The chemical traces of water have been found in this moon rock,
called the Genesis Rock. The moon rock was collected by
astronauts during the Apollo 15 mission in 1971 and is thought
to be a piece of the moon's primordial crust. Image:
NASA/Johnson Space Center The discovery of "significant amounts"
of water in moon rock samples collected by NASA's Apollo
astronauts is challenging a longstanding theory about how the
moon formed, scientists say. Since the Apollo era, scientists
have thought the moon came to be after a Mars-size object
smashed into Earth early in the planet's history, generating a
ring of debris that slowly coalesced over millions of years.
That process, scientists have said, should have flung away the
water-forming element hydrogen into space. But a new study
suggests the accepted scenario is not possible given the amount
of water found in moon rocks collected from the lunar surface in
the early 1970s during the Apollo 15, 16 and 17 missions. By
"water," the researchers don't mean liquid water