Hi,(adsbygoogle = window.adsbygoogle || []).push({});

I think I have several misconceptions about the theoretical framework of black holes, I'm just not sure where my intuition (or, lack of) goes wrong. So sorry if this sounds really stupid, any help is appreciated.

The scenario that I find confusing is what Alice sees when she throws Bob into a black hole, and what happens to Bob as he passes the event horizon (other than the extreme tidal forces he experiences). As far as I understand, Bob passes the event horizon fine using proper time, but Alice is in hyperbolic coordinates (don't know if that's the right name) so she sees Bob asymptotically approach the horizon for infinity but never cross it. The signal every tick of Bob's clock sends back to Alice is increasingly redshifted so she sees Bob's time slow down. Now, assuming I got all that right, here's what I don't get. If Bob brought everything but the kitchen sink with him into the black hole, than theoretically Alice would see Bob and everything but the kitchen sink outside the black hole forever. Wouldn't black holes be kinda luminous than? Would Alice never see the black hole grow as the result of Bob and everything but the kitchen sink? Don't we "see" black holes grow, and call them black for a reason? Does this have anything to do with the Unruh effect (which I've heard of but know nothing about) or the radiation jets I see in pictures but also know nothing about? Also, the equation I know for the Schwarzschild metric is dτ^2=[1-(2MG/r)]dt^2 -[1-(2MG/r)]^-1dr^2 -dΩ^2 . So after passing the horizon (r=2MG), the t and r components of the metric switch signs as if time and space have swapped roles. What am I missing there? Finally, does anyone have any good references on Rindler coordinates? When I was trying to read up on this there was something about the singularity lying on the time axis therefore being time-like rather than spatial--which I'm sure I just stupidly misunderstood but I'd like som intuition about that too.

A huge thanks to anybody who read all that! And once again, I apologize for my chaotically incorrect reasoning. Any hints are appreciated!

Sent from my iPhone using Physics Forums

**Physics Forums | Science Articles, Homework Help, Discussion**

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Help understanding black hole theories

Tags:

**Physics Forums | Science Articles, Homework Help, Discussion**