Neil Bowles keeps a spare scientific instrument in an Oxford basement. He built it to study the moon, but the spacecraft it was meant to fly on failed soon after launch in 2025. Now Bowles, a professor of planetary science at the University of Oxford, is waiting for another chance to send it into space.
"It was always a bit weird that the Apollo samples appeared to be so dry," Bowles told me in his office. Those samples—rocks collected by astronauts during NASA's moon landings in the 1960s and 70s—seemed to show our nearest neighbor was almost completely dry. But that idea has been turned upside down.
Scientists now know the moon does have water. It's just not sitting in lakes or pools. Instead, it's locked inside a mineral called apatite, trapped at the atomic level. Apatite crystals are tiny—only a few hundred microns across, about the width of a human hair. But these little crystals hold clues that could change how we understand Earth's entire neighborhood in space.
The story of this discovery goes back to 2009, when NASA crashed a rocket into the moon's south pole and found water ice hiding in permanently shadowed craters. That was exciting. But recent research points to something even more surprising: most of the moon's water isn't on the surface at all. It's buried deep inside the rock.
Why does this matter?
It helps explain how the Earth and moon came to exist as a pair. About 4.5 billion years ago, a Mars-sized object slammed into the infant Earth. The debris from that collision eventually clumped together to form the moon. Scientists still don't fully understand how water survived that violent process or where it ended up.
"We need all the evidence we can get to understand how you end up with the moon as we see it today, but also how the moon has influenced Earth," Bowles says. Because Earth and the moon are a system, he explains—two worlds that shaped each other over billions of years. That's rare in our solar system.
Bowles hasn't given up on his basement instrument. He's hoping it will fly aboard a future NASA mission called UCIS, which would map water across the lunar surface. It's a story about curiosity that refuses to quit—and proof that sometimes, even when a mission fails, the quest to understand our cosmic home continues.
For those dreaming of someday walking on the moon, the science offers a quiet reassurance: our neighbor is not the dead, dry rock we once imagined. It has water. It's still full of mysteries. And scientists like Bowles are still trying to figure them out.