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As we know that the black hole is a lump of highly dense matter, and that's the reason for it's so strong gravitational force. Bat let us assume that it has sucked up a huge amount of mass and it's gravitational force has become of very high strength. Than what will happen. Will the black hole collapse in itself like a dying sun an give birth to another worst nightmare for the cosmologist or anything else will happen.

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Meanwhile someone with actual knowledge of general relativity and/or cosmology writes an answer, as a comment I may add that you can't collapse what already collapsed –  Jorge Feb 22 '13 at 16:21
    
Your question presumes that a black hole has some structure/size, so that it could in principle collapse. That it NOT correct. –  Siva Mar 20 '13 at 5:27

3 Answers 3

According to general relativity, the matter in a black hole is already collapsed down to a volume of exactly zero. It is not meaningful to talk about further collapse.

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How can general relativity theory say it have collapsed to a zero volume. It have mass and it also occupy some volume in space. it have a shape, and even a radius? –  Akash Feb 22 '13 at 16:59
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@Akash: are you talking about the central singularity or the horizon that grows around the central singularity? If it's the singularity, then it is definitely an object that is of a dimension smaller than the enveloping space, and therefore, has zero volume. For instance, a spinning Kerr black hole has collapsed to form a ring-shaped object of zero thickness. We don't expect general relativity to be exactly right here, and that it will be corrected by quantum gravity. But if you believe relativity literally, the object has COMPLETELY collapsed. –  Jerry Schirmer Feb 22 '13 at 18:34
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A spinning black hole probably doesn't have a ring-shaped singularity (despite the fact that this is a solution of Einstein's equations), as that produces all sorts of paradoxes (including closed time-like curves, otherwise known as time travel). It may spontaneously break symmetry to become several point-shaped singularities orbiting around a center. But nobody really knows for sure. –  Peter Shor Feb 24 '13 at 2:22
    
@PeterShor: sure, but it's all speculation regardless, and the Kerr singularity is the best model we have. The CTCs are all confined to the interior of the inner horizon anyway. But yeah, until you have quantum gravity to resolve the issue, no one knows. You could also probably resolve the CTC issue with a gluing condition, too. –  Jerry Schirmer Feb 24 '13 at 3:02

A black-hole is the most dense, most collapsed object or state of matter in the universe. To our knowledge, nothing really changes as a black-hole increases in mass except that it gets bigger, and its gravity stronger. Its properties are, for most intents and purposes, scale invariant1.


1: Hawking Radiation is, in a way, an exception to this, but not astrophysically relevant.

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You are right it is something which collapsed really to a great extent. But what if it does collapse further the pressure and temp at it center will be like hell in a hell. Those conditions could give rise to pretty interesting event's that we don't know till the date. –  Akash Feb 22 '13 at 16:45
    
Hum, I'm puzzled by your statement " Its properties are, for all intents and purposes, scale invariant". A Schwarzschild black hole for example as a radius, a mass, so is not properly scale invariant (not to my definition at least), which properties are you thinking about? –  Learning is a mess Feb 22 '13 at 18:56
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@Learningisamess The gravity and radius both scale linearly with mass, is basically what I meant. There are no characteristic scales at which the properties change---for example, there is no special mass limit, or radius limit, etc. –  zhermes Feb 22 '13 at 21:12
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@Akash I didn't say its something 'greatly collapsed', I said it is the most collapsed. It can not collapse further. –  zhermes Feb 22 '13 at 21:12

Black holes can evaporate. Black holes formed beneath the Chandrasekhar limit will evaporate quickly.

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What does this have to do with anything? –  zhermes Feb 24 '13 at 1:28
    
You have a very strange definition of "quickly". –  Peter Shor Feb 24 '13 at 2:26
    
To decay "quickly" by the Hawkings process an black hole would have to have a mass around that of a smallish asteroid. One with a more than a solar mass would not be in any danger of going away any time soon, and in any case that process would not be described as "collapse". –  dmckee Feb 24 '13 at 5:13
    
I think the answer means to say something to the effect of: the black hole will not collapse (into itself). Instead, all its energy eventually goes out due to "evaporation". –  Siva Mar 20 '13 at 5:30

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