« on: 30/01/2024 22:27:28 »
So from what I can tell from reading about this is that it actually seems to support the possibility that once the black hole does not contain enough mass to maintain the gravity well it's radius would become larger than its Schwarzschild radius and is no longer a black hole as light can then escape.
No, the event horizon radius would shrink in proportion to the shrinking in mass. Remember, all of the mass is concentrated into a singularity of zero size (this is why Halc says it doesn't have a meaningful density. Objects of zero size would have infinite density).
I found that in fact density is a vital part of calculation for the Schwarzschild radius of a black hole. And in fact that to exist smaller black holes must have an increased density. The increased density ultimately sets the size limit of black holes with smaller sizes based on the particles being squashed more, until we reach the limit of what can be squashed.
Density is important for when an object becomes a black hole. You can calculate the density of an object if all of its mass exists within its own Schwarzschild radius. However, it doesn't stay at that density. Since no force exists which can support a mass against such crushing force, it all collapses down into a singularity: an object of infinite density.
So as a black hole gets smaller it must increase in density to maintain the Schwarzchild radius.
We need to differentiate the density of a black hole as its mass divided by the volume of the event horizon versus the density of the singularity. All black hole singularities have the same density: infinite. What the wiki article is referring to is creating such a black hole from non-black hole matter (such as collapsing stars). It isn't referring to an existing black hole undergoing Hawking decay to become a smaller black hole.
The gravitational strength at the singularity is infinite is because the distances involved are zero. This is true for any finite value of mass. So even very tiny masses experience infinite gravitational force and thus the singularity cannot decrease its density to become something else.
However, all of these things are based on classical physics. It's quite possible that a black hole doesn't collapse to zero size due to quantum effects getting in the way. However, such a quasi-singularity would still be extremely small and extremely dense compared to anything else in the Universe.
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