Here's why:
* The Moon has less gravity: With weaker gravity, the Moon's crust doesn't need to be as thick or strong to support mountains. This limits how high they can grow.
* No tectonic plates: Earth's tectonic plates collide and uplift mountains. The Moon doesn't have active plate tectonics, so its mountains are formed mostly from impacts.
* Impact craters: Many of the Moon's highest peaks are actually the rims of ancient impact craters. While these craters can be quite large, they rarely reach the heights of Earth's mountains.
The highest mountain on the Moon is Mons Huygens, which rises about 4,700 meters (15,400 feet) above the lunar surface. This is about half the height of Mount Everest!
