Everyone Can Chill Out About the Moon
Scientists have detected evidence of water in an unexpected place—a significant, but not earth-shattering, discovery.
Last week, NASA announced that scientists were preparing to reveal “an exciting new discovery” about the moon—something significant for future astronaut missions to the lunar surface. The space agency was otherwise light on details, and speculation swelled. Had NASA found aliens? Is the moon haunted? Is it actually made of cake? “What a tease!!” Chris Evans, Captain America himself, cried. “Just Tell Us the Moon News!” The Cut wailed. After months of isolation, illness, and unnatural disasters, the prospect of yet another surprise made people panic a little.
The news is finally out today, and everyone can calm down. The moon is fine.
The discovery is not as earth-shattering—or rather, moon-shattering—as the hype suggested: Scientists have detected the presence of water in sunlit parts of the moon’s surface. See? It’s fine.
Scientists already knew that there’s water on the moon. In the past decade, spacecraft missions have detected evidence of frozen water at the moon’s poles and water-like molecules clinging to minerals on its surface. Like Earth, the moon likely acquired most of its water early on, by way of rocky asteroids bearing frozen water. The impacts scattered water ice across the lunar surface, and some particles drifted across the regolith and settled in perpetually dark spots, such as craters and even a boulder’s shadow. Away from the shadows, a chemical reaction between lunar soil and sunlight produces hydroxyl, a close relative of the water molecule.
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.
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.
But in 2020, the unrelenting pace of bad news has curdled our reactions toward potentially lovely surprises into dread. We have been conditioned to expect the worst. Live this long in a heightened state of anxiety, and the smallest sound can make you jump. The unknown, especially NASA’s dreamy brand of the unknown, is particularly unnerving, because it seems to promise yet another disruptive event that could cleave our collective memory, drawing another line between the time we viewed the world one way and a time when that vision no longer applied.
But that hasn’t happened. We have simply learned something new about our moon. Earth can go on spinning, and the moon along with it. At a time when so many things aren’t fine, it is a comfort to be reminded of something that is.