Earth-Moon Water

A new study using rock samples taken by Apollo 17 astronauts in the lunar highlands-- the oldest lunar rocks yet collected-- suggests that water on Earth and on the Moon came from the same source.

That, in turn, implies that water somehow survived the fiery collision of Earth and a Mars-sized body which, according to current theory, created the Moon, and that a tiny fraction of that water transferred to the Moon.  It might seem an unlikely possibility at first glance, but the universe is a strange old place.