There are many, many of them on the Moon.
Water discovered in billions of glass spheres on lunar surface, continuously replenished by solar wind hydrogen bombardment. Extraction would be challenging but feasible through heating; NASA plans crewed lunar return by end of 2025 to explore south pole ice deposits.
- Water discovered in glass spheres formed by meteorite impacts on the lunar surface
- Chang'e 5 mission returned 32 analyzed spheres in 2020
- Solar wind hydrogen continuously replenishes water supply
- NASA plans crewed lunar return by end of 2025 to south pole
Chinese lunar samples reveal water trapped in glass spheres formed by meteorite impacts, offering a potentially renewable water source for future lunar missions and rocket fuel production.
In 2020, a Chinese spacecraft returned to Earth with lunar soil that would reshape how scientists think about water on the Moon. Researchers analyzing those samples found something unexpected: water trapped inside tiny glass spheres scattered across the lunar surface, formed when meteorite impacts melted rock and sent it flying into the vacuum. The discovery, published this week in Nature Geoscience, suggests the Moon holds far more accessible water than previously understood—and that this water is being continuously replenished.
The glass spheres are everywhere on the Moon, ranging in size from a human hair's width to something larger. Hejiu Hui, a researcher at Nanjing University who led the analysis of 32 randomly selected spheres from the Chang'e 5 mission, explained that water makes up only a small fraction of each sphere. But the sheer abundance changes the equation. Billions upon billions of these spheres litter the lunar landscape, the result of countless impacts over billions of years. "Yes, it will require many, many glass spheres," Hui said in an email. "On the other hand, there are many, many of them on the Moon."
What makes this discovery particularly significant is the mechanism keeping the water supply constant. The solar wind—a stream of charged particles flowing from the Sun—continuously bombards the Moon with hydrogen. This hydrogen interacts with oxygen in the lunar soil, creating water molecules that become embedded in the glass spheres as they cool. It is, in essence, a renewable system, one that has been operating for eons and will continue operating indefinitely.
The practical challenge is extraction. Future robotic missions could theoretically heat the spheres to release the water, but substantial work remains before this becomes viable. Scientists must determine whether the process is feasible at scale, whether the extracted water would be safe to drink, and what energy costs would be involved. The payoff, however, could be enormous. Water on the Moon means drinking water for astronauts, yes, but also rocket fuel—hydrogen and oxygen are the most efficient propellants known, and producing them on the Moon would eliminate the need to launch them from Earth.
This discovery builds on earlier findings. Apollo astronauts brought back lunar samples more than fifty years ago that contained water in glass spheres formed by volcanic activity. Those samples hinted at the possibility; the Chang'e 5 samples confirm it on a much larger scale and reveal a second mechanism—meteorite impact—that produces water-bearing spheres. The implications are not lost on space agencies. NASA has committed to returning astronauts to the Moon by the end of 2025, with the south pole as the destination. That region contains permanently shadowed craters believed to hold vast deposits of water ice. As missions return to the lunar surface, the question shifts from whether water exists to how quickly humans can learn to use it.
Notable Quotes
It will require many glass spheres, but there are many, many of them on the Moon.— Hejiu Hui, Nanjing University
The Hearth Conversation Another angle on the story
So these glass spheres—they're not rare or hidden. They're just sitting on the surface?
Everywhere. Billions of them. Every meteorite impact that's ever struck the Moon created them. They're as common as dust.
And the water inside them is being made right now, continuously?
Yes. The solar wind brings hydrogen, the lunar soil has oxygen, and the result is water molecules that get trapped in the glass as it cools. It's a process that never stops.
Why hasn't this been a major story until now?
Because the water content is tiny in each sphere. You need to look at the right scale—not one sphere, but the trillions of them. That's when the numbers become real.
What's the actual barrier to using this water?
Extraction. We know heating the spheres would release it, but we don't know yet if it's practical, safe, or worth the energy cost. That's the next phase of research.
And if it works?
Then the Moon stops being a place you visit and becomes a place you can sustain. Water for drinking, water for fuel. Everything changes.