Water on the Moon

Three different spacecraft have confirmed there is water on the moon.

A favorite theory is that water, either as water by itself or as its components of hydrogen and oxygen, was deposited on Earth during its early history–mostly during a period of "late heavy bombardment" 3.9 billion years ago–by the impacts of comets and asteroids.
Because the Moon shares the same area of space as Earth, it should have received its share of water as well. However, since it has only a tiny fraction of Earth's gravity, most of the Moon's water supply should have evaporated and drifted off into space long ago. Most, but perhaps not all.