Why does the moon have craters?
The countless craters on the Moon were formed as a result of asteroid impacts, particularly during the Late Heavy Bombardment. Some may ask, "Why doesn't the Earth have a lot of craters like the moon?". Much of the surface of the Earth is recycled by tectonic activities (and by erosion) from plates, which is why we have few craters on Earth compared to the Moon. Impact craters, formed by meteor impacts, are found throughout much of the lunar surface.
Moon craters are formed when meteorites and asteroids strike the surface of the Moon. Many of the craters on its surface are mostly impact features caused when meteorites or comets hit the Moon. Most of these craters are thought to be older, formed in the early stages of the Moon's evolution through heavy impact bombardment by materials left behind from the accretion disk of the Sun. A significant fraction of the Moon's craters formed during the Late Heavy Bombardment, event which occurred about 3.9 billion years ago, where large numbers of impacts hit many bodies of the inner Solar System.
Early in the formation of our solar system (before 3.9 billion years ago), a large amount of large debris struck young planets and moon surfaces; these older impact basins are more extensive than more recent impact craters. Early in the formation of our solar system (before 3.9 billion years ago), there was lots of large debris striking the surfaces of the young planets and moons; these older impact basins are larger than the more recent craters. The scientists at the Massachusetts Institute of Technology, the University of Paris, and other universities have suggested that from the sizes of craters and the Moon's pools, the Moon and the other planets were subject to massive asteroids.
However, scientists at the Massachusetts Institute of Technology, the University of Paris, and elsewhere now found that the impact basins of the near side of the Moon might not be representative of the impact strength of asteroids during this time. In particular, scientists have based most of their theories of that period on the impact basins found on the Moon's near side -- the side always facing the Earth -- and the Moon's near side -- the side always facing the Earth assuming, from the size of the craters and basins of the Moon, that the Moon and other planets endured impacts from massive asteroids. Scientists from MIT, the University of Paris, and elsewhere have found that craters on the near side of the Moon may not reflect the intensity of asteroid impacts from that period. Because when an asteroid crashed onto the surface of the Moon during early solar system history, the crust melted away like butter, producing massive flows of molten rock, which filled up impact craters, turning them into pools.
Giant impact basins formed on the Moon's surface through these impacts. This caused the melting rock to rise and form huge pools of cooling lava, which now resembles crates. Detailed analyses of moon rocks brought back by Apollo astronauts revealed volcanism and impact basins shaped the Moon's surface from the time it formed, some 4.5 billion years ago, not long after the formation of the Earth. Throughout the Moon's existence, comets and asteroid fragments have bombarded the Moon, creating the numerous impact craters that we see today. The Moon is devoid of water, an atmosphere, and tectonic plates -- the three forces that degrade Earth's surface -- meaning all but the newest meteor impacts are invisible.