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>Rather than compressing particles [...] If you packed enough photons into one spot I haven't watched the video, but if we're compressing electrons, neutrons,

by tux3 22d ago

>Rather than compressing particles [...] If you packed enough photons into one spot I haven't watched the video, but if we're compressing electrons, neutrons, or other fermions, I imagine if we want to keep compressing that down to an arbitrarily small radius, won't we pretty quickly find it favorable to shift those fermions to something else, probably photons, to respect Pauli exclusion? Really, I don't know enough physics to figure out the reason why it shouldn't always end up in this incorporeal energy-curving-space situation either way, if we're compressing arbitrarily far.

cscheid 22d ago
Pauli exclusion is a QM thing. Black holes are a GR thing. Famously, we don’t know how to mix the two.
- eru 22d ago
  We don't know how to mix the two in general. There are plenty of tame enough special cases where we know how a mixture has to look like. Finding a tame enough special case was how Hawking discovered his radiation.
  - ben_w 19d ago
    > Finding a tame enough special case was how Hawking discovered his radiation. It's how it was formulated, but the radiation is far too weak to measure to know it's a real thing on an actual black hole; from this calculator, a 1 solar mass black hole has a Hawking radiation power of 9e-29 W: https://www.vttoth.com/CMS/physics-notes/311-hawking-radiation-calculator https://www.vttoth.com/CMS/physics-notes/311-hawking-radiati... We do see analogous effects in physical analogues of black holes, but we don't know for sure that Hawking radiation actually comes off of actual black holes. Worse, when they're small enough(!) to be luminous enough to actually observe, they should be hot enough to be spewing out a whole load of exotic nonsense particles (not just photons) that we don't really know how to model correctly with regards to Hawking radiation even if it is part of whatever ends up unifying QM and GR. Given even the event horizon of a BH doesn't play well with QM, it's probably best to wait for some physicists to work out how to combine QM and GR better.
inigyou 22d ago
But then you "fill up all the photon slots" too (not literally because they are not fermions, but they do spontaneously convert back into things like electrons at that density) and you can work around the Pauli exclusion principle by stacking your electrons at higher and higher energy levels. Pauli exclusion isn't an impenetrable force field - as you say, it's just often more favourable to do something else than to work around it. Consider an iron atom with however many electrons though - all those orbitals except the inner one are electrons working around Pauli. I'm not a physicist either.
georgeburdell 22d ago
Pauli Exclusion is just another “force” that can be overridden. Nature isn’t a list of rules

by tux3 22d ago

cscheid 22d ago

Pauli exclusion is a QM thing. Black holes are a GR thing. Famously, we don’t know how to mix the two.

eru 22d ago
We don't know how to mix the two in general. There are plenty of tame enough special cases where we know how a mixture has to look like. Finding a tame enough special case was how Hawking discovered his radiation.
- ben_w 19d ago
  > Finding a tame enough special case was how Hawking discovered his radiation. It's how it was formulated, but the radiation is far too weak to measure to know it's a real thing on an actual black hole; from this calculator, a 1 solar mass black hole has a Hawking radiation power of 9e-29 W: https://www.vttoth.com/CMS/physics-notes/311-hawking-radiation-calculator https://www.vttoth.com/CMS/physics-notes/311-hawking-radiati... We do see analogous effects in physical analogues of black holes, but we don't know for sure that Hawking radiation actually comes off of actual black holes. Worse, when they're small enough(!) to be luminous enough to actually observe, they should be hot enough to be spewing out a whole load of exotic nonsense particles (not just photons) that we don't really know how to model correctly with regards to Hawking radiation even if it is part of whatever ends up unifying QM and GR. Given even the event horizon of a BH doesn't play well with QM, it's probably best to wait for some physicists to work out how to combine QM and GR better.

inigyou 22d ago

But then you "fill up all the photon slots" too (not literally because they are not fermions, but they do spontaneously convert back into things like electrons at that density) and you can work around the Pauli exclusion principle by stacking your electrons at higher and higher energy levels. Pauli exclusion isn't an impenetrable force field - as you say, it's just often more favourable to do something else than to work around it. Consider an iron atom with however many electrons though - all those orbitals except the inner one are electrons working around Pauli. I'm not a physicist either.

georgeburdell 22d ago

Pauli Exclusion is just another “force” that can be overridden. Nature isn’t a list of rules