WASHINGTON, Aug. 27 (Xinhua) -- U.S. researchers said Tuesday they have found magmatic water, or water that originates from deep within the Moon's interior, on the surface of the Moon.
The findings are the first such remote detection of this type of lunar water via the U.S. Moon Mineralogy Mapper instrument. Earlier studies had shown the existence of magmatic water in lunar samples returned during the Apollo program.
Scientists used the Moon Mineralogy Mapper, which is on board the Indian Space Research Organization's Chandrayaan-1 spacecraft, to image the lunar impact crater Bullialdus, located near the lunar equator.
Scientists were interested in studying this area because the central peak of the crater is made up of a type of rock that forms deep within the lunar crust and mantle when magma is trapped underground.
"This rock, which normally resides deep beneath the surface, was excavated from the lunar depths by the impact that formed Bullialdus crater," said lead author Rachel Klima, a planetary geologist at the Johns Hopkins University Applied Physics Laboratory, in a statement.
"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.
The detection of internal water from orbit means scientists can begin to test some of the findings from sample studies in a broader context, including in regions that are far from where the Apollo sites are clustered on the near side of the moon, said the researchers. For many years, scientists believed that the rocks from the moon were bone-dry and 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," Klima added.
The findings are published in the journal Nature Geoscience.