While it’s not quite time to build the first lunar swimming pool, scientists do report that they’ve found the chemical signature for water all over the moon‘s surface, not just in the permanently shadowed craters near the poles that recent studies suggested might harbor ice. The findings give new hope to people dreaming of a lunar settlement where astronauts could live off the land.
Evidence of both both water and a closely related molecule called hydroxyl was detected by India’s first lunar probe, Chandrayaan-1, which scientists later lost contact with. The findings were then backed up by measurements from NASA’s Deep Impact and Cassini probes, and the three teams’ papers have been published in Science.
Chandrayaan-1 scientist Carle Pieters explains that the water was easy to miss. “When we say ‘water on the moon’, we are not talking about lakes, oceans or even puddles. Water on the moon means molecules of water and hydroxyl that interact with molecules of rock and dust specifically in the top millimetres of the moon’s surface” [The Times], she says. The scientists say their measurements indicate that the moon has the equivalent of one quart of water per ton of material.
While some of the water may be the result of icy comet crashes, researchers think most of it is produced naturally on the moon as a result of the so-called solar wind, laden with charged hydrogen particles, impacting with the oxygen-rich lunar soil [Bloomberg]. And the amount of water seemed to reflect the moon’s day-night cycle: the lunar soils became increasingly damp during sunlight hours, but dried out again at the end of the lunar day. The waves of damp and dry conditions suggest water is created on the moon every lunar day [The Guardian].
For decades, scientists assumed that the moon was bone-dry. Samples of lunar soil brought back from NASA’s Apollo missions about four decades ago actually did show signs of water, but most scientists working with the samples … dismissed the readings as contamination from humid Houston air that seeped in before the rocks were analyzed [The New York Times]. Since then, probes like the 1998 Lunar Prospector and Japan’s recent orbiter, Kaguya, have focused on looking for ice traces at the poles.
Some exploration advocates will likely use the new findings as an argument for establishing a permanent lunar outpost complete with industrial plants to extract water from the soil and rock. But scientists note that since the water molecules are only thought to be present in the top few millimeters of the surface, extraction would be quite a task. Says Deep Impact scientist Lori Feaga: “You would have to scrape the area of a baseball field or a football field to get one quart of water” [The New York Times].
80beats: Close-Up of the Moon Reveals Coldest Place in the Solar System & Possible Ice
80beats: India’s First Moon Mission Ends Abruptly With a Lost Signal
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80beats: Disappointing News: No Icy Patches in the Lunar Craters
80beats: The Moon Once Held Water, Moon Pebbles Show
Image: University of Maryland / F. Merlin / McREL