I've never understood how Hawking Radiation would work. I don't see how it could cause a Black Hole to shrink. I mean, don't matter and anti-matter behave in a similar way under gravity? (The answer is "yes") That being the case, when a particle pair spontaneously appears near a Black Hole's event horizon, it's gonna be a 50-50 chance as to which one of the two particles falls in. If the matter particle fell in, the black hole would gain mass. On the other hand, if the anti-matter particle fell in, it would cancel / annihilate some of the matter inside the Black Hole, so the black hole would lose mass. If the two processes have an equal chance of happening, there should be no overall effect upon the mass of a Black Hole, because the two would cancel each other out. i.e. over a period of time, on average, the amount of matter and anti-matter falling into the Black Hole would be the same. Furthermore, after one of a virtual particle pair has fallen into the black hole, what exactly makes the remaining particle wander off into the universe? Surely, being so close to the event horizon, it's likely to fall in too after a while (because it would need an escape velocity close to the speed of light to escape). And then there's the question of annihilation. The reduction in mass of the Black Hole appears to rely upon anti-matter particles coming into contact with the singularity, therefore annihilating the anti-matter particle and an equivalent amount of matter. However, as the particles approach the Black Hole's singularity, gravity becomes stronger, so time slows down (or would appear to slow down, if an outside observer could see in). In a massive Black Hole, the falling particles would pretty much grind to a halt. Doesn't this suggest a shell of matter and anti-matter particles pretty much frozen in time, and therefore hanging around for a very long time before colliding? To an outside observer, the Hawking Radiation would feed a large Black Hole faster than the matter and anti-matter inside could annihilate each other (although the outside observer could not directly see what's going on beyond the Event Horizon, any variation in gravitational strength ought to be measureable). That would suggest a Black Hole may go through a long period of increasing mass due to Hawking Radiation. Or am I missing something?