# Are black holes “Immortal”?

Black holes are stars that are so massive, that when they die, they become so dense that not even light can escape. That means that a black hole is costantly adding mass and energy and thus making its gravitational force even stronger. If this is what happens, black holes should live forever right? Is there a mechanism that reduces their mass and energy so as to finally evaporate?

To sum up, do black holes exist forever?

This process begets an energy loss from the black hole, and the latter will slowly vanish. The black hole temperature, in Planck units, is $T=\frac{1}{8\pi\,M}$, where $M$ is the black hole mass. So the hole becomes hotter as it gets smaller, and, by the Stefan Boltzmann law, the radiation power is proportional to the fourth power of the inverse mass. So, at the end of its life, this hole not so much evaporates as explodes.