Moon Water Discovery Hints at Mystery Source Below Surface

By: By Terrell Johnson

Published: August 28,2013

 

 

 

 

 

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The central peak of Bullialdus rising above the crater floor, with the crater wall in the background. (NASA/GSFC/Arizona State University)

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Scientists have discovered evidence of magmatic water on the moon's surface – water that originates deep within the lunar interior – according to a study published this week in the scientific journal Nature Geoscience.
The discovery marks the first time water that originates from the moon itself, rather than water carried there by solar wind or from meteorites crashing into its surface, has been discovered by remote satellites. Previously, scientists had relied on rock samples brought back by astronauts to learn about the moon's internal moisture.
"For many years, researchers had believed that the rocks from the moon were 'bone dry' and that any water detected in the Apollo samples had to be contamination from Earth," said Rachel Klima, a planetary geologist at the Johns Hopkins University Applied Physics Laboratory and the study's lead author.
But new laboratory techniques developed about five years ago revealed that "the interior of the moon is not as dry as we previously thought," she added in a press release from Johns Hopkins University. Around the same time, orbiting satellite detected water on the moon's surface, "which is thought to be a thin layer formed from solar wind hitting the lunar surface," she said.
In 2009, a crater on the lunar surface named Bullialdus was completely imaged by NASA's Moon Mineralogy Mapper (M3), which traveled aboard the Indian Space Research Organization's Chandrayaan-1 spacecraft. The crater's location, within about 25 degrees latitude of the moon's equator, meant that it wasn't a favorable place for solar wind to leave behind surface water.
Klima and her colleagues at the Scientific and Exploration Potential of the Lunar Poles group at the NASA Lunar Science Institute studied the M3 data as well as the rocks within the Bullialdus crater, which likely formed after an asteroid smashed into the moon's surface, carving out a crater about 3 to 5 1/2 miles wide.
Rocks from Bullialdus were thought to hold clues to the moon's internal moisture thanks to both their location and because the crater's central peak is made up of a type of rock that forms deep underneath the moon's crust and mantle, where 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 told NASA's Lunar Science Institute.
The discovery allows scientists to take a fresh look at the moon's surface to learn more about the workings of its interior, including its volcanic processes and how it formed.
"This impressive research confirms earlier lab analyses of Apollo samples, and will help broaden our understanding of how this water originated and where it might exist in the lunar mantle," said NSLI Director Yvonne Pendleton.