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Gravity and other fundamental forces

  1. Aug 24, 2011 #1
    What is it about gravity that is not yet understood unlike other fundamental forces.

    Isn't gravity just another force like the other three fundamental forces.
     
  2. jcsd
  3. Aug 24, 2011 #2
    If i am not wrong thn Gravitational Force is the only force that does not cause repulsion...
     
  4. Aug 24, 2011 #3
    Gravity is well understood in the contexts in which it has been measured so far, and is described using http://en.wikipedia.org/wiki/Introduction_to_general_relativity" [Broken]. The difference between how gravity is understood and how the other three fundamental forces are understood is that unlike the other forces gravity does not have an experimentally supported quantum description.

    General relativity says that the rest mass-energy of a system produces gravity, and that http://en.wikipedia.org/wiki/Black_hole_thermodynamics" [Broken] constantly come into existence and then cease to exist over arbitrarily short time scales, so extremely small black holes would always be forming, but this would violate energy conservation since the black holes could not cease to exist as required by quantum mechanics. Thus, naively combining quantum mechanics and general relativity leads to contradictions. Since gravity is much weaker than the other forces in the situations in which its effects have been measurable there has been no way, so far, to determine what actually happens over the small length and/or short time scales at which corrections to general relativity (or quantum mechanics) become important.
     
    Last edited by a moderator: May 5, 2017
  5. Aug 24, 2011 #4

    HallsofIvy

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    I'm wondering why you think that the "other fundamental forces" are well understood! We know no better what causes electromagnetic force than we do what causes gravity.
     
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