Why is the Moon Covered with Craters?
The heavenly bodies were formed when smaller bodies, a few kilometers across, collided together. Eventually, when the stars, the planets and the satellites were formed, their surfaces were cratered by later collisions. The craters on the moon were formed during the first few hundred million years of the moon. They have remained so since they were formed. The moon cooled down quickly and preserved them forever. Moreover, there is no atmosphere to produce winds and weather which could wear down these craters to some extent. In contrast, the Earth's craters have been worn away by wind and rain. The Earth's crust is thinner and the surface has buckled and spilt.