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I've read once a popular science book, in which the author calculated how long would it take for the most massive black holes to evaporate because of Hawking radiation. He claimed that after that time the Universe will be the soup filled only with elementary particles.

However, what would happen with celestial bodies that aren't black holes? For example, a rogue planet of the size of Earth, drifting somewhere in deep space, in an extremely cold Universe? What known effects would cause that planet to evaporate? How long would it take?

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Assuming that you're talking about Hawking Radiation affecting black holes, no know phenomenon affects planets, stars, or other celestial non-black hole objects. – HDE 226868 Aug 13 '14 at 19:06
up vote 7 down vote accepted

Before the evaporation of black holes that you mention, our universe will enter what is known as the Black Hole Era. About 10^40 years from now, all the protons and neutrons in the universe will have decayed into positrons and neutrinos. This is how the last of the planets will pass away.

The Black Hole Era is so named because at this point only black holes and elementary particles will remain.

It should be noted that there is currently no evidence for proton decay, and so this phase of the Universe is strictly theoretical.


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