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Blackhole decay and gravitational wave

  1. Aug 1, 2005 #1
    hi
    i have few unclear things but i'm not sure if this is the correct thread.
    1.can anyone explain me how does a black hole deacy. please include no mathematics and only logic.
    2.is gravity wave something like electromagnetic wave transmitted by gravitons instead of a photon?but i heard; by some one not related to science; that it{wave of gravitons} comes in existance if only it is in motion relative to something. now doesnt that mean that it can come in existance and fade to black simultaneously[as something can be in motion or rest according to different observers at the same time].
    im not sure if it exists only in motion or at all times.
     
  2. jcsd
  3. Aug 1, 2005 #2

    EnumaElish

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    Yahoo search on " "black hole decay" " yields (inter alia):

    Link # One
    see esp. ---> Link # Two
    Link # Three
    Link # Four
    Link # Five (Look toward the end to see:
    etc.)
     
    Last edited: Aug 1, 2005
  4. Aug 1, 2005 #3
    the 3rd link u precribed says that only negative energy or particle or energy enters the blackhole but not positive thus making it decay. is this true than black hole fed on other particle increases instead of decaying!
     
  5. Aug 1, 2005 #4

    EnumaElish

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    AFAIK, antimatter particles would annihilate (cancel out) matter particles inside the BH, thus reducing the size of the BH. But I'm not a physicist so you shouldn't interpret this information as the "last word on BH decay." It's anything but.

    {P.S. There are messages posted on this or similar issues under threads in Quantum Physics, see e.g. Hawking's preprint: Information loss in Black holes.}
     
    Last edited: Aug 1, 2005
  6. Aug 1, 2005 #5

    pervect

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    Anti-matter particles would make a black hole grow - they have positive energies.
     
  7. Aug 1, 2005 #6

    EnumaElish

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    I hear you pervect. Unless they have negative energy as this link suggests:
    Or, more likely, I misnamed a "neg. energy" particle as "antimatter." Which would explain why I never thought myself fit for a physics degree -- or vice versa, whichever was first. :smile:

    {P.S. Oh, BTW, vice versa means the other way around, too, in Latin. Ahem.}
     
    Last edited: Aug 2, 2005
  8. Aug 1, 2005 #7
    Particles with negative energy and antimatter are different things. Both matter and antimatter can have positive and negative energy, so when matter and antimatter come into contact, although the particles are destroyed, their energy is still conserved, just released in the form of radiation. However, when negative energy and positive energy come into contact, they cancel each other out, and don't have to emit radiation in order to conserve energy (since one unit of energy plus negative one unit of energy is zero units of energy, so energy is still conserved without radiation being released). Hawking states that the reason the particles from the vacuum fluctuations always have negative energy is because the strong gravitational field gives them negative potential energy as they cross the event horizon:
    - Hawking, A Brief History of Time

    However, in Hawking's latest article (http://arxiv.org/abs/hep-th/0507171), it almost sounds like he's saying quantum tunnelling is the reason for black hole decay, which is atleast a different picture from the idea of negative energy particles falling in, although I don't know enough about it to know if it gives different predictions:
     
  9. Aug 2, 2005 #8

    pervect

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    As you guessed, (hypothetical) matter with a negative energy density is not called anti-matter. Sometimes it's called exotic matter.

    http://en.wikipedia.org/wiki/Exotic_matter
     
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