The Lunar Atmosphere

This drawing shows how individual molecules may move near the surface of the Moon to form an atmosphere.

People used to think that moons such as the Earth's moon or the moons of Jupiter had no atmosphere whatsoever. Now, however, measurements have shown that most of these moons are surrounded by a *very* thin region of molecules which can *almost* be called an atmosphere. Such is the case with the Moon.

The atmosphere may come from a couple of sources, one source is outgassing or the release of gases from deep within the Moon's interior. Abundant gases, such as nitrogen and carbon dioxide and carbon monoxide, can be outgassed along with rare gases such as radon.

Another source, as shown in this diagram, are molecules which are loosened from the surface when other molecules from space hit the ground. These molecules may migrate across the surface of the Moon, to colder regions where they recondense into the ground, or they may fly off into space. This mechanism may be a source of lunar water.

Molecules from space come from the solar wind. Because its surface is protected by neither an atmosphere nor a magnetosphere, the Moon is constantly exposed to the solar wind, and these molecules get buried in the Moon's surface. Eventually scientists on Earth will understand more about the process of nuclear fusion, which is another way create energy. Then these molecules buried in the Moon's surface may become an important source of fuel for energy.