Craters on the Moon are formed when an asteroid, meteoroid, or comet collides with the lunar surface at very high speeds, typically faster than the speed of sound. The impact generates tremendous energy that compresses, pulverizes, and vaporizes the rock beneath the collision site. This leads to the excavation of a large hole and the ejection of pulverized material called ejecta, which can scatter around the impact area and form secondary craters. The process has two main phases: excavation (initial hole formation) and modification (shockwaves deforming and collapsing the surrounding ground). Larger impacts can cause the surface rock to rebound like a liquid, forming central peaks and terraces inside the crater. The surface eventually cools, forming a layer of shattered igneous rock called lunar breccia.

The Moon's lack of atmosphere, water, and tectonic activity means these craters remain well-preserved for billions of years. Unlike Earth, which has erosion and tectonic resurfacing that erase craters, the Moon's craters accumulate and dominate its surface.