Scientists find proof of water on moon

Technology to find minute traces of water in rock has improved.

Orlando Sentinel

WASHINGTON — One of the biggest lunar discoveries of the decade — proof that the moon may have had water since its formation — was announced Wednesday by a team of researchers whose background is more in Earth science than moon rocks.

In an article published in the journal Nature, the six-scientist team of geologists and geochemists showed that water from the moon’s interior gushed to the surface more than 3 billion years ago in geyserlike jets of molten magma, disproving a long-standing belief that Earth’s nearest neighbor is almost bone-dry.

The source of their discovery: two 1-gram samples of moon rocks brought back to Earth more than 35 years ago by the Apollo 15 and Apollo 17 lunar missions.

“It’s a real step forward, and it shows we’re still getting things out of the Apollo samples,” said NASA’s David Lindstrom, a program officer and a lunar scientist since Apollo 11.

Why did they do it?

Alberto Saal, a geochemist at Brown University and the study’s lead author, said he was inspired by breakthroughs in the technology that enables scientists to detect minute traces of water in rock. “It was almost a no-brainer to go and see,” he said.

Still, it took three years to get funding because previous studies had found no proof of water. “No one believed there would be anything there,” said Saal. The team ultimately got a $167,000 two-year grant from NASA, Lindstrom said.

How did they find water?

Saal went to Erik Hauri, a college friend and geochemist at the Carnegie Institution for Science, who had helped improve a technique called secondary ion mass spectrometry. The machine blasted the moon rocks with ionized beams and measured resulting changes in the beam’s electrical charge. It can detect water at levels as low as five parts per million.

When the moon rocks yielded up to 46 parts per million, the scientists knew they had made a big discovery.

Where did the water come from?

That’s not entirely clear. The researchers think that water vapor was part of volcanic eruptions from the moon’s core that quickly solidified on its icy surface.