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Does gravity apply at very short distances?

  1. Jan 30, 2008 #1
    What happens to gravity when something is very very dense but not a black hole?

    Do parts of it still attract each other as in less dense objects, ie according to the same inverse square law?
  2. jcsd
  3. Jan 30, 2008 #2


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    Newtonian gravity (inverse square) and General Relativity (Einstein/Black Hole gravity) are both theories - they don't describe what the world does, but, rather, describe what we think the world will do.

    In some sense, the inverse square law is always incorrect. As you deal with more massive objects, the size of the error is larger. There are observable differences in prediction for things like solar system orbital mechanics.


    That said, people don't know how gravity behaves at very short distances. At small scales, the effects of gravity are dwarfed by electromagnetic, strong, and weak forces, so small-scale gravity experiments are very difficult. Predicting and testing the behavior of gravity is an area of active research.
  4. Jan 30, 2008 #3
    What about observations of neutron stars, I understand there's only neutrons in them therefore no E/M interactions. Is there anything that tells us what gravity is like between the neutrons in a neutron star? Maybe the density says something. Is there any way to measure density variation with depth?
  5. Jan 30, 2008 #4
    You want to dabble at stellar activity. SOHO's data is interesting.

    Once thought to induce fission, super-mass now thought to induce fusion. But, I'd speculate there are other activities as well.

    Somewhere, along the way, instead of tending to stay at rest. A star is born. Then you've got an inundation of all types of momentums, tendency to maintain reactions, and what not.

    There's definitely a differencing of the inverse d^2 rule, what with the fusion. Amongst others.
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