Water Found on the Moon

Sept. 23, 2009 -- Shattering a long-held belief that Earth's moon is a dead and dry world, a trio of spacecraft uncovered clear evidence of water and hydrogen-oxygen molecules throughout the lunar surface.

"There's no question that there is OH [hydroxyl, which is made up of one hydrogen atom and one oxygen atom] and H2O on the moon," University of Maryland senior research scientist Jessica Sunshine told Discovery News.

"It's still pretty damn dry, drier than anything we have here. But we've found this dynamic, ongoing process and the moon was supposedly dead," she said. "This is a real paradigm shift."

Aside from scientific interest, finding water on the moon could impact plans for eventual human settlements beyond Earth, said geologist Paul Spudis, with the Houston-based Lunar and Planetary Institute.

"It's a potential resource," Spudis told Discovery News. "If you think there's a long-term future in space, at some point you have to learn to use what you find in space to make new capabilities."

Scientists have suspected water could exist inside deep craters at the moon's poles that are never exposed to sunlight. The new research is surprising because it found chemical bonds between hydrogen and oxygen throughout the lunar surface. The concentrations appear denser near the polar regions.

How much water and hydroxyl is on the moon and where it came from remains a mystery.

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Sunshine suspects hydrogen from the solar wind may be interacting with oxygen in lunar rocks to create trace amounts of water. She estimates that if you filled a soda bottle with lunar soil, there would be about an eyedropper's worth of water.

Whatever mechanism is driving the phenomena occurs only in daylight.

"When you think of evaporation and condensation, you have a day and night cycle. On the moon, it's happening all in the day. There are no changes at night," she said.

Though not understood, the phenomenon is widespread, encompassing an extremely shallow layer of lunar soil on a global scale.

"Every place on the moon, at some point during the lunar day, though not necessarily at all times, has water and OH," Sunshine said.

Also unknown is why the rocks and soil samples retrieved during the six Apollo expeditions to the moon between 1969-72 showed no obvious signs of interactions with water.

University of Hawaii geophysicist Paul Lucey suggests that some rare water-bearing minerals previously observed in lunar samples but dismissed as terrestrial contamination might, in fact, be indigenous.

"Perhaps the most valuable result of these new observations is that they prompt a critical reexamination of the notion that the moon is dry. It is not," Lucey said.

Evidence for a second and potentially richer source of water may come next month.

On Oct. 9, NASA's Lunar Crater Observation and Sensing Satellite will try to directly detect water by crashing a 2.5-ton dead weight into one of the moon's permanently shadowed craters so soil at the of the pit will be hurled into sunlight for analysis by several spacecraft and dozens of ground-based observatories.

The new research, based on observations from India's Chandrayyan-1 lunar orbiter and flybys of NASA's Deep Impact probe and Cassini spacecraft, appears this week in the online journal Science Express.

Related Links:

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Lunar Crater Observation and Sensing Satellite