spacetoday.net: Mars dry ice deposit could cause thicker, dustier atmosphere

Posted: Fri, Apr 22, 2011, 7:24 AM ET (1124 GMT)
Mars seen by Hubble August 2003 (STScI)

A buried deposit of dry ice near Mars's south pole suggests to scientists that the planet's atmosphere may vary significantly as its tilt changes. In a paper published in the journal Science this week, planetary scientists reported the discovery of a reservoir of frozen carbon dioxide with about the same volume of Lake Superior near the planet's south pole; that deposit is about 30 times the size of the known cap of dry ice at the pole. Scientists believe that, as the planet's tilt changes over time, that dry ice can sublimate and increase the planet's atmospheric pressure by 75 percent, causing stronger dust storms and expanding the areas of the planet's surface that could support liquid water. Scientists identified the carbon dioxide deposit in data from a radar instrument on NASA's Mars Reconnaissance Orbiter spacecraft.