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Thread: Could a pair of black holes undo each other?

  1. #1 Could a pair of black holes undo each other? 
    Time Lord
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    Suppose two black holes moved close together, sufficiently close that their gravitational fields strongly overlapped. In the region between them, the fields would begin to cancel somewhat.

    If they got close enough so that some of the matter that comprises the singularity was able to escape into that region (I would expect there is a strong force of repulsion present with matter that has been compacted into a singularity), and enough of it made it out, do you think it is possible that the two black holes might cease to become black holes? Would that mechanism allow the matter to spread out sufficiently so that it would not just immediately collapse again?


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  3. #2  
    Your Mama! GiantEvil's Avatar
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    Astronomers think they may have spotted a binary black hole system; Science Centric | News | Binary black hole system identified.
    In the event of converging black holes they would form a black hole of the sum of the masses of the two initial black holes.
    Things are not dispersed in a gravitational field, remember forces are toward the center.
    See; Spaghettification - Wikipedia, the free encyclopedia.


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    The Doctor Quantime's Avatar
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    Their gravitational fields would behave the same as if two planets were of the same mass and moved towards each other. Their matter would not go from one to the other, don't forget that the gravity acts at a point somewhere in the middle between the two massive objects. So no matter would leave either black hole, they would both simply move towards the middle point where all the gravity was acting and merge with one another. Thus becoming one black hole from the masses of both.
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    Your Mama! GiantEvil's Avatar
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    Quote Originally Posted by Quantime View Post
    gravity acts at a point somewhere in the middle between the two massive objects.
    No, that's not how gravity works. Gravity act's as two points, one each in the centers of the two objects.
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  6. #5  
    Forum Radioactive Isotope MagiMaster's Avatar
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    The point still stands. Black holes just merge. They don't pull each other apart.
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    Forum Freshman gottaBtold's Avatar
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    Quote Originally Posted by MagiMaster View Post
    The point still stands. Black holes just merge. They don't pull each other apart.
    Why would they "just merge" - because they are singularities, or because the math says so? This event would be something to see, that's for sure. I am really wondering what would take place as the two event horizons collide.

    A few questions come to mind. Would 1 singularity + 1 singularity = 1 singularity, or are the properties such that the two cannot "meld" to make one? In the example cited, one black hole is much larger than the other which should mean that the larger one will be the final result after overpowering the smaller. As they come closer together, what would the extraction of mass from one black hole to the other one look like and how much mass would be expelled beyond the new event horizon from the force of the collision? If there were mass ejected, what form would it be in - perhaps dark matter, maybe dark energy?
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  8. #7  
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    They would orbit each other just like any other massive objects, until their event horizons touch. At this point you will see nothing, just a larger ( equivalent to the sum of masses ) event horizon. I don' t recall if Wheeler's 'no hair' theory accounts for this.

    An event horizon is not a physical entity but a mathematical one, you can't touch it, smell it or taste it ( or anything else ). It defines a one way portal to our universe. Anything ( mass, energy, information etc) can go through but the only things that can 'come out' is gravity due to injested/collapsed mass/energy, EM field due to injested/collapsed charge and angular momentum ( spin ) of injested/collapsed mass/energy.
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