# Can a black hole collapse in itself?

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.

• 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
– J L
Feb 22, 2013 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, 2013 at 5:27
• We don't know that a black hole is a "lump" of highly dense "matter." We know that it has mass, and we know that all of its mass is within Swartzchild radius. General Relativity tells us that all of the mass must move toward a single point. But is GR True under such extreme conditions? We don't know, and nobody's yet performed an experiment that can answer that question. Oct 6, 2015 at 14:05

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.

• 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? Feb 22, 2013 at 16:59
• @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. Feb 22, 2013 at 18:34
• 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. Feb 24, 2013 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. Feb 24, 2013 at 3:02
• @Dimensionless, According to GR, It is physically impossible for anything that is inside the Swarzchild radius of a non-rotating black hole to not move toward the singularity if it is not already there. The singularity is an infinitessimal point, so either the density at that point goes to infinity, or else GR diverges from reality under those conditions. So far, nobody's been able to perform an experiment to tell us which is the actual case. Oct 6, 2015 at 14:01

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.

• 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. Feb 22, 2013 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? Feb 22, 2013 at 18:56
• @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. Feb 22, 2013 at 21:12
• @Akash I didn't say its something 'greatly collapsed', I said it is the most collapsed. It can not collapse further. Feb 22, 2013 at 21:12

The collapsing of the black hole is impossible. It is like trying to burn ashes. Ashes are already burnt. Similarly, the black hole is already collapsed. The black hole can evaporate and get bigger, but not collapse.

Well a black hole actually has 5 tons of mass or in other words a stellar hole if it collapsed into itself it would cause a hypernova Because according to the law of consevation of mass that mass cannot be created or destroyed but it can be rearranged in space therefor no mass can be .000000000000000000 Because that would mean a mass has been removed but most black holes have more than 10 times the mass of the sun my source is http://amazing-space.stsci.edu/resources/explorations/blackholes/lesson/whatisit/stellar.html

• How do you know that " a black hole actually has 5 tons of mass"? Oct 6, 2015 at 13:45
• If I'm not mistaken, the smallest observed black hole is $\sim10^{27}\text{ tons}$, which is well more than the five you're claiming. Also, do you have any relevant papers on "a stellar hole collapsing into itself" and hypernovae? Oct 6, 2015 at 14:04
• I am only in the eigth grade but even so black holes can have different masses it all depends of the schwartzchild radius Oct 6, 2015 at 16:49

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

• What does this have to do with anything? Feb 24, 2013 at 1:28
• You have a very strange definition of "quickly". Feb 24, 2013 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". Feb 24, 2013 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, 2013 at 5:30