Water is the most sought-after raw material for planetary exploration
For generations, the Moon was imagined as a world of absolute dryness — a barren threshold beyond which life could not follow. Now, Chinese scientists analyzing samples returned by the Chang'e-5 mission have found water locked inside tiny glass beads scattered across the lunar surface, formed by billions of years of meteorite impacts and continuously replenished by the hydrogen carried on solar winds. The discovery, published in Nature Geoscience, estimates some 270 trillion kilograms of water may be held across the Moon in this form — a finding that quietly reframes the Moon not as a dead end, but as a potential waystation for human civilization reaching further into the cosmos.
- A long-held scientific assumption — that the Moon is completely dry — has now been overturned by evidence hiding in plain sight, inside microscopic glass beads on the lunar soil.
- The scale of the discovery creates immediate tension: 270 trillion kilograms of water sounds vast, yet each individual glass sphere holds only a vanishingly small amount, making extraction a formidable engineering puzzle.
- The water's origin adds urgency to the finding — it is not a finite fossil reserve but an actively renewing resource, continuously generated as solar wind hydrogen bonds with oxygen in lunar minerals through ongoing meteorite bombardment.
- Scientists believe moderate heat of around 100 degrees Celsius could release the water from the beads, making robotic extraction theoretically feasible, though economic viability and safety for human consumption remain open questions.
- The discovery lands at a pivotal moment, with NASA targeting the Moon's south pole by 2025 and researchers suggesting similar solar-wind water processes may be operating on Mercury and beyond — placing this finding at the frontier of a new era of space exploration.
Chinese scientists have identified a renewable source of water on the Moon, hidden inside tiny glass spheres formed when meteorites strike the lunar surface with enough force to melt surrounding rock into small beads. The discovery comes from 117 such spheres collected by China's Chang'e-5 mission in 2020 and analyzed by researchers from the Chinese Academy of Sciences, with findings published this week in Nature Geoscience.
The water trapped within these beads originates from the Sun itself. Solar wind carries hydrogen across the solar system, and when that hydrogen interacts with the oxygen-rich minerals of the lunar surface, water is produced. Because meteorite bombardment and solar wind exposure are continuous processes, this is not a one-time geological event — the Moon is, in a quiet and incremental way, always making more water.
The total estimated reserve is striking: scientists calculate that glass spheres across the entire Moon may hold roughly 270 trillion kilograms of water. Yet the amount in any single bead is almost imperceptibly small, and the aggregate figure only becomes meaningful because of the sheer number of particles blanketing the lunar landscape. Researcher Hejiu Hui of Nanjing University acknowledged that while the quantities are significant, mining this water at scale would present real challenges.
On the question of extraction, coauthor Mahesh Anand of the Open University offered cautious optimism — moderate heat of around 100 degrees Celsius appears sufficient to release the water as vapor, suggesting robotic collection could one day be feasible. Whether doing so would be economically practical, or whether the water would be safe for human use, remains to be determined.
The finding arrives as lunar science undergoes a broader transformation. Once assumed to be completely dry, the Moon has revealed water in multiple forms across recent missions. NASA is preparing to send astronauts to the lunar south pole by 2025, where frozen water is believed to fill ancient craters. And researchers note that similar solar-wind-driven water generation may be occurring on Mercury and other bodies throughout the solar system — suggesting this discovery on the Moon may be the first chapter of a much larger story.
Chinese scientists have identified a renewable source of water on the Moon, locked inside tiny glass spheres formed by the violent collision of meteorites with the lunar surface. The discovery, published this week in Nature Geoscience, comes from samples collected by China's Chang'e-5 mission in 2020 and offers a tantalizing prospect for future explorers: water that could be extracted and used to sustain human presence on another world.
Researchers from the Chinese Academy of Sciences analyzed 117 glass spheres gathered from the lunar surface. The spheres themselves are created through a process that has been happening for billions of years. Without Earth's protective atmosphere, the Moon is constantly bombarded by tiny meteorites. The heat from these impacts melts the surrounding rock and mineral material, which then cools into small glass beads. These spheres act like sponges, trapping water molecules within their structure.
The water itself comes from an unlikely source: the Sun. Solar wind—a stream of charged particles flowing outward from the Sun's atmosphere—carries hydrogen across the solar system. This hydrogen interacts with oxygen, which makes up nearly half of the Moon's composition and is bound within its rocks and minerals. The continuous bombardment of meteorites and the relentless interaction of solar wind with the lunar surface means this water-producing process happens continuously, not as a one-time event.
The implications are staggering in scale. Scientists estimate that glass spheres across the entire Moon contain roughly 270 trillion kilograms of water. Yet the amount stored in each individual sphere is minuscule—a tiny fraction of the bead's total mass. Only because there are billions or trillions of these particles scattered across the lunar landscape does the total add up to something substantial. Hejiu Hui, a researcher from Nanjing University involved in the study, noted that while the quantities are significant, actually mining this water would present considerable challenges.
The extraction process itself, however, appears feasible. Mahesh Anand, a coauthor from the Open University in the United Kingdom, explained that moderate heat of around 100 degrees Celsius would be sufficient to release the water from the spheres. Future robotic missions could potentially heat the glass beads and collect the water vapor. But substantial questions remain unanswered. Researchers have not yet determined whether extracting water at scale would be economically viable, nor have they confirmed whether the extracted water would be safe to drink.
Sen Hu, another author of the study, framed the discovery in terms of what comes next: "Water is the most sought-after raw material for enabling sustainable exploration of planetary surfaces. Understanding how water is produced, stored, and replenished near the lunar surface would be tremendously valuable for future explorers." This discovery aligns with a broader shift in lunar science over the past two decades. For decades, scientists believed the Moon was bone-dry. Recent missions have repeatedly shown otherwise, revealing water in various forms across the satellite.
The finding also extends beyond the Moon. Similar water-generation processes driven by solar wind may be occurring on Mercury and other bodies throughout the solar system. Meanwhile, NASA is preparing its own lunar push. The space agency plans to send astronauts back to the Moon by the end of 2025, with missions focused on the south pole, where scientists believe frozen water fills ancient craters. The convergence of these discoveries and missions suggests that water, once thought absent from the Moon, may become central to humanity's next chapter of space exploration.
Notable Quotes
Water is the most sought-after raw material for enabling sustainable exploration of planetary surfaces. Understanding how water is produced, stored, and replenished near the lunar surface would be tremendously valuable for future explorers.— Sen Hu, study coauthor
The Hearth Conversation Another angle on the story
So these glass spheres—they're not containers someone put water into. The water actually forms inside them as they cool?
Exactly. A meteorite hits, the impact melts rock and minerals, and as that molten material cools, it traps water molecules that have been created right there on the surface through solar wind and oxygen interaction.
And the solar wind brings hydrogen all the way from the Sun? That seems almost too simple.
It does, but it's been happening for billions of years. The Sun is constantly sending out these charged particles. They hit the Moon, interact with the oxygen already there, and water forms. The meteorite impacts just happen to create the perfect container for it.
If each sphere only holds a tiny amount, how does 270 trillion kilograms add up?
Scale. There are trillions of these spheres scattered across the entire lunar surface. Each one is microscopic, but multiply that by the sheer number and you get something real—something that could matter for future missions.
But extracting it seems like the hard part, right? You'd need to heat billions of spheres?
That's the puzzle. Yes, 100 degrees Celsius would work. But gathering enough spheres, processing them, and doing it in a way that makes economic sense—that's still an open question. It's theoretically possible but practically uncertain.
Does this change what NASA is planning for 2025?
Not immediately. NASA is still focused on the south pole and its frozen water deposits. But discoveries like this one add another piece to the puzzle of how water exists on the Moon and where future explorers might find it.