The Moon may be hiding vast deposits of water beneath its surface, according to the results of a study of lunar satellite data.
Scientists from Brown University studied data about the Moon’s volcanic deposits in a bid to learn more about the lunar interior – the mantle that sits below its surface. What they found contradicted long-held assumptions about the Moon’s interior, suggesting that it is rich in water, not dry as was previously assumed.
This supports the analysis of lunar samples from the Apollo 15 and 17 missions, which first cast doubt on the dry mantle theory. Among the samples brought back were volcanic glass beads, which have since been found to contain as much water as some rocks found on Earth.
The research, which is published today in Nature Geoscience, suggests that these samples were, in fact representative of the Moon as a whole, indicating it is far wetter than traditionally thought.
“The key question is whether those Apollo samples represent the bulk conditions of the lunar interior or instead represent unusual or perhaps anomalous water-rich regions within an otherwise ‘dry’ mantle,” said Ralph Milliken, study lead author and an associate professor in Brown’s Department of Earth, Environmental and Planetary Sciences.
“By looking at the orbital data, we can examine the large pyroclastic deposits on the Moon that were never sampled by the Apollo or Luna missions.
“The fact that nearly all of them exhibit signatures of water suggests that the Apollo samples are not anomalous, so it may be that the bulk interior of the Moon is wet.”
The research was conducted using orbital spectrometers, which measure which wavelengths of light are reflected by a planet’s surface. By determining which wavelengths were absorbed and which were reflected, the scientists were able to determine the presence of specific compounds and minerals.
With considerable discussion of the establishment of a lunar base by numerous space organisations, the quantity of water on the planet is significant. Not only is it valuable in sustaining humans and supporting systems, but also can be used as the basis for rocket fuel.
“Other studies have suggested the presence of water ice in shadowed regions at the lunar poles, but the pyroclastic deposits are at locations that may be easier to access,” said study co-author Shuai Li, a former Brown PhD graduate and postdoctoral researcher at the University of Hawaii.
“Anything that helps save future lunar explorers from having to bring lots of water from home is a big step forward, and our results suggest a new alternative.”