How do Black Holes evaporate?

They’re the densest objects in the Universe, but even they won’t live forever. Here’s why not.

“It’s like, how much more black could this be? And the answer is none. None more black.” -Nigel Tufnel, This is Spinal Tap

So you’ve heard of black holes: regions of space where matter-and-energy is concentrated so densely that nothing, not even light can escape from it.

Image credit: NASA/ESA Hubble Space Telescope collaboration.

These objects most certainly exist, and are known to range in size from just a few times the mass of our Sun (like Cygnus X-1, illustrated above) to the supermassive ones at the centers of galaxies. Our galaxy has one that’s about four million times the mass of the Sun (below), but the largest ones can be many billions (or even tens of billions) of times as massive as our Sun.

Image credit: KECK / UCLA Galactic Center Group / Andrea Ghez et al.

The smaller ones are formed when very massive stars — stars around 12-15 times the mass of our Sun (or more) — run out of nuclear fuel in their core. When the fuel runs out, the core…