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Why singularities and not exclusion?

  1. Sep 6, 2004 #1
    Hi, everybody always talks about black holes being singularities, but why does everyone always take GR's side and neglect Pauli's exclusion principle? Why do people assume gravity is stronger?

    Suppose I decide that gravity can't make mass infinitely dense because particles can't have the same state. What's wrong with that?
  2. jcsd
  3. Sep 6, 2004 #2


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    The singularity inside a black hole is a result of using only general relativity. When quantum theory is taken into account, there is no known sensible solution. In other words nobody really knows what happens inside a black hole.
  4. Sep 6, 2004 #3
    I know no one knows, but people still always talk about singularities. Those are the answers that are seen everywhere, and I understand that, but for the time being, I choose that singularities, and wormholes etc. are completely absurd, non-satisfactory, old news, and that there has to be a quantum explanation. What I do not see is what exactly happens when we take into account QM inside a black hole, how does QM fail? What are the non-sensible solutions?
  5. Sep 7, 2004 #4


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    this year Leonardo Modesto, a student of Rovelli at Univ. Marseille, applied QM to black holes and saw that the singularity goes away.
    it is not real.
    in a quantized version of GR it does not exist.
    Modesto paper is online at arxiv, just search by name Modesto


    Last edited: Sep 7, 2004
  6. Sep 7, 2004 #5
    okay.......here's a clue.

    Look for the jets :confused: :smile:
  7. Sep 7, 2004 #6
    Good! I hope Modesto is right! I'm rooting for QM! Woohoo!
  8. Oct 8, 2004 #7
    The exclusion principle is not neglected, it is taken into account in the equation of state, leading to degeneracy pressure. This has been understood since the work of Chandrasekar in th 1930's and is central to the calculation of the properties of compact objects such as white dwarves or neutron stars. However, given a sufficiently massive object gravity will always win out in the end, leading to a black hole.
  9. Oct 8, 2004 #8
    Thank you very much, Chronon. I will have to review this degeneracy pressure. It does ring a bell.
  10. Oct 8, 2004 #9


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    Permit me to add that the term singularity is used to describe where the mathematical model breaks down. Physical reality does not always respect our version of the laws of mathematics.
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