Washington: Scientists have discovered tiny amounts of water in some of the famous moon rocks brought back to Earth by Apollo astronauts.
Recently NASA crashed two spacecraft into the moon and orbiters scanned the lunar surface for telltale light signatures.
And they confirmed existence of water on the moon.
The water levels detected in Apollo moon rocks and volcanic glasses are in the thousands of parts per million, at most.
This explains why analyses of the samples in the late 1960s and early 1970s concluded that the moon was absolutely arid.
"Only in the last decade have instruments become sensitive enough to even analyze water at those kinds of concentrations," National Geographic News quoted Gary Lofgren, the lunar curator at NASA`s Johnson Space Center in Houston, Texas, as saying.
Lofgen, who wasn`t involved with the new research, called it "solid work" worthy of further investigation.
Hints of water in moon samples first surfaced in a 2008 study, in which scientists reported having detecting water molecules in lunar glasses from the Apollo missions.
However, the researchers of that study could not prove that the water hadn`t been introduced to the moon rocks on Earth, perhaps through sloppy handling.
At the time, James Greenwood, a professor of Earth and environmental sciences at Wesleyan University in Middletown, Connecticut, was pioneering a technique that allowed him to study the chemical makeups of Martian meteorites.
He later applied his method to samples of the mineral apatite, culled from a variety of moon-rock types, to determine the fingerprint of the water molecules inside.
The work proves that the moon-rock water "is not from us," he said at a presentation of his findings at the 41st Lunar and Planetary Science Conference in Houston, Texas.
At the presentation, a second team announced the discovery of water in apatite-bearing rocks from one of the moon`s mares— dark regions, which are thought to have been formed by ancient lunar lava flows.
The finding is "one of the first to detect water in a lunar magmatic mineral" and adds to evidence that moon magma, in general, contains trace amounts of water, according to geoscientist Francis McCubbin, who participated in the research.