What is the exact meaning of vicinity of Blackhole or a disk? Is this the same as inside the horizon for black holes? If so, why people don't say inside of BH, simply. What is the difference?
I use this phrase actually! and it may seem obvious but not to me, please somebody make it clear. I searched but I couldn't find an exact answer.
Edited: Until which radius from Blackhole I can use this word meaningfully? It's not clear to me its astronomical dimension. "near" is not enough to me. If it could be inside a horizon and also outside of it, it makes a huge difference from point of view of the observer at infinity, as you know, how I can call them by the same name and sometimes I mean one sometimes the other one.