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Why are meteorite craters found on the Moon, planets, and even comets?

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four impact craters — Meteorite crater Four impact craters of the same size (30 km [20 miles] in diameter) imaged by spacecraft on different solid bodies of the solar system and reproduced at the same scale. They are (clockwise from upper left) Golubkhina crater on Venus, Kepler crater on the Moon, an unnamed crater on Jupiter's moon Ganymede, and an unnamed crater on Mars. The images are oriented such that the craters appear illuminated from the left; the Venusian crater is imaged in radar wavelengths, the others in visible light.

Meteorite craters are found on the Moon, planets, and comets because the formation of the solar system left behind countless pieces of debris, including asteroids and comets.1

Gravitational interactions routinely send this debris on a collision course with solid-surface bodies throughout the solar system. When these objects strike a surface, they create a depression significantly larger than the original projectile. Because most solid bodies in the solar system lack the active geologic processes—such as erosion, volcanism, or plate tectonics—that frequently resurface Earth, these impact craters remain preserved for billions of years.12

While Earth has experienced a similar number of large impact events, its surface is geologically active, which over time obscures or eliminates evidence of these collisions. Consequently, craters serve as a vital record of the history of the solar system, allowing scientists to estimate the relative ages of surfaces on various moons and planets.231