Meteor showers happen when the Earth passes through debris which, most of the time, has been left behind from a comet. As soon as the debris hits our atmosphere it begins to burn up as it falls, which is what we see as a “shooting star.” Most of the debris is small enough that it burns up quickly and completely before it can hit the ground. This is not the case, however, with our Moon. The moon has no atmosphere so any debris it passes through will hit the surface and add to its already many craters.
Tonight the Perseids meteor shower will reach its peak, and the skies will be rather dark since the moon is a its waning crescent phase and will rise late. If you find yourself with clear skies and far from light pollution, you could possibly see around 100 meteors an hour!