How long do black holes live?

In 1975, British astrophysicist Stephen Hawking proved that black holes emit radiation (now called Hawking radiation) that carries away energy, and with it mass. The evaporation is faster the smaller the mass.

A hole with a mass of 200 tons would evaporate in less than a second, releasing energy equal to the explosion of 20 million megaton bombs. However, such small holes have not been observed.

Stellar-mass black holes (the smallest of the black holes discovered) evaporate in about 10⁷⁰ years. This is a trillion trillion trillion times the age of the Universe.