NASA revealed on Monday that it found evidence of water molecules on the sunlit side of the moon, which was previously thought to be impossible.
Scientists working with NASA’s Stratospheric Observatory for Infrared Astronomy, an airplane observatory, made the announcement in a teleconference with reporters. The discovery, using an infrared telescope on SOFIA, upends long-held theories regarding the surface of the moon. Previously, scientists thought that the absence of an atmosphere on the moon would cause any water present on a sunlit surface of the moon to evaporate into the cosmos.
“For the first time, water has been confirmed to be present on a sunlit surface of the moon,” Paul Hertz, director of NASA’s astrophysics division, told reporters. “This is exciting because the expectation was that any water present on a sunlit surface of the moon would not survive the lunar day. … Water might be distributed across the lunar surface and not limited to the cold, shadowed places near the lunar poles, where we have previously discovered water ice.”
This is the first time water molecules have been confirmed on the lunar surface beyond the lunar poles. In 2018, NASA was first able to confirm the presence of frozen water “in the shadows of craters near the poles, where the warmest temperatures never reach above -250 degrees Fahrenheit,” though scientists had speculated about its presence there for decades.
Previously, studies of the lunar surface were unable to differentiate between water molecules — H2O — and hydroxyl — OH, a chemical commonly found in drain cleaners. Using SOFIA, scientists identified the specific chemical signature of water molecules.
The water molecules are spread out too far to form liquid water or ice. Instead, the molecules are distributed across the Clavius Crater at a concentration between 100 and 412 parts per million, roughly the equivalent of 12 ounces of water in a cubic meter of soil.
Comparatively, the Sahara Desert has 100 times the amount of water concentration detected by SOFIA.
“Without a thick atmosphere, water on the sunlit lunar surface should just be lost to space,” said Casey Honniball, a postdoctoral fellow at NASA’s Goddard Space Flight Center. “Yet somehow we’re seeing it. Something is generating the water, and something must be trapping it there.”
Scientists think that the molecules may be trapped in bead-like structures in the soil, possibly formed as a result of the heat created by micrometeorite impacts transforming hydroxyl into water.
The scientists also said their research suggests that “cold traps,” small areas on the moon that never get sunlight, could be far more common than initially expected and may contain extractable frozen water — roughly 15,000 square miles of permanent shadows.
“This discovery is a great example of science and human discovery working hand in hand,” Jacob Bleacher, chief exploration scientist for NASA’s Human Exploration and Operations Mission Directorate, told reporters. “Understanding where water is on the moon will help us prepare to send astronauts to the lunar south pole with our Artemis program.”
The Artemis program is NASA’s two-phase lunar exploration plan to send astronauts to the moon and eventually establish a sustained human presence on the lunar surface. The program’s first manned mission is scheduled for 2024.
“Water is extremely critical for deep space exploration. … Water can be turned into oxygen for them to breathe. It can be a fuel supply that they use later. Obviously, it could be water that they later drink,” Bleacher said. “Anytime we don’t need to pack water for our trip, we have an opportunity to take other useful items with us.”
