Mars' Architect-in-Chief? Water, Says Study

Aug. 25, 2008 -- Scientists are moving closer to a unilateral opinion that water, even in relatively modern times, exists on Mars. The latest finding offers a detailed scenario of how small channels appear on the planet's face despite what appears to be a complete lack of surface water.

Eight years ago, a satellite made a second pass over a patch of Mars and set scientists abuzz with pictures showing small channels where none were seen before.

That got people thinking about how water could exist on the dry, frozen surface of Mars long enough to etch its face. Other researchers credited the gully-like features to bursts of carbon dioxide seeping out of the ground.

"We think that these are really exciting results because they establish a link between recent gullies and major recent (last few millions of years) large accumulations of ice," Brown University's James Head wrote in an e-mail to Discovery News.

Armed with new pictures from a next-generation spacecraft and a painstaking reconstruction of climate change on Mars, a team of scientists this week painted a time-lapse view of gully formation that again fingers water as architect-in-chief.

Head and his colleagues studied a 6.6-mile diameter crater, located at about 40 degrees south latitude, the most common location for gullies on Mars.

The story they pieced together, detailed in today's issue of the Proceedings of the National Academy of Sciences, describes how accumulations of snow and ice on the crater's north wall produced glaciers that slowly slipped to the crater's floor, transporting bits of rock and debris. As temperatures warmed, due to seasonal changes, the ice sublimated into a gas, leaving behind the depressions.