A new analysis of volcanic glass recovered from the moon decades ago found the rocks contain traces of the constituents of water, challenging a long-held notion that the moon is perfectly dry.
Using a technique not available when Apollo astronauts collected the rocks in the early 1970s, scientists were able to detect tell-tale signs of water trapped inside the pebble-like glass. Their discovery suggests water was present deep within the moon between 3.3 billion and 3.6 billion years ago, when the pebbles were formed during violent lunar eruptions.
The report, to be published today in the journal Nature, may cause scientists to rethink theories on how the moon was formed.
“The water that these guys have discovered is a scientific gold mine for us to figure out the history of . . . the moon,” said Jim Garvin, chief scientist at NASA’s Goddard Space Flight Center, who was not involved in the research.
The pebbles, about the size of a period on this page, are made of magnesium-rich green volcanic glass and iron-rich orange glass that solidified moments after eruption. They were recovered from the moon’s equatorial region during the Apollo 15 and Apollo 17 space missions.
Earlier studies of the rocks detected the presence of sulfur and carbon within the pebbles, indicating the volcanic glass was formed in a fiery eruption.
For the latest study, scientists measured the composition of the rocks molecule by molecule, using a technique 10 times more sensitive than that used in previous work.
The finding throws at least a little water on the currently favored hypothesis for the moon’s origin. Many scientists think it was formed when a large proto-planet slammed into Earth, sending molten debris off into space that eventually became the moon.
