* No Atmosphere: The Moon lacks a substantial atmosphere, which acts as a shield for Earth. Earth's atmosphere burns up most small meteoroids before they reach the surface. The Moon's lack of an atmosphere allows even tiny meteoroids to impact its surface.
* No Plate Tectonics: Earth's surface is constantly being renewed by plate tectonics. Mountains rise, volcanoes erupt, and continents shift, erasing old craters. The Moon has no such activity, so craters remain untouched for billions of years.
* No Erosion: Earth's weather and water erosion wear down and erase craters over time. The Moon has no significant weather or liquid water, so craters remain largely unchanged.
In short: The Moon's lack of atmosphere, tectonic activity, and erosion allows craters to accumulate over eons, making it a much more cratered surface than Earth.
