Apollo Moon rocks contained evidence of water

Nature News : Talks at the first Lunar and Planetary Science Conference , held in 1970, described an analysis of Moon rocks collected during the Apollo 11 mission. Petrologist Larry Taylor at the University of Tennessee in Knoxville, described how he saw only pure metallic iron in the samples—a sign that there wasn’t any water around to rust the iron. This and other results that year led to the party line: the Moon is, and always was, bone dry.Forty years on, at the same annual conference, Taylor and his colleagues announced that they have been wrong all along.Three groups presented evidence that certain crystals in the volcanic rocks collected by Apollo astronauts contain as much as several thousand parts per million of water.The results suggest that the lunar interior has always held some water—challenging theorists to change their thinking about how the Moon formed during a fiery impact, and how the once-molten body cooled.The work also hints that comets have played a more important part in delivering water to the Moon than researchers had previously thought.