The Lunar Atmosphere

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

In decades past it was accepted that moons such as the Earth's moon or the moons of Jupiter were airless bodies with no atmosphere whatsoever. Now, however, measurements have shown that most of these moons are surrounded by a *very* thin region of molecules which might be loosely classified as 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 such as radon, which originate 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 by bombardment of the surface by other molecules from space. 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. This mechanism is also a source of abundant helium.

Because its surface is protected by neither an atmosphere nor a magnetosphere, the Moon is constantly exposed to the solar wind, which carries both hydrogen and helium. These molecules become embedded in the Moon's surface. He3, is the ideal material to fuel fusion reactions. When scientists develop a more thorough understanding of fusion, and can practically implement the relevant reactions, the Moon may be a priceless resource, since it is by far the best source of He3 anywhere in the Solar System.