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What Produces Gravity?

  1. Jun 22, 2010 #1
    What Produces Gravity??

    What produces gravity?? Is there any specific theory for this?
     
  2. jcsd
  3. Jun 22, 2010 #2
    Re: What Produces Gravity??

    The general theory of relativity.
     
  4. Jun 24, 2010 #3
    Re: What Produces Gravity??

    You may want to start where Einstein did, with his 1905 paper of Special Relativity: http://www.fourmilab.ch/etexts/einstein/specrel/www/

    Then from there consider, as 16180339887 said, the General Theory of Relativity. In that theory, there is the Stress-Energy Tensor (or Momentum Energy Tensor), which describes the feedback of mass warping spacetime, and following it geometrically in turn. In GR, gravity is not a force, but the geometry of spacetime. You might find the Wikipedia article useful, but I would still consider the Special case first.
     
  5. Jul 12, 2010 #4
    Re: What Produces Gravity??

    The General Theory of Relativity produces books and, unfortunately, Bohr's theories--or was that the Special Theory of Relativity?

    Gravity is a fact of the topology of the universe. Would you ask why there are hills?
     
  6. Jul 12, 2010 #5
    Re: What Produces Gravity??

    Sure. There is a lot of interesting physics going on in hill formation. :smile:

    Bad analogy...
     
  7. Jul 13, 2010 #6

    Chronos

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    Re: What Produces Gravity??

    The short answer is . . . mass. What causes mass is a different berry on a different bush. Most scientiscts still favor the higgs boson. LHC may provide a definitive answer to that hypothesis.
     
  8. Jul 17, 2010 #7
    Re: What Produces Gravity??

    mass or energy bends space-time , a photon has a gravitational field
     
  9. Jul 17, 2010 #8
    Re: What Produces Gravity??

    Not just mass and energy, but the full set of components of the Stress/Momentum Energy Tensor.
     
  10. Jul 18, 2010 #9
    Re: What Produces Gravity??

    What about the speculated gravitons? Don't they "produce" somehow gravity? (by existence of mass ofc).
     
  11. Jul 18, 2010 #10
    Re: What Produces Gravity??

    Even if they exist, they would be the quanta of gravity, mediating interaction, not the cause. Photons are the quanta of the EM spectrum, but they do not "cause" it.
     
  12. Jul 18, 2010 #11
    Re: What Produces Gravity??

    Doesn't relativity say that gravity is a self interacting phenomenon ,
    Is a graviton an excitation of the field , couldn't gravitons interact with each other ,
    Isn't a gravitational wave affected by gravity .
     
  13. Jul 18, 2010 #12
    Re: What Produces Gravity??

    I understand your point about the waves, but how would the quanta of gravity (whatever that would be) self-interact? Unlike gravitational waves, there isn't solid theoretical grounding for gravitons, so I'm not sure I can adequately answer your concerns... maybe others here can. Sorry Crager.
     
  14. Jul 19, 2010 #13
    Re: What Produces Gravity??

    Why does every one spell my name crager and not cragar , I think there some threads that talk about gravitons interacting , Wouldn't a graviton posses energy .
    so why wouldn't this energy be affected by other energy .
     
  15. Jul 20, 2010 #14

    Chronos

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    Re: What Produces Gravity??

    Einstein, in fact, predicted gravitational radiation was self interacting - as well as em radiation.
     
  16. Jul 20, 2010 #15
    Re: What Produces Gravity??

    Hmmm, I never noticed that about your name until you pointed it out, but that isn't atyptical: people work with their expectations.

    So, cragAr, I don't know about gravitons beyond their predicted spin, and what Chronos already said about gravitational radiation... although I think Einstein was thinking of waves and not quanta, maybe it is both. The waves would have to propagate through quanta if gravity is quantized, and if one self-interacts, then the quanta must to allow that to occur. It's logical, but gravitons are still completely hypothetical, whereas gravitational waves are probably on the cusp of confirmation.
     
  17. Jul 20, 2010 #16
    Re: What Produces Gravity??

    The graviton! Muah haha! Seriously...if it existed. Or at least if we could prove its existence. That seems to be the whole point to building the Large Hadron Collider.http://www.star-signs.org/compatible-star-signs.htm [Broken].to figure out and prove what keeps everything in place in the universe. :) A good way to do more research is to learn about the Large Hadron Collider and also to delve into the current String Theories.
     
    Last edited by a moderator: May 4, 2017
  18. Jul 21, 2010 #17
    Re: What Produces Gravity??

    We don't know the ultimate source of gravitation, and the answers to your questions will have several Nobel Prizes attached to them. Regardless of what gravitation is or what produces it, we know very well by now how it works. As many others have mentioned already, GR is our most advanced and reliable theory of gravitation, which is described as an effect resulting from the geometry of spacetime.
     
  19. Jul 21, 2010 #18
    Re: What Produces Gravity??

    I would say the LHC has many purposes, but if there is a single "selling point" it's the search for the Higgs Boson, not the graviton. As for string theory, it needs a lot of work yet before something like the LHC is dedicated to searching for what could only be equivocal evidence of it.
     
    Last edited by a moderator: May 4, 2017
  20. Jul 21, 2010 #19
    Re: What Produces Gravity??

    It is just there.

    Weinberg would disagree with you.
     
  21. Jul 22, 2010 #20
    Re: What Produces Gravity??

    wikipedia --> gravity

    read up
     
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