New evidence has emerged indicating there is water from an “unknown source” locked in mineral grains on the surface of the moon. According to the U.S. space agency, NASA, the source of the water is likely “deep beneath the surface” of the moon.
"This rock, which normally resides deep beneath the surface, was excavated from the lunar depths by the impact that formed Bullialdus crater," said Rachel Klima, a planetary geologist at the Johns Hopkins University’s Applied Physics Laboratory (APL) in Laurel, Maryland, in a statement
Researchers used data from NASA's Moon Mineralogy Mapper (M3) instrument aboard the Indian Space Research Organization's Chandrayaan-1 spacecraft. The data showed evidence of “magmatic water, or water that originates from deep within the moon's interior, on the surface of the moon.”
The central peak of the Bullialdus crater is made up of a type of rock that forms deep within the lunar crust and mantle when magma is trapped underground.
"Compared to its surroundings, we found that the central portion of this crater contains a significant amount of hydroxyl -- a molecule consisting of one oxygen atom and one hydrogen atom -- which is evidence that the rocks in this crater contain water that originated beneath the lunar surface," Klima said.
In 2009, water molecules were discovered by the M3 instrument in the moon’s polar regions. That water is thought to be only a thin layer formed when the solar wind hits the moon. The Bullialdus crater area is in an area where solar winds would not lead to the production of water.
The findings, published Aug. 25, in Nature Geoscience
, represent the first detection from lunar orbit of this form of water. Earlier studies had shown the existence of magmatic water in lunar samples returned during the Apollo program.
For many years, researchers believed the rocks from the moon were completely dry and that any water detected in the Apollo samples had to be contamination from Earth.
"Now that we have detected water that is likely from the interior of the moon, we can start to compare this water with other characteristics of the lunar surface," said Klima. "This internal magmatic water also provides clues about the moon's volcanic processes and internal composition, which helps us address questions about how the moon formed, and how magmatic processes changed as it cooled."