I am looking at the way how Hawking radiation is derived: http://en.wikipedia.org/wiki/Hawking_radiation Where can I find more info about it? (for amaters like me) Formula for the Unruh temperature gives an infinite temperature at the horizon. At the same time AFAIK the apparent horizon recedes in front of the falling observer. Also, is my assumption correct that observer sees radiation from an apparent horizon, not from an absolute one? The Hawking radiation looks very intensive but extremely red-shifted by the gravitation. Like almost infinity devided by almost infinity. So I wonder how intensive the Hawking radiation is for the freely falling observer.