At Second Glance, Apollo Moon Rocks Reveals Signs of Native Water

Four decades after the Apollo missions, scientists took a second look at the sample of rocks brought back from the moon and, voilà, they have found signs of ‘native’ water.

By ‘native’ they mean water brought not externally by comets, asteroids and other heavenly objects, but water from the inside of the moon itself. That is to say that at some point in its early days, the moon's interior may have been a little damp.

“Indeed, the samples returned by the Apollo missions that visited the lunar highlands seemed to confirm that Earth's cold, rocky companion was bone-dry,” said University of Notre Dame geologist Hejiu Hui, who led the new analysis.

Published online Sunday in the journal Nature Geoscience, this discovery supports mounting evidence that the moon once contained some "native" water and gives a black eye into current beliefs about how Earth's companion formed.

The current understanding of moon’s genesis holds that the moon was created when a Mars-sized body crashed into the young Earth and broke off debris that eventually coalesced into a new entity. In the process, much of the water would have evaporated into space, leaving Earth's new satellite quite arid.

"It's thought that the moon's formation involved the materials getting very hot," said Paul Warren, a UCLA Cosmo-chemist who was not involved in the new study. "It's usually assumed that little water would have survived through that."