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Space Science

Gamma Ray Anomaly Could Test String Theory 128

Posted by kdawson
from the finally-experimental-data dept.
exploder writes "String theory is notorious for its lack of testable predictions. But if the MAGIC gamma-ray telescope team's interpretation is correct, then a delay in the arrival of higher-energy gamma rays could point to a breakdown of relativity theory. A type of 'quantum lensing effect' is postulated to cause the delay, which is approximately four minutes over a half-billion year journey." Ars's writeup is a little more fleshed-out than the Scientific American blog posting.
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Gamma Ray Anomaly Could Test String Theory

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  • by djupedal (584558) on Friday August 24, 2007 @09:07PM (#20350371)
    From the page...

    Update (August 24th): We're starting to see bloggers weigh in, including the inimitable Lubos Motl and Chris Lee at Ars Technica, though I'm surprised there's not more. Here we finally get some observations that probe string theory, if only tentatively, and people who have been loudly complaining about the lack of such observations have gone silent.

    Wow - if that's not a dare to be /.'ed, I don't know what is :)
    • Re: (Score:3, Insightful)

      by Guppy06 (410832)
      "if only tentatively,"

      The process of peer review requires that you actually give your peers time to review.

      "people who have been loudly complaining about the lack of such observations have gone silent."

      If someone's going to get emo over cries of "tests or GTFO," they're in the wrong line of work.
  • Wouldn't it suck to have to reboot during that 4.5 min? Oh crap, guys go home I'll see you in a few billion.
  • by E++99 (880734) on Friday August 24, 2007 @09:21PM (#20350465) Homepage
    While this is great research, even if it can be demonstrated that the higher energy particles traveled faster, this is not a prediction specific to String Theories, but as the arstechnica.com article points out, this is common to most quantum gravity theories. Still, it would be an awesome thing to prove.
    • by hedwards (940851) on Friday August 24, 2007 @09:53PM (#20350631)
      I think that it is definitely important to note, as you did, that this isn't just a matter for string theorists.

      I really wish that string theory wouldn't be glorified the way that it is. I am not aware of a single hypothesis that has been successfully tested and validated under it. And as you mentioned, string theory does predict something like this, but so do other forms of physics.

      This is definitely a significant finding, because gamma rays should be traveling at the speed of light, and only that speed through a vacuum. I read through things quickly, but it doesn't appear that any reasoning was advanced in the article for the delay. But as long as the rays left at the same time, this would be a problem for relativistic physics. Unless it turns out that there is some sort of mass in the medium, in which case the relativity is still fine.
      • Re: (Score:3, Interesting)

        by Anonymous Coward
        I really wish that string theory wouldn't be glorified the way that it is. I am not aware of a single hypothesis that has been successfully tested and validated under it. And as you mentioned, string theory does predict something like this, but so do other forms of physics.

        The neat thing about String Theory is that it is a coherent mathematical framework and a group of related models that unify the theories of several of the fundamental forces as they are currently understood. Essentially, it can't make pr
        • Re: (Score:3, Insightful)

          by Anonymous Coward
          If my understanding is right, though, string theories usually predict an infinite spectrum of increasingly massive particles. What is equivalent to the standard model is the low-energy limit, where we can ignore all but a finite number of low-mass particles. Thus string theories do make predictions that are testable - namely, that we'll keep finding new particles.

          Some physicists have taken certain physical laws as axioms for something like a first-order logic.

          The great part about loop quantum gravity is tha
      • Re: (Score:3, Informative)

        by suv4x4 (956391)
        Unless it turns out that there is some sort of mass in the medium, in which case the relativity is still fine.

        Well, there's some mass in the medium: the vacuum in the outer space isn't perfect. In fact no perfect vacuum exists.

        Relativists could argue this is enough for an effect of 4 min slowdown over 500 million years long travel.
        • That's what I'm inclined to think. But then, since we don't know whether the hi-frequency component was emitted <i>at the same time</i> than the rest of the signal, this observation should be considered meaningless, IMO.
        • Not to mention that the logic they use to compensate for the lack of control they have over the timing of emissions assumes the existence of what they are trying to find.
      • by mdsolar (1045926)
        Under GR, the effect of mass in the medium is to change the geodesic but this is achromatic. Are you thinking of electromagnetic effects that change the index of refraction as a function of wavelength?
        --
        Rent residential solar power: http://mdsolar.blogspot.com/2007/01/slashdot-users -selling-solar.html [blogspot.com]
    • String theory ought to be called bong theory. I'm sure they were high when they came up with it.
    • The problem is not with finding a way to prove string theory so much as find a way to falsify it. There are many ways to prove string theory, but seemingly no way to falsify it. Because every failed prediction it has made so far has been alright because both the failure and success have been within the realm of possibility of the theory. This is why I'm not a huge fan of string theory and generally feel that it is more akin to religion than science. But, then again, I'm not a physicist. So, what do I k
      • Well, the point of trying to prove or falsify physical theories isn't so much to prove it but rather to differentiate among the different theories.

        Basically you need a situation where the outcomes predicted by string theory, M-theory, relativity, quantum gravity, etc. are different. Then you run an experiment emulating this situation and see which one is right. This doesn't prove a theory but narrows down the possibilities.

        If I understand it correctly, right now the problem is that modern theories all expla
      • by sjames (1099)

        The problem is that string theory predicts absolutely everything! That is, you can make it say anything at all you want by plugging in a few variables. The result will be no more predictive of anything else than before the numbers got plugged in.

        String theory is interesting but it is actually too soon to call it a theory. It's more a bag of interesting tools and ideas that may one day be used to build a theory. I wouldn't go so far as to call it a waste of time (though some would), but it's not really wor

    • I did not look closely enough to see this first (perhaps because it is a pet peeve of mine), so I added an entry similar to this.

      Not only am I angry about Superstrings being hyped and taught as though they were fact, so-called "String Theory" is not even really a theory yet. As Ars pointed out, this is no more evidence for that than it is for other quantum gravity models.

      There is an article on the Net (you can find it at YouTube, search for "Ring of Dark Matter" that uses similar propaganda to present a hyp
    • by bcrowell (177657) on Saturday August 25, 2007 @12:12PM (#20354581) Homepage

      ...even if it can be demonstrated that the higher energy particles traveled faster, this is not a prediction specific to String Theories, but as the arstechnica.com article points out, this is common to most quantum gravity theories.
      Yeah, it's even possible to make a pretty reasonable model-independent argument that a variable speed of light must come out of any theory of quantum gravity. Lee Smolin makes a pretty simple model-independent argument that spacetime must be discrete in any theory of quantum gravity. The idea is that the Bekenstein bound [wikipedia.org] says there's a maximum amount of information that can be contained in any region of spacetime (e.g., a black hole has a certain entropy, which is proportional to the surface area of its event horizon). However, if spacetime was continuous, then you could store an infinite amount of energy in any volume of space. (Here [thymos.com] is a longer explanation.) Note that none of this requires any specific model such as string theory or loop quantum gravity. If spacetime is discrete, then there's a scale at which its discreteness occurs, and that corresponds to a certain minimum wavelength that a light wave can have. The propagation of light therefore has to be drastically modified as you approach that scale.

  • correction (Score:3, Informative)

    by Fry-kun (619632) on Friday August 24, 2007 @09:27PM (#20350491)
    the ars article says 3-4 seconds, not minutes
    • Some people ask me why I hate the term "FTW" ("for the win"). Simple: because it's a direct translation of "Sieg Heil"

      Boy, if you're that sensitive the Internet is going to be a very bad experience for you.
  • Ars's writeup is a little more fleshed-out than the Scientific American blog posting.

    I stopped reading Scientific American for the same reason I don't read USA Today. Because reading it is the same as not reading it.

    Now I read American Scientist.
  • Layman Alert. (Score:2, Interesting)

    by StickyWidget (741415)
    What else could have happened over a 4.5 Billion year journey to slow this burst down by 4.5 minutes? Forgive me, but when two cars start at the same spot and report equal velocity over a certain distance, I don't question the fundamental laws of physics, I look for a small bump in the road. Maybe a construct from string theory is the bump, but hows about we work with what we got, then move on to creating a new physics?

    But who am I to argue with quantum mechanics.

    ~Sticky

    • Re: (Score:3, Informative)

      by The_Wilschon (782534)
      I don't know the details here, but if I had to guess, I'd say that the 4.5 minute variation in travel time (or possibly 3-4 second... depends on which article you read) even over a 4.5 billion year journey would correspond to a bump in the road the size of the Matterhorn... In other words, the travel time varies hardly at all (perhaps microseconds, usually) even for very large road bumps, so a variation on this scale is statistically significant. Once again, I don't know the details of this particular exp
    • I never argue with Quantum Mechanics unless I'm at least a 13 level Wizard with plenty of HP, in which case I eat their corpse in the hope of getting speed as an intrinsic.

      But that's just me.
  • Relativity's Dead (Score:5, Informative)

    by einsteindotcubed (1146801) on Friday August 24, 2007 @09:33PM (#20350515) Homepage
    There is no need to confirm a breakdown of relativity. We already know that it is, at the least, incomplete, if not incorrect. Albert Einstein himself saw this, and was on his own quest for a "theory of everything" in his later years. String theory should become fully "testable" with the startup of the LHC (Large Hadron Collider, part of CERN) in May of 2008. Hopefully we may find proof for the God particle, also known as the Higgs boson. In any case, tremendous amounts of data will be reaped from this machine, and we may very well prove or at least expand upon string theory. (We could also completely disprove it, but I'm trying to be optimistic.)
    • No no no (Score:3, Informative)

      by Henry V .009 (518000)
      There is a need to confirm a breakdown of relativity. It's an incredibly well-supported theory that predicts things on cosmic scales down to the Hydrogen atom.

      The Higgs boson is predicted by the Standard Model, not String theory. String theory will be no more testable with LHC than it ever was. It's not even wrong.
      • Re: (Score:3, Insightful)

        by little1973 (467075)
        Actually, if the LHC does not find the Higgs boson that will be quite a win for String Theory. The Higgs boson is responsible for giving mass to the particles according to the Standard Model. String Theory explains the particles' mass in a different way.

        I am not a physicist, but I am under the impression that finding the Higgs boson would be a major setback for String Theory. So, in this way String Theory is 'testable'.
        • Re: (Score:2, Insightful)

          by Anonymous Coward
          I am not a physicist, but I am under the impression that finding the Higgs boson would be a major setback for String Theory.

          This is wrong. Finding a Higgs boson, or several, will not tell us anything about the validity of string theory.

          You're confusing two different effects. The masses that appear in the string spectrum -- corresponding to different vibrational states of the string -- are to lowest order integer multiples of the Planck mass. But we will never see anything but the first tier of excitation
      • by glitch23 (557124)

        String theory will be no more testable with LHC than it ever was. It's not even wrong.

        Actually, parts of string theory (which is really M theory) can be tested by the LHC when it comes online. The part I'm referring to is the existence of extra dimensions. The strings that represent gravitons are the easiest strings to generate and then detect because they require the least amount of energy (because they are closed strings and thus not tied to the brane [part of M theory] of our universe). I forget the exact details (and can't find a reference at this time) but by creating gravitons and de

        • by Xemu (50595)
          by creating gravitons and detecting where they go (if they go somewhere else we say they went to another dimension above spacial #3) we can determine the existence of the extra dimensions

          If we can create gravitons and send them to another dimension, and detect that, doesn't that mean that if people in the other dimensions can do the same, we can communicate with them?

          Graviton telegraph. You heard it here first.

          • That's already been done in a science fiction novel. Forgot it's name though.
            • by nagora (177841)
              That's already been done in a science fiction novel. Forgot it's name though.

              You thinking of The Gods Themselves by Asimov?

          • by glitch23 (557124)

            If we can create gravitons and send them to another dimension, and detect that, doesn't that mean that if people in the other dimensions can do the same, we can communicate with them?

            Uh I guess. The "other dimensions" are about 10^(-19)m in size and these are the extra large dimensions. Regular size dimensions predicted to exist by string theory are about 10^(-34)m in size so if you happen to know of anyone capable of living in space of that size then I guess you can start holding your breath for that signal from beyond.

          • by bentcd (690786)

            If we can create gravitons and send them to another dimension, and detect that, doesn't that mean that if people in the other dimensions can do the same, we can communicate with them?

            If there exists a fourth spacial dimension, then all of us already do live in that dimension. We just don't perceive it because it's incredibly small , as they theory goes.

            Also, just because you can move around a particle along the axis of the fourth dimension doesn't mean that you magically get to ignore the other three. If you want your particle that you manipulate in New York to be observable by your friend in Sydney then the three classical dimensions will need to be traversed before he can see it no m

  • by physicsphairy (720718) on Friday August 24, 2007 @09:43PM (#20350577) Homepage
    If the standard model fails, string theorists will laugh, jump and down, and point their fingers at their former naysayers.

    If the string theory model fails, it will be replaced with a newer, better version of string theory, with bountiful opportunities for new books, conferences, papers, and maybe even some derivative specialities of study.

    YOU CAN'T KILL WHAT LIVES ONLY THE MINDS OF MEN... BUWAHAHAHAHAAAAA!
    • This is exactly how I feel about relativity in general. I believe that yes, it passes every test we can throw at it right now, but one day it'll be shown that it's just plain silly. I don't have a better idea but do not prescribe to relativity.

      (Time dilation due to speed? Pft hardly. Maybe there are subatomic particles such as electronics whose movement becomes dampened when approach speed because they have a fixed absolute speed, or even slow downs at the quantum level [maybe], but that doesn't mean tim
      • Re: (Score:2, Insightful)

        by Anonymous Coward
        Isn't it also egocentric to assume upfront that you have the correct answer and all those other folks who worked on it all there life are a bunch of fools?

        PS I just remembered, your idea of an underlying mechanism was a common idea for a long idea for many scientists including Einstein, it is just that every experiment conceived by them proved them wrong and showed that it was exactly as the theory portrayed. So I wouldn't bet on your idea of how things work to be so certain.
        • by Epistax (544591)
          I don't have an idea of how things work, I just wish people would stop putting so much stock on whatever the belief of the day is.
      • by hankwang (413283) *

        Time dilation due to speed? Pft hardly. Maybe there are subatomic particles such as electronics whose movement becomes dampened when approach speed because they have a fixed absolute speed, or even slow downs at the quantum level [maybe], but that doesn't mean time actually moves at a different speed.

        I think you're talking about special relativity, not general relativity, and that you have never studied it in more depth than at a lay man level. The whole point of special relativity is that time is just an

    • Re: (Score:2, Informative)

      by glitch23 (557124)

      If the string theory model fails, it will be replaced with a newer, better version of string theory, with bountiful opportunities for new books, conferences, papers, and maybe even some derivative specialities of study.

      String theory doesn't really exist anymore or at least it is old news. String theory turned into superstring theory. Then there came to be multiple string theories that were very similar. About a decade ago Edward Witten created M theory [wikipedia.org] by reconciling the 5 string theory variations that existed. Maybe I'm wrong but my view is that M theory is the leading edge. I just got done reading Brian Greene's The Fabric of the Cosmos so it is pretty fresh in my mind but Wikipedia helped me remember a few things jus

      • IMHO, the grandparent was just pointing out that string theory has morphed as necessary to prevent itself from being discarded. M theory is just the latest attempt, but when it loses steam, string theorists will jump on the next "variant" to keep producing the "books, conferences, papers, and maybe even some derivative specialties of study" mentioned by the grandparent, of which Brian Greene's book is an excellent example.
        • by glitch23 (557124)

          M theory is just the latest attempt, but when it loses steam, string theorists will jump on the next "variant" to keep producing the "books, conferences, papers, and maybe even some derivative specialties of study" mentioned by the grandparent, of which Brian Greene's book is an excellent example.

          Right, because books, conferences, papers, etc. are only created for theories that can't be proven easily (or ever). String/M theory with regard to being researched and discussed in print is no different than any other theory. Brian Greene's book (Fabric of the Cosmos for those who didn't see my original message) is about more than just string/M theory. In fact, those topics aren't discussed until at least 75% through the book. I assume you haven't read it otherwise you would have known it isn't the sole

          • by kalidasa (577403)
            So I take it that both GP and P are fully versed in topology, abstract algebra, and the other fields needed to understand the mathematical underpinnings of M Theory, and so capable of directly evaluating the mathematical propositions of the theory/ies? 'Cause I know I'm not well enough versed in the necessary math, and I am sure as hell not going to try to take sides in the debate on the basis of a reading of either Brian Greene or Peter Woit.
    • weird interaction with noscript.

      How do you kill what which has no life?

      If you kill a sand worm, it will only shatter into many sand trout to form other worms.
  • Pah! (Score:3, Funny)

    by Reed Solomon (897367) on Friday August 24, 2007 @09:55PM (#20350649) Homepage
    Nothing can stop Hulk from Smashing string theory to bits. Hulk will destroy puny humans who betrayed him. Wait, that's a Skrull. Is nobody a human anymore?
  • The research looks legit, but the Slashdot tagline does not. The existence of such phenomenon does not appear to favor Superstring hypotheses any more than it supports a number of other hypotheses that are currently under investigation. ("Hypotheses", because they have not yet earned the name "theory" via prediction or testability.)

    Perhaps this will help sort things out, and even boost one or more of these ideas into actual theory status. Until then, it is premature to imply that this research constitutes e
  • Important caveat (Score:5, Insightful)

    by jlkelley (35651) on Friday August 24, 2007 @11:28PM (#20351213)
    IAAA [I am an astrophysicist], and I'd like to point out what I feel is an important caveat to this nevertheless very interesting work. From the paper itself:

          "We cannot exclude the possibility that the delay we find [...] may be due to some energy-dependent effect at the source."

    What they are saying is that there are still details we don't understand about AGN [active galactic nuclei] like Markarian 501. So, while this effect could be a first sign of quantum gravity (*not* string theory in particular, as others have pointed out), it could also simply be something going on in the intrinsic spectrum of the flares themselves. I'd personally consider the second explanation more likely at this stage.

    As they also point out, one approach to sort out the ambiguity would be to observe other flary AGN at different redshifts (distances). One could then, for example, see if the delay gets shorter or longer as the distance changes, as one would expect with a quantum gravity effect due to propagation to Earth.

    • by bcrowell (177657)

      What they are saying is that there are still details we don't understand about AGN [active galactic nuclei] like Markarian 501. So, while this effect could be a first sign of quantum gravity (*not* string theory in particular, as others have pointed out), it could also simply be something going on in the intrinsic spectrum of the flares themselves. I'd personally consider the second explanation more likely at this stage.
      Yeah, could you say more about this? My basic picture of an AGN would be that you hav

      • by TMB (70166)
        Most AGN are variable, most likely due to hydrodynamic instabilities in the accretion disk around the black hole (it's easy to get instabilities if the disk is massive enough, since clumps can then grow through gravity, but I think you can also get some due to the interaction with the wind and/or photons coming from right at the black hole/inner edge of the accretion disk due to self-shielding effects).

        [TMB]
        • by bcrowell (177657)

          Most AGN are variable, most likely due to hydrodynamic instabilities in the accretion disk around the black hole
          So why isn't it possible to have one flare that emits relatively low energies, and then four minutes later a second flare that emits relatively high energies?

    • by Fyz (581804)
      Since you're an astrophysicist, let me ask you something related to this topic. Do you think that the discovery of the OMG proton [wikipedia.org] and the fact that its observation casts doubt on the Greisen-Zatsepin-Kuzmin limit could be an indicator that new physics are needed?
  • Occam's Razor (Score:3, Interesting)

    by DynaSoar (714234) on Saturday August 25, 2007 @12:09AM (#20351407) Journal
    The simplest explanation is most likely to be true. Here's a hypothetical that's simpler than any quantum effect.

    The gamma rays are due to infalling material. Flares are due to sudden large amounts of material falling in. As it falls in it gets hotter. The frequency of the emissions increases as the material heats, going from lower gamma rays to higher gamma rays. These are all accepted as fact. The hypothetical: The 4 minute delay is the time it took for the material to fall in far enough to raise the emission frequency by the observed amount.

    Much simpler and neater. Even if I had the observed data and the data on the mass of the galaxy observed, I'm not capable of the relevant calculations, but the logic follows.

    On the other hand, Willam of Ockam didn't have a razor -- he had a beard. Einstein trumped Newton with a more complex theory, so the parsimony beloved by scientists doesn't always hold. But in this case, I suspect it will.

    • by DynaSoar (714234)
      > Einstein trumped Newton with a more complex theory

      The CEO reminded me that Newton only described, and admitted he didn't know how it worked, but Einstein explained which led to testable hypotheses. Thus the former was not much of a theory if at all by the definition, whereas the latter is a very good example of a theory.

      I had no idea she paid that much attention to my caffinated breakfast table rants. Obviously I don't.
    • Re: (Score:3, Insightful)

      by TrekkieGod (627867)

      On the other hand, Willam of Ockam didn't have a razor -- he had a beard. Einstein trumped Newton with a more complex theory, so the parsimony beloved by scientists doesn't always hold. But in this case, I suspect it will.

      Although it is true that sometimes the simplest explanation isn't the right one, the breakdown of Newtonian physics at relativistic speeds isn't an example of a failure of Occam's Razor. We say that the simplest explanation that fits observations tends to be the right one. Since Newton's equations don't work at relativistic speeds, it doesn't fit observations, so it's obviously incomplete. That's why it gets trumped. If relativity made the exact same predictions, then we'd say that this whole relative

    • Venturing off-topic here, but I can only imagine how many Einstein's and Newtons that have been killed by such a BS education system and societal upbringing. If find it very likely that the next Eianstein is collecting my trash and I just can't stand it anymore damn it.

      So Darwin was right, but his whole theory is breaking down with time. Survival of the fittest my ass. Survival of the economic producers and consumers, nuts to everyone else. Only stupid people are breeding. I'd really like to think tha
    • "Einstein trumped Newton with a more complex theory."

      Is it "parsimonious" to say Einstein generalised Newton? - One of Newton's stated assumptions was "time is constant". :P

      OTOH: 100 or so years after the Principa was published a (French?) woman of noble birth corrected Newton's kinetic energy equation by emprical means (ie: dropped steel balls into clay and mesured the craters).
      • Re:Occam's Razor (Score:5, Interesting)

        by DynaSoar (714234) on Saturday August 25, 2007 @08:36AM (#20353321) Journal
        > OTOH: 100 or so years after the Principa was published a (French?) woman of noble
        > birth corrected Newton's kinetic energy equation by emprical means (ie: dropped
        > steel balls into clay and mesured the craters).

        You're thinking of Emilie du Chatelet, paramour of Voltaire. I don't know how noble, but her family lived in a 30 room apartment overlooking Tuileries gardens in Paris. Certainly rich by birth, and married to a rich French military officer who conveniently left on a polar expedition.

        And you're not quite correct about what she did; it was much better than that. The dropped ball and clay experiment was done by Willem 'sGravesande in the Netherlands, but he didn't have the theoretical background to understand what he had -- the craters got deeper with the square of the height (== energy). Liebniz had previously specified that energy should increase with the square of velocity, but that was somewhere between intuition, anti-Newtonian leanings (Newton got credit for calculus rather than he; Newton was pushing for mass times velocity, no square) and fortuitous guesswork. He didn't have the practical sense to develop a means to test it (or perhaps thought that beneath him). What du Chatelet did was put the two together and show the precise relationship between energy, mass and velocity that was supported by the data: E = mv^2.

        Smiling Uncle Albert had it half written for him. What he plugged in was c for the Latin celeritas (rapidity), which he showed to have a limit of the speed of light, and that the E and m then equated completely and were thus interchangeable through it. Had she had the verification of Roemer's measurement of the speed of light to work with (said verification was just a few years old and not widely accepted yet) and had more time to work on it (she died from an infection after giving birth) she might have made progress towards that herself.

        If she had done so, Poincare probably would have grasped the significance of his "theory of relativity" (Uncle A. never used that term until well after it became popularized, but Poincare used it explicitly in his own) and formulated the famous equation himself. He was, after all, right on the verge of it, and refused to talk about Ol' Al forever more because he failed to get all the way there first. It riled him no end, until the end of his days. Had he been younger and the age earlier, he might have challenged the young Bavarian Jew to a duel. A duel such as Francois-Marie Arouet threatened against a certain French nobleman, which resulted in his expulsion from France to England, where he learned of Newton and his work, which he brought back to France, along with his nom de plume, Voltaire. Or the duel (fencing match, actually) in which Jacques de Brun, the head of the King's bodyguards, was bested by a 16 year old girl named Emilie de Breteuil, as such was her family's name when they lived above Paris's Tuileries gardens.

        If this was Connections, and I were James Burke, I'd be making a lot more money than what I'm getting for having written this. I am, however, every bit as pretty as Burke on camera, which is to say not at all.
        • "If this was Connections, and I were James Burke, I'd be making a lot more money than what I'm getting for having written this. I am, however, every bit as pretty as Burke on camera, which is to say not at all."

          Thankyou, I always forget her name as well as other details. That peice really is worthy of Burke, the thought even occured to me before I read the last line. I was addicted his column in Scientific american decades ago, I particularly liked the one explaining why the diameter of the space shuttle
          • by DynaSoar (714234)
            > Thankyou, I always forget her name as well as other details. That peice really is worthy
            > of Burke, the thought even occured to me before I read the last line.

            My wife made the same observation as I was preparing to submit it. The last line was hidden in the editing window. The construction was my own, but my source of information and inspiration was David Bodanis's "E=mc^2: A Biography of the World's Most Famous Equation". A very good science and technology history book in the spirit of Burke's work
    • Actually that is not true. When you apply Newtonian physics on a large scale you have to deal with things like infinite velocity, and things get pretty weird.
    • by Keys1337 (1002612)

      The simplest explanation is most likely to be true.

      The explanation for everything must be God then. That's as simple as it gets. I'm not sure how the mass interpretation of Occam's razor became going with the simple explanation. What does that have to do with a razor anyway? It seems to me the correct interpretation is Cut the crap.

  • String "theory" (Score:2, Interesting)

    Could someone explain to me a single phenomenon that is explained by string theory? Or a single predictive theorem, where thanx to string theory we expect to find x if conditions y are met? I need to know what I'm even looking for here.
    • Re:String "theory" (Score:4, Informative)

      by JetJaguar (1539) on Saturday August 25, 2007 @12:52AM (#20351599)

      Actually, there are a great many phenomena that string theory explains, the subject of this story, for example is potentially one of them, there's also some things about black holes (like Hawking radiation) which string theory predicts, but other theories also predict Hawking radiation.... plus there's a whole host of things that it predicts that occur at very high energies. But that's essentially the problem with string theory. The kind of things string theory predicts that would confirm it require energies that we are simply incapable of achieving, and the more mundane predictions made by string theory also happen to match predictions by competing non-string theories, making it pretty much impossible for string theory to distinguish itself using modern technologies.

      That being said, I think string theory is beautiful, however, it could very well turn out to be the most beautiful theory of physics ever constructed as well as the biggest dead end.

      • I too think it is a beautiful philosophy. Calling it science or even "theory" seems a stretch at best (scientists use the word theory a lot less loosely than other disciplines), and flat out insulting at worst, at least to the rest of us who bend over backwards trying to disprove ourselves, which is what any good theory does.
        • by JetJaguar (1539)
          Actually, I am a physicist by training. And while you are correct about the more formal definition of theory, colloquially most physicists and scientists in general are not nearly as precise talking amongst themselves as you suggest. I agree that it is sloppy though. mea culpa.
      • Thank you, do you have a link for something more specific? For Newtonian physics vacuumes proves things like inertia (no friction). For Einstinian, time dilation is strong evidence(and easy to understand, relatively). For string theory what kind of smoking guns/phenomenon work? I know you said Hawking radiation but that is pretty much heat from black holes, why would strings cause that? I'm just looking for a cause-effect relationship, doesn't have to be prove string theory, just show what it would predict
        • by JetJaguar (1539)

          Well, let's just take something really simple. String theory predicts the existence of...wait for it...strings (or branes depending on which form you are talking about) and extra dimensions. If the geometric structure of one of these things could be detected, that would be THE thing that would confirm the hypothesis beyond any shadow of a doubt. Directly detecting a string though runs into what I alluded to in my previous comment. The energies required to do this are beyond anything we are currently capabl

          • Lol, I get it, vibrating strings, but there isn't any way to detect them without using, wait for it, strings. Same problem we have with sub atomic particles, you can't really detect them without using them, but you can make perditions, like protons are made of certain mixes of quarks. I will accept that it may take more powerful science to detect them, but I won't accept a science unless it actually claims something. Otherwise I propose my trapezoid theory of the universe, that the universe is made of trape
            • by JetJaguar (1539)
              Well, you're more or less correct, however what I was getting at is that, there is a detectable difference between a string and point particle at high enough energies. So scattering strings would have different properties than scattering point particles. That is how you would make the detection, theoretically.
              • I understand, but there is still a lack of E=mc^2 to the whole thing (testable hypothesis), but I probably wouldn't understand it if it was told to me anyways.
    • by glitch23 (557124)

      Could someone explain to me a single phenomenon that is explained by string theory? Or a single predictive theorem, where thanx to string theory we expect to find x if conditions y are met? I need to know what I'm even looking for here.

      Have you taken a look at String theory [wikipedia.org] yet?

      • I purposefully did not, I find in it's own way the slashdot crowd knows how to cut to the chase faster than wiki. I went to wikipedia now and just don't have time to check the references. I'll try with I'm done researching Einstine's work.
  • can be found here:

    http://xxx.soton.ac.uk/abs/hep-th/0501117 [soton.ac.uk]
  • By itself variable speed of photons does not violate relativity. Suppose one day experiments would have shown that photons had a mass, like neutrinos. Then photons would not travel exactly the limit speed C. Relativity relies on this limit speed, not on the actual speed of photons. Electromagnetism does use C as speed of light. But then again, who expects such level of precision from a classical theory.
    • by Eukariote (881204)

      By itself variable speed of photons does not violate relativity.

      A variable speed of photons means a variable speed of light. And that does violate relativity theory since one of the postulates on which the theory is based is a constant speed of light in all reference frames.

      If you look into the history of light-speed measurements, you'll see that there is actually quite a bit of other evidence for a variable speed of light. The measured variations are small but well within detection capability of the ex

      • Are you talking about the errors of the experiment? Well, no device is perfect, all of them create errors.

        If you read the article, you'll see that the precision of similar experiments have grown a lot, and such errors never repeat on a highter precision experiment.

        • by Eukariote (881204)

          Are you talking about the errors of the experiment?

          No, I am talking about deviations from c markedly larger than the expected error magnitude of the instrument in question. Another series of experiments you might want to look at are those of Dayton-Miller. In particular his original papers and what the man himself thought http://en.wikipedia.org/wiki/Dayton_Miller [wikipedia.org]. There have been concerted attempts to explaining away those results by defenders of relativity theory...

          • Well, I can not explaint things better than the link you posted (maybe you should read it again). But I can point you that newer and more precise experiments weren't able to reproduce the results (your link points to some of them).

            • by Eukariote (881204)

              Well, I can not explain things better than the link you posted (maybe you should read it again).

              If you read carefully, you can see what his experiment found, and that the validity of those findings has retained support. That others tried to explain the results away is not surprising: obviously relativity has won the war of words and minds. The neutrality of the article is under dispute for a reason. One side would like you to please move along, nothing to see here, which you of course would prefer to do r

    • by opaqueice (602509)
      The result was that higher energy photons arrived later, and therefore (IF they were emitted at the same time) moved slower, not faster (which is what adding a mass would do).

      There is no even remotely conventional way to explain such a result.

      • ... higher energy photons arrived later ... There is no even remotely conventional way to explain such a result.

        Hold yer horses!

        In classical physics, the speed of light is a derived quantity: c = 1 / sqrt(epsilon * mu). Epsilon is the electrical permittivity of the vacuum, the degree to which an electric charge induces dipoles in (polarizes) the vacuum. Mu is the magnetic permeability, which arises from the geometrical effects of the Lorentz transform for particles in relative motion.**

        As a geom

    • First, photons have no mass. If you find some new particle with mass, well, it is not a photon. That is by definition.

      Second, relativity says that particles without mass travel exactly at C. That includes photons.

      Third, modern relativity comes directly from eletromagnetism. Both theories use the same experiments to calculate the light speed (actualy, C is defined, so those experiments ended up as the definition of a meter), so both have the same precision.

      • by tinkerton (199273)
        My apologies for not replying earlier. I was away.

        Your understanding of the relations between the theories and experiments needs some work. You can make a theory that has photons with mass 0 by definition, but photons are also experimental things. If a photon turns out to have mass it ruins the theory, but you're not suddenly going to call it by another name. Physics is not axiomatic mathematics.

        Nobody expects photons to have a mass. If photons had a mass it would be a disaster for some theories but not for
  • There are a couple of confusions here.

    First of all, this observation is FAR more likely to be due to variations at the source (which may have simply emitted the high-energy photons a little later than the low energy ones) then to some huge new discovery.

    Second, if this really is due to fundamental physics, it's a violation of Lorentz invariance (special relativity) and it would be about the best possible *disconfirmation* of string theory you could ask for (IAAST). If there's one basic prediction of

  • String Theory ST) has been tested as thoroughly as the Standard Model (SM). It's an alternative model, and physics presents mathematical models of the world. The models aren't the world. Insofar as String Theory predicts the same things as the Standard Model, it is just as tested as the Standard Model. All this talk of "untested String Theory" misses the point. It is very difficult to create tests that distinguish ST from the SM. But the observations predicted by each have been throughly tested because the
  • This could also mean the distance of the galaxy (and other objects) has been mistaken based on misconceptions of light. The distance is calculated with photons, but if the gamma ray follows a non-standard speed, who's to say the photons are going the right speed?
    • Go read up on google about that.

      C has changed, along with other "constants".
      • by Zareste (761710)
        Read about what? I don't see a contradiction anywhere
        • The contradiction is that the very fabric that controls C and other "hard variables" changes itself.

          What is the drift of C over 4B years? How could we even calculate an unknown drift value?
  • Hello:

    Like a good /. nerd, I do have my own unified field theory which has several testable hypotheses. It is 4D, I've got the action, field equations, and exponential metric solution for a point source. A discussion of the idea happened here:
    http://www.bautforum.com/against-mainstream/61876- gem-rank-1-unified-field-proposal.html [bautforum.com]
    One test is to measure bending of light to second order PPN accuracy, basically a million times more than was needed to tell the difference between GR and Newton. Do that for GR
  • We all know that Einstein space time is not euclidean. So if there is outward expansion from what we believe to be the big bang, which only moments before was a singularity, why is space time curved. Perhaps higher energies are closer to being mass, because they have more energy. Why can't we reverse E=MC2 and produce mass from energy, perhaps this could be source of dark matter. According to Einstein, more energy is required than is in the universe to accelerate a particle that is going less than the speed

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