3 ms·

Well yeah, probably, but sometimes very weird analogies between systems turn out to produce real physics, and it doesn't even seem impossible to me that there's

Well yeah, probably, but sometimes very weird analogies between systems turn out to produce real physics, and it doesn't even seem impossible to me that there's something similar happening behind the event horizon of a black hole. I'm just hoping someone smarter than me has already done the math.

SiempreViernes 3y ago
Hawking radiation is due to process outside the black hole.
- andrewflnr 3y ago
  Yeah technically, in the current formulation, but I think at this point the smart money is on Hawking radiation being correlated with something on the inside. For instance this is my favorite solution for the information-loss problem, that the info is carried away by hawking radiation.
- raattgift 3y ago
  > Hawking radiation is due to process outside the black hole. Hm, yes, the Hawking quanta originate outside the event horizon, and not very nearby outside either (Giddings 2015 <https://arxiv.org/abs/1511.08221 https://arxiv.org/abs/1511.08221>, Unruh "Dumb Holes" 2007 <http://pos.sissa.it/cgi-bin/reader/conf.cgi?confid=43 http://pos.sissa.it/cgi-bin/reader/conf.cgi?confid=43>). However it's best to think of "the black hole" as the entire spacetime (in Hawking's 1974 treatment and similar; or alternatively out to somewhere in the asymptotic flatness), in which there are two regions without a horizon, one to the past of the event horizon formation, and one to the future of final evaporation. What goes into the horizon doesn't stay in, therefore what happens inside is part of the picture (and has been speculated about for fifty years! Fifty!)
raattgift 3y ago
There is a relationship in that both the "Spongebob cluster" and a black hole has negative heat capacity. The math is already there in the virial theorem. See <https://en.wikipedia.org/wiki/Heat_capacity#Negative_heat_capacity https://en.wikipedia.org/wiki/Heat_capacity#Negative_heat_ca...>. Detailed treatments of the non-relativistic case you can find in an undergrad astronomy textbook; the relativsitic singleton case ehhhhh I don't think you're ready for it but Wald's General Relativity §12.5 & §§14.3-14.4 would be a good choice (and he shows you the math, which has been known for several decades), and for relativistic orbits I think you need to go beyond textbooks (although you probably could start with numerical relativity textbooks, like Baumgarte & Shapiro or Alcubierre, although I don't have either handy to double-check where they go with thermodynamics. Oh and the paper I linked in a sibling comment has a good and relevant bibliography. <https://academic.oup.com/mnras/article/516/3/3266/6668807 https://academic.oup.com/mnras/article/516/3/3266/6668807>).
- andrewflnr 3y ago
  > the relativsitic singleton case ehhhhh I don't think you're ready for it You're probably right, I appreciate your frankness. :D I'll start with trying to wrap my head around negative heat capacity.
hermitcrab 3y ago
As far as I am aware the virtual particles near the event horizon of black hole behave nothing like stars in a galaxy. For a start, stars much more massive (many many orders of magnitude) and aren't influenced by quantum mechanical effects in the same way as individual particles.

SiempreViernes 3y ago

Hawking radiation is due to process outside the black hole.

andrewflnr 3y ago
Yeah technically, in the current formulation, but I think at this point the smart money is on Hawking radiation being correlated with something on the inside. For instance this is my favorite solution for the information-loss problem, that the info is carried away by hawking radiation.
raattgift 3y ago
> Hawking radiation is due to process outside the black hole. Hm, yes, the Hawking quanta originate outside the event horizon, and not very nearby outside either (Giddings 2015 <https://arxiv.org/abs/1511.08221 https://arxiv.org/abs/1511.08221>, Unruh "Dumb Holes" 2007 <http://pos.sissa.it/cgi-bin/reader/conf.cgi?confid=43 http://pos.sissa.it/cgi-bin/reader/conf.cgi?confid=43>). However it's best to think of "the black hole" as the entire spacetime (in Hawking's 1974 treatment and similar; or alternatively out to somewhere in the asymptotic flatness), in which there are two regions without a horizon, one to the past of the event horizon formation, and one to the future of final evaporation. What goes into the horizon doesn't stay in, therefore what happens inside is part of the picture (and has been speculated about for fifty years! Fifty!)

raattgift 3y ago

There is a relationship in that both the "Spongebob cluster" and a black hole has negative heat capacity. The math is already there in the virial theorem. See <https://en.wikipedia.org/wiki/Heat_capacity#Negative_heat_capacity https://en.wikipedia.org/wiki/Heat_capacity#Negative_heat_ca...>. Detailed treatments of the non-relativistic case you can find in an undergrad astronomy textbook; the relativsitic singleton case ehhhhh I don't think you're ready for it but Wald's General Relativity §12.5 & §§14.3-14.4 would be a good choice (and he shows you the math, which has been known for several decades), and for relativistic orbits I think you need to go beyond textbooks (although you probably could start with numerical relativity textbooks, like Baumgarte & Shapiro or Alcubierre, although I don't have either handy to double-check where they go with thermodynamics. Oh and the paper I linked in a sibling comment has a good and relevant bibliography. <https://academic.oup.com/mnras/article/516/3/3266/6668807 https://academic.oup.com/mnras/article/516/3/3266/6668807>).

andrewflnr 3y ago
> the relativsitic singleton case ehhhhh I don't think you're ready for it You're probably right, I appreciate your frankness. :D I'll start with trying to wrap my head around negative heat capacity.

hermitcrab 3y ago

As far as I am aware the virtual particles near the event horizon of black hole behave nothing like stars in a galaxy. For a start, stars much more massive (many many orders of magnitude) and aren't influenced by quantum mechanical effects in the same way as individual particles.