the lunar interior has a substantial amount of water.
Ancient volcanic deposits on the moon reveal new evidence about the lunar interior, suggesting it contains substantial amounts of water.
Using satellite data, scientists from Brown University studied lunar pyroclastic deposits, layers of rock that likely formed from large volcanic eruptions.
The magma associated with these explosive events is carried to the moon's surface from very deep within its interior, according to a study (Remote Detection of Widespread Indigenous Water in Lunar Pyroclastic Deposits) published today - July 24 - in Nature Geoscience.
Previous studies have observed traces of water ice in shadowed regions at the lunar poles.
However, this water is likely the result of hydrogen that comes from solar wind, according to the new study's lead author, Ralph Milliken, a geologist at Brown University.
The new research reveals there is likely a large amount of water in the moon's mantle, as well.
This suggests that the water was delivered to the moon very early in its formation, before it fully solidified, Milliken told Space.com.
Colored areas on this map
show spots with elevated water content compared
with surrounding terrain on the moon's surface.
Yellow and red indicate the richest water content.
Credit: Milliken lab/Brown University
In order to estimate the amount of trapped water in the pyroclastic deposits, the scientists had to isolate the reflected sunlight from the thermal energy emitted by the moon's hot surface.
Previously, scientists from Brown detected trace amounts of water in similar volcanic samples - which are composed of loose material or "glass beads" - brought back to Earth from the Apollo 15 and 17 missions.
However, the Apollo samples were not collected from the large pyroclastic deposits mapped using the satellite data in the recent study.
This brought into question whether the Apollo samples represent a large portion of the moon's "wet" interior or if they represent only a small water-rich region within an otherwise "dry" mantle.
However, the question of how the water got in the moon's interior remains unresolved.
Evidence of water deep beneath the lunar surface may also have implications for how Earth got its water, scientists say.
Furthermore, the study's findings suggest that the pyroclastic deposits could possibly be mined for water, which, in turn, could fuel future missions to the moon.
Going forward, the scientists would like to map the pyroclastic deposits in greater detail so that they can better understand how water concentrations vary among different deposits on the lunar surface.
Milliken also noted that these deposits would be great targets for future exploration, during which samples could be collected and later studied to further refine the estimated water content of the moon's interior.