Humans have indeed come a long way from jokes about the Moon being made of cheese. Today, scientists are still uncovering surprises about this night-sculpted neighbor, and one of the most intriguing is that the Moon hosts water and hydroxyl beneath its surface. This isn’t a vast ocean or a floating lake, but a far subtler kind of chemistry tucked into the soil and in shadowed regions. What this implies about the Moon’s history and its future as a destination for exploration is still being understood, yet the signal is clear enough to shift our view of this world in space.
Recent measurements have shown that the Moon contains small but meaningful amounts of water and hydroxyl bound in the regolith. In practical terms, this means hydrogen and oxygen have found ways to pair up on the lunar surface, often bonded within minerals or present as ice in permanently shaded pockets. The exact distribution is patchy and depends on where the surface has been exposed to sunlight and the level of interaction with solar wind. These findings have come from a combination of orbital instruments and landed experiments, with several missions contributing crucial clues to the picture. (NASA scientists, 2023)
The guiding mechanism behind this discovery involves the Sun’s solar winds. These streams of charged particles travel through space and reach the Moon, delivering hydrogen to the surface. There, the hydrogen encounters oxygen contained in lunar rocks and minerals, creating molecules of water and hydroxyl. In other words, solar wind acts like a delivery system, while the Moon’s own chemistry does the rest. The result is a tenuous but real reservoir of water-related compounds that challenge the notion of a completely arid lunar surface. (NASA researchers, 2022)
This growing understanding shows the Moon is not a dry, featureless rock, but a world with a dynamic surface chemistry influenced by its solar environment. The water and hydroxyl detected today are not oceans waiting to be tapped; they exist as bound molecules within the soil and in cold traps near the poles. Still, the presence of these compounds offers a tantalizing glimpse into how future missions might utilize in situ resources, reducing the need to haul everything from Earth. Ongoing studies continue to map where these substances accumulate and how they change with the Sun’s activity. (ESA updates, 2021)
This evolving picture of lunar hydration underscores a broader truth about planetary bodies in the inner solar system: even worlds that look dry at first glance can host surprising chemistry under the right conditions. The Moon’s relationship with the Sun, its gravity, and the ancient events that shaped its formation all contribute to a surface that still holds secrets waiting to be unlocked by future explorers. The discovery of water-related compounds is a reminder that the Moon remains a living laboratory, a place where science keeps pushing beyond old assumptions. (NASA science briefing, 2020)
DID YOU KNOW?
- The Moon is not perfectly spherical, but slightly elongated in shape due to its rotation and tidal forces.
- Every year the Moon moves away from the Earth by about 3.8 centimeters, which is roughly 1.5 inches.
- The Moon is about 4.5 billion years old, and the leading theory for its origin is that a Mars-sized body named Theia collided with Earth, throwing debris that formed the Moon.
- We always see only one face of the Moon; the opposite side is called the far side and has a different terrain than the near side.
- Neil Armstrong became the first person to walk on the Moon, and twelve people have walked on its surface in total, spanning several Apollo missions.