The moon is full of meteorite craters. Why don’t more crash on the moon now?

Answer

Dear Kristof,

Meteorites do still crash on the moon. And since the Moon, unlike the Earth (fortunately!), has no atmosphere to burn it up, they all reach the surface and thus all create an impact crater. Once that crater is there, the absence of an atmosphere also ensures that there is no wind or erosion to wear away the crater.

You should, however, take into account a few remarks. First, the chances of seeing a large crater form during our lifetime are very slim. The fact is that the moon has been around for about 4.5 billion years. So the moon has had a very long time to accumulate the (permanent) scars it currently has. In addition, there will have been more craters per unit time in the early history of the moon than now, since there were many more debris of all kinds flying around in the young, wild period of the solar system.