6 upvotes, 0 direct replies (showing 0)
View submission: Ask Anything Wednesday - Engineering, Mathematics, Computer Science
Black holes aren't vacuum cleaners; they don't "suck" matter in. From a distance, they behave no differently than any other object of the same mass would.
Sagittarius A* makes up about a millionth of the total mass of the Milky Way, so except for the relatively small number of stars that orbit close to it, the gravitational influence it has is negligible. For our Sun, even tiny Pluto exerts a greater gravitational force than A* does.
No, there is no evidence for "micro" black holes. Extensive searches have been made, but outside of a few narrow ranges of black hole mass we've been able to rule them out.
Matter falling into an accretion disk reaches very high speeds, and so gains a lot of energy. This energy is released through collisions and friction within the accretion disk, and produces a lot of light and drives some matter outwards in powerful jets. For supermassive black holes, those jets can expel matter into intergalactic space, from where it will eventually, over many millions of years, fall back toward the galaxy.
Most matter in the accretion disk continues to spiral inwards though, until it eventually crosses the event horizon, the "point of no return" beyond which escape is impossible. That matter simply adds to the mass of the black hole.
There's nothing here!