There’s even more water on the moon than we previously thought, according to new analysis of tiny glass beads left over from ancient volcanic eruptions.
The naturally occurring beads were collected in the 1970s as part of the Apollo 15 and 17 missions, which landed near zones of volcanic activity. The beads formed when magma bursting onto the surface crystallized in such a way that water became trapped inside.
However, scientists couldn’t be sure if the Apollo samples are unique or if other volcanic flows on the moon are filled with water-bearing glass. (Find out how flying oceans of magma help demystify the moon’s creation.)
In a new study published today in Nature Geoscience, scientists reexamined the Apollo samples and used more recent satellite data to look for signs of water-bearing beads elsewhere on the moon. They found that the volcanic deposits are indeed widespread, which suggests that the material inside the moon is wetter than previously thought.
“The fact that they see this feature associated with the glasses tells us that there was indeed quite a bit of water in the interior of the moon when these volcanic eruptions were occurring,” says Anthony Colaprete, a NASA scientist who reviewed the paper.
Here’s what we now know about water on the moon.
On 18 November 2008, the Moon Impact probe was released from India’s Chandrayaan-1 at a height of 100 kilometres (62 mi). During its 25-minute descent, the impact probe’s Chandra’s Altitudinal Composition (CHACE) recorded evidence of water in 650 mass spectra gathered in the thin atmosphere above the Moon’s surface.
In September 2009, NASA payload Moon Mineralogy Mapper onboard Chandrayaan-1 detected water on the Moon surface and hydroxyl absorption lines in reflected sunlight. In November 2009, NASA re-confirmed water on moon with its LCROSS space probe which detected a significant amount of hydroxyl group in the material thrown up from a south polar crater by an impactor.
This may be attributed to water-bearing materials – what appears to be “near pure crystalline water-ice”. In March 2010, it was reported that the Mini-SAR on board Chandrayaan-1 had discovered more than 40 permanently darkened craters near the Moon’s north pole that are hypothesized to contain an estimated 600 million metric tonnes (1.3 trillion pounds) of water-ice.
Water may have been delivered to the Moon over geological timescales by the regular bombardment of water-bearing comets, asteroids and meteoroids or continuously produced in situ by the hydrogen ions (protons) of the solar wind impacting oxygen-bearing minerals.
The search for the presence of lunar water has attracted considerable attention and motivated several recent lunar missions, largely because of water’s usefulness in rendering long-term lunar habitation feasible.