Water has been discovered on Earth's moon in quantities much more widespread than previously believed, NASA scientists announced on Monday.
Water is now believed to be trapped in mineral grains on the moon's surface, with it also being likely that more water remains hidden in the moon's shadows.
"Several forces could be at play in the delivery or creation of this water. Micrometeorites raining down on the lunar surface, carrying small amounts of water, could deposit the water on the lunar surface upon impact," explained NASA.
"Another possibility is there could be a two-step process whereby the Sun's solar wind delivers hydrogen to the lunar surface and causes a chemical reaction with oxygen-bearing minerals in the soil to create hydroxyl. Meanwhile, radiation from the bombardment of micrometeorites could be transforming that hydroxyl into water."
The discovery came from NASA's Faint Object infraRed CAmera (FORCAST) for the SOFIA Telescope (Stratospheric Observatory for Infrared Astronomy). SOFIA was able to pick up the specific wavelength unique to water molecules, at 6.1 microns,
"It was, in fact, the first time SOFIA has looked at the Moon, and we weren't even completely sure if we would get reliable data, but questions about the Moon's water compelled us to try," said Naseem Rangwala, SOFIA's project scientist at NASA's Ames Research Center in California's Silicon Valley.
"It's incredible that this discovery came out of what was essentially a test, and now that we know we can do this, we're planning more flights to do more observations."
"A lot of people think that the detection I've made is water ice, which is not true. It's just the water molecules – because they're so spread out they don’t interact with each other to form water ice or even liquid water," said Casey Honniball, the lead author who published the results from her graduate thesis work at the University of Hawaii in Honolulu.
"Water is a valuable resource, for both scientific purposes and for use by our explorers," said Jacob Bleacher, chief exploration scientist for NASA's Human Exploration and Operations Mission Directorate. "If we can use the resources at the Moon, then we can carry less water and more equipment to help enable new scientific discoveries."