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tanzanos

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So how does this mass remain stable long enough to becoming a singularity?

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- Thread starter tanzanos
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- #1

tanzanos

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So how does this mass remain stable long enough to becoming a singularity?

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marcus

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There is no evidence that singularities actually exist in nature. The original meaning of "singularity" in a math-science context is a breakdown in a man-made theory. A place where the mathematical model we are using fails and stops giving meaningful numbers for answers.

Often a singularity is where the man-made mathematical model "blows up" and gives no number at all (infinite density, infinite curvature...)

We do not infer from that that NATURE blows up

That's only the impression given in popularizations, magazine articles, bestseller pop books.

=====================

There's probably something about that at Einstein-Online (link in my sig). But the main thing is that in the history of physics there have been lots of singularities (breakdowns blowups) and they have been FIXED by improving the theory and then checking the predictions of the improved theory.

So Einstein 1915 GR is the theory which, in this case, has a singularity in the Schwarzschild BH model (circa 1920). And the professional reaction is to admit that

we don't know what happens at the place where the classic unquantized theory breaks down

And we just have to wait until people fix the theory so it does not have a singularity, and then test the revised theory to be sure it makes more accurate predictions.

There are already (QG, quantized General Rel, quantum geometry) BH models.

There are BH models which do not have the singularity. Some of the people who have done the theoretical work are Kevin Vandersloot, Leonardo Modesto, Dah-wei Chiou.

But the work has not been observationally tested and AFAIK, the testing experts (phenomenology people) haven't taken the job over.

Work is much more advanced on getting rid of the cosmological singularity. The corresponding thing with BHs seems to be temporarily on the back burner. So we just have to wait and see.

Often a singularity is where the man-made mathematical model "blows up" and gives no number at all (infinite density, infinite curvature...)

We do not infer from that that NATURE blows up

That's only the impression given in popularizations, magazine articles, bestseller pop books.

=====================

There's probably something about that at Einstein-Online (link in my sig). But the main thing is that in the history of physics there have been lots of singularities (breakdowns blowups) and they have been FIXED by improving the theory and then checking the predictions of the improved theory.

So Einstein 1915 GR is the theory which, in this case, has a singularity in the Schwarzschild BH model (circa 1920). And the professional reaction is to admit that

we don't know what happens at the place where the classic unquantized theory breaks down

And we just have to wait until people fix the theory so it does not have a singularity, and then test the revised theory to be sure it makes more accurate predictions.

There are already (QG, quantized General Rel, quantum geometry) BH models.

There are BH models which do not have the singularity. Some of the people who have done the theoretical work are Kevin Vandersloot, Leonardo Modesto, Dah-wei Chiou.

But the work has not been observationally tested and AFAIK, the testing experts (phenomenology people) haven't taken the job over.

Work is much more advanced on getting rid of the cosmological singularity. The corresponding thing with BHs seems to be temporarily on the back burner. So we just have to wait and see.

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- #3

marcus

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...

So how does this mass remain stable long enough to becoming a singularity?

We don't assume singularities exist in Nature. We don't know the max density that is achieved in a BH collapse. (Although there are some preliminary models, nonsingular BH models in QG, that offer some estimates. Untested.)

We don't know what happens to matter contained at higher densities than neutron matter, I don't mean the very brief collision timescale in collider experiments---not sure how much can be deduced that is relevant to what would happen to neutron matter when further compressed.

You understand we are not talking about atomic nuclei, and ordinary radioactive decay.

Unconfined neutrons decay---they are not stable. But neutron matter is stable. It is energetically favored at the relevant (high) densities.

Beyond neutron matter, I have seen references to "quark matter" that is even more dense than neutron matter. And people write papers about the possibility of a "quark star".I think this is simply speculation, but I don't know about it. For me, anything denser than neutron matter is an area of ignorance.

Right now they are working on the big bang ("quantum cosmology"). We wait and see. Eventgually they'll get some cogent ideas about what happens at the pit of a BH.

- #4

tanzanos

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Thank you. You have partly answered my question! :)We don't assume singularities exist in Nature. We don't know the max density that is achieved in a BH collapse. (Although there are some preliminary models, nonsingular BH models in QG, that offer some estimates. Untested.)

We don't know what happens to matter contained at higher densities than neutron matter, I don't mean the very brief collision timescale in collider experiments---not sure how much can be deduced that is relevant to what would happen to neutron matter when further compressed.

You understand we are not talking about atomic nuclei, and ordinary radioactive decay.

Unconfined neutrons decay---they are not stable. But neutron matter is stable. It is energetically favored at the relevant (high) densities.

Beyond neutron matter, I have seen references to "quark matter" that is even more dense than neutron matter. And people write papers about the possibility of a "quark star".I think this is simply speculation, but I don't know about it. For me, anything denser than neutron matter is an area of ignorance.

Right now they are working on the big bang ("quantum cosmology"). We wait and see. Eventgually they'll get some cogent ideas about what happens at the pit of a BH.

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