US scientists have found evidence that water was held in the Moon's interior, challenging some elements of the theory of how Earth's satellite formed.
Scientists thought the heat from this impact had vaporised all the water.
But a new study in Nature magazine shows water was delivered to the lunar surface from the interior in volcanic eruptions three million years ago.About 95% of this water vapour was lost during the volcanic activity.
"Since the Moon was thought to be perfectly dehydrated, this is a giant leap from previous estimates," said co-author Erik Hauri, from the Carnegie Institution.
"It suggests the intriguing possibility that the Moon's interior might have had as much water as the Earth's upper mantle. But even more intriguing: If the Moon's volcanoes released 95% of their water, where did all that water go?"
OK, it wasn't a serious followup question as the moon's gravity apparantely has always been to weak for an atmosphere...unless it was some sort of real freaky underground Moon life.