NASA confirms there's helium in the Moon's atmosphere. But where did it come from?

When astronauts from the Apollo 17 mission landed on the Moon in 1972, one of their mission objectives was to analyze the tenuous atmosphere using the Lunar Atmosphere Composition Experiment, a mass spectrometer (with a shape and appearance weirdly reminiscent of a modern day printer/scanner combo) designed to detect… »8/17/12 7:13pm8/17/12 7:13pm