The discovery of widespread but small amounts water on the surface of the moon, announced yesterday, stands as one of the most surprising findings in planetary science.
Three spacecraft picked up the signature of water, not just in the frigid polar craters where it has long been suspected to exist, but all over the lunar surface, which was previously thought to be bone dry.
"Widespread water has been detected on the surface of the moon," said planetary geologist Carle Pieters of Brown University in Rhode Island, who led one of the studies detailing the findings.
While the findings, detailed in the Sept. 25 issue of the journal Science, don't mean there are pools of liquid water sitting on the moon, it does mean that there is — entirely unexpectedly — water potentially tied up or mixed in the minerals that make up the lunar dirt.
"What we're detecting is completely unexpected," Pieters said. "The moon continues to surprise us."
The moon dirt would be akin to soil from an arid environment like Arizona — it wouldn't feel wet to the touch, but there's certainly water bound up in it, Pieters told SPACE.com.
This discovery may well revolutionize our understanding of the nature of the moon's surface, experts say, and it has geologists eager to go back to the moon and dig up some lunar dirt.
"I rank this as a game changer for lunar science," said University of Colorado astrophysicist Jack Burns, chair of the science committee for the NASA Advisory Council. Burns was not involved in the new findings. "In my mind this is possibly the most significant discovery about the moon since the Apollo era."