Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: acecharly on 28/08/2012 11:02:44

Title: Does matter enter a blackhole from any position?
Post by: acecharly on 28/08/2012 11:02:44

Does a blackhole have an entry point similar to how particles from the sun are pulled towards the poles in the aurora   or can matter enter from any position?

Cheers Ace

Title: Re: Does matter enter a blackhole from any position?
Post by: evan_au on 28/08/2012 12:43:26

An isolated, non-rotating black hole could have matter approaching from any direction, and orbiting in any orientation, and entering the event horizon at any point.

An active black hole is often surrounded by a massive, incredibly hot accretion disk of matter which orbits it like the rings of Saturn.  Matter falls into the black hole from the inner edge of the accretion disk, forming a preferred "entry point". Matter orbiting in other orientations will collide with the accretion disk, and be absorbed into it.

Rotating black holes have a phenomenon called "frame dragging", which would tend to pull nearby matter into the rotational plane of the black hole.

It's not quite clear why, but some galactic black holes seem to have large jets of matter expelled at high speed from their polar regions, which can be seen by radiotelescopes. I guess this forms a preferred "exit point" from the vicinity of the black hole.