so, it's not that nothing escapes a black hole, Neutrino do?
@artemis Nothing escapes black holes themselves. But the regions near black holes are where some really high energy things take place, including electron corona, accretion disks that release monstrous amounts of energy, and jets of material. It is these regions that produce emissions such as the neutrinos detected here.
@JWilliams
Awesome. Thank you for explaining. So, the regions nearby... Amazing how things are inter-connected.
@artemis yes. And the tremendous gravity well results in material which is falling in (being accreted) radiating away up to ~42% of the material's rest mass.
By contrast, nuclear fusion converts about 1/2% of rest mass into energy.
Accretion is the most efficient means known (aside from matter-antimatter annihilation) to convert matter to energy, and the regions near supermassive black holes are the most powerful long-term sources of energy in the known universe.
@JWilliams
So interesting.
I know this is a different sort of physics, but w'd I be wrong to interpret what you r saying as a form of energy conservation law? and, that energy and matter are part of a fluid continuum?
@artemis it's all conserved, yes. It gets kind of funky because the energies are so extreme that relativistic effects come into play. But the energy gained due to the change in potential as material falls into a black hole has to go somewhere -- in this case, it's being converted to heat (and radiated away), or neutrinos through other high energy processes.
@JWilliams
Amazing.
So tempting to imagine that one day it might* be possible to harvest this accretion energy.
@artemis the most current thinking (for which Hawking is known) is that black holes themselves are pretty much indestructible, BUT they do "evaporate" through radiation due to pairs of quantum particles that randomly pop into existence at the event horizon. These particles normally do that everywhere. But at the event horizon, one particle of the pair may be sucked into the black hole while the other radiates away, taking energy with it. After trillions of years, the black hole disappears.
@artemis of course, our observing time for black holes is a pretty short period of time, so it's entirely possible that there is other unexpected phenomena that impacts them.
Thank you for indulging my ignorance & my poetizing stars 😊
So, the fate of a black hole is inexorably unidirectional. If this has anything to do w/entropy, I kinda get it (somehow). Fascinating that random pairs of tiny quantum particles kamikaze themselves to slowly, but surely, 'evaporate away' the mighty dark black hole. Even more fascinating that one particle takes away the energy & runs with it, going somewhere. Perhaps, to make light. This is one heck of a cosmic dance.
@JWilliams
Cool. I mean, super-hot, at this levels of energy :--)
So, given the dynamic nature of this 'primordial soup' of energy and mass, w'd it be possible that a black hole is in fact, a temporary state, and that one day, it may wake up ? Yes, one day ,i.e. after ~ 1B+ years.