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Gravitons are still theoretical, of course, but I'm not quite sure how

  1. Dec 12, 2009 #1
    Gravitons are still theoretical, of course, but I'm not quite sure how they're supposed to fit into the current picture. If gravity is, in basic terms, caused by the curvature of spacetime around objects with mass, then what role would the theoretical graviton be playing? What comes first, the curve or the graviton? I just have no idea how the two fit together.

    Thanks for any help.
  2. jcsd
  3. Dec 12, 2009 #2


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    Re: Gravitons

    The bottom section of the virtual particles FAQ has some good info on this:
  4. Dec 12, 2009 #3
    Re: Gravitons

    How do gravitons cause light to bend?

    Also, could you clear out you PM?

    I wanted to ask you something and I do not want to hijack a thread.
  5. Dec 12, 2009 #4
    Re: Gravitons

    Well, I can understand light following a straight path through curved time, thus bending. So it's the curve that causes it to bend, if I'm understanding it right.

    I guess me asking, "what comes first, the curve or the graviton?" is sort of like asking, "what comes first, the photon or the light"? Anyway, thanks for pointing me to the FAQ. That clears it up a little.
  6. Dec 13, 2009 #5


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    Gold Member

    Re: Gravitons

    You shouldn't be too literal about interpreting curvature. Technically, curvature is a mathematical defect in space-time which is useful in creating gauge theories of gravity like GR ( which can be made by fixing a global->local invariance breaking under a transformation from a symmetry group). It's possible to construct theories theories that give the same predictions as GR using different symmetries and defects.

    However, if you insist on the reality of curvature, and you manage to quantise this approach, then gravitons will carry curvature, not momentum as in energy based gauge theories.
  7. Dec 13, 2009 #6
    Re: Gravitons

    Ahh, I get you. That's a helpful explanation.

    Right, that makes sense. I sort of figured that when I made my last post. Thanks for the reply.
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