Washington, Oct 27: The NASA's Stratospheric Observatory for Infrared Astronomy (SOFIA) has confirmed, for the first time, water on the sunlit surface of the Moon. This discovery indicates that water may be distributed across the lunar surface, and not limited to cold, shadowed places, according to a statement by NASA.
NASA scientist on Monday said that though the moon lacks the bodies of liquid water that are a hallmark of Earth, the lunar water is more widespread than previously known, with water molecules trapped within mineral grains on the surface and more water is perhaps hidden in ice patches residing in permanent shadows. A team led by Casey Honniball of NASA's Goddard Space Flight Centre in Maryland detected molecular water on the lunar surface, trapped within natural glasses or between debris grains.
The SOFIA has detected water molecules (H2O) in Clavius Crater, one of the largest craters visible from Earth, located in the Moon's southern hemisphere. Previous observations of the Moon's surface detected some form of hydrogen, but were unable to distinguish between water and its close chemical relative, hydroxyl (OH).
"Data from this location reveal water in concentrations of 100 to 412 parts per million - roughly equivalent to a 12-ounce bottle of water - trapped in a cubic meter of soil spread across the lunar surface. The results are published in the latest issue of Nature Astronomy," the statement read.
"We had indications that H2O - the familiar water we know - might be present on the sunlit side of the Moon," said Paul Hertz, director of the Astrophysics Division in the Science Mission Directorate at NASA Headquarters in Washington. "Now we know it is there. This discovery challenges our understanding of the lunar surface and raises intriguing questions about resources relevant for deep space exploration."
As a comparison, the Sahara desert has 100 times the amount of water than what SOFIA detected in the lunar soil, the statement read. Despite the small amounts, the discovery raises new questions about how water is created and how it persists on the harsh, airless lunar surface.
"Prior to the SOFIA observations, we knew there was some kind of hydration," said Casey Honniball, the lead author who published the results from her graduate thesis work at the University of Hawaii at Manoa in Honolulu. "But we didn't know how much, if any, was actually water molecules - like we drink every day - or something more like drain cleaner."
SOFIA offered a new means of looking at the Moon, NASA said. Flying at altitudes of up to 45,000 feet, this modified Boeing 747SP jetliner with a 106-inch diameter telescope reaches above 99 per cent of the water vapor in Earth's atmosphere to get a clearer view of the infrared universe. Using its Faint Object infraRed CAmera for the SOFIA Telescope (FORCAST), SOFIA was able to pick up the specific wavelength unique to water molecules, at 6.1 microns, and discovered a relatively surprising concentration in sunny Clavius Crater.
"Without a thick atmosphere, water on the sunlit lunar surface should just be lost to space," said Honniball, who is now a postdoctoral fellow at NASA's Goddard Space Flight Centre in Greenbelt, Maryland. "Yet somehow we're seeing it. Something is generating the water, and something must be trapping it there."