Scientists: Martian chunks must be ice

TUCSON, June 20 (UPI) -- Scientists with the U.S. space program say chunks a rover scooped up from a Martian trench must be ice because of the way the they reacted to air.

"It must be ice," said Dr. Peter H. Smith of the University of Arizona in Tucson, the mission's principal investigator. "The whole science team thinks this. I think we feel this is definite proof that these are little chunks of icy material."

Now scientists can address their main issue of whether ice ever melted, turning Mars into a habitable place, The New York Times reported Friday.

In a photograph of a trench the Phoenix lander dug into the Martian soil, some white patches observed earlier shrank and several chunks disappeared.

Until now, scientists with the mission said they weren't sure if the previously discovered white material was ice or a salt. But because water ice changes to water vapor when exposed to air -- and salt doesn't -- they now think the white chucks are water.

To see the ice was "tremendously exciting," Smith told the Times. "One of the biggest fears I've had on the mission is that we'd dig and dig and never find anything."