Question:Why is the surface of the Moon covered in craters?
The craters were caused by asteroid collisions with the surface.
This picture shows the Tycho crater on the moon - named after the famous astonomer Tycho Brahe.
Craters are much bigger than the asteroids that make them. The size of the asteroid combined with the very large speeds give the collisions enormous energy and the ability to create craters much larger than the actual size of the asteroid.