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Two Black Holes collide

  1. Aug 8, 2013 #1
    If two black holes with equal mass were to collide when they reach the point where their respective centers are at the schwarzchild radius of the other black hole could the spacetime distortions caused by their masses cancel out in such a way that matter/energy could escape along the plane of neutrality between their centers? Could there be other solutions if they are rotating or approaching one another at odd angles or tangentially to their surfaces?
     
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  3. Aug 8, 2013 #2

    PAllen

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    This sort of thing has been modeled in ever more detail using numerical relativity. It is important to understand what GR says about this process as well as possible because it would be an intense source of gravitational radiation. Detecting the predicted character of such an event would be a stringent test of GR in a new domain.

    What is expected per GR is simply a merger, with 'ring down' of the event horizons with release of characteristic, intense gravitational radiation. There is no indication of any possibility for matter to escape.

    A good place to browse for the latest on this is: http://www.black-holes.org, for example: http://www.black-holes.org/explore2.html
     
  4. Aug 13, 2013 #3
    Something related you might would want to check out are "short gamma-ray bursts".
    Some of them are considered to be merging black holes.
    Hope that helps.
     
  5. Aug 13, 2013 #4

    Chronos

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    The problem with the short gamma ray burst explanation as merging black holes is it fails to account for their distance. Why wouldn't their numbers tend to increase as cosmological distance decreases, where the universe is more ancient and black holes are consequently more numerous?
     
  6. Aug 13, 2013 #5

    phinds

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    The bolded part doesn't make sense to me. As cosmological distances decrease, we are seeing a LESS ancient universe, are we not?

    In any case, why would an older universe have more black holes? That implies that the universe has been losing black holes over time, whereas I thought it had been gaining black holes over time.
     
  7. Aug 13, 2013 #6

    Chronos

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    I think you misunderstood me, Phinds, stellar mass black holes should become increasingly numerous as the universe [and stars within it] ages. The nearby universe is more ancient than more remote [high redshift] regions. In fact, we reside in the most ancient region in the known universe. The light we receive from the moon is 1/4 second younger than us, the sun several minutes, alpha centauri about 4 years, etc.
     
  8. Aug 13, 2013 #7
    But then I don't understand how this conflicts with the interpretation of SGRBs being binary black hole mergers. Could you give your arguments for this suggestion?
     
  9. Aug 13, 2013 #8

    phinds

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    You are right ... don't know how I confused myself on this one, but I clearly did. Thanks.
     
  10. Aug 13, 2013 #9

    Chronos

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    Here is a link that may be interesting: Demographics of the Galaxies Hosting Short-duration Gamma-Ray Bursts; http://arxiv.org/abs/1302.3221. Obviously, we have limited data about galaxies where SGRB's occur [they are, after all, of short duration by definition]. The consensus is they tend to be more nearby than LGRB's, but, that species is also much brighter, hence, visible at greater distances. It is suspected that LGRB's originate from ginormous stars in young galaxies - which makes sense. SGRB's are still pretty much a mystery.
     
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