String theory

Discussion in 'Physics & Math' started by ScRaMbLe, Dec 16, 2004.

  1. ScRaMbLe Chaos Inc. Registered Senior Member

    Messages:
    666
    I've been watching a program called "The elegant universe" on SBS. Its basically string theory for dummies... I quite enjoyed it.

    Anyway, it's left me with a few questions...

    Is string theory gaining real acceptance in the physics community and what are the chances of them being able to test it at the CERN collider in 2007?

    From what I understood from the program, according to string theory (or m-theory?) gravitons can escape from our universal membrane and cross over onto other membranes... Is this a possible explanation for dark matter, in that, it's really just gravitons escaping other membranes and entering ours?
     
  2. Google AdSense Guest Advertisement



    to hide all adverts.
  3. Alpha «Visitor» Registered Senior Member

    Messages:
    1,179
    That show's probably based on the book of the same name by Brian Green. It's quite good, and I'd recommend it.
     
  4. Google AdSense Guest Advertisement



    to hide all adverts.
  5. mathman Valued Senior Member

    Messages:
    2,002
    "Is string theory gaining real acceptance in the physics community and what are the chances of them being able to test it at the CERN collider in 2007?"

    String theory has a lot of followiers and many theoretical physicists are working in it. So far they haven't reached the point of defining any experimental tests.

    As for CERN 2007, they may be able to test supersymmetry or the existence of the Higgs boson. However, neither of these implies string theory is valid, but it is a step in the right direction.
     
  6. Google AdSense Guest Advertisement



    to hide all adverts.
  7. QuarkHead Remedial Math Student Valued Senior Member

    Messages:
    1,740
    You obviously know what you're talking about - please bring me up to speed with the Higgs Field (boson)
     
  8. ScRaMbLe Chaos Inc. Registered Senior Member

    Messages:
    666
    supersymmetry is testing whether there are the correct amount of gravitons after a collision, right? If there are less than there are supposed to be, then thats pretty strong circumstantial evidence towards string theory, as one explanation is that they possibly escaped our dimensional universe... have I got this right?

    I know the Higgs boson has been dubbed the "god particle" by some, but I dont know much else about it either...
     
  9. PhysMachine MALLEUS SCIENTIARUM Registered Senior Member

    Messages:
    208
    I'd say, from a school where most of the professors are opposed to string theory, that string theory isn't really gaining acceptance, but is merely "the only game in town." It has many problems that are being brushed under the rug, and many of the alternatives (such as loop quantum gravity as a theory of quantum gravity) are not as prominent in the public relations department.

    I personally do not believe in a theory of everything, and am extremely suspicious of any theory that claims to be one. As Richard Feynman once said "If theory doesn't follow experiment, then it's wrong" and so far string theory has yet to even have an experiment one way or another.

    If they discover supersymmetry or whatnot predictions in CERN, I will change my tune, but right now I regard string theory as an interesting exercise in mathematics that's lacking in real-world grounding.
     
  10. blobrana Registered Senior Member

    Messages:
    2,214
    Hum,
    did Feynman also say "If your mathematics doesn't match the experiment then it's wrong."

    Anyway,
    The people at the Department of Energy's Fermi National Accelerator Laboratory ( on June 9, 04) announced new results that change the best estimate of the mass of the postulated Higgs boson from approximately 96 GeV/c2 to 117 GeV/c2.
    They used precise measurement of the top quark mass to home in on the energy level of particle collisions required to produce a Higgs, and also verify whether the boson's existence is consistent with experimental data.
    "The result yields a greatly improved precision, of 5.3 GeV/c2, in the Dzero top mass measurement. The new measurement is comparable to the precision of all previous top quark mass measurements put together.
    When this new result is combined with all other measurements from both the Dzero and CDF experiments, the new world average for the top mass becomes 178.0 4.3 GeV/c2..."

    < edit - link lost >
     
  11. Onefinity Registered Senior Member

    Messages:
    401
    I think a theory is viable so long as it is useful. Just so long as people realize that models are models, and are not the same thing as the imaginary entity being modeled.
     
  12. PhysMachine MALLEUS SCIENTIARUM Registered Senior Member

    Messages:
    208
    The problem with that is that if you say there are 11 spacial dimensions to move around in, you have to have 11 spacial dimensions. If I say that atoms are made out of little turtle-people civilizations, but develop a theory that predicts atomic behavior, it's still absurd and requires that we observe little turtle-people building skyscrapers in the nucleus. The point is that, if you make some assumption that is completely physical, you had better be able to back up your physical assumption with experimental fact. Otherwise you have complete quacks making up models with no experimental support and proclaiming them true.
     
  13. Lucas Registered Senior Member

    Messages:
    447
    http://en.wikipedia.org/wiki/Higgs_boson
    "Higgs bosons are hypothetical elementary particles predicted to exist by the Standard Model of particle physics. These bosons are thought to play a rather fundamental role: according to the Standard Model, they are predicted to be the carrier particles of the Higgs field which is thought to permeate the universe and to give mass to other particles. As of January 2005, no experiment has detected the existence of the Higgs. The Higgs field is perceived the same from every direction and is mostly indistinguishable from empty space.

    A special article is dedicated to the Higgs mechanism, a physical phenomenon that is responsible for the spontaneous breaking of the electroweak symmetry.

    The Higgs boson, sometimes called the God particle, was first predicted in the 1960s by the British physicist Peter Higgs. The Higgs mechanism for giving mass to particles was actually first proposed in the context of solid state physics to explain how particle-like structures in metals can act as if they had an effective mass."
     
  14. Yuriy Registered Senior Member

    Messages:
    1,080
    Guys,
    we have wonderful thread in our Forum devoted to Higgs bosons: lette spend a lot of time to tell us quite complete story of these amazing bosons. Why, instead of go and read there, you are repeating whole way right here, in this thread?
     
  15. Lucas Registered Senior Member

    Messages:
    447
    Because Higgs bosons are an ingredient of string theory
     
  16. Yuriy Registered Senior Member

    Messages:
    1,080
    So, because the string theory (appeared after Higgs bozons already were invented!) did include the Higgs bozons in, we now should neglect the thread where we have a good description of physics of Higgs bozons and start to repeat the basics ... of Higgs bozons again (BTW: on much worse level then it already was done!) in this thread?
     
  17. fo3 acdcrocks Registered Senior Member

    Messages:
    552
    According to string theory, how big should the strings of energy be?
     
  18. geistkiesel Valued Senior Member

    Messages:
    2,471

    Please Register or Log in to view the hidden image!



    Didn't Fynman also say on page , 3-1-10 ch1, vol III of Feynman's, "Lectures on Physics":

    " We would like to emphasise a very important difference between classical and quantum mechancs. , , ,has physics given up on the problem of trying to predict exactky what willl happen in a definite circumstance? Yes physics has given up. We do not know how to predict what would happen in a given circumstance, and we believe now that is impossible - that the only thing that can be predicted is the probability of different events. ...It may be a backward step but no one has seen a way to avoid it."

    Are you using Richard Feynman as a positive reference that exhibtis itself as a knowledgeable source of useful information in the general field of physics and science?

    geistkiesel​
     
    Last edited: Mar 13, 2005
  19. ScRaMbLe Chaos Inc. Registered Senior Member

    Messages:
    666
    Ease up tiger. Quit your whingin and post a link already!

    Please Register or Log in to view the hidden image!

     
  20. Yuriy Registered Senior Member

    Messages:
    1,080
    Ask QH, he was the most active guy in that thread.
     

Share This Page