How do black holes die?
In: Planetary Science
Short answer – rather slowly.
‘Empty’ space is actually full of stuff – pairs of one particle and one anti-particle are constantly appearing everywhere. Normally they annihilate each other more or less instantly, and we don’t notice them.
But if they appear _just_ the right distance from a black hole, one will fall in allowing the other to escape. (These escaping particles are called Hawking Radiation.) Because the universe needs to conserve energy, the positive energy carried by the escaping particle is balanced off with a reduction in energy inside the black hole.
Because energy and mass are fundamentally the same thing, this means a reduction in mass for the black hole. If nothing else is falling in from outside, the mass will eventually reach zero through this ‘evaporation’ process, and the black hole is no more.
Emphasis on ‘eventually’. A black hole the mass of our sun would take something like 10^67 years to evaporate in this way, which is many, many orders of magnitude longer than the age of the universe.
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