The scientists relied on samples of the Moon’s soil, brought back by the Chinese rover of the Chang’e 5 mission in 2020. By analyzing them, they observed microscopic glass beads. They usually form when pieces of space rock hit the surface of another object. The impact vaporizes molten minerals which can cool and solidify into tiny particles. These glass balls would thus have been formed after the impact of meteorites or asteroids on the Moon two billion years ago.
active water cycle
According to researchers from the Chinese Academy of Sciences who conducted the investigation, these glass balls would have initially lost most of their water, before being swept away by solar winds. These winds then delivered them hydrogen which would have mixed with the oxygen atoms contained in the balls, forming water molecules. According to estimates, between 3 and 5% of the lunar ground would be covered with these glass beads. Tests have shown that water diffuses in and out of marbles over a period of years, confirming that a water cycle is active on the Moon.