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How gravity can be bent if its just a messender particle.

  1. Feb 20, 2010 #1
    im very confused on how gravity can be bent if its just a messender particle.

    try to tell me as simple as possible so i can understand it im just a high school student
     
  2. jcsd
  3. Feb 20, 2010 #2
    Re: gravity

    In the classical theory of gravitation (general relativity) there is no messenger particle. Gravity is a manifestation of deformations in the space-time manifold due to distribution of energy in various forms. Gravitons are predicted to be the bosons (massless and with spin-2) that mediate a quantum theory of gravity, but we don't actually have a well-defined quantum gravity theory yet.
     
  4. Feb 20, 2010 #3
    Re: gravity

    so in other word gravity could come from a strech of space and time or it could be the transfer of the graviton? we just dont know yet?
     
  5. Feb 20, 2010 #4

    SpectraCat

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    Re: gravity

    In the Standard Model model of particle physics, all the forces have carrier particles ... for example, the photon is a carrier particle for the electromagnetic force. So in order for gravity to be described in that framework (which it currently is not), it must also have a carrier particle .. that was the predicted "graviton" that Tao-Fu mentioned. It is possible that we will eventually discover that there is no carrier particle for gravity, but in that case it would be part of some more general theory that we are not aware of yet.
     
  6. Feb 20, 2010 #5
    Re: gravity

    but if we know that space is conected to gravity in how gravity is bent by large mass objece why do they think it has a messenger particle
     
  7. Feb 21, 2010 #6
    Re: gravity

    Nobody really knows if there is a graviton. We're stuck with two problems:

    1.) The predictive success and some experimental verification of Relativity

    2.) The predictive success of Quantum Mechanics... or rather, its success in 'making stuff'.

    This is one of the many reasons why a unified theory of gravity (quantum gravity) needs to be developed. Your question is one of the most fundamental, if the THE fundamental problem in GR/QM right now.
     
  8. Feb 21, 2010 #7
    Re: gravity

    Can we think of gravitons as the ether in the case of gravity. The stress and strain of space as the pressure of gravitons?
     
  9. Feb 21, 2010 #8
    Re: gravity

    We don't know anything of the sort. Interpreting gravity as deformations in a manifold is consistent with our observations so far and it has made predictions that have been verified to a degree (frame dragging, for example), however, this does not mean that it it is somehow true. It is still a theory and must be compared with and tested against other theories. Obviously, there must be correspondence with any alternative theories -- i.e. the predictions that GR gets correct must be replicated by the competing theory in whatever domain they are both valid.
     
  10. Feb 21, 2010 #9
    Re: gravity

    Why ether? They don't imply any rest frame. A more direct comparison would be photons appearing as elements of electromagnetic fields. If I wanted to look for gravitons I would try hard to see classical gravitational waves and then work to get the sensitivity up and see if I could see evidence of quantization.
     
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