Here's why:
* Lack of atmosphere: Both Mercury and the Moon have very thin atmospheres, offering little to no protection from impacts by asteroids and meteoroids.
* Geological inactivity: Both celestial bodies are geologically inactive, meaning they don't have active volcanoes or tectonic plates to erase the impact craters.
* Ancient surface: Both Mercury and the Moon are very old, giving ample time for countless impacts to leave their marks.
While other planets and moons in our solar system also have craters, Mercury's surface is particularly heavily cratered, making it resemble our own Moon.
