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Name: Will C. B.
Status: educator
Age: 60s
Location: N/A
Country: N/A
Date: 11/15/2004

How small can a black hole be? That is, what is the smallest the event horizon can be? Could it be as small as the nucleus of an hydrogen atom?

It is now thought that black holes must slowly "evaporate" by spontaneous generation of radiation and particles at their "surface". The smaller they are, the more intense this evaporation gets. They eventually flare to extinction, almost explode. There is some smallness at which the remaining lifetime becomes less than a second, and before that point the radiation nearby is pretty violent. Unfortunately I have not learned what that size is, but I think it is larger than a proton. Some web-surfing might pick up the number. Or even the way to calculate it.

So, yes, it could exist, for a vanishingly brief time. And it would be extremely "white" hot at that brief moment. Not what you would think of as a sneaky, immortal little black hole in space.

Jim Swenson

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