When Comets Break Up, the Fragments Can Be Devastating If They Hit the Earth

Comet breakups are a timely topic right now. The interstellar comet 2I/Borisov just broke into at least two pieces. And though that comet is speeding out of the Solar System, never to be seen again, most of them don’t leave the Solar System. Most of them orbit the Sun, and return to the inner Solar …