What Would Happen if the Moon Exploded?
The Moon explodes, shattering into seven large chunks. Who did it, or why, is unknown. Before long, the seven chunks smash into each other, rapidly disintegrating. The debris falls towards the Earth, enters the atmosphere and heats the planet so much that it becomes uninhabitable for five thousand years.
This terrible scenario is the opening premise of Seveneves, a science-fiction novel by American author Neal Stephenson. Seveneves belongs to the hard science-fiction genre, which stresses scientific accuracy and realism. But how scientific is his exploration of an exploding Moon? What would really happen if the Moon exploded tonight?
The idea is not as absurd as it sounds. Moons do sometimes explode. This can happen in two ways — they can be struck by something big, or they can be ripped apart by gravitational disturbances. These two possibilities are not even that rare — the rings of the gas giants in our solar system may have formed from the remains of exploded moons.
Exploding moons and planets were much more common when the Solar System was young. At that time the Solar System was a chaotic place. Unlike today — with eight planets following steady orbits like clockwork — there were many small planets flying all over the place. Sometimes they would collide — the early Earth was almost certainly struck by another planet at…
