A new study led by Roger Clark, Senior Scientist at the Planetary Science Institute, has unveiled a complex and diverse distribution of water and hydroxyl on the Moon. This research, published in the Planetary Science Journalindicates that water-rich rocks are not confined to the polar regions as previously thought. Instead, these valuable resources are present even near the Moon’s equator.
The findings stem from an analysis of data collected by the Moon Mineralogy Mapper (M3) on India’s Chandrayaan-1 spacecraft, which orbited the Moon from 2008 to 2009. Clark and his team used infrared spectroscopy to detect water and hydroxyl in both the near and far sides of the Moon
“Future astronauts may be able to find water even near the equator by exploiting these water-rich areas,” said Clark. This revelation is significant as it contradicts the long-held belief that the most abundant sources of water were limited to the Moon’s shadowed polar craters. The presence of water in sunlit areas opens up new opportunities for lunar exploration and potential habitation.
Clark’s research highlights that water on the lunar surface is metastable which means that while H2O can slowly degrade over time, hydroxyl (OH) persists. “A cratering event that exposes sub-surface water-rich rocks to the solar wind will degrade with time, destroying H2O and creating a diffuse aura of hydroxyl, OH, but the destruction is slow, taking thousands to millions of years. Elsewhere on the lunar surface, there appears a patina of hydroxyl, probably created from solar wind protons impacting the lunar surface, destroying silicate minerals where the protons combine with oxygen in the silicates to create hydroxyl, in a process called space weathering.”
This new analysis challenges findings from NASA, which identified water primarily in the Moon’s shadowed regions through neutron measurements. While NASA’s data suggested that water was predominantly found in the coldest areas, Clark’s study expands the narrative by showing that sunlit regions are also viable sources. As the scientific community continues to explore lunar geology, the understanding of where water exists on the Moon is evolving rapidly.
