Main Engine Cut Off

On 17 July 2018, an ancient lump from space thwacked into the Moon with enough energy to produce a brilliant flash of light. With another space rock seemingly in pursuit, a second flash lit up a different region of the Moon almost exactly 24 hours later (see GIF).

Current estimates suggest these two impacting ‘meteoroids’ — fragments of asteroids and comets — were both about the size of a walnut. They likely originated from the Alpha Capricornids meteor shower — itself the result of Earth and the Moon passing through the dusty tail of comet 169P/NEAT.