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Will black holes evaporate, if they evaporate? When and why do they evaporate? What are the conditions for evaporation? Under what principle do they evaporate?

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The evaporation occurs through Hawking radiation. This is a very slow and low energy process. So low that the cosmic microwave background radiation, which is just a few degrees above absolute zero, pours far more energy into the black hole than Hawking radiation takes away. So in principle a black hole cannot evaporate.

With the exception of conjectured atomic sized black holes, that is, as Hawking radiation would be more pronounced then.

Edit: See this answer on the physics SE: The black hole would need to be less massive than the moon to radiate more energy than it absorbs. Bigger than atomic size, as I suggested.

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@HDE226868 I found a similar question and answer on the physics SE, and added a link to it in my answer. – zibadawa timmy Aug 25 '14 at 18:08
@Dilaton Which part is incorrect, then? What you say is what that answer says, so I'm not sure what is being disagreed with. – zibadawa timmy Aug 26 '14 at 0:47

hawking radiation. electrons and positrons created from the vacuum must 'repay' their energy, usually through annihilation of each other. however, if one crosses through the event horizon of a black hole and the other escapes, the energy from the black hole as well as that of the particle will 'repay' and the escaped particle becomes real. this is a very slow process and in most circumstances I would assume that a black hole would accumulate more energy than it loses.

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I don't think they are electrons and positrons but virtual particles. – Yashbhatt Sep 1 '14 at 16:23

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