Gravity Repulsion

  1. Every other force attracts and repels, gravity does not. Gravity only attracts. This is assymmetrical. We like to assume things that are not symmetrical are wrong. Why do we not assume this is wrong?

    Is there any possible way gravity could be repulsive? I know there is staggering amounts of evidence to suggest it isn't, but why not on very small lengths, say planck length, that gravity actually becomes repulsive.

    Maybe the repulsion is just "gravitons" get so thick in an exchange between two particles it just pushes them away to a very small length until the density of them goes down.

    Things like this idea would solve the idea of a singularity existing at the center black holes and such.

    Do we have any experimental data at such small scales? Do we have anything that disproves an idea like this?

    Just wondering.
  2. jcsd
  3. Search for the phrase "The nuclear force is only felt among hadrons. At much smaller separations between nucleons the force is very powerfully repulsive," in

    How could anyone find a gravitational force at small distances with strongly interacting particles around? Perhaps using weakly-interacting non-electromagnetic particles?

    Bob S
  4. mgb_phys

    mgb_phys 8,809
    Science Advisor
    Homework Helper

    Theres no evidence that gravity can be repulsed or even changed.
    Yes that doesn't fit into the pattern but thats not a very good reason to base anything on.
  5. Maybe the inability to see it is why we think it isn't there. Perhaps there is some way to assume what it is SUPPOSED to be, and we can see if there is any difference between that and what we experimentally see. Maybe the difference is gravity.

    Because gravity is very weak anyway, the repulsion would logically be weak.

    Also, on another related question (so as not to make another thread), if dark matter only interacts through the gravitational force, why is it not all just clumped together in one spot? Since there is no electromagnetic force to repulse it.
  6. A negligible scattering cross section plus remanent angular momentum of individual dark-matter particles around galactic centers will prevent clumping.
    Bob S
    Last edited: Jan 14, 2010
  7. A point in space where the total magnitude of energy is less than zero from our frame of reference. Better known as the theoretical negative mass. Let's just say physics isn't directly touching that subject yet, but there are people thinking about it.

    Oh and it's pretty arrogant to assume dark matter doesn't contain it's own particles of time interaction capable of repulsing each other. Do you really think everything is just made of protons/neutrons/electrons?
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