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Could gravity be a physical thing?

  1. Dec 17, 2015 #1
    Things like light waves and radio waves move at a similar speed. So in stead of saying radio waves travel at the speed of light, which is true, saying "the speed of information" also makes sense, because that's basically the univeral limitation for information to travel.

    However, I've heard that gravitational waves are said to move at the speed of information as well. If the sun were to disappear, we wouldn't actually fly out into the galaxy until another 8 minutes or so. If the same applies with light, and light is made up of photons, would gravity be made up of some physical thing like photons are? Photons are able to be sent out and absorbed. Gravitational waves are able to move at the same speed as light, so wouldn't it be delivering some sort of physical communication?
  2. jcsd
  3. Dec 17, 2015 #2


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    You are describing gravitons - the theoretical particle that mediates gravity - and would reconcile GR with Quantum Mechanics.
    They are the Holy Grail of particles. But so far, we have not found them.
  4. Dec 17, 2015 #3


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    We also don't have a chance to find them with any https://en.wikipedia.org/wiki/Clarke's_three_laws]reasonable[/PLAIN] [Broken] experiment, unless there are exotic things like small extra dimensions.
    Gravitational waves: problably within the next years. Individual gravitons, even if they exist: way too weak.
    Last edited by a moderator: May 7, 2017
  5. Dec 17, 2015 #4


    Staff: Mentor

    Yes; gravitational waves carry energy, just like light waves do. But gravitational waves are, on average, a lot weaker than light waves--more precisely, sources of strong gravitational waves are a lot rarer than sources of strong light waves. So it's much harder to detect gravitational waves than light waves.
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