Scientists have found a new source of water on the moon: trapped in tiny glass beads formed millions of years ago when asteroids and other impactors hit the lunar surface.
In a study published in the Nature Geoscience journal on Monday, researchers estimated that the glass beads—pellets the width of strands of hair that are ubiquitous on the surface of the moon—collectively may hold up to 270 trillion kilograms of water. Enough to fill 100 million Olympic-sized swimming pools, this reservoir of water can potentially supply astronauts in future space exploration.
Videos by VICE
“The moon is constantly bombarded with impactors—for example micrometeoroids and large meteoroids—which produce impact glass beads during high-energy flash-heating events,” Sen Hu, a co-author of the study, told VICE World News. The spheres were formed as material melted under the kinetic energy from the collisions and hardened as it cooled, added Sen Hu, a professor at the Chinese Academy of Sciences’ Institute of Geology and Geophysics.
The dozens of impact beads analyzed in the study were hand picked from a lunar soil sample obtained by China’s Chang’e-5 moon mission in 2020. The unmanned spacecraft, which collected 1.5 kilograms of material with a mechanical scoop and a drill, delivered new lunar samples to Earth in December that year—more than four decades after the Soviet Union’s Luna program and the U.S.’ Apollo missions.
While the presence of water on the moon has been known for decades and confirmed through many studies, scientists were baffled by how water appears and disappears over the lunar day on the moon, which suggested there was a reservoir of water that had yet to be identified in the lunar soil.
This latest finding provides an answer. While the beads are tiny in size, ranging from a few tens of micrometers to a few millimeters, they have a water content of up to 0.2 percent of its weight.
Analyzing their hydration profile, researchers traced the origin of the water to the solar wind, a continual stream of protons and electrons that flows outward from the corona, the sun’s outermost layer of atmosphere, through the solar system. The solar-wind hydrogen reacts with oxygen present at the surface of the lunar glass beads, producing water that diffuses into the orbs, Hu said.
These beads also release their entrapped water into space, which explains the water cycle on the lunar surface, Hu said.
The finding of substantial water contents in these beads has implications for other airless bodies, such as the planet Mercury and the asteroid Vesta, where impact craters have also been detected.
Researchers are also looking into ways of collecting the water from the beads, which can pave the way for in situ resource utilization—the use of local material obtained and manufactured on astronomical objects—and missions further into the solar system.
“Knowing how water is produced, stored and replenished near the lunar surface would be very useful for future explorers to extract and utilize it for exploration purposes,” Hu said.
