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Math Science

String Theory Put to the Test 407

Posted by ScuttleMonkey
from the line-em-up-and-shoot-em-down dept.
secretsather writes to mention that scientists have come up with a definitive test that could prove or disprove string theory. The project is described as "Similar to the well known U.S. particle collider at Fermi Lab, the Large Hadron Collider, scheduled for November 2007, is expected to be the largest, and highest energy particle accelerator in existence; it will use liquid helium cooled superconducting magnets to produce electric fields that will propel particles to near light speeds in a 16.7 mile circular tunnel. They then introduce a new particle into the accelerator, which collides with the existing ones, scattering many other mysterious subatomic particles about."
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String Theory Put to the Test

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  • by hypnagogue (700024) on Wednesday January 24, 2007 @02:53PM (#17741060)
    Welcome to slashdot; here's your junk science for the day.

    You can't prove string theory through experimentation, all you can do is attempt to disprove it.
    • by stevesliva (648202) on Wednesday January 24, 2007 @03:00PM (#17741176) Journal
      Welcome to slashdot; here's your junk science for the day.
      Welcome to Slashdot; here's your whining about semantics for the day. Pretty soon you're going to tell me that "subatomic particles" aren't actually particles, per se.
      • by rumblin'rabbit (711865) on Wednesday January 24, 2007 @03:12PM (#17741398) Journal
        I don't think it's whining. The public's confusion about science surely stems in part from sloppy reporting.

        How often have we heard someone claim that we shouldn't allow something because it has never been proven to be safe? Such comments show serious misunderstanding about the nature of knowledge.
        • Re: (Score:2, Funny)

          by stevesliva (648202)
          How often have we heard someone claim that we shouldn't allow something because it has never been proven to be safe?
          Indeed, especially with regard to GMOs. Safety is a testable theory though, and "proven safe" is generally the third option of "lies, damn lies, and statistics."
        • Re: (Score:2, Informative)

          by cwm9 (167296)
          This is more than just "can't prove" in the "you can't prove you're alive" sense. It's more in line with the "you can't prove God exists" sense.

          If you think gravity causes objects to attract one another, you can test the theory by putting two objects near each other and measuring their force upon one another. A big part of your experiment is showing that it isn't an electrical or magnetic field that is causing the attraction. You show that the two objects attract one another in some new way outside of th
        • Re: (Score:3, Interesting)

          by gstoddart (321705)

          How often have we heard someone claim that we shouldn't allow something because it has never been proven to be safe? Such comments show serious misunderstanding about the nature of knowledge.

          OK, then disallow them until they have rigorously been established as not being dangerous. We'll grant you your metaphysical wiggling and make it nice and obfuscated (but logically and epistomoligically correct).

          Way too many things have been released where the person says "it's perfectly safe" and has no evidence to ba

          • Re: (Score:3, Insightful)

            OK, then disallow them until they have rigorously been established as not being dangerous. We'll grant you your metaphysical wiggling and make it nice and obfuscated (but logically and epistomoligically correct).

            It's not "metaphysical wiggling". It goes right to the heart of how we make decisions as a society. We ignore a deep understanding of the nature of risk at our peril. And this peril takes at least two forms: (1) avoiding beneficial practices because we mistakenly assume them to be too risky, a

    • by Bastian (66383) on Wednesday January 24, 2007 @03:04PM (#17741238)
      I wouldn't call that junk science so much as failure to make a pedantic distinction.

      If experiment can show that string theory makes predictions more accurately than current models, I'd say that proven is a good enough word to describe what has happened. Not in the sense that it's been shown to be an absolutely correct description of the machinations of the universe. Proven in the way that General Relativity was proven - decades before all of its predictions had been tested. Proven as in "it's been shown to be a better model," i.e., proven in about the same sense a person can "prove himself."

      • by PCM2 (4486)

        If experiment can show that string theory makes predictions more accurately than current models, I'd say that proven is a good enough word to describe what has happened.

        Part of the problem with string theory is that it makes no testable predictions at all. The experiment mentioned is intended to test some of the assumptions upon which string theory rests. Disprove those, and expecting string theory to produce meaningful predictions starts to sound a little silly.

    • by giminy (94188) on Wednesday January 24, 2007 @03:06PM (#17741292) Homepage Journal
      Thank you.

      Please vote to give this article the scientificmethodcantproveonlydisprove tag :).

      Cheers,
      Reid
      • Re: (Score:3, Funny)

        by truthsearch (249536)
        Please vote to give this comment the concatenated-words-need-hyphens-to-be-readable mod :).
    • by kripkenstein (913150) on Wednesday January 24, 2007 @04:31PM (#17742632) Homepage
      Welcome to slashdot; here's your junk science for the day.

      You can't prove string theory through experimentation, all you can do is attempt to disprove it.

      Depends on what philosophy of science you subscribe to:

      1. According to the 'old consensus' (e.g. the Logical Positivists, early 20th century), you can prove scientific theories.
      2. According to Karl Popper, you cannot prove theories, you can only disprove them. It appears that you follow this approach.
      3. According to W. V. Quine, you cannot prove or disprove theories, strictly speaking; evidence is taken along with previous information in order to arrive at conclusions.
      4. And if you listen to Thomas Kuhn, you get a really different picture from all of these (which I won't go into).

      Note that both Popper and Quine are among the most influential philosophers of the 20th century. It is of course legitimate that you are presenting the views of one of them. However, Slashdot readers should be aware of the existence of other views, both in science and in philosophy.
  • Bah (Score:5, Informative)

    by Phanatic1a (413374) on Wednesday January 24, 2007 @02:53PM (#17741066)
    It can't prove string theory. It can *support* it, or it can disprove it, falsify it, contradict it. But it can't confirm it. All the experimental data in the universe can't do that.
    • Re:Bah (Score:5, Funny)

      by Bluesman (104513) on Wednesday January 24, 2007 @03:05PM (#17741276) Homepage
      Actually, ALL of the experimental data in the universe could do that.

      • Re: (Score:3, Insightful)

        by Sunburnt (890890)
        Actually, ALL of the experimental data in the universe could do that.

        Of course, how would one know when they got there?
      • Re:Bah (Score:5, Insightful)

        by alienmole (15522) on Wednesday January 24, 2007 @03:18PM (#17741474)
        Not so fast -- for a start, you'd need all data from the universe's future, too. But even then, you still won't have proved your theory, unless you count all possible parallel universes too. Even if every event in the history of the universe fails to falsify a theory, it is still possible that you just got lucky, and nothing ever happened in such a way as to disprove the theory. Of course, I'll concede that in that situation, you've got a pretty useful theory and the errors it contains are moot for someone living in the universe in question.
      • Unfortunately that collection of data would have to part of the data itself, since it's part of the universe. And the part of the collection of data that represented the thing that collected data would have to be part of both the original collection, and part of the collection that represented the collection of data. And so on.


        Enough to give Bertrand Russell a splitting headache, who's memory would also be part of the collection.

    • Re:Bah (Score:5, Informative)

      by radtea (464814) on Wednesday January 24, 2007 @03:40PM (#17741852)
      The tests proposed would not "prove" string theory. They are only testing some of the fundemental assumptions on which string theory is based.

      The assumptions are:

      1) Lorentz invariance
      2) Analyticity
      3) Unitarity

      The problem is that these are not exactly assumptions but rather desirable characteristics of any good theory in this domain, period. If anyone comes up with an alternative to string theory that is even remotely within the bounds of conventional physics, it will also have these chracteristics.

      Lorentz invariance means that the theory is consistent with special relativity. Since our universe is manifestly correctly described by SR to a very high degree of accuracy, this is a desirable property of any theory of everything.

      Analyticity (am I spelling that right?) means that the theory is mathematically continuous, which is again something that seems to be highly desirable as our universe contains very few (probably no) formal sigularities. One major goal for theories of everything is to show that the singularities in general relativity are smoothed away at small enough scales.

      Unitarity means that the propogator conserves what is being propogated, so spontaneous creation or destruction of stuff doesn't just happen. Again, this is considered a generally desirable property, to the extent that any theory that lacked any of these three properties would be considered a very bad theory. The creator of such a theory would have to give some account as to why it was ok for their theory to not be Lorentz invariant, analytic or unitary.

      So this is not so much "testing string theory" as "testing some very basic assumptions about the constraints any good theory should fulfill." This is a good and worthy goal, but it is a very weird bit of marketing to advertise it as "testing string theory" rather than putting it in its more fundamental context.

  • by ThinkFr33ly (902481) on Wednesday January 24, 2007 @02:55PM (#17741092)
    The tests proposed would not "prove" string theory. They are only testing some of the fundemental assumptions on which string theory is based.

    If the test shows that one or more of these assumptions is incorrect, however, then it would probably force a very fundamental rethinking of string theory... essentially disproving it.
  • by eviloverlordx (99809) on Wednesday January 24, 2007 @02:55PM (#17741094)
    42.

    Did anyone honestly think that the answer would be different?
  • by elliott666 (447115) on Wednesday January 24, 2007 @02:57PM (#17741128)
    Oh...Large Hadron Collider. If it was in the Castro district I would really be suspicious.
  • by rewt66 (738525)
    Grinstein also noted that if their test does not substantiate what the theory predicts, one of the key mathematical assumptions about the current string theory would be incorrect.

    As opposed to the whole idea being bogus? The difference is whether you go for the New, Improved String Theory, Now With Fewer Bogus Assumptions(TM), or whether you throw the whole thing out. Sounds like the physicists want to try to tweak it rather than junk it, even if it fails the experiment.

    Note that "starting over with

  • Epicycles redux? (Score:5, Insightful)

    by sjbe (173966) on Wednesday January 24, 2007 @02:59PM (#17741154)
    I'm by no means an expert in string theory. I barely grasp the basic concepts. However I am an engineer who has taken a LOT of physics classes over the years and I'm not completely ignorant either.

    String theory has always struck me as a modern day version of epicycles before it was realized that planets follow ellipses instead of circles. It just seems like we're trying to fit the math to the model instead of modifying the model so that the math makes sense. Add in the fact that it makes no testable predictions (not yet anyway) and it's bordering on not being science anymore. Maybe technology advances will change that but then again maybe not.

    Maybe string theory is right, I don't honestly know. But it seems like a lot of group think is going on and little progress is being made.
    • Re: (Score:3, Informative)

      by stevesliva (648202)
      String theory has always struck me as a modern day version of epicycles before it was realized that planets follow ellipses instead of circles
      Epicycles were a way to explain why planets that were orbiting the earth apparently reversed their direction in our sky for certain periods of time.
    • Re:Epicycles redux? (Score:5, Interesting)

      by Ambitwistor (1041236) on Wednesday January 24, 2007 @03:28PM (#17741634)
      Everyone always seems eager to compare to epicycles any modern physics theory they don't care for. String theory, dark matter, what have you...

      Physicists were led to string theory in a search for a consistent theory of quantum gravity, not in a search to make up the most complicated theory possible to fudge arbitrary data. For more on why string theory should be taken seriously as a solution to this problem, you can read a long analysis in a previous post of mine here [slashdot.org]. String theory itself cannot be modified to "fit" to a model; it is a unique theory with no adjustable parameters or interactions. However, you can construct various string models to fit observations, as you can presently using quantum field theory models like the Standard Model.

      It is also not correct that string theory doesn't make testable predictions. This whole story is about testing predictions of certain string models. However, we can't presently test predictions of all string models at once, and thus rule out all of string theory. But then, the same is true of quantum field theory models as well; there are infinitely many such models that could be true but which we can't yet test.

      • by Ambitwistor (1041236) on Wednesday January 24, 2007 @03:46PM (#17741974)

        This whole story is about testing predictions of certain string models. However, we can't presently test predictions of all string models at once, and thus rule out all of string theory.
        Shame on me for not RTFA. The story is about testing all string models at once. However, the tests of are a very general sort (e.g., "do probabilities add up to 1") so, with the possible exception of Lorentz invariance (obeying special relativity at all scales), even non-string theorists would not bet highly on violations being seen.
    • by alienmole (15522) on Wednesday January 24, 2007 @03:29PM (#17741654)
      I think you're quite right. The problem, though, is that we really don't know how else to do this kind of science at this point. We've reached the edges of our ability to test theories, not just for want of bigger particle accelerators, but also because of more fundamental issues -- we're inside the universe, and there's no fundamental reason that we should be able to figure out exactly how it universe works, from the inside, any more than a creature inhabiting the two-dimensional surface of a balloon can figure out that the balloon's surface is supported by air pressure in a three-dimensional space.

      So in a sense, string theory is just the cover story that scientists use to continue conducting research. It's something to focus energy around, like the space program was for 1960's America. Eventually maybe we'll hit on some experimental data or a less unconstrained idea which gives us a clue as to how to proceed.
  • The LHC is at CERN (Score:5, Interesting)

    by Anonymous Coward on Wednesday January 24, 2007 @03:01PM (#17741182)
    I think it's funny how the article forgets to mention that the LH collider is located at the CERN (the European nuclear physics institute). As a matter of fact, it is not only in Switzerland, but extends to France as well. The article only mentions it is similar to the U.S. Fermilab accelerator, but then forgets to add that there are many kinds of accelerators world wide.

    Funny, ain't it?
    • by GrayCalx (597428)
      Funny? Funny how? Funny as in it personally offends you that its specific location isn't mentioned?

      Funny like, you naturally assuming the editor purposefully left out the location because it was not an American location?

      Or funny like "Hahahah that old woman slipped on some ice and broke her hip" funny? Cuuuuz I gotta tell you, I didn't laugh as hard as I did at that woman this morning.
  • Nothing new (Score:4, Informative)

    by forand (530402) on Wednesday January 24, 2007 @03:02PM (#17741200) Homepage
    The tests being proposed by the physicists in this blog would not test string theory, in that it does not test any prediction of string theory but the underlying assumptions. The write up is very misleading since Lorentz invariance has been tested throughout the past 80 years and always stood up to the tests. I suspect that someone wants to get more funding and mentioned testing string theory to a funding agency.
  • All the tests in the world can only do one thing with string theory: show that we haven't found a way to disprove it yet. All scientific theories are open to being disproven, that is the beauty of science, that is why it is not a religion, as much as religious types would like it to be, and despite the fact that many so-called scientists actually use it as a religion. The best one can hope for is that observation continues to bear out the predictive abilities of the theory. And you can consider a well te
  • Black holes? (Score:3, Interesting)

    by egrinake (308662) <erikg@code p o e t . no> on Wednesday January 24, 2007 @03:05PM (#17741274)

    I remember hearing about plans to use the LHC to produce and study miniature black holes. These are supposed to evaporate nearly instantanously due to Hawking radiation, but such radiation is only a theory without any experimental verification, and apparantly quite a few scientists are concerned it will just go ahead and gobble up the earth.

    At least it will be quick :)

    • The energies that will be created in the LHC happen on a daily basis in our upper atmosphere. The only difference is that we will have detectors in the immediate vicinity.
    • I remember hearing about plans to use the LHC to produce and study miniature black holes. These are supposed to evaporate nearly instantanously due to Hawking radiation, but such radiation is only a theory without any experimental verification, and apparantly quite a few scientists are concerned it will just go ahead and gobble up the earth. At least it will be quick :)

      First of all the black holes being created by the LHC are not intentionally being created -they are a predicted (by some) consequence o
      • Re:Black holes? (Score:4, Insightful)

        by vondo (303621) on Wednesday January 24, 2007 @03:36PM (#17741766)
        Second of all, a miniature black hole, even if it didn't dissipate due to Hawking radiation, wouldn't gobble up the Earth. It would still have the gravity of a mere two protons, since that is what constitutes its mass.
        Not quite. The theorized micro-black-holes would have masses of about 1000 protons, the amount of energy available in the collision.
        • The theorized micro-black-holes would have masses of about 1000 protons, the amount of energy available in the collision. That's a neat trick -but it makes sense. Thanks.
  • by hhr (909621) on Wednesday January 24, 2007 @03:07PM (#17741312)
    "The canonical forms of string theory include three mathematical assumptions--Lorentz invariance, analyticity and unitarity. Our test sets bounds on these assumptions." --Benjamin Grinstein

    Don't quantum mechanics and GRT also include the above? Meaning if the experements don't confirm the above then more than just string theory is in trouble.

    Of course analyticity probably has some very subtle meaning in string theory. Any one here in the know?
  • by Rob T Firefly (844560) on Wednesday January 24, 2007 @03:07PM (#17741324) Homepage Journal
    November 2007? Sure, what the hell, I've had a good life.

    So, who wants to loan me large sums of money? Pay you back in December?
    • by Quiet_Desperation (858215) on Wednesday January 24, 2007 @03:47PM (#17741994)
      We can have a raffle! How will the LHC destroy us? Check one: [ ] Microscopic black holes [ ] Trigger collapse of the false vacuum [ ] Strange matter [ ] Magnetic monopoles [ ] Disruption of the Wigner observer cascade causes a universal system reset [ ] God notices and stuffs us all into Carlsbad Caverns
  • Oh ye of little faith
  • by mugnyte (203225) on Wednesday January 24, 2007 @03:09PM (#17741342) Journal

      It thought this was cleared up years ago:

      Scanning/Copying based on a terminator byte pattern is fraught with error and is definitely not secure.

      Buffer sizes are terribly problematic when left tot he caller to check on overflow. It must be in the methods, and thus part of the data structure. (see point above).

      Strings these days are UTF-7 or 8, which makes them an even better candidate for a object-based construct rather than a memory map.

    I'd like to point out the....oh, wait...
  • If this is the same story referenced here [ucsd.edu], it's bogus [columbia.edu]. To quote Not Even Wrong [columbia.edu],

    It is based on a paper which has nothing to with string theory and doesn't do a string theory calculation at all. The paper first appeared on the arXiv last April with the title Falsifying String Theory Through WW Scattering, and was extensively discussed here. In October a new version of the paper was put on the arXiv, with a changed title Falsifying Models of New Physics via WW Scattering (and this was discussed here). I'm gu

  • by TheWoozle (984500) on Wednesday January 24, 2007 @03:18PM (#17741476)
    In what other endeavor can you persuade people to spend hundreds of millions of dollars to build complicated machinery and pay you a salary based on the following (roughly paraphrased) prospectus:

    "You see, what we'll do is accelerate some shit up to within a hairs-breadth of the speed of light then smash it into some other shit and see what happens."

    Gotta love those wacky physicists! ;-)
    • "You see, what we'll do is accelerate some shit up to within a hairs-breadth of the speed of light then smash it into some other shit and see what happens."

      Other than the speed of light part, most anyone who ever worked on a military weapons contract.

  • In Brian Greene's book The Elegant Universe (1999), he claimed that the LHC would be able to find the existence of superparticles that were predicted by string theory. I'm unable to explain a lot of the details there, but this new article seems pretty similar. 8 years ago we were waiting for the LHC to come along and have a chance of confirming string theory, and now some scientists tell us to wait for the LHC to be able to prove string theory. It's not like we ran out of ways to prove/disprove string th
  • by WED Fan (911325) <[akahige] [at] [trashmail.net]> on Wednesday January 24, 2007 @03:28PM (#17741628) Homepage Journal

    String Theory was proven on July 16, 2003, and confirmed after peer review and over 20 separate duplicated efforts, including a lab in Dallas, Texas.

    Proven: When you need a piece of string to tie something up, and you find a piece of string in a junk drawer, it will always be too short for use, or too long and when cut to the appropriate length, the remaining piece will be too short for further use.

    A similar, but as yet unproven theory is in testing: When you have a piece of string and measure it by "eyeballing" it will always be too short for actual use.

  • Some questions: (Score:3, Insightful)

    by Quiet_Desperation (858215) on Wednesday January 24, 2007 @03:32PM (#17741708)
    1. Which string theory? There's a few. Anyone who says "M-Theory" will get slapped.

    2. What predictions does the string theory in question make?

    3. Are the predictions unique to string theory?

     
    • Re:Some questions: (Score:5, Informative)

      by Ambitwistor (1041236) on Wednesday January 24, 2007 @03:42PM (#17741882)

      Which string theory? There's a few. Anyone who says "M-Theory" will get slapped.
      All of them. (And "M-theory" is a perfectly legitimate answer; you can't escape the fact that all the string "theories" are really just different regions of solution space of the same theory.)

      What predictions does the string theory in question make?
      In this case, unitarity, analyticity, Lorentz invariance, and crossing. (Or rather, that all those properties are obeyed to arbitrarily high energies.)

      Are the predictions unique to string theory?
      No, they're also axioms of standard relativistic quantum field theories.
  • If anyone cares to read a highly technical discussion of the paper by its first author (Jacques Distler), you can read his blog entries and the accompanying comments here [utexas.edu] and here [utexas.edu].
  • Mythbusters (Score:5, Funny)

    by Cervantes (612861) on Wednesday January 24, 2007 @03:44PM (#17741936) Journal
    it will use liquid helium cooled superconducting magnets to produce electric fields that will propel particles to near light speeds in a 16.7 mile circular tunnel. They then introduce a new particle into the accelerator, which collides with the existing ones, scattering many other mysterious subatomic particles about.

    This is why the Mythbusters should not be allowed to design scientific equipment. I can picture Adam dancing about in girlish glee even now...
  • Back when folks were still trying to figure out the Periodic Table of Elements, there was a promising idea which came out of the field of topology. It was based on the topology of knots, such as one could visualize as closed loops of string. It seemed to "predict" chemical properties for elements as heavy as Calcium but broke down beyond that. The similarity of the two patterns turned out to be only a coincidence, so the theory was discarded.

    I predict that this new incarnation of "string theory" will b

    • Wow, a theory totally unrelated to modern string theory was once disproved, and you "predict" that string theory will also be disproved for similar reasons.

      News at 11: phlogiston disproved, therefore string theory is wrong.

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