Using data from the Indian Space Research Organisation’s (ISRO) Chandrayaan-1 lunar orbiter, two researchers from Brown University found something thought to be long gone: Water on the surface of the moon. But don’t expect to go swimming anytime soon; it’s trapped in rock.
The researchers specifically focused on pyroclastic rock, which is volcanic in origin. Samples returned from Apollo 15 and 17 showed an abundance of water trapped in glass “beads” within the rock, but researchers have since debated whether these rocks in particular were saturated with water for a unique reason or if all pyroclastic rocks on the moon develop these tiny pockets of water. It now seems that the evidence supports the latter, and pyroclastic rocks all over the moon contain notable stores of water.
“We saw that there were enhanced absorptions in the pyroclastic deposits but not in any of the surrounding terrains,” says Ralph Milliken, a professor of planetary science at Brown University. “This was a key indicator that there was something different about these regions and that they were water-bearing relative to other nearby terrains.”
Shuai Li, a graduate student at Brown and co-author on the paper, cautions that the water doesn’t appear to be in an ice form, but rather is trapped in the minerals. Milliken and Li are also still trying to determine if it’s actually hydrogen dioxide or or if it might be hydroxyl, a similar compound made of one hydrogen atom and one ionized oxygen atom. Whether it’s water or hydroxyl “cannot be discriminated based on current satellite data,” Li says.
There’s no evidence that this finding is connected to ice deposits, and Li says that there’s “definitely no” oceanic source of the water. But the water or hydroxyl does come from fairly deep below the lunar surface. “This water is inside the glass and…