Does 'Stuff' Ever Disappear? From The Universe?

RJM Corbet

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What happens to 'stuff' that reaches the singularity at the centre of a black hole? DOES stuff ever reach the singularity? Or is the singularity always in the future for the 'stuff'?

Is the singularity always receding? Is infinite mass unreacheable by definition? This would seem to be the case?

I hope this is not too dumb a question?
 
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Laughingbuddha

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As far as I know, Stephen Hawking suggested that the black holes are gradually "vaporising" by means of the Hawking radiation, so that could be an answer to your question. Anyway, the black holes themselves are actually also part of our Universe, so technically the stuff, that got sucked by them is not disappearing from our big U, it just cannot get out of the black hole's premises.
 

RJM Corbet

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... the stuff, that got sucked by them is not disappearing from our big U, it just cannot get out of the black hole's premises.
But that isn't that 'stuff' trapped behind the event horizon that is still on its way 'down' to be crushed to infinity at the singularity -- at which point it ceases to be and leaves not even a dot in spacetime to show that it ever was or where it went?
 

tegeus-Cromis

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You can only look at the black hole from outside the black hole. The black hole's mass increases by the mass of the stuff it ingests, so that stuff does not disappear from our universe.
 

Laughingbuddha

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I think that any human language is inadequate for description of processes ongoing near the event horizon. Probably all this can be properly described only by means of really complicated mathematics, and have practically no analogues in the "common sense language", as it goes in all quantum physics.
 

RJM Corbet

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You can only look at the black hole from outside the black hole. The black hole's mass increases by the mass of the stuff it ingests, so that stuff does not disappear from our universe.
Then it is not a true singularity, but just a very heavy object? Where is the singularity that is actually creating the BH?
 

RJM Corbet

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I think that any human language is inadequate for description of processes ongoing near the event horizon. Probably all this can be properly described only by means of really complicated mathematics, and have practically no analogues in the "common sense language", as it goes in all quantum physics.
Yes I completely agree. But the BH effects and event horizon are a manifestation of the singularity, where all the calculations go to infinity?
 
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Laughingbuddha

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Then it is not a true singularity, but just a very heavy object? Where is the singularity that is actually creating the BH?
There are now several supposed ways leading to the formation of black hole, and the most common one is collapse of neutron star. So if we talk about numbers, the mass of neutron star should be at least 2.01-2.17 of solar masses to make it possible to collapse into the black hole. Its called the Tolman-Oppenheimer-Volkov limit, if I remember correctly.

And actually those calculations don't really go to infinity, I think they are exponential, and thats not quite the same
 

RJM Corbet

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There are now several supposed ways leading to the formation of black hole, and the most common one is collapse of neutron star. So if we talk about numbers, the mass of neutron star should be at least 2.01-2.17 of solar masses to make it possible to collapse into the black hole. Its called the Tolman-Oppenheimer-Volkov limit, if I remember correctly.

And actually those calculations don't really go to infinity, I think they are exponential, and that's not quite the same
Ok, I understand that the density of a BH must be greater than a neutron star. So what I'm after is whether there is such a thing as a true singularity, or whether that is really just an exponential division -- eg: by a half, then a half of that, then a half of that, etc -- with no actual 'singularity' but rather an ever receding movement toward an infinity which, by it's nature, can never be reached?
 

Laughingbuddha

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I think that the very term of "movement" is becoming totally meaningless once any amount of matter is dropping below the event horizon. That would be my best answer, but you know what? It's a really interesting question and I will try to find somebody competent to get a proper answer to this. You can try to do the same, so later we can share and compare our newly acquired knowledge )))
 

Venusian Broon

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But the BH effects and event horizon are a manifestation of the singularity, where all the calculations go to infinity?
Just because our calculations from an incomplete theory that we know is not a full description of the universe, goes to infinity at a point, doesn't mean that real stuff does the same. But I'd rather interpret the singularity as a breakdown of our understanding - it's as far as these mathematics can take us. Divide by zero is not calculable. It has no meaning.

I'd be willing to be bet that a real 'singularity' is in a new phase of matter or more probably a new phase of space-time, or whatever fundamental 'thing' that makes up the building blocks of the universe, that allows the black hole object to exist in some stasis that is not infinite. Until Hawking radiation, as @Laughingbuddha mentioned, evaporates it.

However I can't see a good way of actually experimentally figuring out what lies past the event horizon, as I can't see a way of getting results back 'out' back past that screen. So how could I ever know?

Perhaps if we came up with a better theory of everything we might have a different idea.

There are, of course, other ideas floating about, about black holes and what they contain. I recently read up a bit on Gravastars - essentially black holes - a few days back, where matter is compressed so much that it gets to the scale of 'superfluid space-time'. At that point the mass at a deep level is instantaneously converted to energy and space-time there goes to a different phase of being because of the influx of energy (a bit like the phase change when ice turns into water.) This new space-time exerts a negative pressure, counteracting the postive pressure of the gravitational mass. Further infalling matter from the shell of matter, after the initial set up, is converted to energy in the new space-time...which when expressed will, through the equivalence of mass and energy, produce some matter in the new space-time. Furthermore at the boundry of the superfluid vortices form, vortices that can guide and 'trap' the masses being produced into random densities.

So you have an expansionary space-time (a.k.a there is your 'dark energy') with mass and energy set in a random density distribution....sounds a lot like a new universe!

Anyway, pinch of salt time - this theory is really only being pushed by a couple of people, so it's not 'mainstream'. Is space-time a superfluid? Could it exhibit phase-changes? Is dark energy actually real anyway, as a number of results have shed some doubt on it? If the universe inside a gravastar is a superfluid it should be rotating - as it has to conserve the angular momentum of the initial star, so is our universe rotating? Are we inside a Gravastar?

Loads of questions, I'm afraid, not so many answers!
 

Brian G Turner

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What happens to 'stuff' that reaches the singularity at the centre of a black hole?
I don't think anyone knows - so far as I'm aware, the laws of physics as we know them break down after the event horizon.
 

Bagpuss

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Is infinite mass unreacheable by definition?
Usually, when theories predict that something becomes infinite or can increase without limit then it's a sign that there's something missing from the theory.

I think the reality is that notion of the "singularity" is a bit like "dark matter", it's a term that's been invented by physicists to cover up the fact that they have an observable effect, but they can't really explain the cause. It's quite possible that at some point in the future the physicists will figure out the missing piece (at the moment some theories of loop quantum gravity suggest that the singularity doesn't exist), and then the idea of infinite gravity or a "singularity" will be dropped in favour of whatever the real explanation might be.

Possibly, it could be that the centre of a black hole really is just a super-dense piece of matter that produces this intense gravity field (which is basically all the event horizon is). However, I'd be reasonably certain that whatever the final explanation is, "stuff" doesn't vanish from the universe. It might get converted from matter into energy and re-radiated as something else - but it doesn't disappear.
 

RJM Corbet

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There are, of course, other ideas floating about, about black holes and what they contain. I recently read up a bit on Gravastars - essentially black holes - a few days back, where matter is compressed so much that it gets to the scale of 'superfluid space-time'. At that point the mass at a deep level is instantaneously converted to energy and space-time there goes to a different phase of being because of the influx of energy (a bit like the phase change when ice turns into water.) This new space-time exerts a negative pressure, counteracting the postive pressure of the gravitational mass. Further infalling matter from the shell of matter, after the initial set up, is converted to energy in the new space-time...which when expressed will, through the equivalence of mass and energy, produce some matter in the new space-time. Furthermore at the boundry of the superfluid vortices form, vortices that can guide and 'trap' the masses being produced into random densities.
Oh ... kaay, lol
Thanks VB
:)

The 'edge' of.spacetime?
 
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Parson

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Parson holds hands on the side of his head .... I think my mind is disappearing into a black hole where nothing exists.


You all are way too smart for country parsons.
 

Star-child

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The definition of "singularity" in cosmology is simply that the tidal forces at the event horizon make what's under it impossible to measure or predict. The word doesn't mean "wormhole" or anything particularly concrete, but a lack of knowable meaning.
 

Ray Zdybrow

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Just because our calculations from an incomplete theory that we know is not a full description of the universe, goes to infinity at a point, doesn't mean that real stuff does the same. But I'd rather interpret the singularity as a breakdown of our understanding - it's as far as these mathematics can take us. Divide by zero is not calculable. It has no meaning.

I'd be willing to be bet that a real 'singularity' is in a new phase of matter or more probably a new phase of space-time, or whatever fundamental 'thing' that makes up the building blocks of the universe, that allows the black hole object to exist in some stasis that is not infinite. Until Hawking radiation, as @Laughingbuddha mentioned, evaporates it.

However I can't see a good way of actually experimentally figuring out what lies past the event horizon, as I can't see a way of getting results back 'out' back past that screen. So how could I ever know?

Perhaps if we came up with a better theory of everything we might have a different idea.

There are, of course, other ideas floating about, about black holes and what they contain. I recently read up a bit on Gravastars - essentially black holes - a few days back, where matter is compressed so much that it gets to the scale of 'superfluid space-time'. At that point the mass at a deep level is instantaneously converted to energy and space-time there goes to a different phase of being because of the influx of energy (a bit like the phase change when ice turns into water.) This new space-time exerts a negative pressure, counteracting the postive pressure of the gravitational mass. Further infalling matter from the shell of matter, after the initial set up, is converted to energy in the new space-time...which when expressed will, through the equivalence of mass and energy, produce some matter in the new space-time. Furthermore at the boundry of the superfluid vortices form, vortices that can guide and 'trap' the masses being produced into random densities.

So you have an expansionary space-time (a.k.a there is your 'dark energy') with mass and energy set in a random density distribution....sounds a lot like a new universe!

Anyway, pinch of salt time - this theory is really only being pushed by a couple of people, so it's not 'mainstream'. Is space-time a superfluid? Could it exhibit phase-changes? Is dark energy actually real anyway, as a number of results have shed some doubt on it? If the universe inside a gravastar is a superfluid it should be rotating - as it has to conserve the angular momentum of the initial star, so is our universe rotating? Are we inside a Gravastar?

Loads of questions, I'm afraid, not so many answers!
We know so little.
 

dannymcg

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There's "stuff" disappears from my fridge in large amounts, especially when grandkids are in
 
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