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To a planetary scientist, discovering a new source of water does indeed count as major moon news. Scientists have never before detected the signature of molecular water—real, bona fide H2O—in a region that receives sunlight. Until now, scientists didn’t think water could survive in sunlit spots. “We thought that it would be lost” to space, says Casey Honniball, a postdoctoral fellow at NASA’s Goddard Space Flight Center and the new study’s lead researcher. The scientists suspect that the water resides among grains on the lunar surface or within glass beads, the delicate remnants of surface-melting meteor impacts.
This discovery also could help NASA build its case for a visit to the moon. The Trump administration has directed the space agency to send astronauts to the moon by 2024 under the Artemis program, named after the sister of Apollo. (The choice has a double purpose: This mission will be a sibling to the Apollo moon missions of the 1960s and ’70s, and, NASA promises, will feature the first woman to walk on the moon.) But members of Congress haven’t decided to fund the White House’s billion-dollar moon ambitions, and the NASA administrator, Jim Bridenstine, has spent more than a year trying to sell them on the moon’s potential. Future spacefarers, Bridenstine often says, could mine deposits of water ice and use it in the life-support systems of their moon bases.
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Honniball and her colleagues’ discovery might make that job easier. If water turn outs to be widespread in sunlit areas, astronauts might not have to trudge into the unforgiving, darkened craters of the moon’s poles to excavate the frozen H2O there, and instead could target the water molecules at higher, warmer latitudes. But this future is speculative; no one knows how much water the moon actually has, whether frozen or suspended in glass, and moon-mining technology is still in blueprints.
Tapping water on another world so close to home is a tantalizing prospect. And although we’re spoiled with it here on Earth, water isn’t as special as our little oasis in the cosmos might suggest. Many of this solar system’s prime destinations have water, in one form or another. Mars has salty lakes beneath its surface. Europa, a moon of Jupiter, and Enceladus, a moon of Saturn, have underground oceans, possibly even tiny forms of life. Pluto probably has a hidden ocean, too. Even Mercury, the closest planet to the sun, keeps a supply of water ice in eternally shadowed craters at its poles. And hints of water vapor have been detected more than 100 light-years away from Earth, on a planet astronomers can only daydream about.
Perhaps in 2019, or what is wistfully known as the Before Times, a cryptic NASA announcement about an important discovery might have prompted a different reaction. The suggestion of aliens would have come up, of course, but most of the public likely would have met the prospect of moon news with equanimity or dreaminess in place of slight panic. Like taking a hike or walking through autumnal city streets, contemplating the wonders of the universe can help soothe the mind, or at least distract it for a while.