place a marble on that sheet, it rolls towards it. The problem is that we only know how to make depressions in the rubber sheet, we can't pull it up. If we could figure out that then we'd have a way of creating anti-gravity.

There is one light at the end of this tunnel (and in factone that might show up in the LHC tunnel). That's the existence of dark energy. Now I mentioned dark matter - an exotic matter that doesn't interact with light but makes up 5 times more of the universe than atoms and molecules - but dark energy is even more mysterious. Basically the universe is expanding and it keeps getting faster. Now the only force acting on the scale of galaxies and above is gravity and it's only attractive. So if gravity is the only game in town then everything should be getting closer together, or at least be slowing down as it expands. This is not the case. And the amount of energy needed to maintain this behaviour is huge. This repulsive force has been named dark enegy, and no-one really knows what it is. It may be some form of anti-gravity, but it could be hundreds of other things as well. Given this is a huge gap in our knowledge, we expect a major revolution in physics when it is understood. And revolutions in physics come with useful, or at least interesting, spin offs.

The first effect of any great discoveries will be new terms and ideas popping up in science fiction. Some of them will be wildly off, but others may be possible. Given some time and clever experimental physicists and engineers, we'll get new gadgets and tools from this stuff that we can't possibly predict now. However, it is a good bet that a revolution in our understanding of gravity _will_ have an impact on everyday technologies. I just don't think we'll see that revolution at the LHC.

So back to the question. I don't think there's any top secret research being done at the LHC. I'm certain that there's no hidden understanding of what's going to be found at the LHC. To know what it was going to find, you'd have to have built one already - and it is far too large and expensive for any one country, or small group of countries, to build on its own - let alone a company or military research unit. Also, if it could be done on a smaller scale, we'd know about it. Governments don't spend this much money unless they know it really can't be done any other way. Finally, CERN is an entirely non-military institution. No military budget is funding the LHC, and all the research is public. It's one of the only areas of science where you can read any item of research without paying for a subscription. All research is out there and available to anyone. Just go to here uk.arxiv.org, click on the experimental high energy physics link and browse until your heart's content. It's nice to work in such an open field - and the reason why I think there are no great secret plans.

Oh, my papers are here if anyone is truly bored!

----------


## RPMiller

So the universe's expansion isn't the same as say air pumped into a container expands to fill the container?

----------


## torstan

Nope. The reason air spreads out to fill a container is that there is air pressure. Now that is caused by the air molecules bouncing off each other. Galaxies and stars don't have that interaction to force them apart.

Now even in space the air molecules would keep expanding. That's because the molecules would be given an impetus when they were close together and bouncing off each other. They all keep on going in a straight line from the las point of interaction - so away from the place where they were close to the rest of the air. However they keep going at the same speed, or in a perfect vacuum they would slow down minutely due to the gravitational force from the other air molecules dragging them back.

The universe on the other hand does not seem to be expanding outward steadily at a constant rate. The rate of expansion is higher than can be accounted for by gravity and the initial impetus of the big bang. There needs to be some force pushing it outwards. Again, cosmology isn't quite my area, so that's a rough sketch of how I understand it to be, but might be a bit off.

----------


## RPMiller

That's very interesting. That is the first time I heard about the expansion actually speeding up. I can definitely see why there would be a strong belief in something pushing outwards.

----------


## torstan

Yep, the evidence definitely points to the universes expansion speeding up. There's some debate about the evidence because measuring the expansion rate of the universe right now is tricky, measuring its expansion rate millions of years ago is downright hard - and requires assumptions about stars - for example that a supernova we see today has certain key features that are identical to one that went off millions of years ago. However all the evidence, particularly that from the WMAP satellite, supports theories in which there is a pressure accelerating the expansion of the universe.

----------


## delgondahntelius

humpf... I always thought the universe was static... its always been here.. it always will be...  weird... this is all news to me...!!

----------


## Drazi

> measuring its expansion rate millions of years ago is downright hard - and requires assumptions about stars - for example that a supernova we see today has certain key features that are identical to one that went off millions of years ago.


Wouldn't most all things that we are able to observe in space today (supernova, galaxies, etc..) actually have happened millions of years ago since that is how long it takes for light to reach Earth? So, how is it that we're guessing here?

----------


## NeonKnight

> Wouldn't most all things that we are able to observe in space today (supernova, galaxies, etc..) actually have happened millions of years ago since that is how long it takes for light to reach Earth? So, how is it that we're guessing here?


I think it is the case of, Is a Super Nova we are seeing today (Date + 1 million years), equal to a super nova that would have been observed say 65 Million years ago (date + 65 Million, +1 million).

----------


## torstan

Drazi, you are dead right. Things we see in the sky now did indeed happen many thousands or millions of years ago. The key is that a supernova we see that occurs 100,000 light years away occurred 100,000 years ago (the time it took for the light to reach us - light covers 1 light year per year). Another supernova that we see which is 1 million light years away must have occurred 1 million years ago. In this way, as we look at fainter and fainter supernovae, we are looking into the past of the universe. By studying their traits over increasing distance, we are able to measure the history of the universe. The problem is that this assumes that a supernova that occurred 1 million, or 10 million years ago has the same traits and structure as one that occurred 100,000 years ago. There's good reason to believe this to be the case, but its still a source of error that is being actively addressed.

Supernova have been observed as far away as 10 billion light years, so they act as very useful reference points when scanning the distant universe.

----------


## Drazi

So, I was watching Nova Science Now on PBS and they had a special on  Dark Matter. They mentioned in it that it is likely that a mass of dark matter in space could act like a lens and magnify the space beyond it. Is it possible to compensate for the added distortion when calculating things like rate of universe expansion and distance between galaxies?

----------


## torstan

Absolutely. The lensing effect is well understood and is actually one of the ways of looking for dark matter. The reason for this is that a lens distorts as well as magnifying. Here's a galaxy acting as a lens on the light from a galaxy behind it:



You can see that there are a number of long curving images in the picture, around a central bright galaxy. Now they are normal galaxies that are behind the bright galaxy. The light is bent around it, and the lensing effect distorts the image. Incidentally, as it is the mass of the galaxy that is distorting the light, you can use this effect to weigh the galaxy that is acting as a lens. Once again you come up short if you only consider the visible matter, and have to assume that there's a lot of dark matter too.

The point of all this is that if dark matter is acting as a lens, it doesn't just magnify an object, it also distorts the image of it. As long as we're really careful about checking for distortion, it's possible to precisely measure when an object is being lensed, and by how much. This allows astrophysicists to accurately place lensed objects, no matter what it is that is causing the lensing.

The science of gravitational lensing is now very precise and can be used to measure not just the mass of a lensing object, but also the precise distribution of mass throughout the object. It's a very useful tool.

----------


## Drazi

Is it very likely for us to be able to study Dark Matter here on Earth without being able to create it ourselves?

And also, do we know if the presence of Dark Matter effects the way light behaves? I saw a special on the Science Channel about the Big Bang that mentioned that if the Universe was as old as today's scientific models claim than we shouldn't be able to see as much light as we do (I'm butchering the theory here so apologies for that). So they supposedly have a problem where the only solution was to change the speed of light from being a constant to being variable over time. Now they theorized that perhaps an outside force was acting upon the light just after the Big Bang that made it move faster than it traditionally should. So, the question is could the large concentration of Dark Matter/Energy at the time of the Big Bang affect the Speed of Light?

----------


## torstan

Your last question first - there are a couple of fairly odd theories that incorporate a variable speed of light. You definitely don't _need_ it, but I believe that some things fall out a little more neatly if you have it. Unfortunately my knowledge of those theories is pretty much non-existent. One of the main proponents of the theory is a guy called Joao Magueijo who's based in either Cambridge or Imperial at the moment - I forget which. If you are interested in this, google his name and VSL. Just don't believe everything that you read. It made a big splash a few years ago and then pretty much disappeared. I wouldn't put a lot of money on it.

Models of dark matter/energy generally don't affect the speed of light, just the way it moves. However the early universe is a weird place and there's a lot still to be understood about it that is still up in the air.

We do know that dark matter affects the way that light travels. One thing dark matter must have is mass. That's because it needs to have a gravitational pull to explain the rotation of galaxies that we observe, as well as the behaviour of clusters of galaxies. Now we also know that anything that gravitates also bends light. This was shown in the early 20th century when it was observed at an eclipse that astronomers could see stars that were _behind the sun_. The sun had bent the light from those stars around it so that they could be observed on earth. This was a key prediction of relativity over Newtonian gravity and was seen as one a proof of Einstein's relativity.

If dark matter has a mass - which it must - then it has to bend light as well whenever there is a lot of it in one place. This can be observed in so called dark galaxies. These are galaxies in which almost all of the luminous matter has been stripped away by collisions or some catastrophic event, but has left the dark matter galactic halo behind. This object is dark, but has an enormous gravitational pull. It shows up when you look at the bending of light.

Incidentally, the behaviour of light in a gravitational field is the reason balck holes are called that. The gravitational pull of a blakc hole is so strong that light cannot escape. Near the event horizon of a black hole, light is bent so strongly that it will curve in a perfect circle around the blak hole and never escape.

Right, finally we get to your first question. Is it very likely we can study dark matter here on earth if we can't produce it? Well there are two answers to that. Firstly, we might produce it on earth when the LHC turns on, so in that sense yes - hopefully we'll be able to create dark matter and study it directly. If we aren't able to then we can still study it in two ways. We can't create stars on earth, but we can get a really good idea of how they work by studying their existence in the universe around us. We look at the light they throw out and the effect of their presence on the objects around them and work back to a detailed understanding of what they do. We can do the same with dark matter. We already know what it does and doesn't do - it does have mass and a gravitational pull, it is electrically neutral and doesn't interact through the strong nuclear force. It is massively abundant and it is stable on lifetimes similar to those of the universe. So yes, we can study it without producing it. We'd get a better idea of what it was if we could produce it, but we're doing pretty well so far. Finally, even if we can't produce it, we can still find it - because it is already here. It keeps the galaxy together and is like a diffuse gas throughout the whole galaxy. If our theories of dark matter are correct then roughly 1 billion particles of dark matter are passing through each person's body every second. It hardly interacts at all, and when it does, we'd never notice it. So we build detectors that would notice such an interaction. In mines in Asia, the States and Europe there are detectors in operation and yet more being constructed in deep mines behind layers of shielding trying to find elusive interactions of the dark matter that permeates the universe around us. They will be able to test the theories of dark matter independently from the collider at CERN. If we find signals of dark matter in both places then we will have two separate windows on one of the great mysteries of the universe - and both sets of experiments should be reporting important data in the next few years.

----------


## Drazi

Thanks for that response. As you might have guessed already I'm a bit of an armchair enthusiast when it comes to theoretical physics. I find the logic behind new theory to be very exciting. I've always equated theoretical physics to philosophy, in a way it seems to satisfy the same part of me that demands a logical system for things to work in. At a time I considered theoretical physics as a possible career choice, but I find the math involved with it to be tediously boring, I'm much more fond of the ideas and how they relate to on another. Anywho, thanks for the great info, I'll be posting again if I come up with more questions.

Looking forward to hearing about the collider in action.

-Drazi

----------


## torstan

Well, you're preaching to the converted on that one. I did a joint honours in physics and philosophy. We did the maths in the physics course and read the original papers of Einstein, Bohr, Newton et al in philosophy. There is a lot of interesting philosophy going on in physics at the moment, especially while we wait for the new data.

I'm more than happy to keep answering questions - and will keep the guild updated on the collider as long as there is an interest  :Smile:

----------


## RPMiller

> Incidentally, the behaviour of light in a gravitational field is the reason *balck* holes are called that. The gravitational pull of a *blakc* hole is so strong that light cannot escape. Near the event horizon of a black hole, light is bent so strongly that it will curve in a perfect circle around the *blak* hole and never escape.


WARNING: Thread derailment imminent...

Just curious if these were intentional misspellings because of this:
http://cityhallblog.dallasnews.com/a...-turns-ra.html

Yea, it is really ridiculous and I would suggest *not* reading the comments that follow it. I was just curious since they are all different.

----------


## Torq

> Well, you're preaching to the converted on that one. I did a joint honours in physics and philosophy. We did the maths in the physics course and read the original papers of Einstein, Bohr, Newton et al in philosophy. There is a lot of interesting philosophy going on in physics at the moment, especially while we wait for the new data.


One of the other boards that I visit a bit has a guy that has the following in his sig:

"Observer-dependent physics undermines the gods' decision 3000 years ago to ban cats from straddling the borders of the netherworld. We won't have it!". I laugh every time I see it.

Torq

----------


## torstan

Oh dear  :Smile: 

White holes are hypothesised to exist - they would be the opposite of a black hole - spewing out and almost endless stream of light and matter. They are hypothesised as the 'other end' of a black hole. But there again we head out of what I know and into the dark depths of wikipedia.

@Torq: That's an excellent sig. That should bait pretty much everyone on the science/religion divide.

----------


## Turgenev

Just wanted to say this has been a great thread. I'm an armchair science nut. I might not understand it all but I love reading up on the stuff (especially astrophysics, astronomy, paleontology, archaeology, and biology). 

When I hear about White Holes, I always think of the Red Dwarf TV show where Lister shoots pool with planets to close a White Hole.  :Laughing:

----------


## torstan

Absolutely, red dwarf was a stroke of genius.

I have to say that I've greatly enjoyed writing the posts in this thread (did the length of the posts give it away  :Smile:  ?) and I'm glad that people are enjoying the read.

----------


## helium3

Interesting.

I didn't know that failing to produce/find the Higgs Boson would result in disproving the entire Standard Model.

What are the competing theories that would then move up to replace it, if that happens? Or would theoretical physicists just stand around looking confused for a while?

Also, there's a pretty decent hard sci-fi book called "Einstein's Bridge" by John Cramer. It's about a mist-like event that occurs at the (never built in our timeline) SSC in Texas.

Oh, and I think the physics shop here at the UW in Seattle built some of the components of one of the detector modules. I've actually seen what they look like on the inside. Lot's and lot's of tubes. Not sure if the tubes were for coolant or "detector fluid."

----------


## torstan

Failing to produce a Higgs boson will disprove the Standard Model. That doesn't mean it's not useful. The major elements of the structure will be part of any future theory. Think of it this way. We know Newton's theory of gravity is fundamentally wrong. It claims that gravity is a force that acts instantaneously at a distance. So if the sun vanished now, the earth would immediately stop going in a circle and start going in a straight line. Now that's not the case. From relativity we know that gravity is communicated by the shape of space and time, and that changes to that shape propagate at the speed of light. Therefore if the sun vanishes in an instant, the earth will keep going in a circle for around 8 minutes, until the effects reach us. However that doesn't mean that all the _results_ of Newton's theory of gravity are null and void. We can still use it for most calculations about the movements of planets, the course of satellites and space missions with complete faith. However the vision of reality that underlies those equations is wrong. In the case of the Standard Model, if we don't find a Higgs boson then the structure that the Standard Model is based on is wrong. However, the equations that describe it do an excellent job of describing reality in all the situations we have investigated so far - and they will continue to be a good description for calculational purposes, whether we find a Higgs or not. It's just that if the Higgs ain't there, then we know the basic principles are wrong.

There are a few theories that would predict no Higgs boson. There's three reasons we might not see a Higgs boson, and each have theories associated with them.

1. The Higgs boson interacts very weakly to normal matter and could thus avoid detection. So it's there, and possibly even produced, but we don't see it.
2. The Higgs boson is very heavy, so it is outside the reach of this accelerator.
3. There is no Higgs boson at all.

Now 1 is very tightly constrained already. This is because a Higgs boson must couple to matter to give it a mass. So there is only so far you can go in making such a particle 'invisible' before it just stops doing its job. The only models I know of with such an invisible Higgs also have heavier Higgs bosons to help finish the job. An example of a model with a light invisible Higgs is the Next to Minimal Supersymmetric Standard Model (NMSSM). Yes, we are very bad at making up names. It's a failing.

In the case of 2 this is also pretty constrained. Now the standard model can't have a heavy Higgs. This is because the Higgs boson is tightly linked to the W and Z bosons, that have been found already. Now the Z boson has a mass of 91.14 (in units of giga-electron volts or GeV - it's a convenient unit of mass, because if we weigh things in grams the numbers are so small they get very cumbersome very fast). Now for a first calculation of the Higgs mass in the Standard Model you find that it must have a mass of equal to or less that the Z mass. However experiment tells you it can't be lighter than 114GeV. So you see the problem. A more detailed calculation in the Standard Model allows you to get up to about 135GeV before you run out of options. Now the LHC will run at an energy of 14TeV (=14000GeV) so we should definitely be able to produce a Higgs if it weighs less than 135GeV. So a heavy Higgs (outside the reach of the LHC) is well beyond what could be done in the Standard Model. Furthermore, because of the nature of the W and Z bosons, a heavy Higgs is always going to be very problematic as, by its nature, it must be directly involved with the W and Z bosons. If it is separated from them in mass by a lot, then this connection is very hard to maintain. To achieve this you need to alter the nature of the W and Z bosons from the form they take in the Standard Model.

You also need to do this if there is no Higgs boson at all - option 3.

As the Higgs boson is intimately related to the W and Z boson, the lack of a Higgs boson at the LHC will have clear implications for our understanding of those particles (that we _can_ produce, and in large numbers). Models that have no Higgs, or a heavy Higgs, generally fall into the category of composite Higgs models, or extra-dimensional models. One clear problem is that if you take the Standard Model as is, and take out the Higgs, funny things start to happen. One such funny thing is that if you collide two W bosons off each other, then at high energy the chance of getting two W bosons out of the collision is greater than 1. Now that is definitely not allowed. The inclusion of the Higgs boson sorts this out.

So you can measure the odds of getting two Ws out of such a collision over a range of energies in your experiment and see whether the result agrees with the Standard Model or deviates from it. If it deviates, and you've found no Higgs boson, then you know you've found evidence of non-standard model physics. This would be an obvious place to look if we don't find a Higgs boson. This could tell us that the W and Z bosons are not fundamental particles, but that they are made up of smaller components - like an atomic nucleus is not solid but rather a collection of protons and neutrons. It could also tell us that W and Z bosons can move in extra dimensions of space that we haven't been able to access before. This can result in alterations to their collision behaviour which avoids the embarrassing problem of getting more out than you put in that I mentioned above.

So there are a few avenues to consider if we don't find a Higgs boson, and some obvious areas to study that should break if the Higgs boson isn't where we expect it to be. However, the expectation is that we'll probably find a number of different Higgs bosons as well as a slew of other stuff.

As for whether the scientists will be scratching their heads? Well, yes. It's not the expected result - and it will disprove a lot more than just the Standard Model if we don't find a Higgs - most of the extensions have one or more Higgs bosons in them already. However it will only be a few weeks before people start coming up with weird and wonderful solutions that fit the data and can themselves be tested. Hence the progress of science  :Smile: 

Hmmmm, that got a bit long and technical. Sorry about that. Hope it wasn't too heavy. If you want me to clarify any of it, please say so.

Yes, the SSC (Superconducting Super Collider) was never built - though they did dig the tunnel. It was supposed to do what the LHC is doing now. They screwed up the budgeting for it and congress threw it out. It's now one of the most expensive mushroom farms ever built. I'll have to look out that sci-fi book you mention. Sounds like an interesting read.

----------


## NeonKnight

I theorize that the reason we see no Higgs boson is because they exist outside the 4 dimensions we know.  :Razz:

----------


## Redrobes

Heres a set of wooly questions. So the engineers finish the building tweaking and tuning and hand the keys to the big red button to the physicists. Whats the order of tests that they would perform - i.e. is looking for Higgs the first test and is that going to be done with the two W boson probability test thing. Its like building the Hubble and asking so what do you point it at first ?

Also, I am not clear about how you try to generate a Higgs Boson. Is the idea that you accelerate matter in the ring and then crash it into each other ? What matter do you accelerate ? Does it have to be a stream of protons or something like that or does the accelerator just gain more energy in massless 'particles' and then these new particles just take some of this energy and create themselves. If not then whats special about the matter used that is thought to create the Higgs. Doesn't all the matter go around the ring at the same speed or is it switched into a stationary 'block' of something and thats where all the action takes place.

And...(as if that wasn't enough)... why doesn't the system create more lighter particles instead of one heavy one - is that just down to probability and you get a slew of everything.

----------


## torstan

That is indeed quite a series of questions. I'll try to get through them all, but not necessarily in the order they were asked:

1. Is the idea that you accelerate matter in the ring and then crash it into each other?
Yes.


2. What matter do you accelerate?
Protons. This is because they are charged - necessary if you are going to accelerate things with an electric field. Also they are relatively heavy in the world of subatomic particles. This means they don't lose as much energy when spun round a ring. Electrons lose a lot, which is why they aren't used any more.


3. Doesn't all the matter go around the ring at the same speed or is it switched into a stationary 'block' of something and that's where all the action takes place?
Half the protons go round the ring one way, half the other. They collide head on at two points on the ring. That's where the energy is produced, from the annihilating matter in the protons. It's this energy - that only gets created here - that allows for the production of new particles.

4. Does it have to be a stream of protons or something like that or does the accelerator just gain more energy in massless 'particles' and then these new particles just take some of this energy and create themselves?
It can be any type of particle that has mass - because massive particles must couple to the Higgs. It must also be charged - hence the proton. Actually the proton is a collection of quarks - which are the things that really collide. The quarks do couple to the Higgs and so can be used to create one.

5. Why doesn't the system create more lighter particles instead of one heavy one - is that just down to probability and you get a slew of everything.
It will create more light particles than heavy ones. Most of the interactions will spit out a massive array of Standard Model particles and experimentalists will have to hunt for the interesting new signals amongst that morass. That's really why we need the vast computing power of a world wide grid. We're hunting for one MB sized needle in a petabyte of haystack.

The exception is when you are precisely on the mass of the particle you want to produce. Then there are effects that kick in that greatly enhance the likelihood of getting that state over other states of different mass. But yes, fundamentally it's quantum mechanical, so it is always about probabilities.

6. What's the order of tests that they would perform?
Well sadly this isn't like the Hubble. This machine just does one thing. You turn it on at one energy and then watch what comes out. It will precisely measure every interaction for 10 years. If some of those interactions produce interesting stuff then we are in luck.

6b. So the question really is, when we get the first years data set, what's the first thing the experimentalists will look for in it?
The first thing to look for is the Standard Model. Not a Higgs, but all of the W and Z bosons, the quarks, electrons and so on. The Standard Model has never been studied at these energies before, so they need to understand that before they go any further. Then they will look for a heavy copy of the Z boson. This is predicted by a few theories and is really easy to spot. Then they'll go to work on the Higgs, as that is the most widely sought particle. They'll also look for weird and wonderful new signals such as dark matter.

If they find nothing, then they start looking at W-W scattering. The reason to wait is that this is a subtle effect - not the production of a new particle, but rather the modification of the scattering of two particles. Now rmember we're colliding protons, not Ws, at the LHC. That means the Ws are going to have to have been created from a proton-proton collision _and then_ have been created in such a way that they collide with each other - and then we still have to be paying enough attention to have seen it. So it's a phenomenally tricky measurement to make - and probably won't be done unless we really need to figure out what's up with our broken models.

So the order is:
1. Find the Standard Model again
2. Look for easy signals - like a heavy Z (imaginatively titled the Z')
3. Look for the Higgs (well even experimentalists can't resist the lure of a Nobel Prize)
4. Look for clear signals of the big contenders for theories of physics - supersymmetry and extra dimensions. This will be a matter of looking for dark matter and fancy new particles
5. Look for the tricky signals - such as WW scattering. These tend not to involve the creation of new particles, but are instead a modification of existing processes.

----------


## Redrobes

Thanks, thats really lit up some dark corners about all of this in my head. I studied electronics so I did bits of Maxwells and Schrodingers but there are only a handful of everyday electronic components that work at the quantum level so I never did any subatomic physics, not counting the electron of course. Its really interesting and moving very fast.

----------


## torstan

Roughly the speed of light normally  :Smile: 

Sorry, couldn't resist.

----------


## Ascension

Don't know if any of you knew this or not, but this weekend there were 2 separate programs on the LHC on the Science Channel...one called "The 6 billion dollar experiment" and another called "The big bang machine".  I watched em both cuz, well, that's what I do while I map, unless there's a Cardinals game on.

----------


## torstan

Yep, there was a big article on the BBC as well talking about how the LHC was set to become the coldest place in the universe which isn't an unreasonable claim.

2 weeks to start up if nothing goes wrong.

Were the programs any good?

----------


## jfrazierjr

> Yep, there was a big article on the BBC as well talking about how the LHC was set to become the coldest place in the universe which isn't an unreasonable claim.
> 
> 2 weeks to start up if nothing goes wrong.
> 
> Were the programs any good?


Hey, my birthday's in 3 weeks!  Any chance for a short delay so I can get my birthday presents before the world implodes?  :Wink: 

On a side note, everything I see this thread pop up, I misread the word collider and replace it with the word colander and wonder why I am all of a sudden very hunger for spaghetti.

Joe

----------


## Robbie

I just realized that torstan never commented on my rendering of the CERN site in 2012...I'm terribly offended (or maybe torstan is)

edit: I just lol'd at the tags

----------


## torstan

I was wondering how long it would take for someone to notice. Unfortunately only the 'dark matter' one makes the tag clud search  :Smile: 

Good alteration to the CERN site actually. Geneva is one city that could only be improved by the addition of a black hole. Just my opinion of course.

----------


## jfrazierjr

> I just realized that torstan never commented on my rendering of the CERN site in 2012...I'm terribly offended (or maybe torstan is)
> 
> edit: I just lol'd at the tags





> I was wondering how long it would take for someone to notice. Unfortunately only the 'dark matter' one makes the tag clud search 
> 
> Good alteration to the CERN site actually. Geneva is one city that could only be improved by the addition of a black hole. Just my opinion of course.



Heh.. you still should mock one up with some of the worlds monuments being sucked in.... :Smile:

----------


## yu gnomi

I hadn't expected to find a thread about high energy physics at this sight, but it is a very pleasant surprise. 

Regarding Dark Matter: From what I can gather (mostly from watching TV programs like "Nova") theorists speculate that dark matter is exotic, and not the same as matter we are familiar with.

What I don't understand is why dark matter couldn't be ordinary bits of matter like space dust, space rocks, etc? 

Or even less tangible, but ever-present particles like neutrons and neutrinos?

----------


## Turgenev

I'm not really a rap fan but the *Large Hadron Rap* has to be heard to be believed.  :Cool: 

http://www.youtube.com/watch?v=j50ZssEojtM

----------


## torstan

We know that there is a certain amount of space dust in the universe - in fact there is a lot of it. Dust and gas make up the dominant source of 'normal' mass. However both dust and gas do interact with light. Hydrogen has a very specific spectrum at which it absorbs and re-emits light. That means we can 'see' it by looking for dips in a spectrum at the relevant frequency. The same actually goes for dust and rocks. Because dust absorbs light, we can see how much of it there is by noting how obscured light is from distant objects. Basically there's an important distinction here. 'Dark' in the context of dark matter means that it doesn't interact with light, not that it absorbs it. So gas and dust and rocks can't be the dark matter because they do interact with light.

Neutrons and neutrinos are another matter. Neutrons can't be dark matter for two reasons. Free neutrons are unstable, decaying after about 15 minutes into a proton, an electron and a neutrino. The proton will capture an electron and form hydrogen. So there's no chance of having neutron dark matter. Also, neutrons are strongly interacting. If there were 1 billion neutrons streaming through us, we'd notice. To an atom, an incoming neutron looks like a ten ton truck. Note that high energy neutrons are what split uranium nuclei to cause nuclear fission. They're pretty destructive.

Neutrinos are a different matter. They have mass (just), they are weakly interacting, they are electrically neutral and they are stable - so they cover all of the relevant criteria for dark matter, and indeed they were proposed as a solution as soon as it was discovered that they had mass. However those theories have been disproved. There are two reasons for this. Firstly, there simply aren't enough of them. They are weakly interacting, but not so weakly that we can't detect them. There are huge detectors in deep mines that have been studying neutrinos for years - one up in Sudbury, another in Japan and smaller ones around the world. They have pinned down a decent measurement of the number of neutrinos in the universe and it isn't even close to the number that would be required to make up the missing mass. Note that neutrinos are incredibly light - at least 10 billion times lighter than a neutron - so you would need a lot of them to make up all the missing mass. The second reason they can't be the dark matter is more subtle. Basically, neutrinos travel very fast - almost at the speed of light. s such they are known as 'hot' matter. This means that they don't really notice the effects of gravity.

To explain this I'm going to have to use a bit of an analogy. Gravity works a bit like a large shallow bowl. If you send a ballbearing around a shallow bowl it will roll in a spiral, dropping towards the center as it loses energy. If there were no friction, the ball-bearing would roll in a circle forever - like an object in orbit. The space around a massive object is curved, just as the bowl is and this causes objects to orbit the heavy object. Space is frictionless, so planets move in circles rather than spirals. Now consider the situation where you roll a small light ball bearing into the bowl at high speed - it just goes in one side of the bowl and out the other. It may well come out at a slightly different angle, but it won't stay in the bowl. This is the case with neutrinos. Because they are moving so fast, they don't get trapped in so called 'gravitational wells', even when the well is created by something as massive as a galaxy, or cluster of galaxies. They go in one side of the dip and come straight out the other side. This is a problem. We know from the way that galaxies rotate that the dark matter must be arranged in a cloud around each galaxy with the highest density at the center. This can only happen if the particle that makes up the dark matter can be trapped in a gravitational well. For this to happen, it must be a slow particle, or 'cold'.

So we now know that dark matter must be cold, as well as all the other properties that have been assigned to it. That rules out neutrinos.

----------


## torstan

@turgenev: That's great! Thanks for the link.

----------


## RobA

> I'm not really a rap fan but the *Large Hadron Rap* has to be heard to be believed. 
> 
> http://www.youtube.com/watch?v=j50ZssEojtM


You beat me to it!  (another boingboing reader?)

-Rob A>

----------


## yu gnomi

Wow that was quick. Thank you Torsten for the thoroughness of your answer and the speed with which it was posted. 

I figured that there had to be some reasoning as to why the normal everyday cases of matter were ruled out as being dark matter, but I've simply never seen it explained. Your responses all made sense to me.

I know that there are now theories that galaxies, including our own, circle around black holes. Could it be that dark matter is simply black holes (and maybe neutron stars, which I believe are similar) ?

I do realize that this would mean a lot of black holes and neutron stars.

----------


## Turgenev

> You beat me to it!  (another boingboing reader?)


LOL! Guilty as charged.  :Wink:  When I saw that vid I instantly thought of this thread.

----------


## torstan

Yes, our galaxy rotates around a supermassive black hole - and indeed we know how massive the black hole is. Neutron stars also exist, they are collapsed stars that are not massive enough to form a black hole. They consist only of neutrons (hence the name) and are as compact as the nucleus of an atom, but are macroscopic (big) objects. They are therefore the densest material in the universe and pretty exotic.

So you are right that both of these types of objects are large heavy objects that don't emit light. They are also very localised and so wouldn't show up through their obstruction of light (you'd have to be able to resolve something about a kilometer wide as far away as alpha centauri to see the shadow of a neutron star). So they get around the dust evidence too.

As I understand it there's a few reasons why it can't be black holes or neutron stars. Firstly, and I think least convincingly, is that we can see black holes and neutron stars to some extent. Black holes pull in matter and collect a disk of host gas and dust around them. As this gas falls into the black hole, it's going pretty fast and there are interactions with the rest of the dust that's falling in. This gives off radiation and can be seen. So though we cannot see the black hole itself, we can see the accretion disk of matter that it gathers. Okay, so you could have a black hole without a disk for some reason, or a lot of small black holes without visible disks or so on, but it would be had to justify where all of them come from. Equally, neutron stars spin and there are effects on the objects around them that allow us to get a fair estimate of how many there are.

The reason I don't like that answer is because it relies on complete faith in our pretty indirect methods of detection of these objects. However I am not an astrophysicist so I can't tell you what kind of errors you'd expect on the measurement (estimate?) of the amount of mass that is bound up in black holes and neutron stars.

The other reasons that I find a little more convincing are firstly that we know that the mass of dark matter must be distributed throughout the galaxy, and that this distribution should be relatively smooth. In contrast, a load of black holes would be lumpy. You can measure the movements of stars and use that to constrain the distribution of the mass that they are being affected by. I have been to a couple of talks that have claimed that we can now show that large concentrations of matter are now ruled out by such tests, but again, I'm not an expert on those studies. Also, they tend to rely on large numerical simulations of galaxies to prove their results and people aren't certain about the accuracy of those yet. We probably need more computer power to answer that one conclusively.

However the best reason I know of is that dark matter has to have existed in the early universe. By studying the last light from the big bang we see that there must have been a lot of matter that did not interact strongly with the plasma. Now all the matter we know of would interact strongly, so we need something else. The same matter is needed to amplify small fluctuations in the early universe and turn them into galaxies and stars. Now neutron stars and black holes are both the results of dying stars so our evidence for dark matter precedes the time at which we expect black holes and neutron stars to appear on the scene.

That's the reasons I can think of off the top of my head. Obviously each has ways out and we definitely need to obtain a better estimate of the amount of matter in neutron stars and black holes in the universe, but the weight of evidence seems to say that they aren't the matter we're looking for,

----------


## yu gnomi

I've taken some college physics, but dark matter, dark energy and a lot of other cutting edge theoretical stuff, hardly ever got a mention in the courses I took. Every resource I've found via search engine on these topics is either too dumbed down to be useful, or too advanced for me to possibly understand. Your replies are pleasantly neither. Thank you.

While a lot of aspects of the standard model are completely beyond my ken, I do know that finding the various particles responsible for the various forces is ultimately essential. I'm optimistic that they will succeed, although I don't believe that the standard model will get thrown away overnight if they don't. I'm always keen on learning about the scientific cutting edge.

Oh yeah, in case you didn't read my introductory post, thanks for recommending this site to me.

----------


## jfrazierjr

Ok, so it's now August.... exactly which day does the world end?  I seem to recall you saying it would be before my birthday on the 13th, so I need to get all my partying planned out before I die....

----------


## torstan

I believe that around the 13th is still current. Nobody's saying any more than that yet. I'll let everyone know if I find out any more.

----------


## RPMiller

I have a question. What is it going to be powered with, and how loud is it going to be when it fires up?

----------


## torstan

It gets powered off the standard electricity grid. They buy in a large quantity of electricity and that is drawn in from French power stations.

I don't think it will make much of a noise when it starts up - though you'd have to hope that it would make kind of whoooom-thrum-thrum-thrum noise. Sadly the noise of a hadron collider was never covered in my courses  :Smile: 

I guess not a lot of noise though as there are no moving parts. It's a matter of large magnets and electrical currents - the same as a TV screen just on a much larger scale. So there's no obvious source for noise. As for the collisions themselves, they are very small and a very long way away from anyone who might be able to hear them. So I guess it's a matter of - does a colliding proton beam make a noise if there's no-one there to hear it?

Other news - it looks like the beam people have done their job and the ring is pretty much ready to take the beam. Now it is a matter of getting the two detectors (ATLAS and CMS) finished so that they can close the caverns and turn it on. This is good news and means there should be a beam in the ring in August, but it's looking like first collisions will be pushed back a little. There are conflicting reports from different people and no official news yet, so it's still a little unclear. I'll post more when I find out more.

Oh, and Yu-gnomi. Thanks for the comments. That's precisely the balance I've been trying to strike. I'm glad I'm succeeding to some extent!

----------


## Midgardsormr

> I guess not a lot of noise though as there are no moving parts. It's a matter of large magnets and electrical currents - the same as a TV screen just on a much larger scale. So there's no obvious source for noise.


So I take it you're one of those lucky people who can't hear the flyback transformer in a TV.  

Lessee, these particles are travelling near the speed of light, yes?  So that's 299,792 km / s.  The thing is 27 km in circumference, so that gives a frequency of about 11.1 kHz, which is about where the letter 'S' lives, if I recall my equalizer cheat sheet correctly.

So if it were exposed, it would sound like an enormous snake, but frequencies that high are easily absorbed by the earth, so I doubt anyone will be able to hear it.

----------


## torstan

Well the particles themselves are travelling in a vacuum so they shouldn't create any noise. However the electromagnetic currents that are used to accelerate them in the radio frequecy cavities are likely to cause stresses on the machine that will create noise. However any noise is lost energy, as well as repetitive stress, so I'm guessing that they have minimised it as much as they can. Interesting note about the frequency though. I love the fact that the LHC should sound like 's'.

----------


## torstan

Update, the first particles should go round the ring on the 10th of September. That's the official date released by CERN. No collisions that day I expect but hopefully closely following it. So it looks like I might get my wedding in before we definitely don't end the world.

----------


## RPMiller

Sweet! Going out with a bang is always a good idea.  :Wink:

----------


## torstan

:Smile: 

Sorry for relative silence recently - in the middle of 2 international moves and a wedding, will be posting more regularly during October when I have internet in new home in NY!

New study out relatively recently on LHC safety: http://arxiv.org/abs/0806.3414.

My favourite quote from the abstract:
"Any microscopic black holes produced at the LHC are _expected_ to decay by Hawking radiation before they reach the detector walls." (my emphasis) 

So that's okay then  :Smile:

----------


## Robbie

So...are you moving to NY because you have a new job not working on the LHC or are you moving to NY because you're fleeing the imminent danger of a black hole sucking in all of EU?

----------


## torstan

New job, still working with the on dark matter at the LHC. You lot funded it too  :Smile:  I'll be at NYU for one year for sure and hopefully a couple more. I guess I'll be doing some teaching at NYU as well as research. Should be fun! Though knowing my luck NY will stand up to its Hollywood reputation of being ground zero for most major disasters and the New York collider - RHIC (Relativistic heavy Ion Collider) - will produce a black hole from colliding gold atoms....

----------


## delgondahntelius

congrats on the move and job and all that.... travel safe and hurry up with the maps  :Very Happy:  you know we all can't wait for your next big map  :Very Happy:

----------


## RPMiller

Looks like all systems are a go: http://news.zdnet.com/2424-9595_22-217914.html

----------


## delgondahntelius

> Looks like all systems are a go: http://news.zdnet.com/2424-9595_22-217914.html


"I got a baaad feeling about this..." 

First star wars quote has been noted @ 1:20 pm Sep 2, 08

----------


## Valarian

Any Black Holes or rips in the space-time continuum yet?

----------


## torstan

Not yet, but then they just* sent a small bunch of protons a hop skip and a jump around the ring - 3km of a possible 27km. No collisions yet. The test was done to see whether the little ring (the SPS) could throw a bunch of protons into the bigger ring without the bigger ring fumbling the catch. Now think how much difficulty the American relay teams had doing this stuff last week (yes, the Brits screwed it up too, but I can't say I expected much more...) and this one has to be done with sub-microsecond precision. That was definitely a non-trivial manoeuvre and they deserve a lot of credit for managing it first time.

It'll be interesting to track the large number of 'End of the World!' stories as a function of how close we get to the LHC start next week (note that there will be no collisions for a while, and they will be low energy when they start).

Here's my first contribution:
http://www.dailymail.co.uk/sciencete...d-halt-it.html

If you get any, post them here.

*For a given value of 'just'

----------


## RPMiller

> Here's my first contribution:
> http://www.dailymail.co.uk/sciencete...d-halt-it.html


So do whack jobs like that get stripped of their scientist badge or anything? I mean I have to think that everything you've pointed out thus far is in the scientific norm and can't understand how anyone calling themselves a scientist wouldn't know this stuff. Maybe I'm missing something?

----------


## Redrobes

From daily mail article...

Within four years, one of these 'celestial vacuums' could have swollen to such a size that it is capable of sucking the Earth inside-out.

Four years ??? That's a pretty slow exponential growth then. So if you have a while, then if you discover one of these holes in the middle of your machine infinitesimally small but growing, can you just hold it there and wait for the Hawking radiation to evaporate it ? Would you need to be able to control its position ? Does that imply a need for a graviton/gravity wave generator to move it or do you move bits of mass about to position it.

----------


## RPMiller

I just realized something. If a black hole forms inside the collider, wouldn't that stop all future experiments since the black hole would then suck in any future particles that go near it? I think that would be a good indicator that there might be a black hole forming.

----------


## Valarian

Just have to quote Babylon 5 here ....



> No boom today... boom tomorrow. There's always a boom tomorrow.

----------


## jfrazierjr

> Not yet, but then they just* sent a small bunch of protons a hop skip and a jump around the ring - 3km of a possible 27km. No collisions yet. The test was done to see whether the little ring (the SPS) could throw a bunch of protons into the bigger ring without the bigger ring fumbling the catch. Now think how much difficulty the American relay teams had doing this stuff last week (yes, the Brits screwed it up too, but I can't say I expected much more...) and this one has to be done with sub-microsecond precision. That was definitely a non-trivial manoeuvre and they deserve a lot of credit for managing it first time.
> 
> It'll be interesting to track the large number of 'End of the World!' stories as a function of how close we get to the LHC start next week (note that there will be no collisions for a while, and they will be low energy when they start).
> 
> Here's my first contribution:
> http://www.dailymail.co.uk/sciencete...d-halt-it.html
> 
> If you get any, post them here.
> 
> *For a given value of 'just'




Hmmm... 8/8/8  sounds like a triple digit date that would be a great day for the world to end.

----------


## torstan

Unfortunately you can discredit people all you like but they can still call themselves scientists as long as they can produce evidence of a PhD, unlike doctors who can have their status stripped by the medical council (I believe). So nutters who really think that we'll destroy the world can take it to a paper and get equal say to the scientists and because everyone loves an underdog almost as much as they love a disaster story it gets printed.

Redrobes: You are right, black holes form slowly due to the capture of matter. They also lose mass through Hawking radiation. For a large one, the accretion of matter is much faster than the decay but for a small one the decay is much faster than the accretion and a microscopic black hole should never become a large black hole. For something other than this to happen, the laws of physics would have to be very different from what we think they are. As the CERN report pointed out, if you change the laws of physics you usually see an effect of it somewhere else first - in this case through cosmic rays hitting earth, or any other nearby large object. Essentially, these collisions are happening on all objects in space and none of the nearby celestial bodies have been swallowed by a celestial void or black hole yet so we are fine.

RPMiller: If a black hole formed and did not dissipate then it would be affected by gravity, so it would gravitate to the center of the earth (like any massive object). It would not be very heavy, so it would take a bit of time to do this. It would cause damage at the atomic scale (though very little in reality) as it travelled. Once at the center of the earth it would slowly accumulate matter (hundreds of years is a number I've heard thrown about but I haven't done the calculation myself) until it became large enough to be an issue. Again, if it were to happen here, it would already have happened all over the universe, and especially in our solar system. We don't see objects being eaten from the inside by black holes, so it is safe. But the short answer to your question is that the black hole only sucks matter in by gravitational force, and it only has the mass of the objects that created it. Now two hydrogen nuclei are pretty light so the gravitational force is fantastically small. Therefore the experiment would be able to occur around it without feeling any effect from the gravity of the black hole. Only when it got large would it start to affect the experiment, and by that time it will have moved outside the area of the detector.

----------


## Valarian

> For something other than this to happen, the laws of physics would have to be very different from what we think they are.


It'd be a hell of a time to go "Oops" though. I can just see red-faced scientists trying to explain why Switzerland is sinking.  :Very Happy: 




> Therefore the experiment would be able to occur around it without feeling any effect from the gravity of the black hole. Only when it got large would it start to affect the experiment, and by that time it will have moved outside the area of the detector.


 :Very Happy:  So what you're saying is that, even if a black hole is created, we won't know about it until it eats the Earth because it's travelled outside the detector range. Comforting  :Wink:

----------


## Turgenev

This just blows my mind...

 Scientists get death threats over Large Hadron Collider

There are a few other interesting links in that article as well.

----------


## Valarian

There's a perverse part of me that _really_ wants all the scientists to be wrong and they have to go "Oops". Then again, it'd mean that the doomsayers are right and I'd _hate_ that.

----------


## Morshwan

I am living not so far from the Hadron collider. When they will launch the first test, I will try to post here to tell you how dark is the black hole ;-)

----------


## Robbie

I had to do it...again...this one is animated  :Arrow:

----------


## RPMiller

> I am living not so far from the Hadron collider. When they will launch the first test, I will try to post here to tell you how dark is the black hole ;-)


Something tells me that the Internet access may be an issue.  :Wink:  LOL

----------


## RPMiller

> I had to do it...again...this one is animated


You stopped too soon. Isn't the Earth supposed to get turned inside out?  :Wink:

----------


## torstan

@Arcana: That's brilliant! I'll definitely be passing that round the office....

----------


## torstan

@Turgenev: Much as I dislike the telegraph, that's actually a very reasonable article. Thanks for the link.

----------


## Redrobes

Beeb has a whole section of their web site devoted to it now !

http://news.bbc.co.uk/1/hi/sci/tech/7543089.stm

Hope you caught El Regs slightly more irreverent take on the whole thing  :Smile: 

http://www.theregister.co.uk/2008/09...nuum_unripped/

----------


## torstan

Very good. Yes I noticed the BBC is having a big bang day. It's nice to see a physics experiment generating so much interest - it's just a shame we won't get big results for 18 months!

----------


## Redrobes

Yes, its great. Maybe all physics experiments should have the capability to swallow the earth so that the media get interested ! All the astro radio telescopes funding got the chop in the UK and the ISS is going to be stranded by the US as from 2010 from a lack of shuttles unless there is a rethink about NASA funding. Perhaps they are not dangerous enough to open administration and government purse strings.

And what you doin' in Scotland now. I thought you were over the pond now you jet setter  :Smile:

----------


## torstan

I've had a bit of an international month of it. Poland to the UK at the start of the month - along with a separate removal of a full flat's worth of furniture, a month in the UK including wedding next weekend and then off to NY at the end of the month. I'm currently down in Southampton teaching students how to do dark matter calculations.

The BBC does seem to have latched on to the destroying the world aspect - which is fair enough as it is a great way to capture people's imaginations. The down side is that people phone up in abject fear and ask us not to do it - this happened to my old supervisor yesterday. It will be great for the funding bodies to see an experiment they funded getting so much attention, particularly as particle physics is usually way too dry to get much attention. We're always jealous of the astrophysicists as they get all the pretty pictures and everyone therefore thinks that space is cool (which it is).

The LHC was exempt from the cuts this year because the UK is legally tied into funding it. The question will come when the next collider is planned. If the LHC doesn't find anything exciting then it will be extremely hard to convince the funding bodies to cough up - again you'd have to feel that that was fair enough. The problem comes if we find nothing at all - because that would be a huge result - as it would disprove a theory that has stood for decades. However convincing governments that not finding something was really exciting is a pretty hard sell!

And just a short clarification - a few of the radio telescopes that were going to be dropped got refunded again as it would have cost the UK too much to pull out. However the STFC funding debacle was a bit of a nightmare. Hope that all sorts itself out.

----------


## jfrazierjr

So, whats the point of this experiment?  If won't blow up (or implode as the case may be), whats the point?  I mean, is this expected to find us a new power source for cheap efficient energy (I kind doubt it given how much it costs), or solve world peace (well, if the world ended, it would achieve that objective), cure hunger, or give all the people of the world free health care?

From a armchair conspiracy theorist who pretty much made D's in physics in high school, I just don't get the point.  Oh, and don't you dare say "just to see if we could" :Razz: .

I mean, are there any real expected improvements to society that are expected within a few years of the project gathering its data (assuming the world does not implode) or do we just not know what might be dreamed up until it is dreamed?

----------


## torstan

Funnily enough this question is getting asked quite a lot at the moment. Everyone is saying that it costs a lot. Yes, it cost £3 billion which is objectively an awful lot of money. This money is split between contributions from all the countries involved and has been spent over more than 10 years of research, development and construction. It's still a lot of money - but remember that the money is sourced from a lot of countries so the orders of magnitude are a little different from normal - and still a tiny fraction of what the US spent on the invasion and occupation of Iraq (over a mush shorter time period).

Right, now the finance is out of the way let's get on to the point of the whole endeavour. First let's note that the LHC should be compared to experiments such as the Hubble space telescope. It is a scientific instrument designed to progress the knowledge of a branch of physics. If we'd gone out to design a new power source we'd be working on fusion power and creating a fusion power station - which is actually happening and costing a similar amount of money. In that case the cost is in the design, and should allow cheaper power stations to be built in countries around the world later that generate power from water and lithium.

The LHC will advance our knowledge of theoretical particle physics. This is useful to humanity because it will provide useful technologies further down the line. Electromagnetism was a purely theoretical construct in the same field that now gives us everything to do with electricity and electronics. Relativity was a dry theory about the speed of light which now gives us lasers and theories of radioactivity and nuclear power (and yes, the bombs too - that's one reason CERN bans cross-over technology proposals with the military). We don't know what theories will arise out of the collider, because if we knew the next theory, we wouldn't have to build the collider. I can assure you though that as soon as we know what the new theory is, there will be  lot of very clever and ambitious people trying their damndest to come up with industrial applications.

In the shorter term, the experiment has a load of useful spin-offs - the previous collider gave us the protocol that runs the web. This one should mark a sea-change in the scale of distributed computing with the creation of the largest ever distributed computing network - the Grid. As CERN is a non-profit based organisation, these inventions are allowed owed into the world for free. Equally, the work at CERN has led to developments in climate modelling, cloud formation, medical imaging, cancer treatment and the safe disposal of radioactive waste through nuclear transmutation. These developments can be used by the countries that fund CERN and provide an economic and social benefit. Any time a new experiment is proposed at CERN it has to show that the technologies developed will be of use in wider society.

So we have built it to search for new theories. That's the goal. We expect the end result to benefit society. We know that the technology developed on the way there is already benefiting society.

Importantly, there are very few international collaborations of this scale in the world and very few endeavours that require this level of technological innovation. If there were no LHC, many of these technologies would never be developed.

----------


## jfrazierjr

And if all else fails, Switzerland will have the worlds largest indoor dog walking park.....umm that cost 3 billion pounds....I hope the dogs really appreciate the expense.... :Wink:

----------


## Micco

I think the HLC is exactly the right thing to be doing as a joint world project. The benefits will be very similar to the race to the moon...lots of secondary and tertiary technologies that will drive the next economies and improve the human condition. If we are very lucky we'll figure out some real fundamental knowledge that will change everything (like figure out how to tap into ZPE!)

I think a manned mission to Mars needs to be on the short list of the next great joint ventures. We need to get some breeding pairs off the planet before it is devoured by black holes!  :Wink: 

Seriously, I'm somewhat if a lay-fan of Stoichiometric Electro-Dynamics. Any chance we'll learn more about that huge energy constant sticking on the end of all those complex unifying theories? (Understanding that, being a particle physicist, you probably are not a fan of SED...)

----------


## torstan

Well Zero Point Energy and enormous wealths of free energy are generally considered to be myths, but it's well outside my field so I can't really take them on from much of a point of knowledge. I do know that you don't get any serious seminars about them, so I think they can probably be kept in the cupboard with the perpetual motion machines. However that is a sociological rather than scientifically based view. I'm afraid for a fuller answer you'd need to ask someone else (or I have to brush up on a few of the other areas of physics).

----------


## jfrazierjr

> I think the HLC is exactly the right thing to be doing as a joint world project. The benefits will be very similar to the race to the moon...lots of secondary and tertiary technologies that will drive the next economies and improve the human condition. If we are very lucky we'll figure out some real fundamental knowledge that will change everything (like figure out how to tap into ZPE!)
> 
> I think a manned mission to Mars needs to be on the short list of the next great joint ventures. We need to get some breeding pairs off the planet before it is devoured by black holes! 
> 
> Seriously, I'm somewhat if a lay-fan of Stoichiometric Electro-Dynamics. Any chance we'll learn more about that huge energy constant sticking on the end of all those complex unifying theories? (Understanding that, being a particle physicist, you probably are not a fan of SED...)





> Well Zero Point Energy and enormous wealths of free energy are generally considered to be myths, but it's well outside my field so I can't really take them on from much of a point of knowledge. I do know that you don't get any serious seminars about them, so I think they can probably be kept in the cupboard with the perpetual motion machines. However that is a sociological rather than scientifically based view. I'm afraid for a fuller answer you'd need to ask someone else (or I have to brush up on a few of the other areas of physics).


OH OH OH.... I want my ZPM.   I wanna power a flying city or an Antarctic super weapon.   Gimme, gimme, gimme.....

----------


## Micco

Interesting. I'll have to go dig up the references to it, but about two or three years ago I did quite a bit of reading on some research being done by the Physics Department at Cal State. They were investigating Stochastic Electrodynamics as a unifying theory. It appears from the Wikipedia Article that "classical" physicists are still quite opposed to the notion. Not like that hasn't happened before.




> All four papers are today recognized as tremendous achievementsand hence 1905 is known as Einstein's "Wonderful Year". At the time, however, they were not noticed by most physicists as being important, and many of those who did notice them rejected them outright. Some of this worksuch as the theory of light quantaremained controversial for years.[26][27]


But, of course, I'm not seriously comparing Haisch to Einstein (but you never really _know_, do you?) Ironically, SED is fundamentally based on Plank's arguments _against_ quantum mechanics in his series of papers entitled The Theory of Heat Radiation. 

I understand that the "Zero Point Field" is considered to be in the land of crackpots, but I found the SED theories to be very intriguing and possessing a certain elegance that Particle Physics is sorely lacking. Call me a simple engineer (you'd be right), but I just don't believe that the universe is as complicated as particle physics demands. While (as an engineer) I value empirical learning, I am left wholly unsatisfied with the results when the objective is _ab initio_ understanding based on first principles. But that's just me.  :Wink: 

None-the-less, HLC will at least keep the particle physicists busy with the pretty lines...and maybe we'll discover that there really is "mana" available to power our spells after all! Just let me know when that HLC comes up with a good explanation of the Casimir effect!  :Wink:

----------


## torstan

Note its the LHC not the HLC.

I'll have to look into those now. Any references you have would be good and I'll see if I can give a more intelligent answer than 'it's not my field but it smells fishy'!

Other news - first beam has made it around the LHC. That was the stated goal for today. Now they will try to get the second beam in the opposite direction.

----------


## Valarian

> I think they can probably be kept in the cupboard with the perpetual motion machines.


You mean strapping buttered toast to the feet of a cat _doesn't_ work?

----------


## torstan

I have to say that was always my favourite one. Unfortunately as cats are quantum beasts (c.f. schroedinger) they never stay where you put them. The cat/toast machine is fundamentally unstable.

----------


## Micco

> but it smells fishy'!


It is definitely fishy!! But that doesn't mean it's not _possible_. And I found it strangely compelling in a science fiction type of way. So my interest is likely more "hope" than anything else. I'm also a skeptic in the true sense of the word...I am skeptical of both the quacks and of those who dismiss them out-of-hand.

The elegant explanation of the Casimir Effect is what has me wondering, somewhere deep in the recesses of my mind, if maybe these guys are on to something.

----------


## NeonKnight

DON'T LOOK AT THE CAT!!!!!!!!!!!!!

You'll KILL it!!!!!!!!!!!

----------


## Steel General

Cats, I hate cats...I'm extremely allergic to the durn little furry beasts.  :Frown:

----------


## RPMiller

So it appears that all your work is for nothing Torstan. At least that is what Hawking says, and if he says it than you know it must be true.  :Rolling Eyes: 

http://www.breitbart.com/article.php...show_article=1

----------


## Valarian

It could be Prof. Hawking's habit of backing something both ways. 
i.e. If the LHC finds something, he loses $100 but gets the joy of CERN having discovered something. If CERN fails to find anything, at least he gets $100.

He did something like this for his black hole theory (a complete set of the Encyclopaedia Britannica vs. a year subscription to Playboy IIRC).

----------


## torstan

Well, not quite. He says they won't find the Higgs boson, but goes on to say this:




> While questioning the likelihood of finding Higgs Bosons, Hawking said the experiment could discover superpartners, particles that would be "supersymmetric partners" to particles already known about.
> 
> "Their existence would be a key confirmation of string theory, and they could make up the mysterious dark matter that holds galaxies together," he told the BBC.


I work on supersymmetric dark matter. Nuff said.

I think they should find the Higgs, because almost any theory suggests you should see it. To hedge my bets though I have a paper on a Higgsless model, because frankly we don't know and I don't want to be out of a job if they don't find it!

----------


## torstan

Favourite link of the day:

http://hasthelargehadroncolliderdest...eworldyet.com/

----------


## RPMiller

> Favourite link of the day:
> 
> http://hasthelargehadroncolliderdest...eworldyet.com/


I saw that over on the RPTools forum thread and just about fell out of my chair laughing. That is awesome!!

----------


## Steel General

> Favourite link of the day:
> 
> http://hasthelargehadroncolliderdest...eworldyet.com/



Gotta like it, short and to the point!  :Very Happy:

----------


## Airith

http://hasthelhcdestroyedtheearth.com/

Heh I thought they were the same. Anyways, I'm kinda on the fence about how it went today. I mean awesome we're still here, but I was hoping it would all end, I have it in my mind it would be hilarious. Maybe I'm crazy  :Very Happy:

----------


## Ascension

Now that's my kind of website!  Short and to the point, nothing misleading, no spin, easy to navigate, excellent  :Smile:

----------


## RPMiller

Check out the HTML source for the site. Specifically look at the comment tags.  :Wink: 

Oh, and if you don't find it. He created an RSS Feed for the page.  :Laughing:

----------


## Turgenev

> Check out the HTML source for the site. Specifically look at the comment tags. 
> 
> Oh, and if you don't find it. He created an RSS Feed for the page.


Oh man, that's just hilarious! I love it.

----------


## RPMiller

Um... it looks like we may have a problem. Webcam at the collider:

http://www.cyriak.co.uk/lhc/lhc-webcams.html

Here is a great "rap tutorial" on the collider. Actually quite educational.

http://www.youtube.com/watch?v=j50ZssEojtM

Big_Mac over the RPTools forums posted these links. Thanks go to him.  :Smile:

----------


## Turgenev

> Um... it looks like we may have a problem. Webcam at the collider:
> 
> http://www.cyriak.co.uk/lhc/lhc-webcams.html


That was quite funny. I've seen that link floating around for a while now but this was the first time i actually looked at it.




> Here is a great "rap tutorial" on the collider. Actually quite educational.
> 
> http://www.youtube.com/watch?v=j50ZssEojtM


I agree about the rap tutorial. It is a great link so that is why I posted it back on page 9 (post 86) of this thread.  :Laughing:  To those who haven't seen this vid yet, it is worth checking it out. I even added it to my Facebook page.  :Wink:

----------


## RPMiller

> I posted it back on page 9 (post 86) of this thread.


But I'm only on page 4.  :Wink:

----------


## Redrobes

Just in case the 6 billion doesn't discover the Higgs Boson then don't worry, you can now just buy one for $9.75  :Smile: 

http://www.particlezoo.net/individua...iggsboson.html

----------


## Midgardsormr

Wow.  It really is an enormous hadron.

----------


## RPMiller

*snicker*  :Laughing:

----------


## ravells

Here is the webcam from CERN so you can see the world implode!  :Smile:

----------


## RPMiller

> Here is the webcam from CERN so you can see the world implode!


ROFL, apparently we like that one a lot.  :Wink: 




> Um... it looks like we may have a problem. Webcam at the collider:
> 
> http://www.cyriak.co.uk/lhc/lhc-webcams.html
> 
> Here is a great "rap tutorial" on the collider. Actually quite educational.
> 
> http://www.youtube.com/watch?v=j50ZssEojtM
> 
> Big_Mac over the RPTools forums posted these links. Thanks go to him.

----------


## Drazi

I thought, since it hasn't been mentioned yet in this thread, that I would plug a couple of things I enjoy. 

First off: The Big Bang theory - A show about a bunch of physics nerds. Really funny stuff, definitely worth a watch. 

http://www.youtube.com/watch?v=9eTUz61LNjo

And second: Dr. Who (or rather the Dr. Who spin-off- Torchwood) - Recently there was a BBC radio drama featuring Torchwood. The cast has been called to CERN to solve a mystery at the LHC. Yes, it's a shameless plug for the LHC, but it's worth the listen.

http://www.bbc.co.uk/radio4/bigbang/torchwood.shtml

----------


## torstan

Yep, the launch went really well. Unfortunately things haven't been so rosy since then. They had a massive helium leak that meant that the magnets warmed up by around 100 degrees and stopped being superconducting. That lead to a small explosion in the tunnel. Nothing too serious thankfully, but it means it needs to be slowly warmed up (takes a few weeks), checked and fixed and then cooled back down again. They won't get it cold again until the scheduled winter shutdown so no more particles in the pipe until the spring restart at full energy. It shouldn't affect anything as spring was the scheduled start of the full energy beam anyway, but it is an unfortunate turn of events.

I almost missed it in the news as I was away getting married. Now that is done, all I have is the small issue of moving country before I am a regular on the boards again. Here's looking forward to a good October! (No one's got a spare flat in NYC they just happen to need to let do they?  :Smile:  )

----------


## jfrazierjr

> I almost missed it in the news as I was away getting married. Now that is done, all I have is the small issue of moving country before I am a regular on the boards again. Here's looking forward to a good October! (No one's got a spare flat in NYC they just happen to need to let do they?  )



Congratulations!   Looking forward to you being stateside.

----------


## Ascension

I saw a headline about this the other day and had to do some serious digging in order to retrieve it.  Bit o humor that I thought was pretty funny.

http://www.bbspot.com/News/2008/09/s...l-smasher.html

----------


## torstan

Very good. More squirrels should be collided at high speeds.

I made it to the US! I'm now in my shiny new office at NYU and settling in nicely. All I need now is an apartment and I'll be golden. Hopefully that will be nailed by the end of the week.

----------


## RPMiller

Welcome to the States!  :Wink: 

Hm... your location says you in the south of England.  :Confused:

----------


## torstan

Fixed. Unfortunately changing the CG location was not high enough on my to do list  :Smile:  Never again.

----------


## RPMiller

Hm... but you could just be saying you are in NYC, but not actually there so as to throw off your pursuers.  :Wink:

----------


## Drazi



----------


## Ascension

That is awesome! I'm putting that pic on my work station...although I'm probably the only one who will understand it.

----------


## Turgenev

That's hilarious, Drazi!  :Laughing:

----------


## torstan

Oh dear, and here was me trying to keep this thread clean...

 :Very Happy:

----------


## Drazi

Pfft, it's still clean. If you don't need a translation to tell you why it's funny, than clearly you don't need to have it censored from you.  :Razz:

----------


## torstan

Okay, a small update. Unusually for this field there have been some dramatic developments. Firstly, there is news on the LHC.

The bad news is that the LHC suffered an unfortunate incident in which a ton of liquid helium escaped after an electrical fault. In the technical report it mentioned some damage to 25 magnets (that's a lot, each full magnet using it the length of an articulated lorry) but CERN has assured everyone it has enough spare parts to repair them all. The safety systems worked, but the damage will take at least until the spring to repair. The LHC was scheduled to be off over winter anyway so this isn't too much of an issue. Unfortunately it means that the scheduled work for the winter - getting the LHC ready for its first full energy run - will have fewer people working on it. That means the LHC probably won't start at full energy, bt will instead (hopefully) make it to full energy some time in the summer of next year. So its a set back but not a catastrophic one.

At the same time there have been new developments in space! A satellite experiment called PAMELA has reported that it has found a lot more antimatter than we ever expected to be up there. They've also found that the anti-matter has a distinctive energy. One theory (and the leading one at the moment) is that dark matter is annihilating in the galaxy and producing electrons and their anti-particle positrons with lots of energy. Those then fly through the galaxy and some of them hit the satellite. If this is true then we have just seen the first experimental signal of dark matter annihilations and we have a lower limit on the dark matter mass. That has, unfortunately, ruled out a couple of my predictions, but has opened up some interesting possibilities. So its interesting times for dark matter.

Obviously happy to answer questions if anyone wants to know more.

----------


## RPMiller

So I assume that means that the LHC still hasn't destroyed the world?  :Wink: 

Are there any suspicions of sabotage? We have seen a lot of crack pots and their worries, I'm wondering if they could have done something by working on the inside.

Can you explain more about the "dark matter annihilating"? I'm not sure if that is a typo or I'm just not following it. Does that mean that dark matter is "less strong" and more likely to be destroyed rather than destroy something else?

----------


## torstan

Its not sabotage thankfully. There was a pressure control valve that was faulty. It slowly opened when it should have remained shut and let liquid helium out. They found another couple that had the same fault so its manufacturing rather than sabotage. They'll replace them over the winter as well as cleaning up the damage from the problem.

The dark matter can annihilate with itself. In particle physics we see that a particle and an anti-particle can annihilate. So if an electron and a positron (its antiparticle) hit each other then they annihilate to energy. Now we believe that whatever particle dark matter is made of has the bizarre property of being its own antiparticle. This means that if two particles of dark matter hit each other then they can annihilate to energy. This energy then produces two particles - in this case an electron and a positron.

Now when two particles annihilate, their mass turns into energy. The amount of energy is given by E=mc^2. Now c^2 is a large number so you get a lot of energy for your mass. When that energy is turned back into matter - ie when the electron and positron are produced - you use some of that energy to create the mass - again through E=mc^2 - and the rest is kinetic energy. So by measuring the kinetic energy of the produced particle, you can find out information on the mass of the particles that annihilated to produce them.

Now the issue here is that they've found positrons with energy that would require the annihilation of a particle with at least a hundred thousand times more mass than an electron, and about a hundred times the mass of a proton, and this gives us our first hint about the mass of dark matter. It means that the dark matter must be at least has heavy as an iron atom for example. Now an iron atom is a large object made of all sorts of substructure whereas we currently believe that the dark matter particles are fundamental objects - so that's pretty heavy.

The fact that dark matter can annihilate is nothing too remarkable. If it hits normal matter it won't disappear - it has to hit another dark matter particle. In the same way, if an electron hits a proton it won't disappear, it has to hit a positron.

----------


## RPMiller

Science is cool...  :Cool:

----------


## torstan

Repped for making my day!

----------


## jfrazierjr

Does it scare the hell out of anyone else that they went "opps, mechnical failure caused something we did not anticipate in a project dealing with hugh amounts of energy in an attempt to create/detect theoretical particles that we really don't understand".




> You know it's a bad sign when the scientist says uh-oh, and and then runs from the room.

----------


## Ascension

Doesn't bother me at all, it just gives me something new to map  :Smile:

----------


## RPMiller

> Doesn't bother me at all, it just gives me something new to map


Would that be post-apocalyptic Europe?  :Twisted:

----------


## Ascension

I'll leave that for the Alternate Earth guys, I'm gonna jump into the black hole and map that sucker so no one gets lost when we all get whooshed in  :Smile:

----------


## jfrazierjr

> I'll leave that for the Alternate Earth guys, I'm gonna jump into the black hole and map that sucker so no one gets lost when we all get whooshed in



Actually, given that you have more mass than the computer or paper you are using to map with, I suspect you have those items ripped from your hands.... Of course, I have NO clue what the hell I am talking about, so I am sure Torstan (or someone else) will tell me just how bad I am mangling physics with this absurd statement.

----------


## torstan

Well objects of different mass fall at the same speed - true of a black hole just as it is true here on earth. However close to a black hole the difference in gravity at your feet and your head (if you are falling in head first) is huge, so your body would be torn apart by the tidal forces as your head gets pulled in faster than your feet - well its almost Halloween, the thread deserves a little gore.

I have no worries about the fact that the LHC threw a mechanical fault. The thing that went wrong is an engineering problem. The physics that we are testing is a theoretical physics problem. The two aren't really related. One thing I can say for sure is that the LHC is unlikely to destroy the world until late 2009 at the earliest  :Smile:  as that is the first time it is likely to hit full energy.

Edit: Woot - 2 pips!

----------


## Steel General

> Woot - 2 pips!


WooHoo!!!!! 

Congrat's Torstan - we are having an epidemic of multiple rep pips lately.

----------


## Ascension

Physics schmysics, I'm a mapaholic.  Whenever I get a new game I get more enjoyment out of mapping out the whole thing than by playing it...been doing that since MUDs were all the cool thing.

----------


## CC_JAR

> At the same time there have been new developments in space! A satellite experiment called PAMELA has reported that it has found a lot more antimatter than we ever expected to be up there. They've also found that the anti-matter has a distinctive energy. One theory (and the leading one at the moment) is that dark matter is annihilating in the galaxy and producing electrons and their anti-particle positrons with lots of energy. Those then fly through the galaxy and some of them hit the satellite. If this is true then we have just seen the first experimental signal of dark matter annihilations and we have a lower limit on the dark matter mass. That has, unfortunately, ruled out a couple of my predictions, but has opened up some interesting possibilities. So its interesting times for dark matter.
> 
> Obviously happy to answer questions if anyone wants to know more.


Ha, that's interesting, before I had even read this part, I had planned on asking what correlation dark matter had with anti-matter, if any. still a valid question though.

Another question I had planned on asking kinda deals with the same thing you're talking about there.
people have already experimented with creating anti-matter right? yet as soon as it's created doesn't it sort of attach its self to matter and null?
so what if dark matter has some sort of this effect?

----------


## CC_JAR

> I had to do it...sorry...
> 
> May I now present to you the site of CERN LHC...August 2012.


And as for that pic..
they just had to divide by zero, didn't they?

----------


## torstan

Sorry CC_JAR I read the second of your posts but not the first. Didn't mean to ignore this question.

Yes, anti-matter does annihilate when it hits normal matter - as long as they are of the same type. So an anti-electron (a positron) will annihilate when it hits and electron, but not when it hits a neutron (for example). The same is true of dark matter, you would expect a dark matter particle to annihilate when it hits another dark matter particle. However the dark matter is so widely spread out, and the particles are so effectively tiny, that the odds of a dark matter particle hitting another are close to zero. Hence there is a lot of dark matter left over from the early universe when it was created. As it is not of the correct form to annihilate with normal matter it is harmless to us.

As for 'normal' anti-matter - we have indeed been playing with that for a long time. You are right in saying that if it hits anything after it has been created then it tends to annihilate. That's because only stable antimatter (antimatter that won't decay on its own) is the positron, anti-proton and anti-neutron. Now those are precisely the anti-matter versions of normal matter - electrons, protons and neutrons. Thus if stable anti-matter hits an atom, there's always something there it can annihilate with. The way around this is to create antimatter and then not let it touch anything. To do this you use a strong magnetic field. This doesn't work with neutrons - they have no charge so don't get affected by magnetic fields - but works well with positrons and anti-protons. If you keep them in a vacuum and use a magnetic field to keep them away from the walls of your vacuum container then you can build up a store of them and hold them indefinitely.

This is what was used in LEP - the predecessor of the LHC. LEP stands for Large Electron Positron collider. So they were colliding antimatter and matter together. The Tevatron in the US - currently the highest energy collider in the world - collides protons and anti-protons. So we are definitely able to create and manipulate anti-matter on a regular basis.

----------


## torstan

*LHC Update*

Bad news I'm afraid. The LHC isn't going to turn on again until June at the earliest. The repairs are estimated to cost £14 million and they haven't even finished the full analysis yet. Not the most illustrious start ever. Ah well.

----------


## RPMiller

That's a bummer... Looks like they'll be putting off destroying the world for quite a while longer.  :Wink: 

Interestingly my son is currently studying periodic table in his 8th grade science class. Just helped him put together a Potassium atom last week. Apparently one of the other students mentioned the LHC and the teacher was apparently clueless regarding all the really "deep" stuff that you've been explaining. I told my son he should come here and read up on it.  :Smile:  Unfortunately he isn't that excited about it... apparently he doesn't think it is relevant to his currently chosen profession of doctor.... Yea, not looking forward to that college tuition bill.  :Wink:

----------


## RPMiller

I forgot to ask my question...  :Frown:  So what is it about the anti-matter that makes it get destroyed by matter? That has always been a big question of mine.

----------


## torstan

Hmmm, it's all a bit quantum. The first time that you get the creation and annihilation of matter is in quantum field theory. In QFT you have to understand particles as the excitations of a field. The interaction of particles is then the interaction of modes of a field. Now you cannot have a continuous spectrum of excitations of the field - they are quantised. We identify these quanta as particles.

Right, now we've got fields with states that we interpret as particles. When those states interact we are interested in the interaction of fields. The details of this are seriously messy - but the quantising of fields throws up things called creation and annihilation operators in your maths that correspond in reality to the creation and annihilation of particles. When you construct consistent theories with this framework you find that some things must be conserved. These are called quantum numbers. Now an electron carries a few different quantum numbers - one of which is called lepton number. A positron carries the opposite quantum numbers. Therefore you can have a term in your equations in which an electron and a positron annihilate because their quantum number cancel out. Before the interaction you had a total lepton number of 0 (+1 for the electron, -1 for the positron) and after the annihilation you have a photon, and a lepton number of 0 (photons don't carry any lepton number).

Unfortunately that's about as far as I think I can go without actually writing equations. I know that it's a bit like saying 'because they do' (spot the sentence above that could be substituted for that  :Smile:  ). If you've got any specific questions then ask away and I'll do what I can to answer them.

----------


## RPMiller

So a photon is a light particle right? Is it a field that produces light... er something? I guess the related question would be what exactly is light?

----------


## torstan

Light is an excitation of the electromagnetic field.

There's a useful distinction to bring in here. There are bosons and fermions in the world. These are two separate types of particle that are differentiated by something called spin. Spin is another of those quantum numbers. It's not that these things actually spin round, but rather that the maths of spin is similar to the maths of angular momentum. Anyway, a fermion has a spin of 1/2 (or more generally half integer) and a boson has a spin of 0 or 1 (or more generally integer values).

All very good, but what use is this? Well it turns out that bosons are force carriers whereas fermions make up the matter in a theory. So quarks and leptons (that include electrons) are fermions whereas photons - the particles of light - are bosons.

Forces appear in a theory when you impose something called gauge invariance. Now this is the equivalent of saying that if you do certain things you don't expect there to be any physical change. Say for example that you have a perfectly circular cake. You rotate it any amount and it's still observably identical to how it was before you rotated it. That's called rotational invariance. Now say you draw a line straight through the middle. It's now only rotationally invariant for rotations of 180 degrees, 360 degrees, 540 degrees and so on. You have broken the continuous symmetry down to a discrete one.

Right, this is going somewhere, trust me.

Now if you construct a theory in which there are only electrons an you require it to obey a symmetry - in this case the symmetry of quantum electro-dynamics - then you find that you can't. If you apply a transformation to your electrons you get an observable result. To make sure it obeys the symmetries you have to introduce a new particle that interacts with the electrons in a very specific way. The new particle must be a boson. You then find that this particle is massless and only interacts with charged objects. We call it the photon. It is the particle that carries all electromagnetic force.

Now it turns out that our eyes also interact with photons that have certain energies - so we can see them. Hence light is a subset of electromagnetic radiation. Hope that makes a bit of sense.

----------


## RPMiller

Wow... it actually does... for the most part. So if photons are massless, how do they interact with a reflective surface and "bounce".

----------


## torstan

The short answer is that they interact with the electrons that surround atoms - they get absorbed and then re-emitted. The direction they are re-emmitted in is (I believe) governed by the conservation of momentum. I'm not 100% on the details of optics and there's definitely a whole load of complicated physics that gets you from individual particles back up to large scale optics with diffraction, refraction and so on but the basic process is the interaction of photons with the electrons in the atoms.

----------


## RPMiller

That seems simple enough to understand. Thanks for answering all the questions.

BTW, this all gives me ideas for possible superhero powers at some later date.  :Wink:

----------


## torstan

Not a problem at all. I'd be intrigued to hear about the ideas for powers!

----------


## RPMiller

That's the cool thing about the Hero System, you build powers based on special effects... Quantum Man can destroy matter by firing his Quantum beam of anti-protons... that sort of thing.

In the system that would be simply built as Ranged Killing Attack, Armor Piercing, Penetrating. So not even armor would completely protect you unless it was Hardened x2.  :Wink:

----------


## torstan

That's quite neat. I may have to look at Hero when I get a chance to actually play some games again. Moving country seems to have eaten my free time, and trying to organise games over a 5 hour time difference is a bit of a killer.

If quantum is the defining feature of your person the best property would be something like blinking (to use an easy D&D analogy). Quantum behaviour is best embodied by the probabilistic behaviour of objects that only become deterministic when you look at them. So a quantum person would be in a number of places at once until someone looked at them - at which point they would be in a specific place. Anyway, enough physics for tonight.

----------


## RPMiller

That can be done a number of ways. I would give him transdimensional movement, and teleportation. Probably desolidification to allow him to pass through objects would be an option as well.

Perhaps I'll consider running a MapTool session of Hero some time.  :Wink:

----------


## Steel General

Something like Dr. Manhattan from the Watchman story?

----------


## RPMiller

Oh! Yes, I can see the similarity there for sure. Of course he was even more powerful than my suggestions, but yes good example.

----------


## torstan

Just went to an interesting talk by a Cern physicist who has spent the last year working solely on issues of safety of the LHC. Unsurprisingly the conclusion was that there is no chance that the LHC could destroy the world. However he made an interesting point that I had not appreciated. I was wrong when I said that cosmic ray data rules out any chance that the LHC processes could destroy the earth. The reason is that when a cosmic ray hits the atmosphere, the results of that collision are moving very fast. Think of it this way, a car hits another car head on, the two stop. A car hits another car at rest and after the collision the two cars move in the direction the first was travelling in. Now a cosmic ray is an example of the first situation, whereas the LHC is an example of the second. The amount of energy in both cases is the same - so the 'damage' to the entities involved is the same, but the remains of the collision are moving at different speeds in the two cases.

So why do we care how fast the remains are moving? A slow black hole is the same as a fast one right? Well, not quite. Take the worst case scenario where all we know is wrong and we can create stable neutral black holes in particle collisions then a black hole created by a cosmic ray collision would be moving so fast that it would exceed the escape velocity of the earth and go tearing off into space. It would pass through the earth and have no effect. However a black hole created at the LHC would be moving slowly and would gravitate to the centre of the earth and start to grow.

Now we need to find out whether such a thing could be possible. Now remember that all physics that we believe to govern black holes would have to be wrong for us to even begin to worry about such a scenario. However, we want an argument like the cosmic ray argument that doesn't rely on any assumptions at all.

The argument goes as follows:

High energy cosmic rays don't just hit earth, they hit all other things in the universe. So there are high energy collisions with energies greater than the LHC on all objects. Our problem with the earth is that a created black hole could theoretically pass straight through the earth and leave no trace. Therefore we need to find an object where a cosmic ray created black hole would stop rather than pass straight through. Such things exist. They are called neutron stars and are the densest objects in the universe. They are so dense that a black hole would certainly not pass straight through, but would stop instead. This would mean that neutron stars would be eaten by black holes.

Now we see a lot of neutron stars out there and we know how old they are. We can therefore out limits on the speed that any captured black hole would grow to a size at which it would be a danger. It turns out that even if all we know is wrong and collisions of these energies can create stable black holes then such black holes would have to grow so slowly that they would pose no threat to the earth until well after the sun had exploded - by many orders of magnitude.

It was very interesting to hear a long and detailed analysis of the risks from someone who has had to do the work and stand up and argue it in front of lawyers and politicians who are concerned about the risks. And the seminar was followed by pecan pie, which is always a plus.

----------


## RPMiller

Mmm... pie.... what? Oh, yea, that other stuff is great news!  :Wink:   :Very Happy:

----------


## torstan

So there have been a few developments recently that are worth mentioning. The full story of the CERN magnet failure has come to light. A large helium leak wrenched apart some very large and expensive pieces of machinery. The valves that were supposed to stop this just couldn't deal with the pressures involved. As I understand it, the plan is to replace the ones that were failing and improve the monitoring systems. This will take them through the summer and the LHC won't be starting up until September. They expect to get first collisions - still below the full energy of the machine - in late November, early December I think. They will then run through the winter which is more expensive as the electricity prices go up. However this will give them an opportunity to produce data people can get to work on, and start the all important work of getting the machine to full energy with a tightly focused beam.

In response to this, the tevatron - currently the highest energy collider in the world, and a US endeavour - said they hope to find the Higgs boson before the LHC can be competitive. The project manager for the LHC estimated that the tevatron had about 2 years before the data from the LHC swamps the total data the tevatron will have taken. That gives a pretty good estimate of the amount of time before the LHC produces interesting results. We may get hints and rumours before then though.

The other developments recently have been that the ATIC experiment that claimed in November to have seen dark matter might well be disproved by a new NASA satellite that's been taking data for the last 9 months. This is good news for me as it would mean my theories were not disproved. All good news on that front  :Smile: 

Just thought I'd drop in a short update for those that have been keeping up with this thread. I'll mention other things as and when they pop up.

----------


## Ascension

I, for one, always like to hear the news on what you guys are doing.  Fascinating stuff.

----------


## Steel General

I agree...even I don't understand the majority of it.

----------


## torstan

Well, as always, feel free to ask questions about the bits that I don't explain properly and I'll try to be clearer.

Oh, here's the picture from the BBC of the damage at one of the magnet junctions:



Note that this should all be in a straight line for the particles to travel around the ring. That helium leak really made a mess.

----------


## Karro

I'm curious, and maybe this was posted upthread and I missed it, what was your theory that may or may not be disproven based on whether or not ATIC had seen dark matter (and who is ATIC?)

Also, your previous post on the issue of why the earth won't be swallowed in a black hole made in the CERN labs is somewhat disappointing.  Now we have to figure out how to spawn a post-apocalpytic setting all-over-again.

----------


## jfrazierjr

> Well, as always, feel free to ask questions about the bits that I don't explain properly and I'll try to be clearer.
> 
> Oh, here's the picture from the BBC of the damage at one of the magnet junctions:
> 
> 
> 
> Note that this should all be in a straight line for the particles to travel around the ring. That helium leak really made a mess.



Heh... it's "accidents" like this that don't really engender feelings of confidence that this thing won't end up destroying the world..... :Razz:

----------


## torstan

@Karro I'm not sure there would be a lot of world left to be 'post-apocalyptic' if a black hole ate it. What we really need is a disaster that 'just' does serious damage to the planet, without destroying it and/or the accompanying universe.

The theory I work most with is called supersymmetry and it works really well if there are new particles and the lightest new particle is around 100 times heavier than the proton. This is within the reach of the LHC and they would be produced in the lab in numbers that could be measured. They should already be produced very rarely by the tevatron, but their event rates would be so low that they would never see them.

The lightest of these new particles is the dark matter candidate in these theories. Now dark matter is the most prevalent form of matter in our universe, and holds the galaxy together. It interacts very rarely. However, it is possible for one dark matter particle to annihilate with another dark matter particle. In this case you would get two high energy 'normal' particles out, like an electron and a positron. They would each have an energy equal to the mass of a dark matter particle. When the dark matter particles annihilate their mass goes to energy through E=mc^2, so we know the energy of the produced particles. A number of experiments have been looking for these high energy particles.

Now the experiment ATIC (Advanced Thin Ionization Calorimeter) and the PAMELA satellite both claimed to see high energy particles. To cut a long story short, ATIC saw electrons with an energy up to 1000 times the proton mass. Now, you'll see that's 10 times larger than the masses I would like to see. Not only that, but that would set the mass of the lightest new particle. All the other more exotic particles would be heavier. It would be very bad if this were the case. Thankfully the ATIC data seems likely to be disproved so I can breath a little easier and get back to analysing how supersymmetry would show up at the LHC.

@Joe I noticed the quotes around 'accident', which rather suggests you know it was something more than that. Come clean. I know you did it. If you come quietly, I promise to make it swift and painless. If the experimentalists get to you first I can't help you...

----------


## Karro

Supersymmetry...

It sounds like beautiful math.  Sadly, calculus and the accompanying calc-based physics is as high as I ever got in college on this stuff.  I was smart enough to do very well there, but perceived myself to be a  half-tic not-smart-enough to go any further down the path of SCIENCE.  So I sold out... got a business degree instead.  (What I really wanted to do was write  :Frown: )

Ah, but we fantasize, and a word like supersymmetry is just the sort of thing that sci-fi is made of!  Beautiful, elegant, and I have no idea what it means.

Also... I suspect that Joe did what he did...









....with _MIND BULLETS_.

----------


## jfrazierjr

> @Joe I noticed the quotes around 'accident', which rather suggests you know it was something more than that. Come clean. I know you did it. If you come quietly, I promise to make it swift and painless. If the experimentalists get to you first I can't help you...


I will quote from one of my all time favorite shows: Hogan's Heroes:




> Sergeant Schultz : I know Nooothingg....

----------


## torstan

Yes, there seems to be a very deep set of relations at the heart of physics that are based on symmetries like those of shapes, for example a circle has a continuous rotational symmetry whereas an equilateral triangle has a discrete rotational symmetry (you can only rotate it in angles of 120 degrees if you want it to look the same after the rotation). An analagous mathematical formalism describes how different particle states can be related to each other - so you can 'rotate' between particles if they fall within the same symmetry group. It's very clean and powerful but it does tend to screw with your head.

Supersymmetry takes these symmetries one step further and relates the class of particles that photons belong to to the class of particles that electrons belong to. This doubles the number of particles in the theory and gives us lots of new particles to look for. All because we added an extra symmetry to the theory.

Yep. The Mind Bullets. I didn't want to mention them here for fear of attracting Official attention to the thread but I fear Joe's involvement may well be out of the bag now. Ah well, he was a good CL when we knew him.

----------


## Karro

> Yes, there seems to be a very deep set of relations at the heart of physics that are based on symmetries like those of shapes, for example a circle has a continuous rotational symmetry whereas an equilateral triangle has a discrete rotational symmetry (you can only rotate it in angles of 120 degrees if you want it to look the same after the rotation). An analagous mathematical formalism describes how different particle states can be related to each other - so you can 'rotate' between particles if they fall within the same symmetry group. It's very clean and powerful but it does tend to screw with your head.
> 
> Supersymmetry takes these symmetries one step further and relates the class of particles that photons belong to to the class of particles that electrons belong to. This doubles the number of particles in the theory and gives us lots of new particles to look for. All because we added an extra symmetry to the theory.
> 
> Yep. The Mind Bullets. I didn't want to mention them here for fear of attracting Official attention to the thread but I fear Joe's involvement may well be out of the bag now. Ah well, he was a good CL when we knew him.



Hmm.  That kind of makes sense in a pop-sciency kind of way. Thanks.

Joe:  Sorry I ratted you and your secret powers out.

----------


## Steel General

Hmmmm....I had Joe pegged as working for the Dharma Initiative  :Wink:

----------


## jfrazierjr

> Hmmmm....I had Joe pegged as working for the Dharma Initiative


Heh.. I was once known as Dr Marvin Candle....

That reminds me, I was watching the credits for Survivor last night and there was something one there at the end for something like :

Dharma Creative blah blah blah.....

I just found that rather ironic...

----------


## RPMiller

Joe, just remember this word: FNORD.

Oh crap, I'll have to say it again as you will have forgotten it after reading. Remember this word: FNORD.

Hm... I don't think this will work after all. Nothing to see here, move along.  :Wink:

----------


## jfrazierjr

> Joe, just remember this word: .
> 
> Oh crap, I'll have to say it again as you will have forgotten it after reading. Remember this word: .
> 
> Hm... I don't think this will work after all. Nothing to see here, move along.



What word?   your talking nonsense now.... What word should I remember(and why)?

----------


## RPMiller

Exactly.  :Very Happy:

----------


## Nomadic

Sure it has the possibility to uncover the truth behind the Higgs Boson... but can the LHC uncover the fnords?

----------


## jfrazierjr

> Sure it has the possibility to uncover the truth behind the Higgs Boson... but can the LHC uncover the ?


Uncover the WHAT????   WHY ARE PEOPLE WRITING INCOMPLETE SENTENCES TODAY????????  argh!

----------


## Turgenev

Chorus: "_FNORD! FNORD! FNORD! FNORD! Lovely FNORD! Lovely FNORD!_"

Waitress: "Bloody Vikings!"

 :Laughing:  :Laughing:  :Laughing:

----------


## RPMiller

> Uncover the WHAT????   WHY ARE PEOPLE WRITING INCOMPLETE SENTENCES TODAY????????  argh!


What were talking about?

----------


## torstan

Fnord is old school as it can sometimes be circumvented by newfangled technology. These days it is         that those who shall not be named use for their dark plans.

----------


## joão paulo

Where they want to go with it ?

----------


## torstan

So apparently the LHC has been fixed - just in time for the release of Angels and Demons. I'm sure there's no coincidence there... I predict we'll see a small flurry of CERN stories over the coming months. There's a new one today on Yahoo! UK:

http://uk.news.yahoo.com/4/20090504/...d-41f21e0.html

A few choice lines:



> Engineers have fixed the "Big Bang" machine after an *electrical fault* led to it being shut-down in September last year.


Well I guess electricity and electronics were at fault, but I'd say "explosion" would be closer to the mark. Good to know it's pretty much nailed now. The next 4 months will be taken up with cooling and testing of the machine so that they can hit the September restart.

On the subject of Angels and Demons I hear that ATLAS - one of the detectors at the LHC - has been pressed into use as a bit of set for the film, masquerading as an antimatter creation machine. It'll be nice for the experiment to get a bit of Hollywood glamour  :Smile: 

On the dark matter side, new data released by the Fermi/Glast satellite over the weekend has thrown all models out of the window. Back to the drawing board for structures of dark matter this week. The race is on to fit the new results.

And that's all for this months update. And oh, just to keep us all up to date with events, and for nostalgia's sake:
http://hasthelargehadroncolliderdest...eworldyet.com/

----------


## RPMiller

Thanks for the updates T. It is also great to know that the LHC has not ended the world. I'm thankful that that site is up to let us know when it happens.

----------


## torstan

I believe it even has an rss feed....

----------


## RPMiller

Yes it does. I was subscribed to it at one point, but unsubscribed when the LHC went down. Figured it was no longer necessary to be warned if it wasn't running.

----------


## NymTevlyn

New data from the LEHC (Low-energy home collidor):

http://www.youtube.com/watch?v=y-7XwboOx98

----------


## torstan

That's pretty cool  :Smile: 

Here's a shot of someone fixing the magnets:
http://atlas-service-enews.web.cern....photo4_580.jpg

I just love the way you can only just see the curvature of the tunnel.

----------


## Ascension

That was freakin cool Nym, nice find.

----------


## RPMiller

...other than the spam-age in the description, yea, the guy definitely knows how to create some very cool special effects. I'm curious what software he used to create it because it is definitely professional grade CGI for sure.

----------


## RPMiller

We haven't had any news in awhile so I thought I would give it a little bump and also put up a diagram of the ATLAS detector for everyone's amusement.

----------


## töff

Recently I was pondering (again) the concepts of faith & knowledge, with a view toward the endless (and absurd) "science vs. religion" war. It struck me that black holes are a prime example, on the scientific side, of faith. Think about it: we can't see them. We can't even get near them (assuming they exist). We only assume, because of thought experiments (call it math if you like), that they _must_ exist, because we see some things that we can only explain if there's such as thing as a black hole, with such-and-such characteristics, causing those secondary phenomena to occur.

... does that sound like God?

For the record, I'm a devout atheist (_not_ anti-religion, though!), and I pretty much do believe in black holes, and I pretty much think that the scientific method leads to truth.

But again ... that's faith, isn't it. The "other side" (those of religious faith) are doing _exactly the same thing._

----------


## Karro

> Recently I was pondering (again) the concepts of faith & knowledge, with a view toward the endless (and absurd) "science vs. religion" war. It struck me that black holes are a prime example, on the scientific side, of faith. Think about it: we can't see them. We can't even get near them (assuming they exist). We only assume, because of thought experiments (call it math if you like), that they _must_ exist, because we see some things that we can only explain if there's such as thing as a black hole, with such-and-such characteristics, causing those secondary phenomena to occur.
> 
> ... does that sound like God?
> 
> For the record, I'm a devout atheist (_not_ anti-religion, though!), and I pretty much do believe in black holes, and I pretty much think that the scientific method leads to truth.
> 
> But again ... that's faith, isn't it. The "other side" (those of religious faith) are doing _exactly the same thing._



QFT.

I am both a non-atheist (i.e. I have a strong religious faith) and a believer in science (including such general truths as evolution, which seems to be a particular flash-point among some religionists, whereas I find the concept of evolution to be divinely sublime, and in no way denigrates my existence as a human being).  I find both requires a certain type of faith - especially as a non-scientist, per se (as in... not beyond the simple experiments you can run in a freshman college physics class) although I think the nature of that faith, between the two, differs.  I think my religious faith is testable, in a "scientific"-like manner, where the testable results are feelings and emotions, and not exactly precisely quantifiable.  Scientific faith, obviously, is also testable, but the testable results _are_ precisely quantifiable, and appeal to logic as opposed to emotion.  Still, as a human being, I find emotion insepperable from my experience and understanding of the world.

----------


## torstan

I have to disagree with that (well I would have to wouldn't I  :Smile:  ). There are certainly good points in what you say - there's an interesting discussion to be had about the foundation of our belief in the way science approaches the truth. However let's start a little earlier. So to start off with there's a clear difference between the scientific method and religion in that if there are two scientific theories about a phenomena then there will be a test that would tell you which scientific theory is correct or whether neither is correct. In the case of religion, if there are two separate religions explaining a phenomena then there will be no tests that can be done to tell which of those religions is correct as the foundation is purely that of belief rather than empirical test.

The two approaches are founded on separate bases from the start.

Black holes are a prediction of general relativity, which has been experimentally tested (and continues to be tested) against other theories. Also explanations of phenomena using black holes are experimentally tested against other hypotheses for the mass at the centre of galaxies. If it turned out that those tests failed then the scientific community would be forced to give up on the concept of supermassive black holes holding galaxies together. These sorts of changes do happen, and surprisingly often. However the black hole hypothesis has been tested many times and found to be a consistent explanation of the phenomena so it is still our current best description of that reality. That's equivalent to saying that we know they exist.

There's some other interesting stuff going on in this field too, but let's talk about this for a bit first.

----------


## Karro

> snip.


But here's the thing: for us lay-persons who can't actually _do_ science, or sometimes even necessarily _understand_ science... _we_ can't prove or test directly whether any given scientific theory is correct.  Those of us who believe in the scientific method/process but can't prove it directly for ourselves have to take it as an article of faith that what those of you who can, the scientists, are telling us the truth.  The simple-to-explain parts of it... seem to make sense and jive with what is observable about our world, so we roll with it.  In that sense... science, from the perspective of the masses, is exactly like religion, and scientists are it's "priestly" caste.

Most of us approach religion in the same manner - none of us (at least no one I have talked to) has ever seen God/Allah/Deity-of-your-choice directly.  Our experience of the world, though, seems to suggest the existence of a higher power... having no ability to test that theorem directly, we rely on the understanding of those who have a greater knowledge of deity.

But you're right, on a macro-scale, we can't _prove_ that one competing religious "theory" is any more correct than another.  From my experience, the provability is at a very personal level: do I _feel_ that one religious doctrine is more true than another.  It's a science of the heart, but it's very personal.  Still... I happen to believe that one particular religious doctrine is the most correct/true of all available doctrines, but I can say that I don't think, logically, that I have the authority to say to another person that the doctrine s/he follows is incorrect - beyond my own personal experience I have nothing to offer as direct evidence of such a statement.  So... no... they're not _exactly_ the same... but there's still an overlap in the way we lay people experience it.

That being said: keep up your good work sciencing.

----------


## töff

I think you'll find a lot of Christians saying that the Trinity is a consistent explanation of why many phenomena occur, and so that's equivalent to saying that we know Christ exists.

Scientists can apply science to disprove God.
Christians can apply doctrine to disprove science. (Yes they can; some specific aspects of it, anyway.)

Once you get into such details, you've already chosen a side, and that choice dictates your entire paradigm.

But if you step back and think OUTSIDE that choice (objectively, if such a stance is really possible), there's this amazing parallel. And I think that recognizing that parallel can lead to a greater understanding of the "other side."

Yes, I know, science and math and empirical evidence are, to us non-religious types, "PROOF" of our beliefs.  Belief becomes "fact." ... But it's the same thing for religion. To the faithful, doctrine is "PROOF" -- it's fact.

From either side, the other side looks absurd and misguided. But the absurdity, running both ways, is parallel. I think that's amazing.

----------


## töff

> if there are two scientific theories about a phenomena then there will be a test that would tell you which scientific theory is correct or whether neither is correct


The incompatibilities of quantum mechanics vs. relativity is a really good place to start with this idea. They've both been "proven," but they disprove each other. The GUT eludes us, so far.

----------


## torstan

I would never ever consider religion to be absurd. I also do not find religion and science to be in conflict. I heard somewhere that the proportion of people with deeply held religious beliefs is actually higher in physicists than average. I'll address the other points in an hour or so, but right now I need to eat lunch.

----------


## töff

I guess my point is, a friend of mine declared quite absolutely and vehemently that "science is not a belief system." But I think it has to be. It's a way of perceiving reality. But it's also quite incomplete and uncertain in many ways.

Sure, scientists chase after "truth" rather than philosophical doctrine -- they declare something to be a "theory" and they apply tests and interpret evidence in the hopes of disproving it ... but eventually they give and and say, "Okay, this is a LAW. It's scientific FACT." And they have every reason in the world to believe it.

... to "believe" it. Within science and math and logic, some things just can't be argued.

Once again, I believe it, too. This is my own personal approach. I'm not saying it's wrong.

I'm just saying, it really boils down to a belief system.

And the religious faiths, in so many ways, work exactly the same way.

----------


## töff

> I would never ever consider religion to be absurd


Me neither ... even Heaven's Gate, which almost the entire world calls bizarre and insane and absurd and tragic. But many people of the scientific approach do consider even the world's oldest and most "refined" ("evolved"?) faiths to be built on concepts that are scientifically absurd.




> I also do not find religion and science to be in conflict.


We can point to scientific or religious concepts that are in findamental conflict with the other side. But I don't want to start the war here all over again.

----------


## töff

Another attempt at expressing my idea ...

"Fact" is the endpoint of a line of "belief."

Nothing we conceive can reach that endpoint. We might THINK it does -- something we "believe as fact" might feel as if it's 100% true and factual -- but it seems more realistic to place each of our beliefs somewhere along the line. Some points on MY line (the points will be elsewhere on yours):

 The "law" of gravity? 99.99999% -- this one's a really accurate perception, I think.Black holes? 99.9%Saddam's WMD programs? 99% (see Halabja, where he used a chemcial WMD).The magic bullet that killed Kennedy? 50%. A god (or something else) behind the comet that the Heaven's Gate people were shooting for? 0.0001% (not zero).
But if we can't ever get to that 100% endpoint of "fact," then EVERYTHING IS A BELIEF. Our perceptions and interpretations of reality are never certain. We all just believe things. Sometimes we can't see the gap between 99.9999% and the endpoint ... and so we think we "know" something. And that seems absolute. It seems like the endpoint. We just KNOW it's true.

Ask a scientist about black holes, and she'll say she KNOWS they exist. They have to, according to the sum of all the things that are our world. Has she ever seen one? No (except in her mind).

Ask a Christian about God, and she'll say she KNOWS He exists. He has to, according to the sum of all the things that are our world. Has she ever seen Him? No (except in her soul).

We place beliefs on the 100% endpoint, and call them fact.

----------


## Karro

> We can point to scientific or religious concepts that are in findamental conflict with the other side. But I don't want to start the war here all over again.


Not to belabor an argument, if there has been one, but do you mind terribly sharing your opinion on where these fundamental conflicts exist?

As a believer in both science and religion, I am unaware of any fundamental conflicts that I have been unable to resolve to my own satisfaction.

----------


## töff

> sharing your opinion on where these fundamental conflicts exist?


Adam & Eve vs. Lucy, for example; whence cometh Original Sin per Darwin?


> unaware of any fundamental conflicts that I have been unable to resolve to my own satisfaction.


Then you are fortunate to be aware of threats to your belief system and to have avoided or decided them. Not everyone is so fortunate.

***

I just wanted to say this, to those who, _like I do_, believe in science:

Think about what we "know" and what we believe. Think about black holes ... think about the elusive GUT. Think about the nature of empirical "fact" and "law" in the framework of interpreted perceptions.

Perhaps you, like I have done (to some degree, I hope), might gain an insight into religious faith, which, for so many people who share our science-based outlook, can seem (and often _is_) irrational and naïve and blind and science-antagonistic.

I say this in the hopes that someone might gain a new perspective on the barriers that divide us within the human race ... barriers that have led, least case, to misunderstanding and separation ... worst case, to murder and war and horror.

----------


## torstan

@Karro: That's a very good point. Many scientists do just say 'I've tested this' or 'I've researched this' and so you must believe it to be true, without any consideration for the level of belief that engenders. That certainly does have parallels with religious belief where people are required to believe something on the word of someone else.

The issue that should be made clear is that tests are done, and that theories are measured off against one another. If it can't be disproved then there's an argument for saying it's not science. That's unique to science and holds it apart. I would never hold any religion to that standard - that would be crazy. That's at the heart of the difference between the two fields. Whilst that difference exists I have to disagree that the two are the same.

Now, on to Toff's point.

Science cannot disprove God and should never try. If you take a view that a deity of a religion is omnipotent then any argument you place against the existence of a deity is flawed as any evidence (including your own logic) is based in the world created by and manipulated by that deity. Therefore there is no logically consistent way science can prove or disprove the existence of an omnipotent deity.

Religion cannot disprove science either and shouldn't try. Say I hold a deep religious belief that God causes all objects to fall down. Now a scientist says that gravity causes objects to fall down. Now say that in one bizarre turn of events an object does not fall down. A scientist says that his gravity theory is wrong. The person with the religious conviction says that God decided that the object wouldn't fall down this time. Is that a disproof of the science? No. The omnipotent God can cause the object to move in any way. This means that the hypothesis cannot be proved or disproved. The scientist accepts that the empirical evidence (not the religious theory) has refuted his theory so he goes away and does more tests to formulate a consistent theory that incorporates the new phenomena. That theory will have testable consequences that the scientist (if he has any rigour) will go and attempt to test.

There are many instances where there have been conflicting scientific theories proposed that are _motivated_ by religion. But the debates have been settled through the scientific method rather than an appeal to belief.

Right, before Toff jumps in I need to address the core of his argument, which I've been skirting up until now.

How do we know the scientific method has any bearing on the way the universe works? We don't. It is a belief, and one that is at the heart of science. This is the place that science and religion do cross paths. Both are founded on the basis of belief. The difference is in what those beliefs are. In science the beliefs are of the form of things such as:

1. There are laws that the universe obeys. If something happens time and time again there must be a very good reason if it suddenly does something different. That reason will also be some form of rule or law that if the same scenario were to repeat, the theory could predict the behaviour accurately. This is essentially a law of inductive reasoning.
2. It also requires that we trust our interaction with the world. Essentially this is Descartes Evil Demon argument (or the brains in vats of the matrix). We cannot prove that the world is not an illusion presented to us by some omnipotent malign intelligence. Therefore we must believe that this is not the case and act accordingly.

Now on the basis of these two principles we can make enormous progress, and make sensible informed decisions.

Religions have very different core beliefs which define how relative decisions are made about the explanations of the world we experience. 

These two sets of beliefs define how we make relative choices between explanations. If you apply the criteria of choice at the heart of science to two religious explanations then you aren't having a religious debate any more. If you apply religion's decision making criteria to a choice between two scientific theories then you aren't doing science. This is a clash of paradigms (as introduced by Thomas Kuhn) just as Toff mentioned.

This is why (I believe) there will always be conflict between the two, and also why I feel that the two sides are not actually in conflict.

Sorry for the long post, but I hope it was an interesting read. Right. Off to see if I can make some falsifiable predictions now.

----------


## Karro

> Adam & Eve vs. Lucy, for example; whence cometh Original Sin per Darwin?


Ahh.  So these examples are doctrinaly-specific conflicts, and not general in nature.  (As a for-instance, the doctrine of my church of choice rejects the concept of Original Sin and has what I might characterize as a somewhat nuanced view of Adam & Eve.) 




> Then you are fortunate to be aware of threats to your belief system and to have avoided or decided them. Not everyone is so fortunate.


Thank you; yes, I think that I am fairly fortunate.  Howbeit... I don't think I have specifically _avoided_ threats to my belief system.  I'm actually a religious convert, consquent to just such threats to my belief system that, once resolved, required for me a change in my church of affiliation.

----------


## Karro

> @Karro: That's a very good point. ...Sorry for the long post, but I hope it was an interesting read. Right. Off to see if I can make some falsifiable predictions now.


Right-o Torstan! Good luck!  (And thanks for the reasoned response.)

----------


## töff

> ... before Toff jumps in I need to address the core of his argument ... science and religion do cross paths. Both are founded on the basis of belief. The difference is in what those beliefs are


Oh, I don't want to jump on anybody or anything. I'm just trying to express a perception that, from a particular angle of thought that I've come across, science and religion are identical pursuits. Sure, in general, they use utterly different tools of thought. But compare Christianity to Buddhism, and you'll find as much difference as Christianity compared to Darwinism ... and as much similarity.

Those of us with convictions, of whatever sort, see our paths of thought as true and valid ... which MIGHT be why we follow those paths. As a byproduct, we often see other paths of thought as invalid. Often, we don't even fully realize the consequences of such a stance ... except when others take such a stance against our own beliefs.

----------


## torstan

Certainly wasn't accusing you of jumping on anything! It was as much a reminder to myself that I'd been attacking a straw man up until that point and hadn't addressed your argument that belief is at the heart of science.

For the Christianity-Buddhism vs Christianity-Darwinism I have to disagree again. I can happily believe in both Christianity and Darwinism but I cannot be both a Buddhist and a Christian. Essentially the argument I would make are the Christianity and Buddhism belong to the same paradigm and so can be judged against one another. Holding a belief in both is logically inconsistent. On the other hand Christianity and Darwinism are from separate paradigms and belief in both can be held without any logical inconsistency.

----------


## torstan

As for the relativity and quantum mechanics, yes they are inconsistent at the Planck scale. However we have theories that do reconcile them (string and M-theory) as well as arguably loop quantum gravity. So there are consistent and competing theories to describe that conflict and because a conflict exists there is substantial active research in the area. Now there are currently no clear experimental tests available to choose between those theories but they are testable _in principle_ which is the best we can do right now. If we're lucky then the LHC might give us some early hints along those lines. A light supersymmetric spectrum of new particles would certainly make string theorists I know very happy.

----------


## Karro

> As for the relativity and quantum mechanics, yes they are inconsistent at the Planck scale. However we have theories that do reconcile them (string and M-theory) as well as arguably loop quantum gravity. So there are consistent and competing theories to describe that conflict and because a conflict exists there is substantial active research in the area. Now there are currently no clear experimental tests available to choose between those theories but they are testable _in principle_ which is the best we can do right now. If we're lucky then the LHC might give us some early hints along those lines. A light supersymmetric spectrum of new particles would certainly make string theorists I know very happy.


Some friends of yours, eh?  So you're not in the String Theory camp?

You know... would you mind giving us the laymen's really simple and understandable version of String Theory?  I've been trying to build up a basic understanding of it to see if I can use a bastardized version of String Theory as the basis for a magic system...  It would help if I could understand what I was attempting to bastardize.

----------


## torstan

I don't work directly on string theory so I'm not a string theorist. I'd not say I was or was not in the string theory camp. I work on theories that are inspired by string theory but I don't work on the stringy side of them so I'm really not any sort of authority on that stuff.

I'll think about a rough outline. It's a tricky one to pin down and my own understanding is certainly far from complete. I'll see what I can put together though.

----------


## töff

> So you're not in the String Theory camp?


LOL. Sounds like "so you don't believe in the true presence of Christ in the Eucharist?"

I think I've expressed my observation.

Personally, I dig the stringbrane school of multidimensionality.

----------


## torstan

Absolutely, and it made for a very interesting discussion. Thanks for bringing it up.

----------


## Redrobes

This has been fascinating so thanks all. I don't have much to add that hasn't been said so ill stay quiet. I did want to express that for those who haven't read "Zen and the art of motorcycle maintenance" then it really is the belief and concept changing book that it has been claimed to be. It has its share of dull moments too tho but its a must read book.

Id also like to understand the basics behind the string theory. I did a lot of math but my most advanced is probably the opening gambits to what you have to wade through. But if it abso needs math to explain it then just do it and hope that we can follow. I always wondered if its even possible to explain it metaphorically.

----------


## töff

As I understand string theory, it starts with the way you can take a two-dimensional piece of papaer and roll it up reallllllllllllly tight so it looks like a line ... one-dimensional ... its other dimension is "hidden" but it still exists. Then you bring the ends together to make a loop, and there's something about resonant vibrations at different frequencies that make the vibrating loop look like an electron in "our space" ... or a charm quark ... or a Higgs boson ... oh wait, we haven't found that one yet ... a graviton ... oh wait, haven't found a graviton ... a tachyon! yeh ... no ... does that help?

----------


## töff

Just don't get me started on the nine different kinds of angels.

----------


## torstan

What, charm, truth and beauty are all kinds of angels? Finally I can figure out how many of them can get on top of a pin!

I'm glad they changed the truth and beauty quarks to top and bottom. They are still terrible names but at least it sounds a little less we physicists are disappearing up our own behinds. ("Let's name my keys 'truth'. Now I can put out a press release saying I have found truth! How could anyone think that was patronising and misleading?")

I promise I will try to put together a short string theory concept post. It's not that it's hard without maths - it's just hard with or without maths.

----------


## töff

I have some good popular-level books on modern physics and quantum-mechanic theories, including string theory ...

... I just haven't read any of them ...  :Rolling Eyes:

----------


## torstan

That's a very common issue with physics books.

For those that are interested in this stuff (and if you've got to p26 of this thread I'm going to assume you are!) then I can recommend J.S.Bell's Speakable and Unspeakable in Quantum Mechanics as a really good book to flick through.

----------


## Karro

> As I understand string theory, it starts with the way you can take a two-dimensional piece of papaer and roll it up reallllllllllllly tight so it looks like a line ... one-dimensional ... its other dimension is "hidden" but it still exists. Then you bring the ends together to make a loop, and there's something about resonant vibrations at different frequencies that make the vibrating loop look like an electron in "our space" ... or a charm quark ... or a Higgs boson ... oh wait, we haven't found that one yet ... a graviton ... oh wait, haven't found a graviton ... a tachyon! yeh ... no ... does that help?


Actually... that bit about a rolled-up piece of paper, rolled so tight it becomes "one-dimensional"... that kind of helps and makes a certain kind of sense.

And begins to give me a sense of what was meant when I was reading how branes have something to do with dimensions all folded up in on themselves somehow.  That's difficult to conceive, conceptually.

----------


## töff

I can't take credit for the analogy. But yeh, it's a good one, huh ... as analogies go, which isn't far. 

It's like the rubber sheet thing to explain spacetime curvature. Same concept.

----------


## Karro

> I can't take credit for the analogy. But yeh, it's a good one, huh ... as analogies go, which isn't far. 
> 
> It's like the rubber sheet thing to explain spacetime curvature. Same concept.



Yeah, which I always thought was a pretty good analogy.  It had the added benefit of being demonstrable in how it worked.

----------


## torstan

My favourite analogy for explaining compact dimensions has always been asteroids, the game. It is entirely possible for extra dimensions to be wrapped up in a way that if you travel in a straight line you return to where you started. If the distance you need to travel to return is very small then we might not even notice that the dimension is there. Alternatively the dimension could be very large, but we might not be able to travel in it at all. In that case it would be more like our own existence on the earth's surface before we designed planes. We cannot travel up in the air, but we can see things that do. We are restricted to moving in the 2D world of the earth's surface. In the same way string theory predicts that the universe has many more dimensions than we are aware of, but that we are confined to 3D objects within that space called branes (Actually 3+1 dimensions as we always count time as well). So even though the universe has these other dimensions, the universe we deal with is 3D. Stretching the analogy further, the prehistoric man could see that birds travel in the air. In our case, it may be that gravity can travel in the extra dimensions. This has been proposed as a reason for gravity being weaker than the other forces as it spreads out across many more dimensions. Just as if you drop ink on paper and drop ink in a glass of water. If you compare the darkness of the ink on the paper at a given distance from the point of impact to the darkness of the ink in the glass at the same distance, the ink on paper will be darker.

So we expect that there are more dimensions - 11 in total - from string theory. This is required for the theory to be in any way consistent and is one of the clear predictions that it makes. There are then a number of explanations for why we don't see those extra dimensions. In some scenarios we would see hints of those dimensions turn up in the data from the LHC. An example would be if those extra dimensions were hidden by being wrapped up, like the ant on the string. From a distance the string looks 1 dimensional - you can only go one direction on it, along its length. However if you have a good magnifying glass, you can see that the surface of the string is 2 dimensional. If you were very small you could walk around the string as well as along it. Indeed if you were very small indeed the string would seem almost flat. So it's all about the degree of magnification. There will be a degree of magnification at which it becomes clear that the surface of the string has width as well as length.

Now the LHC is a microscope in a very real sense. As you increase the energy of a collider you probe smaller length scales. Therefore if the extra dimensions are large enough, then when we increase the energy of our colliders we may cross the magnification threshold for the extra dimension and start to see effects from its existence.

----------


## Karro

So... what are the implications, practically if there are any, of (a) the existence of additional dimensions or (b) the concept of tiny, pulsating, multi-dimensional strings as the most fundamental building blocks of all matter?

----------


## torstan

The implications will really depend upon the precise form the string theory takes. There are many (10^500 at least) ways to create a consistent universe with string theory. Each of those has different implications. No most of those wouldn't create the kind of universe we see around us, so we can discard the vast majority as reasonable explanations. That still leaves an awful lot of options, and far too many than we can reasonably study to discover possible implications. We'll need a major theoretical or experimental breakthrough to get clear predictions from it currently.

On the other hand, there are some things that all of those cases agree upon. They would result in gravity being transmitted by a particle with clear properties. That would be the graviton. It would have a partner, the gravitino that could be the dark matter in the universe. Because we would have a scenario with gravity being mediated by a particle that is fundamentally governed by quantum mechanics we would have a consistent model of quantum gravity, solving one of the longest running mysteries in physics. That sort of revolution in thinking would rebuild the foundations of modern physics. When those kind of revolutions happen it is impossible to tell what will come out of it, but it will be big.

On the more hypothetical side of things, possible implications would be that there are a number of universe separated in the extradimensions, allowing for the possibility of colliding branes. This could be a cause for the big bang in some theories. I'll mention some other possibilities later today, but right now I'm going to get lunch.

----------


## töff

> We are restricted to moving in the 2D world of the earth's surface.


A good example of the closed-in-on-itself dimension. The surface of a globe is finite but boundless! That's mathematically awesome.

----------


## torstan

It certainly is  :Smile:

----------


## töff

... but somewhat of a pain in the ass for cartographers.

Maybe we should all upgrade to cosmography.

----------


## Karro

> ... but somewhat of a pain in the ass for cartographers.
> 
> Maybe we should all upgrade to cosmography.


What software program do you use for multi-dimensional, non-perceivable cosmography?

----------


## RPMiller

This has been an extremely interesting conversation especially for me because of the fact that I have been studying quite a lot of philosophy this year through my degree program. I am currently in a social ethics class where we have been going through the history of philosophy and discussing each of the great philosophers and their philosophies in fairly good detail.

Interestingly enough, just last night we were discussing the "removal" of God from Philosophy starting around Machiavelli's time and moving into the modern philosophers. One of the big points we discussed was exactly what Torstan stated above--Science really doesn't care about God in the sense of trying to prove/disprove a supreme beings existence, nor should it. It is simply looking for understanding of the universe in a new way, which is really no different than the ancient philosophers. Thanks to the Method that Descartes brought to the forefront of modern thought, science has grown by leaps and bounds. I won't go into the extremely long discussion of philosophy as that is for an entirely different thread, and would take me days to type.  :Wink: 

I do want to comment on this quote from Torstan that really gave me pause:




> I cannot be both a Buddhist and a Christian.


This is actually something of a logical fallacy in the minds of philosophers. It makes a lot of sense to a Western mindset, but becomes a problem from Eastern perspective. The best and greatest example that I can give is Gandhi. He worshiped and believed equally in Hinduism, Islam, and Christianity. This is due in large part to Hinduism itself. Hindus see all the religions as just ways for Vishnu to communicate to us; therefore, they have an innate tolerance for other religions from a purely spiritual context. Politically, not so much. My point here is that there is quite a bit of overlap between all the religions and one could accept them all, and even practice them all if they were so inclined. The real issue becomes one of dogma. Those that are purely of one faith are very likely to declare a multi-religious observer as having no faith, or being wishy washy especially if that individual comes from a more fundamentalist perspective of their particular religion.

So now back to the subject of this thread... torstan, what is the latest news on the collider or on your research?

----------


## töff

> What software program do you use for multi-dimensional, non-perceivable cosmography?


_n_DSmax  :Smile:  ...

----------


## torstan

@Toff: That made me laugh  :Smile: 
@RPMiller: That's an interesting point, and one I had not appreciated. I guess I'd assumed that all religions were against pan-religious beliefs. I'm pretty sure Christianity would be against someone saying they were both Christian and Hindu, but I'm certainly not a theologian.

I'll update the work stuff shortly (sorry, just flown back to the UK for a visa run and to give a talk at CERN so all a little hectic).

----------


## Karro

> @RPMiller: That's an interesting point, and one I had not appreciated. I guess I'd assumed that all religions were against pan-religious beliefs. I'm pretty sure Christianity would be against someone saying they were both Christian and Hindu, but I'm certainly not a theologian.


From a purely dogmatic, institutional perspective, most (though not all) religions are against pan-religiosity.  That being said, many people are not overly dogmatic (just read an interesting stat on the changing face of religiosity in the U.S., and how people are increasingly less dogmatic), and some religions are not institutional, so there's a lot of potential for gray-area and overlap.

Also... just got Toff's joke.  A bit slow, here...

----------


## torstan

First off, LHC news.

So it seems that the LHC will be turning on with a lot less fanfare in November at the lower energy of 10TeV (tera-electron volts or 1 million, million eV or a a thousand billion eV). That will give the experimentalists enough particles and interactions to do proper calibration of the ring and the detectors. It's an open question as to when it will get up to the design energy. Could be a while as it seems that a lot of work would have to be done to replaced some elements. However this should produce enough data to properly run in the full infrastructure including the data grid that was created to handle the output. So we wait for November and hope that no further delays occur.

----------


## Ascension

I'm just waiting for the data to get crunched so that we know those results.  At least I know when it's going to get fired back up.  Good luck, bro.

----------


## torstan

Well the LHC continues to come on. It's confirmed that the collider will be starting up at 3.5 tera-electron volts in each beam, half the originally planned energy. Theorists are a bit down about it, but actually the experimentalists seem pretty upbeat. It gives them a chance to run the machine in under less extreme circumstances and really test the full infrastructure from the acceleration mechanism to the detectors (currently tested using cosmic rays) to the vast computer infrastructure built to handle the data. Equally, it's worth noting that the energy will be 3.5 times higher than the tevatron in the States, currently the highest energy accelerator in the world. So it will still be ground breaking.

Anyway, I'm in CERN this week at a conference so if I hear any juicy tidbits then I'll pass them on. Interestingly it looks like Hawking's giving the symposium on Wednesday. Wonder what he'll be talking about? And I wonder if anyone will ask his opinion on US healthcare  :Smile:  (don't know if his involvement got covered much back in the states but apparently a US politician said that under the NHS Hawking wouldn't be alive - to which Hawking replied that he actually travels back to the UK for his NHS treatments. I'm wildly paraphrasing so please correct me if I screwed up that story).

----------


## Gidde

I heard the same story, so I doubt you're screwing it up -- although the story I heard was also quite paraphrased (Basically that he said it was thanks to the wonderful care given by the NHS that he WAS still alive).

I'm really interested in those tidbits so please do share them  :Smile:

----------


## torstan

Well, that's the end of another conference. It was pretty interesting - especially the experimentalists reporting on a range of astrophysics and cosmology experiments. Lots of new data to come from them, as well as some salutary warnings to theorists about getting over excited by results before they are absolutely confirmed. I can't imagine too many theorists are going to worry overmuch about that. Far more fun to speculate about a result that might be there, especially as we wait for the LHC.

On the LHC front things seem to be going well. All the repairs are complete and the installation of the new checking systems sounds to be going well. Still on track for November at 3.5TeV in each beam by all accounts.

Oh, and because this thread has too little eye candy in it, here's the reconstruction of an event taken by CMS when they rammed the beam into some tungsten:



Note that the barrel is about 5 stories tall and each of those blie bars represents the energy deposits of a particle that's substantially smaller than an atomic nucleus.

----------


## Steel General

Those are some neat images, but I haven't a clue as to what they actually mean.  :Smile:

----------


## torstan

Good call - sorry for not explaining that at all!

The three images are an elevation view of the CMS (compact muon solenoid) detector on the LHC ring, an end elevation and a 3D view.

The detector actually looks something like this:



The white line along the centre of the elevation view represents the beams coming around the ring and meeting in the middle (though this time it was one beam on a fixed target I believe). The white recangles that look like something from the BBC Micra are the different layers of the detector - small and dense in the middle for very precise tracking measurements. The outer elements are larger as they are basically there to stop particles and measure their energy, rather than precisely tracking their location.

Essentially by the time the particle gets to the outer layers what you are doing is putting a wall in the way and measuring how much damage it does to it. You don't really care that much about the location of the hole it leaves to nano-meter precision. The different blue bars represent an amount of energy deposited in a given direction. These correspond to the debris that comes flying out when you smash two particles together. You analyse all the different products and how much energy they were carrying to reproduce what happened in the event.

----------


## Steel General

Ahhh that helps some, thanks.

----------


## Turgenev

I'm looking at the following picture and I'm thinking I could turn that into a space base within a crater. The blue area would be the actual base while the centre area would be the generator/power supply. The surrounding gray areas would be the elevation levels of the crater.  :Wink: 



Your updates are fascinating stuff, torstan. I might understand only half of it but I enjoy reading all of it.  :Wink:

----------


## Ascension

It also reminds me of the thingy in Star Wars where Luke learns that DV is his dad and instead of taking his hand he jumps down this big shaft.

----------


## RobA

Definitely a relative of moonbase Alpha:



-Rob A>

----------


## Turgenev

Ah yes, I've always had a soft spot for Moonbase Alpha. Unfortunately now I have the Space 1999 theme running through my head. Only one way to fix that... by watching the Space 1999/Dallas mash-up.  :Laughing:

----------


## torstan

:Smile:  Definitely a rip off of Moonbase Alpha. I'll let them know their experiment is in violation of copyright....

So after talking to some experimental colleagues (true in a number ways) it seems that the start up is still on track for 5 weeks time. ATLAS - one of the two general purpose detectors, and the one these guys work on - is running data tests next week to get ready. All very exciting, and a lot of people holding their breath and hoping nothing goes pop. The start up will be just getting beam round the ring. Collisions will come some distance down the road. I'll see if I can keep up on developments and post them here.

I am reading a paper today about the sLHC - the planned upgrade of the LHC. This will take the LHC with it's collision energy of 14TeV and increase the luminosity by 10 fold. By luminosity, what I really mean is the rate that interactions happen. So that would give you 10 times the data taking rate. Even before you start dealing with the technological challenges of cramming more protons into your beam, you also have to worry about reading out all that data and processing it. So not only are we dealing with the experiment that we have, but also planning how to upgrade it so that we get the best possible results for the investment.

Other interesting things I came across recently.

The LHC will take more energy to run than Geneva.

Some great panoramas of the detectors:
ATLAS: 
http://petermccready.com/portfolio/05091901.html

CMS:
http://petermccready.com/portfolio/07041601.html
and my favourite one of CMS (the Compact Muon Solenoid):
http://petermccready.com/portfolio/07041602.html

Lots of pics:
http://petermccready.com/

And a schematic of all the rings and subrings that are needed to get the beam into the LHC ring:


The little rings are old accelerators built over CERN's lifetime. You need larger rings for larger energies so the particles that are fired into the LHC will have taken a historical tour through CERN's past to get there. It also gives quite a nice impression of the complexity of the beast.

----------


## torstan

Oh, another figure that might be of interest:

The LHC will be generating 40 PB/s of data (1PB=1000 terabytes). The challenge is in having simple triggers in your detector to make sure that only the important bits of data are written out to tape - and to make sure that the stuff you throw away doesn't have interesting physics in it.

----------


## RobA

A little late to the show, but:

http://xkcd.com/401/

and

http://xkcd.com/637/  "...Scribblenauts lets you summon the LHC..."

-Rob A>

----------


## Karro

So, Torstan, here you are working to unlock the secrets of the universe.  And today the Nobel Prize in physics was announced for Charles Kao, Willard Boyle, and George Elwood Smith for work on Fiber Optics and CCDs (used in digital cameras).  I concede what they did was important... yet my first reaction upon hearing this was kind of disbelief: do Fiber Optics and digital cameras really rise to the level we normally expect of a Nobel Prize-worthy research, does it really answer some fundamental question?  So... as scientist, I'm curious about your thoughts...?

----------


## torstan

So the criteria for a Nobel in physics is that it goes to:

the person who shall have made the most important discovery or invention within the field of physics.

So there's a split between inventions and discoveries. We normally hear about the discoveries getting Nobels, but the inventions are as important under the criteria of the prize. In this case CCDs underpin all of modern astrophysics and the optical fibre underpins our telecommunication. I think that counts as a world changing invention that has deep implications for physics, so yes I'd say that's worthy of a Nobel. Now the question is how long it takes before Tim Berners Lee gets it  :Smile: 

Give it a couple of years and we'll see discovery Nobels for things found at CERN (we hope).

----------


## Redrobes

I think that the CCD having wiped out an entire technology and replaced it is substantial enough to be more than Nobel prize winning. In the same manner for long distance communication its done the same. Wires out, glass in. I know that I type this and it goes down copper as far as the end of my road before that Nobel prize winning invention kicks in and shoots this pretty much uninterrupted until its on the ISP holding this site. I think a whole class of communications guys could get one. Those guys which developed TCP/IP like Vint Cerf & co should be up there as would Lempel and Ziv. In any case I put the Nobel prize in the same category as the Turner prize, Oscars and all the other prizes. The whole thing is only alright if you don't take them too seriously.

----------


## Karro

Well, I guess I'd only really thought of the Nobel prizes in terms of Discoveries as opposed to Inventions.  I suppose I sure am grateful that those guys did what they did, since it certainly does make the world a better place.

----------


## torstan

Yep, I had a look through the list and it's interesting to see that a lot of them are joint invention/discovery prizes for the case where someone invents an experimental tool and then discovers something with it. This one is rather rare in that it is solely an invention.

The Nobels will always be a little skewed - there's no maths or engineering Nobel for example. But yes, looking back through the history of the prize, most of the big names of physics are there at some point, so it's pretty representative.

----------


## torstan

http://news.bbc.co.uk/2/hi/europe/8299668.stm

Interesting. I can't wait to find out what good he thought he'd do at CERN, but finding intelligent educated and capable scientists involved with al-Qaeda is a little disturbing.

Edit: Looks like he's an engineer.

----------


## waldronate

Trying to steal antimatter to use against the Vatican, no doubt.

----------


## Karro

I just read this in the news a minute ago.  Naturally my first reaction was to come here.  Actually, naturally, my first reaction was "WTF?"... then to come here and ask you guys "WTF?".  That's nuts.

Maybe this guy bought into the various sci fi scenarios that've been hashed out, here and in other places.  I guess that would make him a poor scientist/engineer...?

----------


## torstan

Dan Brown has even more to answer for than we had first assumed. Perhaps it was all a plan to make CERN a honey trap for deluded terrorists...

It actually seems more prosaic than that. The guy is an engineer for an affiliated organisation, rather than CERN itself and he was apparently involved in suggesting French targets. So not really anything to do with CERN, but I guess we'll have to wait to find out any more. Certainly no suggestion that I've seen that he was trying to sabotage/steal/misuse anything being done at CERN.

In other news - the injection set-up that gets the protons up to the speed they need for the injection into the LHC has been tested and is working fine. All seems to be going smoothly.

----------


## torstan

The LHC is now cold. All sectors have been cooled down to their operating temperature. So fingers crossed, all is going well and the final stages of commissioning are underway.

----------


## RPMiller

Torstan, are you involved with this project?

http://www.youtube.com/watch?v=gCgTJ...eature=related

----------


## torstan

I'm not, but it certainly has an impact on my work. The mapping of large scale structure is crucial to figuring out the distribution of dark matter. Once we have that nailed down (and its getting better all the time) we can try to recreate it in simulations. So what you do is create a vast numerical simulation of a load of fairly evenly distributed dark matter in the very early universe and then you let it evolve. The gravitiational attraction of a small clump of dark matter pulls in more dark matter over time until the small clumps become large clumps. These orbit even larger clumps and so the distribution goes from smooth to very lumpy. Now these lumps have a large gravitational pull, and the normal matter gets pulled into the middle of them. This is how galaxies form.

We've got a pretty good idea of just how smooth the distribution of the dark matter was in the early universe and we now know (thanks to surveys like the one you linked to) how the dark matter is distributed today. So the numerical simulations can vary the properties of their dark matter model to get the simulation to match up with those boundary conditions. This helps us to pin down the properties of the dark matter.

My interaction with this is pretty much to keep an eye on the limits they come up with and make sure that any model I work on doesn't break those simulations.

----------


## torstan

Oh, and here's a link to quite a nice video of the Millenium Simulation, one of these numerical simulations and one of the largest ever done. Think of it as a map of all the matter in a possible alternate universe. The challenge is to get the rough features looking about right - a little like creating a map with  model of erosion and trying to make sure that none of the rivers violate the river police.

I'm not sure the music adds much though so you might want to turn it off before running through it.

----------


## Redrobes

Your model, is it a pure math model or a software simulation ? If like a simulation then like GTS or perhaps a weather prediction sim these are not exact and open to a lot of parameter twiddling. Is the idea to have a feel for what parameters might give the right output. If math then is the math so complex that its not possible to come up with a proof. E.g. Ye olde E=mc^2 was a theoretical proof that needed experimental evidence but some of the nuke simulations done on the high end iron or the fluid dynamics and finite element analysis is still just numerical modeling.

Here's another question(s). Whats the simplest pure math prediction (i.e. as yet unknown physics) that has been made that the LHC might be able to show evidence for and maybe a curve ball, whats the weirdest and most fantastic claim that any scientist has made that there is a real possibility that the LHC might with a small chance actually show.

----------


## Steel General

Interesting...and I didn't mind the music (but I am a Pink Floyd fan  :Smile: )

----------


## torstan

Simulations of large complex systems are always numerical simulations. This is true for the fluid dynamics in the simulation of nuclear explosions and it's certainly true when you're trying to build a universe. However, the physics underlying the numerical simulation is good. We have solid models of a basic dark matter particle - it's massive and it interacts through gravity, but it doesn't interact strongly in any other way. This means you just set up a simulation with the laws of gravity built in and a number of particles that those laws affect and let it run. The more powerful the computer, the more particles you can place in the simulation.

At the moment each particle is actually an enormous blob of dark matter - with a mass many times that of our sun (roughly 10^4 solar masses if you're simulating a galaxy, right up to 10^12 solar masses if you're looking at recreating the whole observable universe). These blobs interact through gravity and form the clumps and stringy filaments that you see in the millenium simulation. As super computers get better, the mass of each clump is reduced (and the number of clumps consequently increased so the total mass is the same) to see if the more fine grained interactions change anything.

So within the framework of the model - we know the physics exactly. Solving that for billions of particles is impossible, so we run the simulations. If we find some features in our surveys that the simulation can't explain, then we will see if we need to change the physics model (by adding in some interactions between dark matter particles for example) or whether there's some problem with the numerical simulation (perhaps that its not fine grained enough).

In the case of the second question - the simplest pure maths prediction at the LHC is the Higgs boson. It has to be there for the symmetry of the theory to work, and for the amplitude of the scattering of the W bosons not to go to infinity as the energy increases. So that's a pretty clear pure maths prediction. I guess the simplest version of that is that there has to be new physics in the energy range to stop the probability of a specific result in WW scattering becoming greater than 1 (that's generally considered a bad thing). Even if there's no Higgs boson, we know that something new must happen in the energy regime of the LHC. So no matter what, it will find some deviation from physics as we know it.

As for the weird stuff? Well there is a lot of that. Nielsen recently claimed that the universe would conspire against creating the Higgs boson so that CERN would never start. I guess that would be a dramatic example - but I think that's pretty tongue in cheek so shouldn't be taken seriously. Large extra dimensions is probably one of the strangest things that might show up. We might probe down to a length scale where we would be able to see the effect of extra dimensions - and some of the created particles would travel in them. Equally, we might produce microscopic black holes that would decay in a burst of Hawking radiation. That would be really cool. I think those are some of the more bizarre things that have been proposed.

The other thing that we are always told by those scientists that have been through this process before is that experiments always end up showing things that you never predicted. Nature tends to be more inventive than physicists, so we may see something truly bizarre.

----------


## Redrobes

Cool - I did hear about that universe trying to prevent the LHC... worth a small chuckle.

Measureable - as in not requiring a ruler the size of Geneva - extra dimensional spaces would be cool and if you can see what passes through them then I guess thats part way there to knowing how or what to do to build them bigger.

Y'know I am still impressed when you walk down a corridor with one of those little boxes thats like the PIR detectors but have the little radars in them. At the middle of the radar is a little diode which makes the radar. Its a tunnel diode and its a quantum device. I have one here abouts somewhere. A real quantum device. What, 40 odd years ago noone knew anything about quantum stuff and now I have these on a shelf. Nobody knows how these LHC discoveries will filter down to consumer items. Dibs on the first portable hole tho...

The Higgs must be really exciting then to know that theres going to be some new physics cos it just cant not be there otherwise the maths fails. Thats the sort of thing thats cool as you know what your looking for but not what it is. Its not like not knowing what your looking for. Thats like code debugging. You just slice and dice until you find what the issue is. Instead of a typo cut n paste error tho, its a new branch of physics that pops out. Thats pretty cool.

The sim thing sounds a little more dodgy. I have GTS and it has the "water flows downhill" bit of hard physics in it and its always producing terrain thats not quite right and there's always more stuff to add in to make it closer to the desired observable result. But if I get good results from it I don't think its true that the model is right. For a start I guessed all of the math in mine. I didn't even so much as look at any previous works or papers. So its all wrong but looks about right give or take. I could use the app to predict stuff but I still don't think that it makes the underlying model right.

How do you think you know that a sim model is right or is it that you never know but it might allow you to run interesting tests to exercise sim cases to narrow down the math / physics tests required in real life or on the LHC ? Is it like, the sim says at 1.234 TeV you get a spike so lets wind it up and see. If yea then sim looks like it could be right, if nae then its back to the drawing board.

On a side note too. The Hawking radiation. I read that the smaller the black hole the more of it you have which makes small holes unstable. Is that from area of sphere / vol of sphere goes up as r -> 0... anyway, I take it that the radiation comes off as photons and I guess that its not necessarily emitted uniformly - or is there a lot of it so much that it makes no odds. But my question was, How do you know the light came from a black hole instead of something else. I thought that all collisions and electron decay chucked out photons or stuff that turns into photons and I thought that you were making a lot of collisions at this point. Is that all done in the post processing ?

The whole way this thing works is like a wall of fog to me.

----------


## torstan

Yep. This Higgs is really clear. The problem exists in that the theory breaks at a given energy unless something new happens. The Higgs is the simplest hypothesis that solves it. So we see the Higgs, or something new, but we have to see something.

In the sim, let me say a couple of things. Firstly, we know the physics exactly - all we're doing is taking particles and allow them to interact gravitationally. So no-one's 'just guessing'. Nor are we just saying 'that looks about right, let's leave it at that and call it good'. The consistency checks require that over the volume that's simulated then we get X number of galaxy mass clumps per MPc, and Y number of galaxy cluster sized clumps per 100MPc and so on for every scale. You do detailed statistical analysis to find out where your simulation disagrees with the real universe. And as we can look back in time by looking at light from further away galaxies, we can actually see the development of dark matter clumps over time (to an extent) - so we have a lot of data to compare to. If it doesn't fit, then we can look at why.

It may be that the physics is different - and if so we don't say that it _is_ different. We look at possible explanations of why it might be. And then you are dead right - you use it to constrain predictions for other experiments, like the LHC or looking at colliding galaxy clusters or looking for dark matter annihilation in our own galaxy. So each experiment informs other experiments and all of them taken together start to build a picture. The interesting things occur when two experiments seem to require contradictory theories. Then we need to work to find out if there was an experimental error, or the theory needs adapting.

So we can do a sim of the galaxy and that says that there's about 0.4GeV/c^2 of mass tied up in dark matter per cm^3. So if dark matter is a particle with a mass of 100GeV/c^2 then there's one particle of it per 250 cm^3. Now that tells us how many particles we expect to pass through a direct detection experiment per second. If the detector doesn't see it, then we can constrain the interaction strength of the dark matter with normal matter i.e. if it doesn't interact at all then it doesn't matter how much of it there is, the dark matter detector won't see it. Conversely if it interacts strongly then we should have seen a signal long ago - because the simulation tells us there should be lots of dark matter passing through the detector. So, on the caveat that we've taken a number from simulation, we can use direct detection to place an upper limit on the interaction strength of dark matter with normal matter.

Now the LHC will also place a limit on this interaction strength - because if the interaction is strong then the LHC will produce a load of it. If it's weak then it will produce less. Now if the LHC results require a dark matter particle that interacts more strongly than direct detection limits allow then I can guarrantee that people will go and look very carefully at that number of 0.4GeV/c^2 per cm^2. They'll also be coming up with theories about why it just doesn't interact with direct detectors, but does get produced at the LHC.

I hope that answers the question a bit?

As for the black holes - yes the issue is really one of size. When you have a black hole you have an event horizon, where anything within the horizon gets sucked in, and anything outside can escape. Now say you have an e+ e- pair created out of the vacuum (a particle and an antiparticle can always be created, and quantum mechanics says you can and will do that all the time). Normally they just recombine and annihilate with no discernible effect. However in the case where they turn up on the event horizon, the positron could b created on one side and the electron on the other. Now they can't recombine because nothing crosses the event horizon. So the positron falls in and the electron escapes. To an outside observer that looks like the black hole just emitted an electron! Also, because that electron carries energy, for energy to be conserved, the black hole must have lost energy in the transaction (and complex GR calculations show that this is indeed what happens). So the black hole just emitted an electron and lost energy.

Now this process can happen with any particle. So the black hole can radiate any particle at all. For a large black hole this is a small effect. Basically as volume (which can be taken to be proportional to mass) goes as r^3, and the surface area on which the radiation takes place goes as r^2, for large black holes the mass is much larger than the energy loss from hawking radiation. They do lose energy through it, but it's a small fraction of their mass, and they're accreting new mass anyway. For a small back hole r is very small, so suddenly the rate of energy loss is large compared to your mass. And because the mass is small, the gravitational attraction is really tiny so there's no hope of it accreting new mass to replace the energy it's losing through Hawking radiation, so it just evaporates.

Now because it can evaporate into all particles, it's quite a dramatic signal because you just get a burst of all sorts of different things coming out of a point in space, irrespective of what you threw in (I believe).

Hope that makes some form of sense. I'll go over it more later if you want more details, but this post has already turned out to be a bit of a mammoth.

----------


## Redrobes

No thats great. I knew that the radiation emitted was from tunneling across the event horizon because the instantaneous position is statistical from Heisenbergs. I didn't know that it emitted a particle tho. I guess I didn't think how the thing started but I remember that you can have these spontaneous evolutions of stuff that normally recombine. Ok so bursts of all sorts then.

On the sim you say that the physics is all known or exact but then say that it might need to be modified. I think I know what your saying but it seems as tho there is some educated and experimental backed guesswork going on and some of the parameter twiddling sounds like the interaction factor for dark matter and it sounds like the LHC is definitely going to constrain the twiddle range. I guess if some theories require that to be in a range that is outside of the LHC results then its struck off the cards or modified. This sounds a lot like the hubble constant where the telescope nailed it down after a few years and left us all with one theory (expanding wasn't it) instead of three (constant or contracting).

So I have a better idea of what and why its happening now thanks. Ill prob ask more in time.

btw: Is it just me but does anyone else think that the big detector in the photo looks like the MCP from Tron...  :Crying or Very sad:

----------


## torstan

Ah, okay. So on large scales the dominant interaction is gravity - by many orders of magnitude. The self interaction between dark matter particles will have to be very very small so it's a small perturbation on the dominant interaction - so we know the most important numbers already. That's not to say that a small non-zero interaction strength wouldn't do something - and indeed simulations are looking at the variation from that. That's one twiddle. Another is the interaction between the dark matter and the normal matter in galaxies - that will be small, but could be non-zero and might have an effect on how galaxies form. However the large scale bulk properties should be well handled by just dealing with gravity.

If we see some big conflicts between different areas then we can look at what might be screwing up, but we generally start with the simplest cases.

----------


## RPMiller

> btw: Is it just me but does anyone else think that the big detector in the photo looks like the MCP from Tron...


			 		  		 		 			 			Don't be sad...

http://tron-2-trailer.blogspot.com/

----------


## Redrobes

Ok so it didn't take me long to think of another question - sorry...

If a black hole is emitting particles then is it true that it emits about as many particles as anti particles. I mean do electrons come off a black hole and its the positrons that always stay inside in an e- e+ pair.

If as I expect its about the same then the hole is emitting streams of mixed particles then do these recombine and if so does that generate the photons or do they annihilate perfectly with nothing emitted at all just as it would if the e+ e- had recombined back within the event horizon.

In which case wouldn't some or a lot of the particles from a black hole out of the event horizon just pop out of existence and we wouldn't see or be able to detect most of them anyway.

Oh and Tron link - cool though I don't think its going to grab people like the first movie. I collect Syd Mead stuff - not the real stuff I should add, not being a millionaire n'all. But I have some fairly rare stuff. I am missing Kronovector or however you spell it but then I don't have the laser disk player for it anyways. I think there's a book I am still missing as well. Anyhoo thats all a bit off topic. Syd's art is well cool. Its great that many of original cast are back in and lissenberger (sorry spelling again) is part of it. I didnt know about the sequel.

----------


## torstan

Not quite, but I really need to get on the subway and head home.

If the particles have travelled away from the event horizon then they must have a non-zero momentum. Therefore when they recombine they must annihilate to something with non-zero momentum - which is a real thing, not just the generic vacuum that they could annihilate to if they collide head on. So they produce a real photon that travels out (if it's an e+ e- collision) and we might be able to see that. So that's why you might hear of small black holes 'shining'.

But yes, your intuition is right and you should get as many particles as anti-particles. It's just that once you have a stream of particles going out, anything they annihilate into must also go out, due to conservation of momentum. So you'll see stuff traveling out from a black hole, even if the stuff you see isn't quite the same stuff that was created around the event horizon.

----------


## Redrobes

Cool and thanks - you had better get home  :Smile:  Appreciate the explanations  :Smile:

----------


## torstan

No problem. Happy to answer them.

----------


## torstan

First beams have been injected into 2 of the eight sectors successfully. Also, they've had beam through LHCb - one of the detectors that's looking into the nature of bottom quarks (or investigating beauty - whichever naming convention you decide to follow).

----------


## Gidde

I've been reading a book about this stuff lately (specifically The Elegant Universe by Brian Greene) and even though it's right at the edge of my capacity to understand, I'm finding it fascinating. My question is, are we to the point yet where we have a hope of detecting things like gravitons at the LHC, or is that in the future once it gets ramped up to its full capacity?

Also, I was thinking about picking up Lisa Randall's book next; are there any others out there you'd recommend for a layperson interested in string theory/m-theory?

----------


## torstan

Sorry Gidde, I let that slip. Things have been a little busy.

The LHC is not at the point where it will detect gravitons - and indeed no planned collider would be able to. Gravity is very weak, very very weak. Now the chance you produce a particle in a collision is related to the strength of its coupling. The strongly coupled matter - gluons, quarks and any new strongly coupled particle like a gluino or a squark (the supersymmetric partners) - will be produced most often. Then weakly coupled matter - like W and Z bosons - will be produced less often. As the couplings decrease, the percentage of events that will produce the relevant particle decreases. There are other factors too, but the overall production rate depends on the coupling strength in all cases. The graviton coupling is so small that you will never produce enough gravitons for them to be observed.

I'm afraid I'm a terrible person to ask about popular science books. I tend to relax with good sci-fi or other fiction. I tend not to read science books outside work. I can say that Lise Randall is a lovely person - she visits NYU a lot and uses the office 2 doors down - but I've no idea what her book is like! Sorry not to be more help.

----------


## torstan

In other news - beam is now half way around the ring and they're starting to do their final tests before getting a fully circulating beam. It should only be a matter of days (hopefully) before beam makes it all the way round once again.

At that point they'll work on getting the beam running for long periods of time, then work on increasing the energy, focusing the beam in the experiments and getting everything working towards the high energy, high density collisions that we'll need to start investigating new physics. Currently it's all going well. There will be hiccups and delays, but for now things seem to be going smoothly.

One other thing - there was a story last week about a bird and a baguette shutting down the LHC. The claim was that a baguette fell on a wire and broke the LHC. That's not quite what happened. Basically one of the substations had a power cut. This substation helped power the cryogenics that cools the sectors of the ring and keeps the magnets superconducting. The magnets warmed up a little (a degree or so) before power was restored and they were cooled again. This happens, and the machine is built to handle it. It didn't cause a delay - though if it had happened during running they'd have lost a day or so.

The reason the story became big news was that feathers and bread crumbs were found at the substation. This sparked a rumour that a bird and baguette had caused the outage. There is (sadly) no evidence that this is the case, but it made for an excellent headline.

In the meantime my collaborators at CERN are working hard. Hopefully we'll hear more from CERN soon.

----------


## Redrobes

Hey this is cool. Its a link from one of the Atlas guys which pulls together some of the status pages from the LHC which are supposed to all be public but are hard to find.

http://www.lhcportal.com/Portal/index.htm

----------


## torstan

Very nice!

Small update (garnered from the CMS facebook age  :Smile:  ) - apparently they're looking to get beam going all the way round in both directions this weekend! So all signs look good.

----------


## torstan

Protons have now gone all the way round. They're looking to stabilise the beam over the weekend.

----------


## Redrobes

Hi Torstan, I read this week of some novel quantum images being produced by a camera which was not pointing at the scene imaged but collecting photons which had somehow quantum entangled with other photons which had come from the site of the image. I don't get exactly whats going on but it is claiming that you can view stuff through thick fog like a model soldier in the lab I saw. I may be wrong but perhaps each photon contains information about the entire scene in it and that as long as you can get some photons back it does not matter which or how many, the scene can be reconstructed.

http://futurismic.com/2008/07/01/gho...antum-physics/
http://www.sciencedaily.com/releases...0612141344.htm
etc

Anyway, you said that at the energies involved with the LHC there is some non trivial probability that you may create and make detectable some extra dimensional spaces and some particles might travel through this space and some may not.

So heres my thought. What particles do photons quantum entangle with in such a way that what subset of the particle zoo might be able to come through one of these spaces and may in the future allow us to get images of what it looks like through these extra dimensional spaces - all assuming that photons themselves don't go through the spaces so that we can just look and see - because I guess we would have already seen them before.

Just say if I am a million miles from being sensible here... I just want to see through a stargate  :Smile:

----------


## torstan

Before answering that - ATLAS has seen it's first collisions! I had a very happy experimental colleague come running past my office this morning with a print out of the first event. This is amazingly good news. They weren't expecting to get collisions for another two weeks. They're still low energy - 450GeV - but the plan will be to ramp up the energy over the coming weeks. There's a meeting for the experimental collaborations here this morning so we should know more soon.

@Redrobes: Those stories are very cool. I missed those initially - thanks for the link.

The quantum entangled photons work a little differently than that. I'm not entirely sure precisely what they're doing. However the theory is that when you produce two photons in a particular manner, that they are entangled. So even though they may go to entirely different places, they're states are fundamentally linked. If one photon interacts in one way, then it will force it's partner to interact in another. So if you generate such a twin beam and point one at the thing you want to look at then you can find out information about your target by measuring the second beam - the one that's gone nowhere near the target. The photons from the first beam still need to hit the object - just as normal photons would need to. Now it has to be more complicated than that to extract any sort of image - but the fact they can do it at all is amazing.

So, for the second part of your question. Whatever you quantum entangled with would have to go through the extra dimension, so yes, standard photons wouldn't do the trick. I guess you could do the same trick with whatever particle we find that could go through the extra dimension - so say it was a heavy copy of the electron then you'd create a sample of these heavy electrons, keep one of each pair and send the other through the extra dimension. Then by measuring the state of the ones you keep you'd stand a chance of being able to extract information.

Now I'm sure that's actually a similar proposal to the black hole information paradox. I might have to go looking for that. It's possible that it wouldn't work, but I'll see what I can dig up when I have a moment.

----------


## waldronate

Hooray! Looks like somebody finally got around to doing compressed sensing with entangled photons! Or maybe I totally misunderstood.
Edit: Yep, looks like I misunderstood. When I'm wrong I like to be really wrong.

I wonder if light slowing media adversely affect the entanglement. You could emit a split stream of entangled photons that allows one branch to propagate through free space and the other to take the slow path. Measure the slow path photons at various times and you'll be able to tell something about the free-space photons. Exactly what you can tell is an interesting question.

(If you're unfamiliar with compressed sensing then http://www.compressedsensing.com/ may be of interest).

----------


## Turgenev

All I can say is, man I love this thread! Fascinating stuff. Many thanks for the continuing update torstan.

----------


## torstan

@Waldonrate: That's pretty interesting - and way outside my field. Thanks for the link.

@Turgenev: Thanks! It's really exciting to see the LHC finally starting to come together. We're still a long way from new physics data, but given the fact that this was first conceived in '83 - this is a huge milestone. It's just great to have news that things are working. Certainly exciting times ahead.

----------


## Redrobes

Thanks Torstan for keeping up to date. First collisions - wow I thought that was some weeks away...

Yeah I dont get the entangled thing at all. They were suggesting that you could see into the blast from a bomb drop by not looking through the debris but by some other means. If you have to create both photons together then surely you have to send one set into the blast zone in order to look at the other entangled one. Are they suggesting that you send it in but it never gets back out but you dont care cos you have the other one to look at... hmmm ????

I have to admit I still see the entanglement thing with the "spooky action at a distance" metaphor. Its just too spooky for me...

----------


## torstan

I don't think they were expecting them either - but they got them. See here:

http://cms.web.cern.ch/cms/Media/Ima...nts/index.html

You're looking at the middle image on the bottom row. That's a set of particles emerging from the center of the detector and being picked up by the layers of the detector. That's the first collision in CMS.

Also, you can see a press conference here (basically just covering the fact that the beam went all the way round):

http://cdsweb.cern.ch/record/1223965

@Redrobes: I think that's what they're saying, but there's subtleties in there that I didn't really look into.

----------


## torstan

Here are the images!

http://press.web.cern.ch/press/Press.../PR17.09E.html

----------


## torstan

Beam got up to 540GeV overnight. First step along the way to the (initial) operating energy of 3500 GeV.

----------


## Gidde

Thanks for the response, Torstan, been out of it for a couple weeks myself  :Smile:  I too really appreciate the updates in this thread.

----------


## torstan

@Gidde: You're welcome.

*New World Record!*
Last night the LHC became the highest energy collider in the world, having accelerated particles up to 1.18TeV, beating the current highest energy machine - Fermilab's tevatron. To put this in perspective, CERN had been saying that the beam commissioning up to these energies was going to take until Christmas, and they did it in a week. This is fantastically fast. I think everyone was expecting that we'd have glitches and hiccups along the way with such a large and complex machine but it's going wonderfully. They are now aiming to increase luminosity (density of the beams effectively) before running some callibration collisions for the detectors.

Link to the press release:
http://press.web.cern.ch/press/Press.../PR18.09E.html

----------


## Turgenev

So torstan, which one is you in the press release picture?  :Laughing: 

Congrats on the new world record. *thumbs up*

----------


## torstan

As a parasitic theorist I get to sit on the other side of the atlantic and, like the kid in the back seat of a car, ask "are we nearly there yet" to the hard working experimentalists. That's why they get to be in the pictures and all the theorists (including the whole theory division of CERN) are noticeably absent. This time is the experimentalists, specifically the beam and accelerator guys. When we start getting results, then you'll see the pics of theorists and detector guys (though still not my own mug unless I come up with something *really* good).

They've done an amazing job. Let's just hope it continues to go this well.

----------


## Redrobes

Yeah what phenomenal progress. Remind me again. Whats the energy / conditions that the Higgs should show itself and how long after that beam has collided does it take before that data ought to get processed to say just initially that its there or not there. Cos I thought about 1.2TeV was sorta ballpark for this to be the case...

----------


## torstan

The Higgs boson needs 120GeV or so of energy to be produced. Now this machine is running at 10 times that. However, the tevatron in the US has been running at 1000GeV for years and hasn't found the Higgs. That's not to say it's not there. This comes down to event rates and backgrounds.

Say you have an experiment running at one energy and you expect to see 1 Higgs event per billion events. Now you need many billions of events to be sure that you should have a few Higgs boson events in there. Now you've also got to be clear that out of all of those other events that you've got, you're not going to misdiagnose one of them as a Higgs event. Any event that can mimic the one you're looking for is called background and there are usually many more background events than signal events. So you need *lots* of Higgs events before you can say that they're certainly not part of the background. This is shown by summing together all of the events that you've found that look like a Higgs - both signal and background - and showing that your count rate is significantly above what you'd expect if it were just the background. This means you have to understand the background signals really well before you can categorically say that the excess is down to a Higgs.

Now the rates of signal and background events change depending on how you look for it. So you look in lots of different types of events. It also changes depending on the energy. At higher energies I believe that the Higgs backgrounds are better so it should be easier to spot than at the tevatron. But essentially the name of the game is to get the largest data sample so that you can say that an excess is real rather than a random statistical fluctuation. If you predict that out of 1 billion events you'd epect 5 background events and you see 6 then that's not particularly significant. However if you say that in 1 trillion events you'd expect to see 5239 events and you see 6050 events then you can say you've seen something and people can get excited.

So the name of the game is to finish building up the energy to 3500GeV and then run the concentrated beams of particles through. This will generate the large event rates we need and give us the huge number of events that we need to do these studies. It's the luminosity (number of events per second) as much as the energy that contains the real advantage of the LHC. They've not started with the luminosity challenge yet.

Once it's up and running at full luminosity then we'll be collecting yearly data samples and building up a record of all the events. It's a job of statistical analysis at that point to find signals. The more events you see, the more significant the signals are. So the machine becomes more and more sensitive to new physics the longer it runs.

The LHC is designed to be able to see the Higgs with a year or so of data at a good luminosity. It might take an extra year or so to get there, and the analysis will take a while too.

----------


## Redrobes

Ah thanks - so no news breaking story of the discovery any time soon then. That's actually quite good I think. I guess theres a whole network and super computer cluster(s) to commission now with all the new real data.

----------


## Turgenev

> As a parasitic theorist I get to sit on the other side of the atlantic and, like the kid in the back seat of a car, ask "are we nearly there yet" to the hard working experimentalists. That's why they get to be in the pictures and all the theorists (including the whole theory division of CERN) are noticeably absent. This time is the experimentalists, specifically the beam and accelerator guys. When we start getting results, then you'll see the pics of theorists and detector guys (though still not my own mug unless I come up with something *really* good).
> 
> They've done an amazing job. Let's just hope it continues to go this well.


I knew you weren't in the pic, I was just kidding around.  :Laughing:  BTW I've plugged this thread on other message boards when the talk of the LHC sprouts up. It is very helpful when you have a theoretical particle physicist around to help clear things up and put things into perspective. Keep up the great work, torstan.

----------


## Steel General

_WHOOSH!!_

That's the sound of all this Higgs Bosun talk going over my head.  :Smile:

----------


## torstan

:Smile: 

The short version is this. We're looking for a needle in a haystack. By collecting a lot of data, we're making the needle bigger. Right now the needle's so small we wouldn't know it if we sat on it.

@Redrobes: Yep. A huge Grid computing network spread around the world. They're set up to handle the eventual data rate so right now there's this enormous computing system waiting for the data flood and dealing with the trickle that they have. They're testing with this and as the data increases they should be able to sort out all the commissioning of the computing infrastructure to take the strain.

@Turgenev: Glad it's useful. I've enjoyed answering the questions, and it's been an interesting year to be running these updates. I guess the thread is a little unwieldy these days, but hopefully still useful/interesting to people.

----------


## Steel General

Even though the majority is beyond my understanding, I still find the info posted here both interesting and educational.

----------


## Juggernaut1981

> The short version is this. We're looking for a needle in a haystack. By collecting a lot of data, we're making the needle bigger. Right now the needle's so small we wouldn't know it if we sat on it.


Sure it isn't just making more haystacks with the same number of needles in each haystack and crossing-fingers that someone sees something sparkle somewhere?  :Razz: 

But yeah, I'll be curious to see if there are Higgs Bosuns... I just don't want to do the computer programming of the numerous rediculously long applied mathematical equations required to find said needles.

*Goes off to enjoy the chemistry of surfaces, surface energy and bizzarro suspensions and strange properties of common materials like concrete and coffee*

----------


## torstan

@SG Glad to hear it. If there are specific things that don't make sense then say. My plan was to keep this accessible for all.

@Juggernaut: As for the many haystacks, there's some truth in that. However if you see one glint in one haystack then no-one believes you've seen anything. If you see the same glint in 1000 haystacks then people start to believe you've seen a needle. So the significance increases with statistics.

In other news, the LHC has now got bunches travelling around the ring. These are clouds of particles that get moved around in one lump. This is how they increase the number of interactions. This is one of the big steps up from just having a guidance beam going around. They've managed to generate a few million collissions in each detector which is being used for calibration. They'll be moving the beam energy back up to 1.18TeV for collisions this week hopefully so that the experiments can get their teeth into some proper high energy collision data. So far everything is still going well!

----------


## torstan

The LHC continues to go well. They've generated lots of data with colissions at the the injection energy and have managed to get long running stable beams at 1.18TeV. Looks like it's al settling down and progressing nicely. I won't be updating too often about progress now.

In other news, here's an example of precisely why scientists should never be allowed to come up with acronyms:

Gimps from extra dimensions

What starts off as an amusing and eye catching title has the depressing habit of being found in experiment and then we all have to talk about these things at conferences with a straight face. We already discuss wino decay, stuffing branes down throats, penguin and moose diagrams (the penguin diagram was the result of an unfortunate bet and a game of darts - but that's another story). Really, people should know better...

----------


## Steel General

That's funny... and I thought working at a major telecommunications company was acronym hell.

----------


## torstan

Yep, scientists do that too. The hoops they jump through to get a new theory to have a name that they like.

Oh, and another take on CERN disasters - this one's quite funny:
http://odemo.blogaliza.org/files/2009/12/LCH-grande.png

----------


## torstan

And now we have a claim for the first ever evidence of a direct detection signal. CDMS in the Soudan mine has released evidence that they have seen two events consistent with dark matter recoiling off the target material in their detector. There's still a sizable chance that these are just chance events (23% is their number for the chance that this is nothing) so no-ones claiming an actual discovery yet - despite what all the news sources are saying. We need more time and a bit of a technical upgrade to turn that suggestion into solid evidence. But, nonetheless, it looks like we're finally drawing the curtain back.

If this is an actual signal then it rules out one of my papers. That's pretty exciting.

----------


## Turgenev

I was reading about the CDMS at the Starts With A Bang blog. Interesting stuff. I loved the CERN twitter pic! Sounds like someone has been folding space & time to peak at some of my RPG notes.  :Laughing:

----------


## moutarde

Thanks for all the updates Torstan, this entire thread has been a fabulous read  :Smile:

----------


## meleeguy

Forgive me if this is too far off topic, but I posit this thought;

If

spooky action at a distance stands
and there is evidence of non-local determinism
and action and determinism are related (I opine)

then is spooky determinism at a distance possible?

I am a computer scientist by training with a modest interest in things quantum, mainly how they interact with computer science.  Thanks for reading!

----------


## Karro

Melee guy... was that nerd poetry?

Or just peculiar science terminology?

----------


## waldronate

> Melee guy... was that nerd poetry?
> 
> Or just peculiar science terminology?


It certainly seems to have been.

----------


## meleeguy

Indeed.

It pleases me that it may be taken as such, but it is meant as a casual yet earnest inquiry.

----------


## Juggernaut1981

It's bona fide 100% techno-babble.
Although, for those of you with ovaries and nerd tendencies, this may have been close to a Geek-Sonnet.  Short of the amusing one on Think Geek which involves Roses are [colour code], Violets are [colour code].... etc, etc, etc

----------


## meleeguy

In an alternate universe, Einstein carefully prepares to remove the soles of another pair of shoes.

----------


## torstan

Apologies for the total silence - was running round to UK dodging snow storms trying to see all family in 8 days. Done and successful and back in NYC now.

Okay, let's see.

Spooky action at a distance? Well we do have this. The collapse of the wave function is instantaneous and non-local. So if you have two particles that are entangled, then if one goes from a superposition of states (say pointing up and pointing down) to just one of those states (so it's now pointing up, or pointing down, but not both) then the other immediately decides whether it's up or down and is also not in a superposition any more. This does happen instantly and has been referred to as spooky action at a distance. However we can never use this for faster than light transfer of information sadly.

Non-local determinism? What do you mean by this?

Action and determinism are related? Again, can you expand a little on what you mean by this?

Now spooky determinism at a distance is a tricky one. The fact that the only non-local processes that we believe to exist are quantum ones, and therefore fundamentally probabilistic means that determinsim at a distance is unlikely. However, as I mentioned before, there's a degree of determinism here.

Say you have a pair of electrons that are oppositely directed so that if one is up, then the other is down. Now each electron (in this example) is created in a superposition of being directed up and directed down (superposition is just a fancy word for saying that it's a bit of both).

At the start both electrons can be represented by:

(up + down)/√2

(Feel free to ignore the √2 - it's just there to keep the probability of the electron being either up or down to 1)

Now say these go off across the universe. One hits a researcher who looks at it. Now quantum mechanics says that when you look at something it can't be two things at once. It has to be one or the other. So electron 1 has to pick. Let's say it chooses to be directed up (a 50% chance in the example above).

Electron 1=Up

As soon as that happens, the other electron must be directed down.

Electron 2=Down

So with that, a deterministic event has happened, if one changes state then the other changes state in a totally deterministic way, instantly across an arbitrarily large distance. Now the initial event - the choice of electron 1 to be up or down - will always be probabilistic. However the chain of events that follows is entirely deterministic.

----------


## meleeguy

Thank you for your thoughtful reply.  It has given me much to consider, and of course, leaves me with more questions than answers.  

The heart of computational theory may be said to to be the FSM (finite state machine).  There are deterministic and non-deterministic classifications, the former having no ambiguities.  There are further two general models of FSM, Moore and Mealy, which have to do with basic operational considerations.   In general, actions are taken by the FSM based on input.  Thus, I opine there may be a relationship between action and determinism.  You can also think of an FSM as being event driven (passive), or as an input reader (active).  This last seems important, although I cannot say why.

So we cannot make a measurement and presume whether the particle is entangled (?) or not and yet the measurement may have been influenced at a distance.  Curious.  This seems to touch on the very nature of randomness, which is very hard to simulate with a computer and is often best seeded with human input in practice.

----------


## Redrobes

Since were all talking about quantum entanglement (which *was* supposed to create a provable perfect medium for quantum cryptography) I came across this which I somewhat interesting...
http://events.ccc.de/congress/2009/F...s/3576.en.html

----------


## torstan

Thanks for that RR. That's very entertaining! Nothing's perfect I guess.

In other news, the LHC will be ramping up to 3.5TeV per beam and running like this for a year or so. So we can expect lots of high quality data (and hopefully no breakages) but no spectacular discoveries of new particles unless we're really lucky. Still not impossible, just unlikely.

And Obama has completely rebuilt NASA apparently. I've not gone through all the new stuff yet, but I think killing the plan to put people back on the moon is good for science even if it's a blow for public interest in science.

----------


## Redrobes

> I think killing the plan to put people back on the moon is good for science even if it's a blow for public interest in science.


I agree. Now we know its a wasteland and we have already done it, I can see no point whatsoever in having more men jump about, planting flags and driving buggies and so on. The amount of weighty cruft required to keep people alive to get them there and back cannot be justified for such an inhospitable place and no facilities. That and it was dragging loads of budget away from the ISS and a ship to get there and back which has air, electricity, comms, water, a half working toilet, computers and about $30 billion of other gear etc.

----------


## Ascension

The thing is, I don't think that they had any real aim for going back...it was just a toss out line during a speech.  Now if they were going to put a station there as a jumping off point for Mars travel then I could get behind that.  Knowing certain factions here in the states they'd probably just stick a bunch of guns on it and say it's to protect us from solar flares so I could not get behind that.

----------


## torstan

:Smile: 

Well it did seem that the money is being refocused into technologies such as reprocessing mechanics that would allow rocket fuel to be created on the moon from local resources. So it looks like the money is going to be used for permanent structures - in the mid distant future - on the moon. It's just not going to be used to put people in those structures... The suggestion seems to be that if we are to put people in space then the private sector will be doing the R&D. Virgin Galactic suggests that might not be a crazy plan, but it does seem a little bizarre. I really don't see why all of this shouldn't be robotic.

----------


## Ascension

Yeah.  Virgin is leading the charge and has the money so if anyone else jumps in there'll be a commercial race instead of a military race.  We win and lose either way.

----------


## torstan

Yep, it's interesting. There are quite  few private companies interested in spaceflight. The X-prize is now for a full orbit I think. Not to mention private space hotel projects and private solar sail projects. It does at last feel like we're getting close to the future they predicted in the '50s.

----------


## Redrobes

Mwah hah hah hah

http://www.flickr.com/photos/skepchi...07033/sizes/o/

and in other less puerile news.... whats happening down there lately ?

----------


## torstan

That took me a few goes to spot. Oh dear. It really was only a matter of time. Was that photoshopped? I really hope so, otherwise some poor headline writer is i trouble (and I'm never going to be able to scrub that mental image out of my head). I have to say that's just done the rounds of the department here, and I'm guessing will hit our CERN collaborators sometime in the next hour. Thanks for spotting that and giving the guys on ATLAS a good laugh.

You know that somewhere there's going to be a simulated event signal for that...

The rest of the article is actually rather a good summary. Things are going well and the restart has gone smoothly. New collisions are up and the center of mass energy (total energy in each collision) is now 7TeV, which is 7 times the energy at Fermilab, the second most energetic accelerator in the world. It's also now half the design energy originally planned for the LHC. The plan is to run at this energy for the next year to 18 months and generate a large data set before an extended shut down to upgrade systems to hit the design energy. So all is going to plan and the LHC is running at the planned energy faster than (I think) anyone really expected this time round. So the news is good. Now it will go quiet as they aim to increase luminosity (the rate that interactions take place). That's the big challenge and will keep them occupied for a while.

----------


## Redrobes

> Was that photoshopped?


No but corrected quite rapidly I am informed... not fast enough for the internet tho  :Very Happy:

----------


## Rythal

most unfortunate, I cant find what is so juvenile >_<

----------


## RPMiller

Headline....

----------


## Rythal

oh lol I read right over that...  :Razz:

----------


## torstan

http://www.independent.co.uk/news/sc...e-1932744.html

----------


## Redrobes

What a shame it was not build under Westminster - I mean if it did happen to go spectacularly wrong then it wouldn't be *all* bad...   :Very Happy:

----------


## torstan

Nothing like an impending election to irritate the electorate and bring up Guy Fawkes fantasies...

----------


## torstan

So a small update. The LHC is trotting along nicely, operating at good luminosity at 7TeV. This will give everyone enough data so that graduate students around the world can graduate, but is unlikely to throw up evidence of new physics unless we are really lucky. However in other news - the Tevatron at Fermilab near Chicago has pulled a huge result out of the bag right at the time when it's about to be overtaken. They have measured a process that behaves differently for particles than for anti-particles. It's the decay of the B_S (yes really - physicists really should know better when naming things) which is a combination of a bottom quark and an anti-strange. It oscillates back and forth to a strange quark and an anti-bottom (I have to say these sorts of things with a straight face...). The decay of each should be exactly the same (up to a small deviation) but they are not. There's a 1% difference in their decays which cannot be accounted for within the standard model. This is a clear signal of physics beyond the standard model of particle physics. It was discovered by D0 at the Tevatron and we're waiting for a response from CDF (the other big detector) as to whether they see it or not.

Now you may have read that this will solve the question of why the universe is made up of matter rather than anti-matter. It doesn't. However it's certainly pointing in the right direction. It's possible that this is one of a number of such effects that occur at high energies that will tell us where all the anti-matter went. And please discount any quote given by Joe Lykken. This is not the toe of God. He should really know better than to say things like that.

----------


## Jaxilon

You know, I was accepted at University to become a Chemical Engineer but went into Computer Science instead. Today I do something else entirely and run my own business but it is times like this where I wonder if I might understand what you were talking about if I had remained on that Chemical Engineering path. LOL

I will also admit I fell off this thread some time back so maybe if I was to read it all the way through I might follow at this point. Still it is funny some of the names that get chosen. I mean I see a lot of people who could use some anti-bottom, ROFL

----------


## torstan

:Smile:  It's worse in Europe as they name those quarks truth and beauty rather than top and bottom. So in that case it would be a discovery about anti-beauty...

I try to keep things relatively self contained so I don't think there's much earlier in the thread that covers this stuff. I was typing that up quickly earlier this morning more in a response to the news stories than a self contained explanation. I'll see what I can do to remedy that here.

Basically we have a problem. In the early universe we have a lot of energy. That energy is converted to matter through pair production. So a photon (a bit of light) creates one electron and one positron (antimatter electron). The fact that we produce both together evens up the book-keeping and allows for a conservation of the number of electrons. Before the event we have 0 electrons. After the event we have 1+(-1)=0 electrons. So the total number of electrons is conserved.

This has been tested and seen to be true. It's why the LEP collier at CERN collided electrons and positrons, because they would annihilate to pure energy which would then go on to create other stuff. So we know that if we have equal amounts of matter and antimatter we create pure energy and if we have pure energy we can create matter and antimatter.

Now in the early universe we believe that we had a lot of energy that created lots of matter and anit-matter pairs, that then annihilated to energy and so on. If you averaged over the whole content of the universe, all the matter and antimatter even out and the total matter content of the universe would be zero. Obviously that's not the case because we have rather a lot of matter and we don't have a lot of antimatter. So the question is - where did all the antimatter go?

It could just be somewhere else - say our galaxy is made of matter, and another galaxy is made of antimatter? Well that's possible, but you'd have to explain why it all went over there in a great lump. Also, galaxies collide and if a galaxy made of antimatter collided with a galaxy made of matter they would annihilate spectacularly. We see an awful lot of galaxies and a pretty large number of galaxy coliisions and mergers and we've never seen anything that would suggest the existence of antimatter galaxies.

So we have to accept that it really did go away. For it to go away, there must be a flaw in our logic earlier on. There must be something that breaks the symmetry between matter and anti-matter. Now the Tevatron has observed an effect in which B_S mesons decay differently from their antimatter partners so we've seen a violation of that symmetry. It is not in itself large enough to account for the fact that all we see is matter and not antimatter - but it's likely to be the first breadcrumb in a series of clues that leads us to the answer.

As the Tevatron is a lower energy machine to the LHC, anything the Tevatron sees will be visible at the LHC. So we should learn a lot more about it in the next few years and actually get to the heart of the matter/anti-matter asymmetry.

Does that help? Let me know which bits are mystifying (including all of it!) and I'll step back and add in some more explanation.

----------


## Jaxilon

Let's see - Just as E=MC^2,  Energy can become Matter and Antimatter and vice versa. If that' right then I got most of what you said.

The issue as you describe it seems to be that We have lots of Matter we can account for but not an equal amount of Anti-matter? The new findings may show an inconsistency in the math being equal between Matter and Anti-matter and they are now working on that.

If that's pretty much what you said then I am with ya  :Smile:

----------


## torstan

You got it 100%. Good stuff.

Interestingly the maths that would let you solve this inconsistency usually predicts the existence of new particles that we should be able to produce at the LHC. So this is good news for new physics searches.

----------


## torstan

Now I've been a little quiet recently - and this is the reason:

http://uk.arxiv.org/abs/1005.4668

It's an explanation of the observed excess in positrons (anti-electrons) in terms of the magnetic field of the solar system. There are >100 papers on explanations of this effect in terms of annihilating particles of dark matter or in terms of pulsars (rotating neutron stars). This is a totally novel prediction that's testable in a few years and would rule out a slew of papers that claim it's dark matter. And it only uses high school physics  :Smile:  I'm now battening down the hatches and waiting for the storm of objections...

Anyway, normal service will be resumed shortly.

----------


## Steel General

Get 'em Torstan!!  :Very Happy:

----------


## torstan

Thanks  :Smile:  So far one invitation to talk at a conference and no angry emails telling me why it's rubbish. I'll take those numbers.

----------


## Jaxilon

Well, when you bandy words like "heliospheric modulation" around who's going to argue? LOL

So let me see if I get this: You said earlier that from what we know so far about our Universe there is an excess of matter over anti-matter. I take it you are hunting for the anti-matter and have found a excess measurement of it in the solar storms around our Sun. It looks like (or you theorize) there is more anti-matter as the storms increase. This is what "heliospheric modulation" is, the fluctuations in the solar storms around the sun. Do I follow? These are words that I don't use in my everyday life  :Smile: 

Whatever you do, I hope that when you give this lecture you pop out a map of the sun complete with cities and so on to totally blow their minds!!! ROFL

----------


## torstan

So the main points are the following: there's a satellite called PAMELA that was sent up to look for antimatter. The antimatter up there comes from cosmic rays - basically particles that have been accelerated to high energies by exploding stars, rotating neutron stars or spat out of the accretion disks of black holes. So lots of exotic sources, but the end result is that we see high energy particles streaking past earth. Now we have a really good understanding of how all those particles are accelerated so we have a good idea of the number of particles that you'd expect to see. PAMELA saw many more anti-electrons than we expected, and this excess is more pronounced for higher energy particles. That's really surprising, and very hard to fit with conventional ideas of where the cosmic rays come from.

Two ideas were put forward to explain this. The first wasthat there were more rotating neutron stars nearby than we expected (neutron stars don't burn so they are dark and easy to miss with telescopes). However they would still have to non-standard and there would be other hints that they were there and those hints haven't conclusively turned up in the data - so the jury is out. The second idea is that the dark matter than we know exists around the galaxy is annihilating. Now if two particles annihilate they produce energy equal to E=mc^2 where m is their total mass. From that energy you can create lighter particles with lots of kinetic energy, so you could produce an electron and a positron, both carrying a lot of kinetic energy (going very fast). This would give you a large number of high energy positrons and electrons, and can explain the positron excess. However you'd expect to see other products of this annihilation - anti-protons for example. And there's no excess of antiprotons. That's lead to some truly weird and wonderful theories of dark matter where it annihilates through a new fundamental force, or through a mirror world or any number of other ideas.

I've jsut proposed a third solution. The solar system has a magnetic field caused by the solar wind. This stretches out into space 80 times further than the earth is from the sun. Magnetic fields bend different charges of particles in different directions. All I've pointed out is that this acts as a barrier for electrons that try to get to the center of the soalr system, whilst allowing anti-electrons to make it in. So it is the sun, and the solar system magnetic field, that causes there to be more anti-electrons at earth. This will swap over when the magnetic field of the sun flips over in a few years and we should see the opposite - more electrons than positrons. So it's testable and predictive and doesn't involve any new physics. It also rules out two years of frantic theorising about dark matter if it's right - so it's a pretty big deal.

----------


## Jaxilon

Awesome - Sort of reminds me of the fusion engine at the core of the earth. They believe it flips every so many years.

----------


## Scotia

This thread has been really interesting to read, particularly since I've been following a lot of this stuff for a couple of decades. It makes me lament all the time wasted on my education in my youth since 99% of what I learned is now considered outdated (or just plain wrong).

One question...well...multiple questions lumped into one:

Do galaxies generate a galactic equivalent of solar wind...a sort of halo of charged particles as a conglomerate of all of its stars? Or do the charged particles lose their charge (or decay into something else?) that limits the effective range of this shielding effect? Or would it be a case that on average 50% of a galaxy's stars would be throwing out positively charged ions while the other 50% would be spewing negatively charged ions so on a galactic scale they'd cancel one another out?

----------


## RPMiller

I think I found one of Torstan's papers: http://abstrusegoose.com/238

 :Wink:

----------


## torstan

:Smile:  That's a low down, dirty, and excellent idea.

As for the question of the galactic wind - I believe they do. I'm not an expert on that, but it does seem to be the case that there's an overall wind of charged particles throughout the galaxy. Now they'll be both electrons and protons as all stars emit both. In general that means that the overall galaxy is still neutral, however at the particle level the wind is charged. So yo have a movement of charged particles. You also have an overall magnetic field in the galaxy - so charged particles that come into the galaxy from elsewhere are deflected by the magnetic field and don't travel in straight lines. Initially it was thought that the galaxy has a very disordered magnetic field, but more recently evidence has been emerging that the galaxy might have quite a structured magnetic field on large scales. This means we might be able to see a very high energy cosmic ray hit earth (that must come from something outside out galaxy) and track it back, plotting the expected bend from it's passage through the magnetic field and figure out where it came from.

So yes, there is a galactic equivalent of the solar wind. There's certainly an interstellar medium of charged particles and the solar system plows through it with a bow shock as our solar wind hits the interstellar galactic wind (just like a boat forging through a lake). There's also a large scale galactic magnetic field that is intimately connected to the galactic wind. This affects all charged particles to travel through the galaxy, making it hard (but not impossible) to track a charged particle that hits earth back to its origin.

@Jaxilon: You're right that people believe the earth's magnetic field flips over time. The field is caused by the spinning iron core of the earth. Apparently that changes over time which causes the poles of the earth to wander. However there's certainly no fusion at the core of the earth. If there were then we would be a star.

----------


## RPMiller

> However there's certainly no fusion at the core of the earth. If there were then we would be a star.


And I'm pretty sure that would be a Very Bad Thing...  :Laughing:

----------


## Scotia

Thanks for the answer.

Another thing that has me somewhat confused based on the discussion earlier in the thread...

If I understood what you said earlier correctly, dark matter is its own anti-matter and will annihilate when it comes in contact with itself. There's also speculated to be rather a lot of it kicking around -- in the order of 5x the mass of all other particles in the universe -- with most of it nicely clumped along with the visible structures (galaxies and galaxy clusters). I think you mentioned that it's neutrally charged (so presumably it doesn't repel itself) but gravitationally active/attractive (hence Einstein lensing techniques can be used to get an idea of its shape and distribution). Assuming I've got all that right...wouldn't these massive clusters of dark matter have a tendency to destroy themselves over time? I realize that space is unimaginably vast and even this massive amount of dark matter is a drop in the bucket compared to space's emptiness; but one would think that if all of the universe's other (visible) structures have been able to form in the 14 billion years since the big bang, surely dark matter would have been able to do much the same. How is it possible that there's still so much of it kicking around? Does that imply that the early universe had a much, much greater amount of dark matter and it's gradually been whittling itself down to the current 5% figure (and spitting out lots of non-dark-matter particles in the process, thus providing more stuff to make visible structures with)? It just seems a little counter-intuitive for there to be so much of it collected into galactic halos when one would expect that clumping to result in its destruction.

----------


## Juggernaut1981

Usual options for "Why something sticks around..."

#1 Entropy likes it.  Those things with the least energy and the most chaos tend to stick around for the longest.

#2 Maybe we don't know everything about it.  Potentially Dark Matter is smashing with (anti-) Dark Matter and popping, then making more, then popping, then making more... and so on...

#3 Maybe a big pile of other matter becomes Dark Matter... and Dark Matter can become 'normal' matter.

#4 Option 4: Physicist have no clue, not even the sniff of a clue and have their fingers crossed that something really awesome and strange happens.  Cause the stranger it is, the more PhDs you can get AND the more you're likely to actually learn about the stuff.

----------


## Juggernaut1981

> Awesome - Sort of reminds me of the fusion engine at the core of the earth. They believe it flips every so many years.


Also, and I'm sure PLENTY of Scientists have made this jump too... the nice big spinning bar magnet (iron core) to our planet will waggle around chaotically because of the fluxing of the Sun's Magnetic Field.  So as it flips every X years, it probably causes the iron core to go a little off-kilter (just think... HUGE magnet a moderate distance from a weak magnet is likely to do SOMETHING noticable... considering we find new planets and moons by measuring disturbances in orbits using some really shiney energy-based mathematics... [voice=sexy and drooly] mmmm Langrangian Dynamics... Calculus... partial differentials...[/voice])

But no fusion engine.  Fusion requires the kind of heat that outside a really well built laboratory would result in the melting of half the planet... just before it gets sucked in and crushed.

----------


## Jaxilon

> @Jaxilon: You're right that people believe the earth's magnetic field flips over time. The field is caused by the spinning iron core of the earth. Apparently that changes over time which causes the poles of the earth to wander. However there's certainly no fusion at the core of the earth. If there were then we would be a star.


Yeah, now that you point it out that doesn't make sense. I guess I got my wires crossed on what was going on in the center of the earth and what goes on in stars. Too much Discovery channel as I'm falling asleep at night most likely.  :Smile:

----------


## torstan

:Smile:  No problem at all.

@Scotia: There are two things at work. First is the question of how much is in any one place - essentially how dense the cloud of dark matter is. Now we mostly have great big lumps of ordinary matter separated by large tracts of empty space. Dark matter is spread over a much larger volume and much more evenly, so there's never any concentrations as large as we have for ordinary matter. If our ordinary matter were spread out in the same way, the chances of two particle hitting would be relatively. The dark matter also extends way out into the space far from a galaxy so the volume it occupies is much lower.

The second factor is the interaction strength of the force that causes the interaction between two particles to occur. So if you throw together two particles that interact via the strong force then they are more likely to interact than two particles that interact through electromagnetism. So in that example, even if you have the same amounts of both stuff the strongly interacting particles will interact more than the weakly interacting stuff. In the case of dark matter, we know it's very weakly interacting. Therefore you can have a reasonably high density of it and the chances of one particle sailing right by another are quite high. Indeed we see this in space. There were two galaxy clusters that collided. The normal matter (mostly hydrogen gas) interacted and slowed down - you can see the shock waves from the interaction. However the overall mass of the galaxy clusters was still in two roughly spherical blobs way out in front of the gas. So the two dark matter halos basically passed right through each other. This restricts the strength of the interaction that causes the particles to interact. It has to be very weak.

This is also the reason that the dark matter is still in big spherical halos. Normal matter tends to bounce around and interact. That means that it loses energy through colissions and moves closer to the mass that it's orbiting - normally the center of the galaxy, or the local solar system, or the local proto-planet. As it loses more and more energy it falls towards the local gravitating object and sticks to it. Thus it goes from a big cloud to individual clumps. As the dark matter doesn't lose energy through interactions (much) it doesn't go from clouds to clumps in this way and stays very diffuse.

These two things mean that even though it can interact and annihilate, it does so very rarely. The PAMELA satellite was very exciting because it might have been evidence that it interacts more than we thought, but if I'm right then it's not dark matter, and we can leave that evidence to one side.

As for the change over time - we see the evidence for dark matter in the very earliest light we can observe from the big bang and it's there in about the same amount as we see today, so we expect that there's a roughly constant (though possibly lightly decreasing) amount of dark matter through the universe's history.

Let me know if that makes sense? I can go into more detail if you're interested. But it's not entropy, or an exchange process, or the fact that we have no clue. We've got a very good idea what it is. We also have a very good idea about the spinning iron core of the earth and the earth's magnetic field, but that's another story (and one I'm not an expert on).

----------


## torstan

Actually there's an interesting detail that is relevant. I'll post a bit more on it in a second. Have to marinade chicken for dinner first.

Edit: Done.

Okay, so there's an interesting chapter in the dark matter annihilation story. In the very early universe you can have two particles of normal matter annihilating and producing two particles of dark matter. Because the energies of the particles in the early universe are really high, the fact that the dark matter is much heavier is irrelevant. Basically E >> 2mc^2 (where m here is the mass of the dark matter particles). So you can create them from scratch with no difficulty. Equally, the universe is hot and dense enough that dark matter particles annihilate regularly - into normal matter. So you end up with an equilibrium with matter and dark matter sloshing back and forth quite happily. Now cycle forward a little. The universe is cooling down and expanding. This means that the energy in a collision of two particles is getting pretty small. At some point it's too small for two particles of matter to annihilate into two dark matter particles: E < 2mc^2. So you don't get anything going from matter to dark matter. However you do still get dark matter going to matter. Particles collide and annihilate and your dark matter numbers go down fast. This continues as the universe continues to expand and cool. At some point the universe expands so far that the density of dark matter drops to a point where it's really unlikely for a dark matter particle to hit another dark matter particle - this is called freeze out. At that point you sit back and call it done. However much you're left with is now the amount of dark matter in the universe today.

Now you're going to call foul because if you start off with roughly equal amounts of normal matter and dark matter at equilibrium and then allow for the dark matter to annihilate that means there's less dark matter today than normal matter. You're right, and this does not contradict the statement that normal matter makes up only 20% of the mass of the universe where dark matter makes up 80%. The difference is that dark matter is much, much heavier. So for normal matter we can say that the heaviest stable particle is the up or down quark at roughly a third of the proton mass. In contrast, the dark matter is expected to be around 300 times heavier at least. Now remember that a lot of the matter we were talking about earlier is in electrons (1/2000 th of the proton mass) so if you really add up the normal matter, it's not too surprising that there's less mass of it than in the dark matter.

The large mass of an individual particle also means that there's a lower number of dark matter particles in a galaxy than normal matter, (about 1 per 10 cm cube at earth). With that low density, it's not too surprising that they don't annihilate. In fact it's a lot more surprising that they do - hence the surprise from the PAMELA results.

As for the earth's core - I was thinking about it. The average magnetic field from the sun at earth is about a micro-Gauss. This is really weak - note that it doesn't move a nail on the table or cause any noticeable change in the earth's magnetic field (about 10,000 times stronger). As it doesn't affect small magnetised objects, I'd expect it to have very little effect on a magnet the size of the earth's core. Also, the direction of the field from the sun that we feel changes every 27 days so the average magnetic field is really much weaker. However the time it takes is hundreds of thousands of years and there seems to be no clear consensus on the cause so I can't say that the solar magnetic field has no effect, just that due to the numbers the chance is very very small that it does.

----------


## Juggernaut1981

> Let me know if that makes sense? I can go into more detail if you're interested. But it's not entropy, or an exchange process, or the fact that we have no clue. We've got a very good idea what it is. We also have a very good idea about the spinning iron core of the earth and the earth's magnetic field, but that's another story (and one I'm not an expert on).


That's okay Torstan, my sub-atomic physics isn't particularly strong at the best of times.  I did mostly theoretical chemistry and anything smaller than an electron is ignored and treated as "one of those irritating physics things".  So I may be throwing too much "micro-scale" physics into something that is on a significantly smaller scale.

----------


## torstan

Ah, that makes a lot of sense. I can see why entropy and transfer processes were the first things to spring to mind then. In the second of the posts above you'll see that when you come to the earl universe - you were dead right. The equilibrium is indeed due to dark matter turning into stuff that then turns back into dark matter. It's just the current state of affairs that is somewhat different.

----------


## Scotia

@torstan: Thanks for the great explanation...that makes perfect sense.

----------


## torstan

I'm glad that it made sense. It's a pretty fast moving field so that (standard) view might well be blown out of the water in a year or two.

----------


## RobA

> It's a pretty fast moving field


ba-dum tish!

-Rob A>

----------


## torstan

Groan... That was an entirely unintentional pun  :Smile:

----------


## Juggernaut1981

Well lets just hope it remains so and doesn't become a static field, because in the right frame of reference it would just be an ignorable constant...

----------


## cfds

Funnily enough "ignorable constant" fields are a great problem in the attempts to unify gravity and QFT since gravitiy "sees" absolute masses/energies.

----------


## torstan

I missed this April fool when it went round, but it's just done the rounds of our office. Pretty funny:
http://crave.cnet.co.uk/gadgets/man-...ture-49305387/

In other news - the LHC continues nicely and apparently now has enough data to 'discover' the top quark, a process that took the previous accelerator many years to achieve. So all looks on track so far. Latest estimates seem to be one more year at the current energy before an extended shut down before restarting at full energy.

----------


## tilt

yep.. thats it - cut through the bureaucracy and go straight to the top quark *lol* ... fun aprils fool  :Smile:   .. and by the way, Holger Bech is always interesting to watch, in addition to talking a bit funny - he is very enthusiatic  :Smile:

----------


## torstan

It's been a while since this thread was active, but there are some interesting murmerings that the LHC might have the first indications of a Higgs boson:
http://www.guardian.co.uk/science/li.../2011/apr/24/1

That's a good article, because it clearly states just how early this is in the process. However, even a murmur is exciting. Interesting times indeed.

----------


## Redrobes

Did that murmur ever increase in volume to a balls out announcement of the Higgs ? According to this recently, its been officially announced that with 95% probability, there is NO Higgs !

http://blogs.scientificamerican.com/...ysics-history/

Drastic stuff. So whats been going on in the last 4 months ? I thought that there was a blip of probability in one energy band and that it just needed more data to increase the certainly. Now it seems to have gone completely the other way. Whats the inside track on this ? And with no Higgs what does that mean in general and for your theories ?

The general media reporting about the state of affairs at LHC is really confused.

----------


## Ascension

Heck, I don't hear anything about it here in the states.  It's all politics and disasters.

----------


## Redrobes

Complete aside but if Torstan gets to see this pic from the beeb:

http://www.bbc.co.uk/news/in-pictures-14745576

Doesn't the lightning bolt in this image seem odd. Why doesn't it ground itself through the iron work ? How can it come back out of the structure ? Why doesnt the strike hit the lighning conductor on the top of the tower. All looks odd to me.

----------


## Ascension

Maybe the lightning bolt is actually miles away from the tower; just looks like it's enmeshed within it.

----------


## torstan

On the lightning - my guess is that it's a good distance behind the tower - otherwise you're right, it should go through the tower itself.

On the Higgs. It's not ruled out. I'm having a look through that article now.

First off - Peter Higgs is English, he's just based in Edinburgh. That doesn't bode well for the accuracy of the article...

----------


## torstan

Ah, okay. Thats a misleading article. The range that contains the 95% claim that it's not there is >145GeV. The Standard Model wouldn't want a Higgs that heavy anyway, and models of physics beyond the standard model would prefer a Higgs closer to 115GeV. There have been some hints around 140 GeV that look promising - but we need to wait for more statistics to be sure. They'll know for sure within 6 months. My guess at this point - including whispers aroud the department - is that we'll see a Higgs around 140, which is too heavy for the Standard Model (pretty much) and much too heavy for minimal Supersymmetry. That rules out my two of my thesis papers but points to a non-supersymmetric solution to a couple of long standing problems - or a non minimal version of supersymmetry with a few more particles in it.

There are good reasons to expect that a non-minimal version of supersymmetry is the answer and finally it looks like we're getting the data to allow us to actually explore that. Terms about to restart, which means we're about to start internal seminars again. Higgs hunting will be high on the agenda, so if I hear anything (that I'm allowed to repeat) I'll post about it here. The LHC is certainly pulling its weight. It now has half as much data as the tevatron accumulated in its entire lifetime - and they've managed that in 6 months. There's a lot of stuff to come from this in the next 6 months.

----------


## Redrobes

Thanks Torstan, I shall roll back my state machine to the time when there is a few blips of probability and it needs more data to be sure.

There was a good program on the telly a few weeks back about the LHC etc with Prof Cox and he held up a sheet of paper with the standard model equations written on it. Since I had never seen it written down I was quite surprised to see how big it is. Almost all of the equations I know of can be described in a few words roughly what they are talking about. This one seems like a series of terms which summed up make up the standard model. Are all of these terms different things - like the G, the m, and r^2 in gravity or is it a series of different parts of the same kind of thing, like a equation matrix multiply. Basically why is it so large ? I have trawled the web and no web sites list the standard model in this way. Maybe it was written in a longhand form. The best I came up with is this article about a mug...

http://www.quantumdiaries.org/2011/0...a-factor-of-2/

Even tho they say its wrong they do give some clues about the origins of some of the terms.

----------


## jfrazierjr

> Ah, okay. Thats a misleading article. The range that contains the 95% claim that it's not there is >145GeV. The Standard Model wouldn't want a Higgs that heavy anyway, and models of physics beyond the standard model would prefer a Higgs closer to 115GeV. There have been some hints around 140 GeV that look promising - but we need to wait for more statistics to be sure. They'll know for sure within 6 months. My guess at this point - including whispers aroud the department - is that we'll see a Higgs around 140, which is too heavy for the Standard Model (pretty much) and much too heavy for minimal Supersymmetry. That rules out my two of my thesis papers but points to a non-supersymmetric solution to a couple of long standing problems - or a non minimal version of supersymmetry with a few more particles in it.
> 
> There are good reasons to expect that a non-minimal version of supersymmetry is the answer and finally it looks like we're getting the data to allow us to actually explore that. Terms about to restart, which means we're about to start internal seminars again. Higgs hunting will be high on the agenda, so if I hear anything (that I'm allowed to repeat) I'll post about it here. The LHC is certainly pulling its weight. It now has half as much data as the tevatron accumulated in its entire lifetime - and they've managed that in 6 months. There's a lot of stuff to come from this in the next 6 months.


blahdy blah... to many big science words.... just tell me if you guys are still gonna make a black hole that will destroy the planet... especially useful would be the exact date so I can make one of those big poster board signs... I still think it's gonna be Dec 21 of next year just like the Mayan's predicated..

----------


## tilt

destroy the planet, time to max out the credit cards then  :Wink:

----------


## torstan

The LHC won't be destroying the world. At least not until it's upgraded to its design energy sometime in the next 18 months to 2 years.  :Smile: 

The mug is correct (with the debatable exception of the h.c. term). The Lagrangian on the mug details all the interactions between the different types of particles. In this case each 'letter' in the equation is actually a vector or a matrix. So there's a lot of connections encoded into those letters, which is how they can hold the details for every different type of interaction in them.

I'd be interested to see the 'longhand' version you saw. There are certainly ways of writing it out a lot more explicitly than it's done on the mug. For example, the second line on the mug includes this part:

This details the interactions of the fermions (electrons, quarks, muons etc) with the carriers of the electroweak force (photons, W bosons, Z bosons). In the mug's version most of this is hidden in the definition of D-slash in the middle. As mos of the things in the equation above are also matrices, you can see that writing out every term in that equation would quickly get enormous - which is why vectors and matrices are so important and useful.

----------


## Ascension

It's all Greek to me, heh heh.

----------


## waldronate

> It's all Greek to me, heh heh.


There are some Arabic numerals in there as well as a touch of Latin...

----------


## torstan

A quick note on some interesting results appearing in the news today:

The OPERA experiment may have observed neutrinos going faster than the speed of light. They've seen them arrive 60ns (+/-10ns) earlier than they would have at the speed of light. That variation is on an expected time of 2.4ms or so. So it's a variation of 2 billionths. They claim enough statistics and error control to be looking for cross-checks and ideally independent verification.

Here's the AP story - it's a lot better than the BBC one this time round.
http://hosted.ap.org/dynamic/stories...MPLATE=DEFAULT

The comment from John Ellis about the neutrinos from the 1987 supernova are particularly worth noticing. A quick estimate says that if the same phenomena were true for those neutrinos then the neutrinos would have arrived 1/3 of a year before the light (the neutrinos were actually detected 3 hours before the light - for well understood reasons). The neutrinos in that case will have had different energies, but it's a good cross-check that will have to be explained.

Here's a quote from the spokesperson for the OPERA collaboration:
"we are not claiming things, we want just to be helped by the community in understanding our crazy result - because it is crazy" - from the BBC article.

So they are *not* claiming a result yet. Exciting times - and it would be amazing if this were true.

----------


## Ascension

One question I don't know the answer to since I'm not in the physics field (and did poorly in it in college 23 years ago), do neutrinos have mass?

----------


## torstan

23 years ago the answer would have been - we don't know. Now we can say they do, but it's incredibly small - less than 1 billionth of the proton mass. But yes, they shouldn't be able to go at the speed of light, let alone over it.

----------


## ravells

Just spotted on boing boing an article which says they've found particles which can travel FTL?

----------


## torstan

See three posts up  :Smile:

----------


## Djekspek

Hmm, I always found Einsteins statement that the best prove that back-in-time-travel is impossible, is the fact that we haven't met anyone from the future yet... (it was him right?) But hey, I'm no expert on this stuff (tried to read Hawkins' books, but this theoretical stuff is way beyond me). So, if this proves right, would this mean that we can actually travel back in time...?

----------


## torstan

Well as soon as you break the nothing faster than light limit most of relativity is called into question - so any theorems about not travelling back in time derived from it are pretty much up in the air. I'd say if this comes out true then all bets are off.

----------


## Redrobes

Whilst 60nS in 2.4mS is tiny, 60nS is quite a lot as an absolute value. Its like something that at a real push I might be able to make a rough timing of with some home brew circuits on the bench. Heck, a GPS can do 10x that accuracy. I.e. its not like people with a large physics lab could be mistaken by that amount. That's like light being there 60ft closer than it should have been. It will indeed be interesting to see what they find out as being the cause of this.

So I just want to check here. How do they know at the detector when the emitter sent them ? Would they use radio to transmit the sync pulse and assume that the radio pulse goes at c ?

I guess if it were easy it would be a good idea to do the same test halfway across the gap at the same time.

FTL - in my lifetime. No way man !!! Don't we need to get chummy with Vulcans or something for that ???

----------


## cantab

> Hmm, I always found Einsteins statement that the best prove that back-in-time-travel is impossible, is the fact that we haven't met anyone from the future yet... (it was him right?)


The counter-argument is that a time machine can't take you back to before it was built.

There is in fact previous theory suggesting neutrinos could be tachyons - faster-than-light particles. Google tachyon neutrino and you should find a couple of papers. The existence of tachyons might *not* contradict General Relativity.

----------


## torstan

@Redrobes - my guess is synchronised atomic clocks at both locations so they can compare readings at both places.

The likely next step is for Fermilab to reproduce the experiment and see if they can replicate the results.

And the 60ns is +/- 10ns so that gives you an idea of the difficulty there. The size of the error is not in the measuring apparatus, but I'm guessing it comes from the fact that you're measuring a bunch of neutrinos rather than a single one. It's hard to find neutrinos so you need a bunch. It's also hard to make just one, so you get a set of them. Now a bunch has a size and you're never going to pick just one out of there.  So the length of the bunch will relate to the error on the arrival time measurement.

@cantab Yep there's nothing wrong with things going faster than the speed of light. Tachyons are totally legit. But we can't make them and send messages with them - or certainly not until now. The hard and fast law is that you can't go from over the speed of light to under the speed of light. You're on one side or the other. Now neutrinos are massive particles but are so light they go close to the speed of light. Measuring exactly how fast is tricky. The supernova measurement was a good check that they actually travel at almost exactly the speed of light. But yes, tachyons would be a good first go-to as it leaves relativity intact.

----------


## torstan

And the paper's up: http://arxiv.org/abs/1109.4897

Love the free access physics arxiv. The conclusion's worth a read:



> Despite the large significance of the measurement reported here and the stability of the analysis, the potentially great impact of the result motivates the continuation of our studies in order to investigate possible still unknown systematic effects that could explain the observed anomaly. We deliberately do not attempt any theoretical or phenomenological interpretation of the results.

----------


## ravells

Can I commission you to build a warp drive for me please Torstan? It'll be much more fun than making maps!  :Smile:

----------


## Steel General

> Love the free access physics arxiv. The conclusion's worth a read:


I think I hurt my brain trying to read that...  :Razz:

----------


## Jaxilon

I'm not a Physicist nor do I play one on TV. I'm just happy if I can grasp the concepts. 

I have not read the paper linked above because I was afraid I wouldn't know what I was reading. I then hit this news article on the BBC website and now that I think I have a clue what is being talked about I want to read the paper Torstan linked as soon as I get a chance. I don't know if the news article is dumbed down but I figure it might help ease someone else into this if they are tentative about trying to read a paper written for the Physics experts.

----------


## cantab

I wonder, could the problem be in calculating the time taken by _light_ to arrive? Specifically, how much variation could the mass of the Alps, and the distribution within it, cause?

----------


## bartmoss

There was a 2h news conference on the subject that ended an hour ago, did anybody watch it? I only caught a few minutes as I was still at work.




> And the paper's up: http://arxiv.org/abs/1109.4897
> 
> Love the free access physics arxiv. The conclusion's worth a read:


That didn't stop any of the news sites...  :Wink:

----------


## torstan

@cantab - nope, the speed of light that comes into the equation here is the absolute speed of light in a vacuum - not one modified by passage through matter. That being said, if there were a non-trivial effect in the synchronisation of the GPS time synhronisation that could do it. But they've done all the obvious checks - and a whole host of non-trivial checks - to make sure that's not the case.

The other thing that could cause it is that they might have got the distance wrong. They're calculating the speed of the neutrinos using:
speed=distance/time
So at the basic level you need to make sure you've not screwed up the time calculation, or the distance measurement. Now this is a hard problem. You need to make sure you have two clocks at the start and finish that tiem the emission and arrival of neutrinos to within nano-seconds. For context - we couldn't even detect neutrinos untel then end of the last century, let alone time their transit times. Also, gravity affects the speed that clocks tick, so you need to make damn sure your clocks and your GPS satellite all take that into account properly.

Now for the distance - you need to know the distance from CERN to Gran Sasso to within 20cm. That's a pretty small error on a 730km distance measurement, especially when one end of it is under a mountain. Things that have to be accounted for are continental drift, earthquakes and the tidal forces of the moon on the earth's crust. They claim they've got all that under control - which is a mind blowing feat in and of itself.

With all that taken into account they've got the neutrinos getting from A to B faster than it would be possible to send light across the same distance in a vacuum.

----------


## RPMiller

What if, and this is a really out there idea, a micro black hole _was_ actually created along the path that the neutrinos were passing and they were unable to detect it for some reason. Would it be possible for the black hole to suck in the neutrinos and spit them out a given distance away, but in a shorter time span? Essentially, a miniature wormhole being created. Like I said, probably total science fiction, but hey, you never know.

----------


## cantab

> @cantab - nope, the speed of light that comes into the equation here is the absolute speed of light in a vacuum - not one modified by passage through matter.


It's not passage through matter I'm on about, but passage through the _gravitational field_ of that matter - and the fact we don't know that gravitational field precisely (since we don't know exactly what density of rocks are where underground). I don't know enough GR to actually calculate the difference it could make.

RPMiller: The measurements have been aggregated over two or three years. A micro black hole isn't sticking around for that long.

----------


## bartmoss

Some sort of tunneling effect? Gief stutterwarp drives!

----------


## RPMiller

> RPMiller: The measurements have been aggregated over two or three years. A micro black hole isn't sticking around for that long.


It wouldn't have to. Just long enough to affect the passage of the neutrinos during the test, and if the holes were popping up en mass and then collapsing, it would be even more likely. But as I said, wild speculation and science fiction.

----------


## torstan

@cantab - the variation of the gravitational field over their travel distance is negligible in this case. The gravity is dominated by the mass of the earth, and that's going to be more or less identical along the path of their journey.

@RPMiller - actually a variation of that is already being suggested. One proposal is that there's an extra dimension that neutrinos of this energy can access that allows them to shortcut the distance. So they aren't travelling faster than light in our 3D universe and relativity remains unbroken. However this is wild speculation. The overwhelming odds are that this is an experimental error with something like the synchronisation.

----------


## RPMiller

That would make a whole lot more sense, and is far more conducive that to err is indeed human.  :Smile:

----------


## Redrobes

I don't think that measuring the position of the point above the mountain to an accuracy of 20cm is much of a problem. In the UK you can measure positions with a pro GPS (not our lacky hand held jobs) using differential readings from the standard reference points to about 1mm. You can even do this yourselves with a handheld GPS and download the differential offsets from the Ordnance Survey website in the UK. It would be more accurate than the 5m or so the hand helds have - probably something like 0.5m but I am assured that the pro versions time to a much higher accuracy. Some mapping agency in France/Swiss must have the same set of reference points and differential GPS receivers to do this.

So then you have to know the position of the detectors relative to a reference point on the mountain surface. Well again, given that this is a smaller distance to cover then you can do that pretty accurately now with the modern theodolites. So I would think that its not out of the realms of possibility that you could know these distances to a significant accuracy if you trust the measuring tools. The thing is, most of these measuring tools now use c as a constant in the calculations.

A pair of synced atomic clocks would have an accuracy higher than that needed to get to nano second measurements. I would be pretty sure you could do the radio pulse thing too and account for the positions of the radio emitter and detector relative to the particle detectors. I thought it was possible to sync atomic clocks at a distance if you know their position. Presumably this must go on all the time between all the time standardization agencies. Given that you should be able to see 10 or 12 GPS satellites at once and they all radio in the time stamp and they have to do this with 1mm of light speed accuracy then it cant be hard to sync the two ends and you have the redundancy to check that its correct.

The GOCE satellite was supposed to have mapped the earths gravity profile to an accuracy of about 1km so you ought to know to a pretty reasonable degree of accuracy what the gravity factor is right across the path taken to account for that affecting the clock tick. I am sure they know the moons position and mass well enough to account for it. In any case, does it affect the speed of light that much. Its not like its passing close to some black hole. Its so slight that we cant even perceive the change. Must be many many orders of mag down from something which would add 50nS to the error.

There's plenty of parameters to get wrong tho but the basic ones seem like measurements that can be checked with enormous redundancy.

Doing the same experiment in a completely different test setup and location would be the best thing to try tho. Even if the result does turn out to be a miscalculation, a mistaken measurement or some faulty equipment, it would be real interesting to know what it was.

----------


## bartmoss

> @RPMiller - actually a variation of that is already being suggested. One proposal is that there's an extra dimension that neutrinos of this energy can access that allows them to shortcut the distance. So they aren't travelling faster than light in our 3D universe and relativity remains unbroken. However this is wild speculation. The overwhelming odds are that this is an experimental error with something like the synchronisation.


The synchronization is also the absolutely most obvious source of error and probably the best checked. I absolutely agree that this will turn out to be human or systematic error, and it's not like we never did anything with neutrinos before... But hotdamn I hope this is new physics!

----------


## Jaxilon

My goodness...micro black holes warping things through time....now I know what's been happening to my brain!! 

All this is the beauty of science. That we keep learning and finding out that there is more to learn. The Earth used to be the center of the universe, then the Sun was, now it's something else. Gravity has more than one rule and all that jazz. It's awesome stuff. I kind of hope it's not a human error but another door to greater understanding about how things really work.

----------


## torstan

I think the odds on this one really are that it's human error. I'm leading a discussion in the department tomorrow about this. I'll post a note of what comes out of it. Looks like we have Nobels wading in on this now - certainly interesting. But yes, this really is science at work. We figure out what we don't know and then devise plans to slowly close out the possibilities. Quite literally:



> How often have I said to you that when you have eliminated the impossible, whatever remains, however improbable, must be the truth?


In this case the improbable really is very improbable indeed.

----------


## Redrobes

Theres been some talk that there is a some kind of FPGA based timer which is very non standard and could have some dodgy code in it to get the result. Do you know what that device might be. I saw that CERN has an open hardware forum where they are trying to standardize some of the hardware units being used in CERN generally to make this kind of debugging a lot easier. From what I remember they were looking at getting hardware which did very accurate timing in the list of required devices.

Did you catch the XKCD of this one. Obviously he is betting on human error too. I have no idea as its quite a lot of error to get wrong but human error is the most plausible. But I sure am curious about the result.

http://xkcd.com/955/

----------


## torstan

Yep, I saw that. It's great  :Smile:

----------


## Redrobes

Interesting calculation about the possible solution to the FTL.

http://www.technologyreview.com/blog/arxiv/27260/

I'm not buying into this theory tho. Surely they would have checked their local clocks against more than just other GPS clocks. Since the sync of the clocks is the crux of the issue then getting that right in 3 years would have been top priority.

----------


## torstan

Interesting article. It's not really about the synching in this version - this is saying that from the point of view of the satellite, the distance from A to B is actually shorter - because it's moving relative to the experiment. If this all turns out to be down to a version of the 'pole in the barn' problem set for undergrads learning special relativity there will certainly be embarrassment in the OPERA collaboration.

----------


## Redrobes

> The time of neutrino flight is harder to measure. The OPERA team says it can accurately gauge the instant when the neutrinos are created and the instant they are detected using clocks at each end.
> 
> But the tricky part is keeping the clocks at either end exactly synchronised. The team does this using GPS satellites...


But this is saying that they have static atomic clocks at each end and they are synced with GPS clocks which could be slightly in error due to the satellite path. But you would surely check that sync with other ground based atomic clocks as well so that at the point of sync the error would be shown up and not necessarily at the time of doing the experiment. Once your clocks are synced and verified with multiple other clocks then you can start the experiment and the satellite position, path and velocity are irrelevant. As an example, the USNO have a mobile truck with atomic clock which can be synced. I cant believe that at this stage of finding such odd results that they would not employ some similar checks.

----------


## Revock

Gotta put my two cents in although it's late to the thread,,,dark matter is the slight effect the mass of all the alternate universes have on ours,,, and they're populated by Leonard Nimoy with a goatee.

----------


## RPMiller

I'll let the physicist chime in on this one because I seem to recall he knows a little something about the subject matter.  :Wink: 

http://www.msnbc.msn.com/id/45422811.../#.Ts85ZLJC_4E

----------


## Midgardsormr

I love how they wrapped with a quote from a comment on a blog. Now _that's_ journalism!

----------


## Lukc

Journalism is a dying art ...

----------


## torstan

Sorry to have been off the site for a few weeks. We actually had a lunchtime seminar today from one of the ATLAS guys on the Higgs search.

Basically there's a range of masses that the Higgs can have in the Standard Model - from around 90GeV to a few hundred GeV. The last big accelerator at CERN proved the Higgs must be heavier than 114GeV *but* they reported hints of a Higgs boson at around 114GeV. However that hint wasn't enough to keep the accelerator running. It was shut down to make way for the LHC.

The LHC has now ruled out a Standard Model Higgs that's heavier than 141GeV. So the window that is left for a Standard Model Higgs is just 114GeV to 141GeV. They haven't been able to see if it's in the remaining region due to having too little data. This limit (above 141GeV) was setusing the data collected up to June. They now have 4 times the data and can set better limits. The LHC is shut down for winter right now (they're using it to fire lead ions around the ring right now instead of protons) and the experiments are doing analysis on their data over the winter.

*If* there's no Higgs then with 4 times more data then they'll be in a good place to show that over the winter. The first deadline is the 16th of December when the experiments show what they've managed to do to Rolf Hauer - the director general. That may or may not be made public. Then the next deadline is the Moriond high energy physics conference in the ski resort of La Thuile (yep, there are some nice conferences). That's traditionally where the big collaborations release the results of their winter analyses. If they've ruled out the Higgs that's when they'll announce.

At the moment they have some excess events in the regions where you'd expect to see a Higgs. I know that's quite an obscure sentence. Basically if you produce a Higgs boson you don't actually see the particle in your experiment. The Higgs will decay and you'll pick up the things it decays into. It's those that you see. Say it decays into a b-quark and an anti-b-quark. Then you pick those up. They'll each have some portion of the Higgs mass as energy. So if the Higgs has a mass of 130GeV, then you'd expect to pick up some b,anti-b pairs with around 65GeV of energy each. There's some statistical spread in that (you don't always get precisely half in each) so what you see is a bump in your detected events around 130GeV in the combined energies of the b,anti-b quarks detected.

Currently they have some broad excesses in events around 130-140GeV. There's certainly not enough that anyone's actually saying they've found anything, but more than you'd expect if there were no Higgs boson. If those excesses are really signals, then 4 times the data will help them to them down. If it's not there, then with 4 times the data we'd expect those excesses to disappear. We'll know the answer to that pretty quickly.

The one other thing that came out of today's lunchtime talk was that all the news you hear about the Higgs searches is done on the basis that the Standard Model is the be all and end all of particle physics. It's widely believed that there's a lot more to it than the standard model - one possibility being something called supersymmetry that adds new particles, resolves the mystery of dark matter and ... changes how the Higgs boson behaves. The analysis is similar. So it's quite possible (even likely) that over the winter the LHC will rule out the existence of a Standard Model Higgs, but will find a more exotic version of the Higgs boson that tells us what the next big theory is and helps us to resolve the mystery of dark matter and other big questions.

So take any announcement like 'scientists disprove the existence of the Higgs boson' with a hefty pinch of salt.

----------


## torstan

@Midgardsommer: The blog in question is by the press spokesperson for ATLAS - and so is cleared by the ATLAS committee so it's about as official as you can get. But yes, a comment by a non-physicist on that blog is not really relevant for the news story  :Smile:

----------


## torstan

Just a quick note - it appears there's an announcement on Tuesday about the Higgs. It looks like it'll be strongly indicated, but that they won't yet be able to claim a discovery (you need a 5 sigma signal - or be able to say there's less than a 1 in a million chance of it being a fake signal). If it is a clear indication, then hopefully by next summer they'll have enough data to formally announce a discovery. If so, this is the end of a 50 year marathon in fundamental physics research.

There's a nice article on the rumour on the BBC - and I can confirm that the experimentalists I've talked to are also smiling (but remaining tight lipped).
http://www.bbc.co.uk/news/science-environment-16074411

----------


## maxsdaddy

Date.. 12/13/11 msnbc releases anouncement that scientists have"cornered" the Higg's particle. Thats why I love the guild. Maps, art, and astrophysics. Perfect call torstan.

----------


## Redrobes

If the Higgs is supposed to account for mass and the theory says that the vacuum is chock full of Higgs particles that impede the movement of other particles to give them mass then the bit I cant understand is why its stated that the Higgs exists for about 10^-15 of a second or so. How is it that space is chock full of them when they decay so quickly ? If the LHC can only see the remnants of the decayed Higgs and the Higgs were all condensed out at nanoseconds after the big bang then why dont we have mass only nanosecs after the big bang then we all become mass-less after that point ? Is it that the vacuum spontaneously generates loads of Higgs particles then they decay back out of existence again on a continuous basis ?

Oh and did y'all catch this article from MIT where they make a camera take so many frames per second, it can actually film the photons traveling through space (not the one same photon of course, you have a pulsed stream of them). Its an awesome video:
http://web.mit.edu/newsoffice/2011/t...mera-1213.html

----------


## torstan

@Redrobes. Yep, I saw that. It's amazing!

For the Higgs - there's two things at work here. One is the Higgs field, which is the thing that gives particles mass. The other is the Higgs boson, which is basically an excitation of that field (more or less). The particle lasts for fractions of a second before decaying, but the field is stable and present everywhere.

The result of the announcement was that there's a 3.6 sigma signal of a Higgs boson in the ATLAS data and a 2.5 sigma signal in the CMS data. 3.6 sigma means that the data is 3.6 standard deviations away from what you'd find if there were no Higgs boson. Which really means there's a small fraction of a percentage chance that this is just a statistical fluke. You need a 5 sigma result (less than 1 in a million chance of a statistical fluke) before you can claim a discovery. More data will allow them to get to that threshold, and they should have enough data in the next year.

You might also note that each experiment has independent data, so they should be able to improve the confidence of the result by combining data? Well that's certainly true - they've done it once already with the summer data. That will certainly improve the result, but not to the point of crossing the 5 sigma threshold. Those results should hopefully be out for the Moriond conference in Feb/March. However we really want both the experiments to get the 5 sigma confidence level independently to make sure we've really found it. That should be late next year, with a progress report and new data by the summer conferences of 2012.

----------


## torstan

And a good breakdown on the CERN blog of why they're being so cautious: http://www.quantumdiaries.org/2011/1...sing-like-one/

----------


## Bogie

A neutrino walks into a bar, the bartender says "Hey! we don't serve your kind here!,  The Neutrino says "It's OK, I'm just passing through."

----------


## Map4fun

I have a question. What happens to an object if it's exposed to the kind of cold (1.9 degrees above absolute zero) as mentioned about the magnets? I heard years ago that a chair exposed to near absolute zero simply crumbles... I'm a teacher to younger aged students who've asked me this question for the last few years - part of our unit of study for science is space and heat. I've simply told the students to come tell me about it if they get the experience. I'm hoping to know now whether or not things get weird when things get cold... really cold!

Thanks

PS. I just read in discover magazine that we've created anti-helium? In simple terms, what significance does creating anti-matter have?

----------


## Map4fun

Hilarious! love it. I've heard the one of the Mushroom that gets the same treatment. The mushroom simply replies: "Hey, I'm a "fungi".

----------


## torstan

I totally missed this comment I'm afraid. I'm not a condensed matter scientist so I can't really speak to what happens when a chair is cooled to that temperature.

However there are materials that do a lot of fun things when cooled to these sorts of temperatures. At low temperatures helium becomes superfluid, suddenly having zero viscosity. This means it can flow uphill, as long as it ends up lower at the end of it's journey. It's like a syphon, except that it doesn't need any outside force to get it flowing, it just starts flowing over obstacles on its own. Here's a nice short video showing some of that: http://www.youtube.com/watch?v=2Z6UJbwxBZI

In other news - it looks like we might get a Higgs discovery announcement tomorrow morning. All rumours and indications are that they've found something definitive. If so, that's the capstone on the great physics research project of the 20th century, and the first stepping stone in the next revolution in particle physics. I'll be up at 3am to see it.

----------


## Ghostman

So, word is out that the big-ass collider spotted some bosons, and it was party time in CERN  :Laughing:

----------


## torstan

Certainly was  :Smile:  We were up at 3am over here watching the live streaming event. Very impressive work all round. As a theorist I can only look on and be very impressed by what they've achieved! It's really amazing.

----------


## RPMiller

So how do the discoveries tie into your work, Torstan? Does it mean that your theories have more merit and you'll get some more grant money or some such thing?

----------


## torstan

Well, it's ruled out some of my older papers - which is a good thing! The Higgs at 126 times the mass of the proton is heavier than was expected and it's surprisingly tricky to accomodate that mass in many theories of new physics such as those that try to explain dark matter. One very straightforward thing this does for new theories is that previously we had to come up with predictions that allowed for a range of Higgs masses. Now that free parameter has become a constraint that has to be satisfied, so it narrows the freedom we have when creating new theories. Those constraints mean that we can be much more specific with predictions for new theories of physics, which hopefully will lead to new discoveries.

This actually has relatively little influence on my current research as I'm working on cosmic rays these days rather that dark matter and particle physics, but it will certainly be a huge help (and a bit of a head scratcher) for theorists who are working on LHC predictions. Just to give you an idea, here are all the theory phenomenology papers released as pre-prints since last Wednesday's announcement: http://arxiv.org/list/hep-ph/pastweek?show=121 There are 34 with Higgs in the title. Getting a Higgs paper out within days of it being discovered is an impressive achievement, but that's just the start of this field of research. People will be studying this particle in enormous detail in the coming years, looking for any hint that it might not be a common or garden Higgs but something more exotic.

These particles interact with almost everything. We've just discovered a particle that is omnipresent in the universe. It's field literally exists everywhere. Nothing else we know of has that property. If we break it down and understand exactly how it works, we'll have understood one of the fundamental pillars that the universe is built on. That is likely to have wide-reaching consequences that we can't begin to imagine. It's true frontier science.

----------


## RPMiller

Do you think it will change the Standard Model in any great way, or does the Standard Model still handle the properties of the particle as we know it today?

----------


## torstan

So far it's consistent with the Standard Model. But remember, right now all we have is a measurement of 2 decay processes out of tens of different decay processes and interactions. Also, the measurements are still very low on statistics. The productions are showing a little tension with the Standard Model predictions as they're over-producing. But it's not at the level that's statistically significant. If those turn out to be real differences then it's a different matter entirely and would be the first solid evidence of physics beyond the Standard Model.

----------


## RPMiller

Okay, so here's a slightly related/unrelated question. How true is this?

http://what-if.xkcd.com/1/

----------


## Korash

Yes, I believe that it is true...

The batter gets a free trip to 1st base

LOL  :Wink: 

As for the rest, I will let someone in the field try to catch that one

----------


## RPMiller

> Yes, I believe that it is true...
> 
> The batter gets a free trip to 1st base
> 
> LOL 
> 
> As for the rest, I will let someone in the field try to catch that one


Repped for the laugh.

----------


## cfds

Since the baseball has an energy of roughly 3*10^16 Joules (about 7 megatons TNT equivalent) at this speed the described level of devastation seems .. adequate.

----------


## torstan

Actually, yes. That sounds pretty accurate to me. I think the question around how much baseball is left is the biggest question, but given the baseball remains are at least as dangerous as the ball itself, it's immaterial to the level of devastation.

cfds - good call working that out. That's a very good order of magnitude to go with.

----------

