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> Is that true? Probably. We don't know for sure because quantum effects might change things, and we don't yet have a theory of quantum gravity. The event h
by lisper 4y ago
> Is that true?
Probably. We don't know for sure because quantum effects might change things, and we don't yet have a theory of quantum gravity. The event horizon of a black hole is pretty much the one place in the universe where the effects of quantum gravity are most likely to manifest themselves, so one should hedge one's bets when making predictions in their vicinity.
> It has never made sense to me, since we see effects of black holes all the time.
Falling into a black hole is different from falling into a regular gravitational field. All kinds of weird shit happens before you reach the event horizon. Among other things, tidal forces rip you apart, heat you up, and turn you into a plasma. That plasma emits radiation, and that is what you see (because all that happens outside the event horizon).
- bmitc 4y agoIt all depends on the size of the black hole. HUGE black holes have weak tidal forces.
- lisper 4y agoTrue, but the hole under discussion here is not one of those. (And it's important to note that big holes have weak tidal forces at the event horizon. They still probably have pretty significant tides close to the singularity, but God only knows what actually goes on in there).
- libraryofbabel 4y ago> but the hole under discussion here is not one of those. That’s not correct: It’s a supermassive black hole at the center of a galaxy; the tidal forces will be weak at the event horizon.
- lisper 4y agoYeah, I know that's what the news reports say, but I'm pretty sure they got it wrong. A galactic hole doesn't emit radiation (except perhaps Hawking radiation) because its tidal forces are too weak.
- pixl97 4y agoIsn't charge a conserved quantity? Tidal forces may be the least of your problems. The mass of millions of disrupted stars rotating at near the speed of light on powerful charged magnetic fields around the event horizon are apt to be a much bigger problem.