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That's actually a super-interesting result. It would be totally plausible to have supermassive black holes inside of universe-sized black holes. Neat.

by stouset 10y ago

lloeki 10y ago
I'm not sure because the above result doesn't say anything about the distribution of such mass, and intuitively since the light cone tips over once you're past the event horizon, everything inside is converging towards the singularity following a law that may prevent any black hole inside black hole from existing (but that's way over my head now).
- trhway 10y ago
  >everything inside is converging towards the singularity singularities are result of the pure abstract model of [mathematically] continuous spacetime. In real live at small scales the continuity gets broken and as one of the results of it we have QM - if you think about a typical large, star sized, black hole than you can see how degenerate matter in the center would provide the opposite pressure against collapse into singularity similarly like it happens in neutron star. The difference here is that in neutron star the limited existing mass of the star limits the resulting neutron degeneracy level achieved. In case of a black hole the process doesn't stop and as more and more mass comes in the degeneracy goes further/higher with the neutrons being pushed into even higher energy levels and starting to be teared apart into separate quarks and gluons, and as even more mass/energy comes in the quarks get teared apart even further one from another with the new pairs of quarks appearing as a result... That would provide the pressure opposing collapse into singularity. The more incoming gravitational mass/energy pressure the stronger the response. Btw, that boiling quark-gluon soup looks suspiciously like something that is hypothesized as what was in the beginning of our Universe ( what could have triggered the Big Bang explosion/expansion? - may be merge with another super-hyper-gigantic black hole).
  - pdonis 10y ago
    > In real live at small scales the continuity gets broken This is a common speculation in quantum gravity, but at this point that's all it is: a speculation. We have no evidence that spacetime is not continuous. And given the predicted scale at which continuity would break down if the quantum gravity speculations are correct (about twenty orders of magnitude smaller than the smallest scale we can currently probe), we aren't likely to be able to test those speculations any time soon.
  - pdonis 10y ago
    > if you think about a typical large, star sized, black hole than you can see how degenerate matter in the center There is no degenerate matter in the center of a black hole; it's vacuum inside. A black hole is not an ordinary static object with "stuff" inside, that happens to have a radius smaller than the Schwarzschild radius for its mass. It's a fundamentally different kind of thing: it's made of spacetime curvature, and that's all. > In case of a black hole the process doesn't stop and as more and more mass comes in the degeneracy goes further/higher with the neutrons being pushed into even higher energy levels and starting to be teared apart into separate quarks and gluons, and as even more mass/energy comes in the quarks get teared apart even further one from another with the new pairs of quarks appearing as a result... That would provide the pressure opposing collapse into singularity. There have been speculative models along these lines, but none of them have any experimental support. > that boiling quark-gluon soup looks suspiciously like something that is hypothesized as what was in the beginning of our Universe Same comment--there are speculative models along these lines, but none of them have any experimental support. Figuring out a way to test these models, as well as many other different speculative models of the very early universe, is an open area of research in cosmology.
pdonis 10y ago
> It would be totally plausible to have supermassive black holes inside of universe-sized black holes No, it wouldn't. You can't have one black hole inside another one. A black hole is a region from which light can't escape to infinity. There can't be such a region inside another one; that makes no sense.
- stouset 10y ago
  You're playing semantics here. If you define a black hole as a clump of matter entirely contained within its own Schwarzschild radius, then it seems that yes, you can have one inside of another. Even if you define a black hole as "a region from which light can't escape to infinity", a theoretical black hole inside of another black hole doesn't violate this definition.
  - pdonis 10y ago
    > You're playing semantics here. No, I'm using the term "black hole" as it is actually defined in physics. > If you define a black hole as a clump of matter entirely contained within its own Schwarzschild radius Then you are not defining the term "black hole" as it is actually defined in physics. > Even if you define a black hole as "a region from which light can't escape to infinity", a theoretical black hole inside of another black hole doesn't violate this definition. Yes, it does, because once you are inside the boundary of one such region, that's it. There can't be a second boundary further inside; if there were, there would have to be a region from which light can escape to infinity (outside the second boundary), inside a region from which light can't escape to infinity (inside the first boundary). That's not possible. In other words, if one black hole falls into another, what you get is not two black holes, one inside the other. What you get is one black hole. The two holes merge into a single hole.
    - stouset 10y ago
      > > If you define a black hole as a clump of matter entirely contained within its own Schwarzschild radius > Then you are not defining the term "black hole" as it is actually defined in physics. Again, you're playing semantics here for literally no point other than to be a pedant on the Internet. JUST AS COOL AND INTERESTING is a clump of matter that fits inside its own Schwarzschild radius, that's inside a universe-sized black hole. In other words, the exact kind of structure I was talking about before you decided to derail the conversation. What the hell happened to you that you feel the need to remove people's wonder and enjoyment of science by pedantically correcting non-precise word choice? > Yes, it does, because once you are inside the boundary of one such region, that's it. Being inside the boundary of such a region does not preclude a subregion from itself having an escape velocity greater than the speed of light. Such an object seems to me that it still has all of the interesting properties of a black hole, while existing inside of a black hole. Again, do you feel like being a pedant contributed positively to this conversation in any way?

That's actually a super-interesting result. It would be totally plausible to have supermassive black holes inside of universe-sized black holes. Neat.

by stouset 10y ago

That's actually a super-interesting result. It would be totally plausible to have supermassive black holes inside of universe-sized black holes. Neat.

lloeki 10y ago

I'm not sure because the above result doesn't say anything about the distribution of such mass, and intuitively since the light cone tips over once you're past the event horizon, everything inside is converging towards the singularity following a law that may prevent any black hole inside black hole from existing (but that's way over my head now).

trhway 10y ago
>everything inside is converging towards the singularity singularities are result of the pure abstract model of [mathematically] continuous spacetime. In real live at small scales the continuity gets broken and as one of the results of it we have QM - if you think about a typical large, star sized, black hole than you can see how degenerate matter in the center would provide the opposite pressure against collapse into singularity similarly like it happens in neutron star. The difference here is that in neutron star the limited existing mass of the star limits the resulting neutron degeneracy level achieved. In case of a black hole the process doesn't stop and as more and more mass comes in the degeneracy goes further/higher with the neutrons being pushed into even higher energy levels and starting to be teared apart into separate quarks and gluons, and as even more mass/energy comes in the quarks get teared apart even further one from another with the new pairs of quarks appearing as a result... That would provide the pressure opposing collapse into singularity. The more incoming gravitational mass/energy pressure the stronger the response. Btw, that boiling quark-gluon soup looks suspiciously like something that is hypothesized as what was in the beginning of our Universe ( what could have triggered the Big Bang explosion/expansion? - may be merge with another super-hyper-gigantic black hole).
- pdonis 10y ago
  > In real live at small scales the continuity gets broken This is a common speculation in quantum gravity, but at this point that's all it is: a speculation. We have no evidence that spacetime is not continuous. And given the predicted scale at which continuity would break down if the quantum gravity speculations are correct (about twenty orders of magnitude smaller than the smallest scale we can currently probe), we aren't likely to be able to test those speculations any time soon.
- pdonis 10y ago
  > if you think about a typical large, star sized, black hole than you can see how degenerate matter in the center There is no degenerate matter in the center of a black hole; it's vacuum inside. A black hole is not an ordinary static object with "stuff" inside, that happens to have a radius smaller than the Schwarzschild radius for its mass. It's a fundamentally different kind of thing: it's made of spacetime curvature, and that's all. > In case of a black hole the process doesn't stop and as more and more mass comes in the degeneracy goes further/higher with the neutrons being pushed into even higher energy levels and starting to be teared apart into separate quarks and gluons, and as even more mass/energy comes in the quarks get teared apart even further one from another with the new pairs of quarks appearing as a result... That would provide the pressure opposing collapse into singularity. There have been speculative models along these lines, but none of them have any experimental support. > that boiling quark-gluon soup looks suspiciously like something that is hypothesized as what was in the beginning of our Universe Same comment--there are speculative models along these lines, but none of them have any experimental support. Figuring out a way to test these models, as well as many other different speculative models of the very early universe, is an open area of research in cosmology.

pdonis 10y ago

> It would be totally plausible to have supermassive black holes inside of universe-sized black holes No, it wouldn't. You can't have one black hole inside another one. A black hole is a region from which light can't escape to infinity. There can't be such a region inside another one; that makes no sense.

stouset 10y ago
You're playing semantics here. If you define a black hole as a clump of matter entirely contained within its own Schwarzschild radius, then it seems that yes, you can have one inside of another. Even if you define a black hole as "a region from which light can't escape to infinity", a theoretical black hole inside of another black hole doesn't violate this definition.
- pdonis 10y ago
  > You're playing semantics here. No, I'm using the term "black hole" as it is actually defined in physics. > If you define a black hole as a clump of matter entirely contained within its own Schwarzschild radius Then you are not defining the term "black hole" as it is actually defined in physics. > Even if you define a black hole as "a region from which light can't escape to infinity", a theoretical black hole inside of another black hole doesn't violate this definition. Yes, it does, because once you are inside the boundary of one such region, that's it. There can't be a second boundary further inside; if there were, there would have to be a region from which light can escape to infinity (outside the second boundary), inside a region from which light can't escape to infinity (inside the first boundary). That's not possible. In other words, if one black hole falls into another, what you get is not two black holes, one inside the other. What you get is one black hole. The two holes merge into a single hole.
  - stouset 10y ago
    > > If you define a black hole as a clump of matter entirely contained within its own Schwarzschild radius > Then you are not defining the term "black hole" as it is actually defined in physics. Again, you're playing semantics here for literally no point other than to be a pedant on the Internet. JUST AS COOL AND INTERESTING is a clump of matter that fits inside its own Schwarzschild radius, that's inside a universe-sized black hole. In other words, the exact kind of structure I was talking about before you decided to derail the conversation. What the hell happened to you that you feel the need to remove people's wonder and enjoyment of science by pedantically correcting non-precise word choice? > Yes, it does, because once you are inside the boundary of one such region, that's it. Being inside the boundary of such a region does not preclude a subregion from itself having an escape velocity greater than the speed of light. Such an object seems to me that it still has all of the interesting properties of a black hole, while existing inside of a black hole. Again, do you feel like being a pedant contributed positively to this conversation in any way?