Will the LHC Smash Supersymmetry? 196
gbrumfiel writes "The Large Hadron Collider is just getting ready for its next big science run. One thing researchers hope it will find is evidence for supersymmetry, a theory that could help to unify fundamental forces and explain mysterious dark matter. But as Nature reports this week, the LHC has shown no signs of supersymmetry in data from last year's run. If super particles don't appear by 2012, then physicists might give up on the theory for good."
Naive Question (Score:4, Interesting)
Suppose they prove super-symmetry and find the Higgs Boson, what are we going to be able to do with it. Other than completing the theory, is there any practical use for this new found knowledge?
Genuine question, physics isn't my forté.
Thanks,
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Re:Naive Question (Score:5, Insightful)
Didn't we have the same "what use is this" question after that math story the other day? It's like a oblique troll that something is Useless Until Proven Useful.
General Theory of Truth: If something is true, something cool can be done with it. No exceptions. Politics don't count.
I agree *you* don't need this, but someone out there has to know this stuff.
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Politics do count - look at all the lies in politics, obviously politics aren't true. Your rule is not broken, no exception is needed.
Re:Politics (Score:3)
Sorry, I wasn't clear.
I meant that cool stuff "can be done". "Whether it will be done" is the whole other problem with the political side. Sometimes the "can be done" is pretty hard, and politicians hate hard stuff. "We can have a moon base in 20 years" - but only if we were so scared we stopped most of our petty squabbling to do it. Seriously, you engineer types out there, how hard is it really to get a quad-protected airtight building to the moon? Put it at some kind of shade-crossover point to use the so
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The politicians are the Terrorists!
Remember kids, if you support a politician, a terrorist wins!
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It's like a oblique troll that something is Useless Until Proven Useful.
Not unlike the user(s) posting the troll post(s), I daresay.
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The troll in that thread was the idiot who didn't even read the summary where the answer to the question he had was given. In this case, I know I (and I assume the AC) genuinely want to understand what exactly this means because of a lack of understanding about physics.
The way I'd look at it is this:
If someone discovers a proof that P==NP, then even though we haven't found the practical solutions to some problems (factorization or whatever) yet, it means that there IS at least one "quick" solution. So, that
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I'm not particularly up to scratch on high-end physics, either, but you're very much thinking in the right direction, I'd say: proof that a current theory holds it's ground, means you can start looking at the theoretical possibilities that flow from that theory as rather more likely to be possible, which will cause more attention to indeed go towards them, some of which in turn will eventually lead to me zapping to work instead of being stuck in traffic, so to speak.
All knowledge is potentially useful. Some
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If someone discovers a proof that P==NP, then even though we haven't found the practical solutions to some problems (factorization or whatever) yet, it means that there IS at least one "quick" solution.
Unfortunately, no, it doesn't imply a "quick" solution. All P=NP would mean is that these problems have polynomial-time solutions; it says nothing about how efficient those polynomial-time solutions would be. Your only guarantee is that for sufficiently large N, any polynomial bound is better than any expo
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Didn't we have the same "what use is this" question after that math story the other day? It's like a oblique troll that something is Useless Until Proven Useful.
I would use the term "truism" not "oblique troll". I consider the current tired slop, which passes for justification of science, to be abominable. If you do work in the sciences at the behest of someone else, I can only hope that you justify your work far better than what you did here. This is a reasonable question to ask and it is disturbing how frequently it is brushed off.
In the case of figuring out whether supersymmetry is a feature of the universe or not, it is worth noting that advancing fundamenta
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The poster didn't argue that it wasn't useful. They asked if any immediate use is known. Not a dumb question, because often we can think of a specific application for new physics or math. For example, if someone solves does P=NP, we would care pretty fast. Sometimes we find the utility later, and sometimes nothing is found.
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It's one of those questions that can either be honest or a really slick troll.
Fair enough you went honest, and I agree the difference of a word or two can make all the difference. I wanted to call attention to a possible new cross-thread troll trend where, if it happened 4 stories in a row, would set a meme.
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No Politics do count, when a politician tells the truth something incredibly useful can be done with it. This has not been tested in some time however.
Re:Naive Question (Score:4, Insightful)
Nuclear weapons, to be exact. Science brought politicians the bomb. They've been throwing money at physics ever since in hopes of something even better.
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Honestly, "What can we do with it" generally gets answered after we can prove we have it in the first place, but I'm sure there's at least one theory that says supersymmetry allows arbitrarily awesome things like wormholes or something.
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That isn't quite true. For example, even though we don't know if P==NP or not, people have ideas for what could be or could not be done in either scenario. We don't know *how* to implement a quick factorization algorithm, for example, but we know that if P==NP we *could* eventually figure that algorithm out because we would know that it must exist.
And the "theory that super-symmetry allows awesome stuf" is probably exactly what the original poster was asking about, and I'm in the same boat.
A validated theory is a stepping stone ... (Score:5, Insightful)
Suppose they prove super-symmetry and find the Higgs Boson, what are we going to be able to do with it. Other than completing the theory, is there any practical use for this new found knowledge? Genuine question, physics isn't my forté. Thanks,
A validated theory is, if nothing else, a stepping stone to an even more complete understanding. From better understanding comes new, or improved, tools. There is sometimes a time lag between discovery and practical application. Sometimes decades, sometimes a century or more. Consider nuclear fusion (what the sun is doing), potentially a safe and abundant source of power. Figuring out how to build and operate a fusion reactor will require understanding a few theories that were at one time merely theoretical with no practical application.
Re:A validated theory is a stepping stone ... (Score:4, Insightful)
The question then that I would have is "Why don't people who are trying to come up with practical applications act 'as if' the theory were true?"
I guess what I'm getting at (I'm not the AC who started this but I am also in a similar boat, understanding-wise) is: Right now it seems that most physicists THINK this theory is true. If that belief is validated, okay, great, they know they're on the right track, but aren't they already basing a lot of ideas for steps further down the line on the notion that this might be true? And, if that's the case, then aren't people coming up with, or at least thinking about, practical applications based on that assumption?
To me, it seems like the really interesting result would be if this assumption of super-symmetry (or anything else in a particular theory that is widely believed) doesn't actually prove true or doesn't behave like it has to for the theories to be true.
In case I'm being obtuse, I'll use an analogy:
When people were making rockets, they had some theories about what might happen in space, or what might be needed for the rocket to work, or what might happen to the people on a rocket, etc. They behaved "as if" those theories they had were true, or, at least, "as if" the most risky/dangerous versions of their theories were true and designed accordingly. So, they launched rockets, people were in them, and some of their theories panned out, some did not.
What could be built if these theories are true?
And, I am totally 100% behind the idea of learning stuff just to learn it - even if there isn't a practical application, understanding the universe is important.
Bleh, sorry, sick as a dog and on massive doses of NyQuil so I ramble.
Good way to waste time (Score:4, Insightful)
The question then that I would have is "Why don't people who are trying to come up with practical applications act 'as if' the theory were true?"
The other problem is that any effort may be completely wasted. For example Columbus set off to find a passage to India. Had you attempted to set up an Indian spice importing operation before he had returned you would have looked like a complete idiot.
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How long since Newton discovered the nature of laws of gravity and inertia did it take man to reach into space?
The reaching into space preceded Newton and was a significant inspiration for the laws of gravity. As to practical applications of the law of gravity, it was used (along with the first known application of the least squares method) by Gauss to find the position of Ceres in 1801. That's a bit more over a century after Newton's discovery of the law. I'm pretty sure the law was used well before to predict the future position of the four large Jovian moons (particularly to study occultations visible from Earth
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> The experiment always shows the truth^H^H^H^H^H reality and that is what scientists think.
FTFY.
Experiment don't show truth - they show reality -- which _points_ to truth. If you have two experiment, that give contradictory results, you don't have truth (yet), you have a paradox. It takes _further_ experiment, to come to the correct _assumptions_ and _understanding_ of the problem, to reach a valid conclusion.
> That's how science, especially physics, works. It's all about the Real World and real, h
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That's like going back in time and asking Coulomb or Volta about what applications their research would have.
"I don't know. Well, if you could make a small enough electrochemical cell to hide in your pocket, with wires you could shock people when you shake their hands, as a practical joke. Hee hee."
One way supersymmetry would be useful is at the theoretical level - it gives particle physicists another mathematical tool for predicting yet other kinds of particle to hunt for. It might help with understandin
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I bet it was more along the lines of "A Leyden jar that works more than once", or "Zombies!"
To be precise... (Score:5, Interesting)
In fact Faraday's joke was better than that, It was the Prime Minister (in those days called the First Lord of the Treasury, hence your confusion), and the Government had recently introduced some unpopular taxes. So Faraday's actual reply, "I know not, but I wager one day your Government will tax it" was doubly apposite.
The other one of these Victorian quotes is the response of the inventor of the dynamo when asked what use it was: "What use is a new-born baby?"
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Well this theory, if proven would be able to give engineers knowledge on more basic rules, and limitations that they can factor into their designs. Just as electricity was discovered it took a fair amount of time for it to be useful for anything, it took the discovery linking magnetism and electricity before anything of use could be invented. Other then that it was used for well just zapping people, and some cool sideshow effects, as most Electrical energy was generated via static electricity, and chemical
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What's the use of a new-born baby?
-Benjamin Franklin
Re:Naive Question (Score:5, Funny)
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Collect 8 top quarks and 3 anti-hydrogen atoms.
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OMG I already killed thirty two iron atoms and none of them dropped any quarks! How the hell do these atoms not have any quarks in them?!
Re:Naive Question (Score:4, Insightful)
Here's one possibility: All of our favorite science fiction stuff (things that would allow us to effectively have a galactic or even universal civilization) appears to be disallowed by special and general relativity. However, these things necessarily break down in some regard at the smallest (ie highest energy) scales. Understanding quantum gravity (if we can ever do so) will tell us just exactly how relativity breaks down at super high energies. It is possible that the particulars will show us a way to travel and communicate faster than light (think things like the Alcubierre bubble).
The LHC will probably not unlock the secrets of quantum gravity. However, understanding the lower energy phenomena like the mechanism for electroweak symmetry breaking, or supersymmetry (or technicolor, or a variety of other speculative theories) is a necessary step towards understanding quantum gravity. As such, I think that experiments like the LHC are vitally important to the extremely long term survival of the human species (we have to get off Earth and out of the solar system sometime within the next few billion years, at the very least).
As other posters have pointed out, this, along with all other speculative applications of what we learn from the LHC, are probably not going to be seen during our lifetimes.
Utility (Score:2)
is there any practical use for this new found knowledge?
Physics at this level is like abstract mathematics: it exists for its own sake. Practical applications of this physics is like practical applications of number theory: just not in the plan.
Utility is part of the plan (Score:5, Insightful)
Physics at this level is like abstract mathematics: it exists for its own sake. Practical applications of this physics is like practical applications of number theory: just not in the plan.
Completely wrong. I don't know a single physicist who believes that. The reason we do what we do is because we are curious about the universe and want to find better ways to exploit it...but the first step in that is understanding. Practical applications are always part of the plan. The problem is that since we don't yet know the physics we don't yet know how to use it practically. 100 years ago "Physics at this level" was quantum mechanics which, since you are reading this article on a silicon based device, has turned out to be extremely useful. Of course absolutely nobody at the time could possibly have predicted the development of the integrated circuit from an understanding of quantum mechanics.
Even today early particle physics detector and accelerator technology is produced better medical imaging and treatment options. Just because we cannot imagine how today's discoveries will be used in 70-100 years form now does not mean that we don't fully expect them to be used for something.
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I'm a physicist, and I believe that.
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Yeah, there are no real-world applications of number theory
cryptography, data compression, error correction, no sir, number theory is good for nothing sir
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Basic research rarely has obvious applications, and yet it pretty much lies at the heart of all technological advances. Guys screwing around in the 18th century with Leyden jars doing all kinds of interest parlor tricks probably looked pretty silly on the face of it, as well, and yet the ultimate value of these early experiments was enormous.
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Other than completing the theory, is there any practical use for this new found knowledge?
Duh! Flying cars, jet packs, bionic limbs, amusement parks on the Moon... all that stuff they've been promising us for the last hundred years!
Seriously though, the stuff this will give us in the decades to come is so cool and amazing that no one has even imagined it yet. Take a look back at harnessing electricity, harnessing nuclear power, discovering relativity and quantum physics and figure out what those things e
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Suppose they prove super-symmetry and find the Higgs Boson, what are we going to be able to do with it. Other than completing the theory, is there any practical use for this new found knowledge?
Nobody knows, but neither did Maxwell 150 years ago when he formuleted his theory of electromagnetism, nontheless without it you wouldn't have radios, ipods or cell phones. Einsten had no idea what his general relativity was good for but without it you wuoln't have GPSs and Li-ion batteries.
I could go on for a while, but let me tell you that real scientists work because they want to understand nature better, regardless of any pratical use that may stem from their work.
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For a practical application, you can just assume the model is correct. For example ancient swordsmiths knew lots about how to make microstructures in steel without ever being able to see it in a microscope. But it didn't matter, because it worked. Nothing directly is held up by this, if something needs supersymmetry to work we could just build it and see if it works.
However, the more you know the more chance you can come up with something intelligent to try. For example it's highly unlikely you'd come up wi
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It probably has more practical use than the knowledge that Green Bay won the Superbowl.
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IANAP. There will be 1000 responses explaining why I am wrong. But every reply I've seen so far is "it might be useful for some undetermined future reason" which seems pretty weak. So at the risk of technical inaccuracy, here is my speculation:
The Higgs Boson is the particle that assigns mass to another particle. Once we understand it, it opens up a lot of questions and experiments:
- Can we create a Higgs Boson, thus creating artificial gravity? Tractor beams?
- Can we use them for signaling?
- Could we
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Lack of evidence is not evidence of lack, but it is worrisome. It leaves open the possibility that we are off on completely the wrong foot, that reality is really nothing like our mod
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i remember a story about benjamin franklin being asked by fellow congressman what would be the practical uses for electricity. his answer ?
"i don't know what it's usefull for, but i know that in the future you will taxing it".
so, there's your answer.
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supersymmetry doesn't unite the forces. you've got to do something else to do that, such as super(symmetric)gravity and super(symmetric)string theory. they're an extra layer (and a good few extra dimensions) on top of a "standard" supersymmetric model such as the minimally-supersymmetric standard model.
high enough energy? (Score:2)
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most of them are pretty damn heavy. i believe the lsp is expected (from some models of supersymmetry) to show up in the lhc but it's easy enough to make sure it doesn't. if an lsp is found then at least part of the dark matter problem will be found, because that thing's basically stable and doesn't interact with us in any way.
warning: unfocused and off-topic rant ahead.
what's going to upset me is if an lsp is found (which i see as pretty unlikely, in all honesty) people are going to be shouting about how th
Re:high enough energy? (Score:5, Informative)
No. We can never smash hard enough to disprove supersymmetry unless we find something that directly contradicts it. To put it another way, if all the LHC finds is a Higg's and expected results from the standard model, it doesn't actually disprove supersymmetry since any model of supersymmetry has so many parameters that you can tweak a few of them and lift the superpartners back up above the LHC's maximum energies. That is *always* going to be possible -- theoretically a limit would be if we had particle accelerators that reached the Planck energy and people would finally be saying "hang on, something's up here; we should be seeing quantum gravity by now and we're still not seeing the quarkinos", but in reality we're never getting to anything like an energy that would rule it out.
What's a lot more likely in my mind is that more physicists will begin to drop supersymmetry and look at something else that may actually have observable effects at "low" energies while otherwise the supersymmetry bandwagon will roll happily on with slightly more tightly-constrained parameters.
The hope is that the LHC not only doesn't see supersymmetry but *does* see something utterly unexpected. That's what I want from it. (Actually I want specifically no Higg's boson, and no supersymmetry.) Something unpredicted would rule out supersymmetry not least because any supersymmetric model that could account for it would be a posteriori -- constructed purely to do that and most likely grossly ugly as a result. By definition something unexpected is not a straight prediction of supersymmetric theories, and any model constructed purely to explain it will be under suspicion.
Before getting onto the next bit, the Higg's is not associated with supersymmetry, it's part of the standard model and doesn't require supersymmetry to exist. The Higg's is the last part of the standard model that is yet to be observed. They're different topics, and the LHC is hoped to shed light on both of them. As far as supersymmetry goes, the LHC was built basically to give us a pointer for where to go beyond the standard model and forms of supersymmetry are currently the most widely-favoured options.
The fear (at least my fear) is that the LHC will find nothing. Squat. No supersymmetry, nothing outwith the standard model -- but from my point of view, that it does find a Higg's. That would appear to add support to the standard model, which is a bit of a pain because the standard model's already broken since we *know* neutrinos have to have mass and fudging the standard model to put them in is pretty contrived.
However, not finding a Higg's at all would be brilliant -- so strictly speaking, the LHC finding *nothing at all* would be good. Because the Higg's should be within its capabilities and if it's not there there'll be a lot of head-scratching going on, and I always prefer things being rethought and reanalysed over mindlessly employing techniques chiefly developed in the 40s with QED and brought to fruition in the 70s with QCD and the electroweak theory.
But, in all fairness, I'm not a particle physicist, I'm a cosmologist.
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well, if it predicts something, and we show that that something doesn't happen then the theory needs to be change to fit the new data. If it can't be changed, then it's dead.
If I say gravity cause something to fall at a rate dependent on it's mass, and then do tests that show that mass is irrelevant to the rate of fall I have disproved my statement. That I can say either 'gravity' doesn't exist or that it exists but mass is irrelevant to the rate of acceleration during a fall.
true, but... (Score:2)
it's not the theory that needs changing in that case, it's just the parameters in the theory. the theory itself is still fine, you just tweak a few numbers and suddenly it's "oh the lsp is up at 20TeV, sorry guys! you built that 15bn euro machine for nothing!" there's something like 127 free parameters in mssm which gives you a *huge* parameter space to run around in and hide from the experimentalists. play this game and the theory is still "valid". play it long enough and everyone else will give up and go
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:) Don't worry, I criticise cosmologists for doing the same. I've written a couple of wild unfocused rants on this story already and to be honest they're actually more motivated from frustration at astrophysics and cosmology than particle physics...
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But, in all fairness, I'm not a particle physicist, I'm a cosmologist.
What I want from cosmology is the same thing I want from the government: no inflation. A theory that needs a 78 orders of magnitude adjustment doesn't seem quite right to me.
Why not assume that the answer to the horizon problem is that under some circumstances FTL might exist? The problem with relativity is that it denies, in a somewhat dogmatic way, the existence of one absolute inertial reference, when we know there is at least one local reference that's "more inertial" than others because it's at rest wi
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I wrote a long reply to this and lost it by being an idiot :( Anyway, I said firstly to dig out a copy of Joao Magueijo's book which may or may not be called "Faster than the Speed of Light" which postulates a changing speed of light and lets you do away with inflation. I think a lot of people would be happy if we could do away with inflation completely, but anything that replaces it has to repeat its successes, which are many.
As for the CMB, it doesn't violate relativity, it's *predicted* by relativity. Al
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It doesn't pick a physically preferred frame any more than saying "This is MY car and that's a preferred frame!"
Unless you are rotating. Then you have a centrifugal force. Why is it that if you are standing still against the CMB you feel no centrifugal force but if your frame has any rotation at all against the "distant stars" you have centrifugal and Coriolis forces?
OK, rotation has this particular property that translation doesn't have, but if there's one preferred frame for rotation why shouldn't the same frame be special with respect to translation?
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You can get Schroedinger's equation in a totally deterministic (if rather contrived) manner by taking a totally classical system and adding a modification to the potential. If you then take the momentum potential (or action, however you want to phrase it) and the density you can bundle them together as basically the phase and the amplitude of a wavevector that... solves the Schroedinger equation. Totally deterministic and totally indistinguishable from standard QM. It's also very ugly and is riddled with co
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Is supersymmetry really science then? (Score:2)
Since Popper we know something must be falsifiable to be science. If supersymmetry got enough tweakable parameters to account for whatever results might happen in our experiments, it doesn't seem to be falsifiable.
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Don't absolutely rely on me for that - as I say I'm not a particle physicist. I'd more or less agree, except that you can do science degrees in pure maths, which is not only not falsifiable but it in principle has nothing to do with reality. You can play annoying word games and point out that any time you try and apply it to reality you're an applied mathematician. The same goes for things like string theory. But unfortunately high-energy physics will always be like this; there are limits that we can feasib
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The hope is that the LHC not only doesn't see supersymmetry but *does* see something utterly unexpected. That's what I want from it. (Actually I want specifically no Higg's boson, and no supersymmetry.) Something unpredicted would rule out supersymmetry not least because any supersymmetric model that could account for it would be a posteriori -- constructed purely to do that and most likely grossly ugly as a result. By definition something unexpected is not a straight prediction of supersymmetric theories, and any model constructed purely to explain it will be under suspicion.
Two scientists are shipwrecked in a distant land, one a biologist and the other a physicist. They encounter a strange creature with the body of an otter, the beak of a duck, spurs like viper's fangs, and feet like a seal's. The biologist exclaims "My word, we've discovered a whole new species!" "Don't be ridiculous", the physicist replies, "you've just decided that to fit your observations- if you were a real scientist, you would have predicted it!"
A Question for boristhespider (Score:2)
But then a prof of quantum mech at MIT stated that it has never been successfully proven to date.
Also, there appears to be some physicists who believe the existence of Hawking radiation has been completely disproven, while others aren't quite there yet.
Any opinions on the matter??????
Re:high enough energy? (Score:4, Interesting)
1: Pure phenomenology. No-one constructing inflationary models that I know of actually seriously believes that it's fundamental physics (at least, not after the second or third year of their PhD). What they *do* believe, frequently, is that the phenomenology can help guide a more fundamental theory. Personally I don't always agree with that; I think it can shroud a fundamental theory (in a similar vein to how cosmology is built on phenomenology that basically shrouds a very serious and neglected underlying issue).
Unless you're using the Higgs itself to drive inflation -- Guth's first model did this but it ran into problems with a graceful exit; it's recently been reawakened and re-examinded, though -- you're going to have a massive problem identifying an inflaton. We've not observed *any scalar fields whatsoever*. Even the Higgs remains elusive, though that might change in the near future. (Don't hold your breath.) So you immediately have a problem that what you're doing is specious. You can then either ground your inflaton in a well-reasoned model of high-energy physics or, and this is the standard approach, just invent a scalar field, call it the inflaton, and give it an arbitrary potential. So long as you make the potential flat enough that scalar field is an inflaton.
Basically it's phenomenology. But the people who do it are convinced it gives *suggestions* about what lies underneath, and in some ways they've got a point. Inflation works extremely well and it's standard to assume there was an inflationary epoch. You solve the horizon problem, the flatness problem and (if you believe in various GUTs) the monopole problem. (Basically -- why does the CMB look identical in opposite directions when the universe is too young for them to have ever interacted; why is the universe so fucking SMOOTH; and why do we not see any of these magnetic monopoles that GUTs produce in abundance?) Even more importantly, though, the quantum fluctuations of a scalar field coupled to gravity in the early universe produce tiny seeds that are basically exactly right. You can make models that get them exactly wrong but actually you have to work a bit; basic inflation made a prediction of those seeds, and when WMAP came along and looked at the CMB in unprecedented detail, it was dramatically confirmed. Basically those ripples had to be almost exactly Gaussian random, and "scale-invariant" meaning that the extremely large wavelengths were massively more powerful than the shorter wavelengths. That maps through to the formation of the CMB, when electrons condensed into protons to form hydrogen and light rays could suddenly free-stream carrying with them a photograph of the early universe. And it maps through even further, to the large-scale structure of galaxy clusters where we can look at those very same wavelengths. Much of a shift from those early imprints and that distribution is changed actually quite dramatically.
2: Dark matter is a big issue (well, duh). Basically "dark matter" is a catch-all term for whatever is causing rotation curves to deviate from the Newtonian prediction. I get irritated when people immediately assume it's a new exotic species of particle. I've put a couple of rants on this thread aimed at this kind of thing. My feeling is that dark matter in galaxies (and galaxy clusters) is made up of five or six different effects, *all* of which act as "dark matter", ie to flatten rotation curves: exotic particles perhaps, if supersymmetry is true; massive neutrinos since we now know that they are massive even if we don't know the mass, and neutrinos are so abundant that with *any* mass they form at least a dark matter even if it can't be the full dark matter (attributing the entire dark matter to massive neutrinos badly washes out structure on galaxy cluster scales); relativistic corrections coming from our naive assumptions that galaxies inhabit Minkowski (ie normal flat) space, since they don't, and that may -- *may* -- be able to account for up to roughly a tenth or more of spiral galaxies' dark matter; i
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A priori there's no reason to actually connect the dark matter needed for galaxies and clusters with the dark matter employed in cosmology. Cosmology is based on the Friedman equations -- one saying how fast the universe expands and the other saying whether it's accelerating. The "dark matter" in cosmology is just a number that appears in these equations. Identifying it with the dark matter in clusters appears to make sense... but only if you believe the equations are seriously physically meaningful.
Sure, logically you can make that argument. But you have a strong hint, don't you, from the fact that the numbers seem to work out. You hav
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"But you have a strong hint, don't you, from the fact that the numbers seem to work out. You have a number of independent ways of getting at the dark matter in clusters of galaxies -- (M/L), the cluster baryon fraction, weak lensing, etc. -- which are fairly consistent with each other."
Sure :) It's a problem for people like me who more or less oppose Lambda CDM -- anything that replaces it has to work as well as it. And it does work - extremely well. I'm very uneasy about the physical content of it, but up
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Wow! Thanks for the detailed technical reply. I read it twice and have bookmarked it. Grounded skepticism, nice.
Let's see if I can subtract away a bit of the jargon, to abstract the first two problems, so they sound similar. The horizon problem is that all parts of the Universe are traveling at the same speed, but they would always be too far apart from each other to reach an agreement on the speed. Let's call that the constant velocity problem instead. Everyone happens to be traveling at the same
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SUSY *is* a hack-job in my opinion. But what I meant is that in, say, MSSM, you've got well more than a hundred free parameters. Some of them are well-constrained; others aren't. Change a few of these and you can change the phenomenology. But as I've said a few times today, I'm not a particle physicist so I'm also happy to be told I'm wrong -- I talk with particle physicists sometimes, and the rest I get through the kind of academic osmosis that causes confusion worldwide... :)
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Bear in mind that SUSY was not intended to be a hack job. The Coleman-Mandula theorem is pretty definitive - if we want an abstraction that looks like QFT, then it has gravity, a gauge group (so in the real world SU(3) x SU(2) x U(1) at any energy scale we're ever likely to be able to detect / care about). SUSY is just the least messy way of extending symmetry in a way which doesn't violate Coleman-Mandula and which could provide constraints on the Higgs mass.
The original hope was that a) some existing par
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Unfortunately physicists stopped looking for falsifiable theories a long time ago. They're bad for your career. They also forgot about Occam's razor. Supersymmetry is not a theory, but a principle, the simplest theory [wikipedia.org] built upon it has 120 new free parameters. That's to be compared with the 19 of the Standard Model [wikipedia.org]. It may solve one or two problems, at the expense of 120 new ones. As a consequence, it is nearly impossible to disprove supersymmetry. (and definitely impossible using only the LHC) One
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Unfortunately physicists stopped looking for falsifiable theories a long time ago.
Really? Care to explain how the Standard Model will survive if we fail to find a Higgs at the LHC then since the WW scattering cross-section will violate unitarity around 1 TeV without a Higgs. Hence we will either see the SM Higgs or exclude it. Seems pretty falsifiable to me.
Supersymmetry is not a theory, but a principle, the simplest theory built upon it has 120 new free parameters. That's to be compared with the 19 of the Standard Model.
Actually you will find that SUSY has exactly the same number of free parameters as the Standard Model. The only different being that with the Standard Model we have measured the parameters which has allowed us to simplify things e.g
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I clearly was talking about supersymmetry here, in which one can push up the SUSY breaking scale as high as one wants. I did indicate that the LHC will discover the origin of mass...
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I clearly was talking about supersymmetry here....I did indicate that the LHC will discover the origin of mass...
Sorry but you'll have to forgive me if I take a statement such as "Unfortunately physicists stopped looking for falsifiable theories a long time ago." as clearly being broader than just SUSY. Indeed your whole argument is phrased as a general issue with SUSY being one particular example. Hence my counter argument. I should also point out that it is not at all certain that the LHC will discover the origin of fundamental particle masses (not all mass), only that it will confirm or rule out the SM Higgs boson
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Going back to your original comment, you pointed out that WW scattering will violate unitarity within the energy reach of the LHC. So the LHC will discover the mechanism of EWSB, whatever it is.
MSUGRA is not a theor
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The way I understand it, the models predict that at a given collision energy level, there will be a certain probability that a Higgs boson can be detected. If a particle accelerator is run at this energy for a certain number of collisions (at lower energies this could take years due to the extremely low probabilities involved) and there is no indication of the Higgs, it means that the model is very unlikely to be valid. Supposedly at the levels the LHC has been operating without finding evidence of the Hig
No Higgs, no super symmetry, but a t-shirt (Score:2)
The idea: Maxwell's field theory is the best one we have, the basis of the standard model by swapping out the gauge groups. I figured out how to write the Lagrange density (every way energy can be exchanged inside a box) using quaternions. That is not so hard. Do you know how to factor (B^2 - E^2)? If so, then (Del A - (Del A)*)(A Del - (A Del)*) is the same thing, quaternion style. The quaternions cannot do gravity which involves totally sym
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This stuff is way above my head, but I was wondering why the legend for the T-Shirt included × for quaternion multiplication, but × doesn't show up in the equation.
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You could always follow the bit.ly URLs yourself and then post the YouTube URL that results.
That's what's wrong with Physics today (Score:2, Insightful)
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No, we must always be looking for strange new shit that violates the laws of physics as we know them. New particles, new types of matter, dark energy, broken symmetry, anything unusual.
Isn't that kind of, you know, what drives science forward? Questioning the accepted laws as they are and seeking ways to expand upon them, generalize them, or all around uproot them to explain some currently inexplicable observation we've made?
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No, we must always be looking for strange new shit that violates the laws of physics as we know them. New particles, new types of matter, dark energy, broken symmetry, anything unusual.
Isn't that kind of, you know, what drives science forward? Questioning the accepted laws as they are and seeking ways to expand upon them, generalize them, or all around uproot them to explain some currently inexplicable observation we've made?
Not in climate science you don't. If you apply such skepticism to something like the Greenhiuse effect or the utility of climte models, you grt called a Denier and worse.
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Not in climate science you don't. If you apply such skepticism to something like the Greenhiuse effect or the utility of climte models, you grt called a Denier and worse.
Well, yeah, if you doubt the greenhouse effect, you'll get called worse -- like, say, stunningly ignorant -- since not only is the presence of a greenhouse effect on Earth well-established since the mid-1800s, but human habitation on Earth would be hard-pressed if it didn't exist. The terrestrial greenhouse effect is why the average temperature on Earth is something like 15 degrees C and not -18 degrees C.
Hint: "greenhouse effect" is not a synonym for global warming. Anthropogenic global warming is th
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Hum? Kepler's laws do not apply to galaxies. Everybody knows that, and that's why people came out with dark matter. Also, altough the mass distribution of an spiral galaxy isn't very similar to a point mass, eliptical ones are quite well approximated by a point.
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No. No they are not. A perfectly flat disk is not even approximated well by a point. Yes, the distribution of "flux" is symmetric about 1 rotation axis, but the flux density and hence the gravitational pull is not uniform in all directions at the same distance. This means an object won't orbit the disk at the same speed it would a point mass at the centre. That i
Re:That's what's wrong with Physics today (Score:4, Insightful)
Er, they do realize that Kepler's laws do not apply to galaxies. They cannot, in fact, use Kepler's laws because they know quite well that the gravitational contribution of the stuff orbiting the center of mass is significant. That's why they use Newtonian physics in this situation. Our modern understanding of the evolution of spiral arms comes from this sort of analysis. They do not use Special or General relativity in this situation for two reasons. First is that the math is real hairy. Second, at these speeds and distances, it reduces down to good old Newtonian motion anyway.
As for Dark Matter, yes, there was a flash in the pan article a few years back about someone using General Relativity to analyze rotation curves and coming up with enough extra contribution to invalidate dark matter. The paper was up on ARXIV for about four hours before the first math errors were spotted and brought the whole thing crashing down. And even if that paper held, it wouldn't have explained results like the Bullet Cluster (http://en.wikipedia.org/wiki/Bullet_Cluster), where maps of particulate dark matter have been made. No modified gravity theory or assertions that dark matter goes away under SR or GR can explain those findings. Dark matter is real and we now have tools with which we can spot it. The trick is now to figure out what it is.
You seem to have a real misunderstanding of how physics, and all science, makes progress. Once we have theoretical models, they are, generally, perfect. A good theoretical model explains ALL available data, or it isn't a good model. Once we have a good model, the only way to improve it is to go actively looking for where it diverges from reality. Only with this new input, divergence from theoretical predictions, can models be refined, improved or even replaced.
That's why we're hunting the Higgs particle. Fact is, the Standard Model is slightly broken. Without a Higgs mechanism, predicted lepton mass does not conform with experiment. We have a gap right now, a discrepancy. We think we have a solution in the Higgs field. We could, I suppose, assume there's a Higgs field, pick one of the several variants and go with it. Or we could, you know, do some actual science and go looking for the thing and nail down its properties. Along the way, if we see some of the other things we're half expecting, super symmetry, discrepancies in gravity at the millimeter range, broken symmetries, energy leakage at high energies or anything else, so much the better.
The problem with science is not a lack of fundamentals. The problem is the theories are too damned good. Reality simply does not diverge from the theories unless we get into some really exotic conditions. Why do we need a superconducting particle collider with a diameter measured in kilometers? Because our models are frikkin' perfect for everything up to that. We know they're wrong. We know we can't reconcile GR with the Standard Model. But we won't know how to proceed until we can break either GR or the Standard Model. We don't know what piece of the puzzle is missing until we actually go and look at things.
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Dark matter is real and we now have tools with which we can spot it
Or not. The Bullet cluster is one example that confirms some predictions of dark matter, but there still remain other problems, like the cuspy halo problem [wikipedia.org].
Reality simply does not diverge from the theories unless we get into some really exotic conditions
And that should get worse as our theories become more precise.
The problem with general relativity is that it gives very precise predictions for orbits in our solar system, but we do not have good measurements for bigger orbits. The Pioneer anomaly [wikipedia.org] and the flyby anomaly [wikipedia.org] could be indications of a deviation from general relativity. Perhaps a future theory o
Warning: Off-Topic Rant WIthin (Score:2)
"And even if that paper held, it wouldn't have explained results like the Bullet Cluster (http://en.wikipedia.org/wiki/Bullet_Cluster), where maps of particulate dark matter have been made."
Not having a beef with you at all because I agree with basically everything you say, but this is the bit that really upsets me about dark matter studies. (Not you -- about dark matter in general :) ) There is almost certainly no *single cause* of what we call "dark matter" (which is, after all, just the observation of an
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It's not enough to find the Higgs and confirm the standard model. No, we must always be looking for strange new shit that violates the laws of physics as we know them. New particles, new types of matter, dark energy, broken symmetry, anything unusual. And if it can't be proven so much the better. Yes, I'm still waiting for them to realize that Keplers laws do not apply to galaxies, and the galactic rotation curve does not require dark matter to explain. Some of them also fail at application of the divergence theorem when it come to gravity (they basically assume any mass distribution can be treated as a point mass). Let's get the fundamentals right first before we run off looking for actual violations of the laws of physics please.
Well hey, there's still physical phenomena which are poorly understood. OTTOMH, sonoluminescence, turbulence.
Here's some more: http://en.wikipedia.org/wiki/List_of_unsolved_problems_in_physics [wikipedia.org]
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FAIL it may never be ruled out (Score:2)
supersymmetry ain't... (Score:3)
Observation problem: A particle in a field creates a field wave/state. There are not two *-particles. The *-particle/object is observed, or the *-wave/state is observed. A distant *-particle in the same field will show a wave/state relationship with the other particle, but never a particle relationship. Additionally, if the gravity field is uniquely interacting with another field (levity) as a pure gravity field bound by a pure levity field (or more fields) and/or localities/spots of varying strength single mesh-fields... well it could be interesting... %~P
well if the cubs win it all this year (Score:2)
well if the cubs win it all this year (sadly not likely) then look out.
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Luminosity, not energy levels (Score:2)
The energy levels for LHC will be staying about the same from now till 2012. The difference is that it will be collecting more data, and thus increasing the luminocity [wikipedia.org] and statistical confidence that if supersymmetry is correct we would have seen something. This is the same reason that people were betting on whether Fermilab might find the Higgs Boson before the LHC; not because it is increasing energy levels, but because it has had more time to collect data and thus increase its luminosity. So it really is
Different meaning. (Score:2)
What they are saying in that paragraph is that enough data has been collected to rule out the possibility of squarks whose energy is 700 TeV or less. By the end of the year enough data will have been collected to rule out 1 TeV squarks. However, the total energy of the collider will be 7 TeV for the entire duration [web.cern.ch] (two 3.5 TeV beams hitting head-on). This is the same energy level [web.cern.ch] that was met before it shut down for the winter break.
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Werner von Braun said; "Research is what you're doing when you don't know what you're doing".