APOD 1.2

I learned that a black hole has never been seen directly and it is in the center of a swirling whirlpool of hot gas.  There is bright light emitted by the swirling gas and it has been studied in detail.  Interestingly, studies have shown that the surrounding gas flickers at a rate of 450 times a second.  Given its mass, the extremely fast rate of flickering can be explained by a black hole that is rotating amazingly fast.  Lastly, I learned that the physical forces that actually cause this flickering have yet to be discovered.