Here's why:

* Lack of Atmosphere: The Moon has no atmosphere to slow down or burn up incoming meteoroids.

* Low Gravity: The Moon's gravity is much weaker than Earth's, so meteoroids don't slow down as much before impacting.

* No Erosion: Without wind, rain, or plate tectonics, the craters remain largely unchanged over time.

This is why the Moon's surface is covered in impact craters of various sizes, a testament to the constant bombardment it has endured over billions of years.