- #36
Ookke
- 172
- 0
Let's say that a particle annihilates right after crossing the event horizon of a supermassive black hole. The annihilation produces two gamma ray pulses, one directed towards the singularity and other into the opposite direction.
I would guess that the outwards directed pulse can at least briefly visit above event horizon, since the particle is already quite high in gravitation potential when the annihilation occurs, and tidal forces are not strong at all at EH of a supermassive black hole. It's hard to see what mechanism could grab the gamma ray and pull it back before the EH, which was just crossed moment ago (especially when nothing out of ordinary seems to be going on).
However, I find it quite easy to accept that eventually the outwards directed pulse too will be pulled back into the singularity. It's just that the event horizon doesn't seem to make sense as a sharply defined surface, but rather it could be an approximate concept, like "any stuff below EH doesn't usually visit above it, but even if it does, it will be eventually pulled back into singularity". So the black hole would be totally black, when looked from far away enough, but not necessarily so when looked close above EH.
I would guess that the outwards directed pulse can at least briefly visit above event horizon, since the particle is already quite high in gravitation potential when the annihilation occurs, and tidal forces are not strong at all at EH of a supermassive black hole. It's hard to see what mechanism could grab the gamma ray and pull it back before the EH, which was just crossed moment ago (especially when nothing out of ordinary seems to be going on).
However, I find it quite easy to accept that eventually the outwards directed pulse too will be pulled back into the singularity. It's just that the event horizon doesn't seem to make sense as a sharply defined surface, but rather it could be an approximate concept, like "any stuff below EH doesn't usually visit above it, but even if it does, it will be eventually pulled back into singularity". So the black hole would be totally black, when looked from far away enough, but not necessarily so when looked close above EH.