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Tiny glass beads on the Moon could hold a significant amount of water. Photo: Sen Hu
The Moon’s surface is covered in these minuscule glass beads, formed over billions of years from impacts with cold asteroids, which ejected material from the Moon’s surface and then fell back to form the glass beads. The analysis of samples collected by China’s Chang’e 5 spacecraft in December 2020 revealed that these tiny beads contain significant amounts of water. A new study published in the journal Nature Geoscience sheds light on this discovery.
Scientists have previously found evidence of water on the Moon, but its origin and characteristics have remained mysterious. The glass beads found in a 1,731-gram lunar sample returned by Chang’e 5 could provide missing pieces to this puzzle. Billions of years ago, the Moon was likely completely dry, but over time, it was bombarded by solar wind, which carried hydrogen atoms that bonded with oxygen molecules on the Moon’s surface to form water. This ongoing process contributes to the Moon’s water cycle.
Presently, some of this water evaporates as the top layers of the Moon’s surface are heated by sunlight during the lunar day and then re-condenses during the cold and dark lunar night. However, the solar wind cannot account for this replenishment of water, as it would occur too quickly.
The new study suggests that the glass beads could serve as hidden reservoirs, releasing water easily into the dry surface layer during the cold and dark lunar nights. Additionally, the water content in these beads is higher than previously thought.
The research team estimates that up to 270 trillion kg of water may be trapped within the top 12 meters of the Moon’s surface. The chemical composition of the water in these beads also matches that created by solar wind interacting with hydrogen isotopes present in the Sun.
“This discovery indicates that glass beads from lunar impacts and other airless bodies in the Solar System have the potential to store a type of water that originates from solar wind and release it into space,” said Hu Sen, a scientist at the Chinese Academy of Sciences’ Institute of Geology and Geophysics and co-author of the new study.
The experts believe that these glass beads could be a convenient resource for astronauts to extract water in the future, potentially even aiding in the production of rocket fuel on the Moon, supporting missions to more distant locations in the universe.