This undated image taken by the NASA Mars Reconnaissance Orbiter released by NASA/JPL-Caltech/University of Rome/Southwest Research Institute shows a recently discovered underground deposit of carbon ... more 
This undated image taken by the NASA Mars Reconnaissance Orbiter released by NASA/JPL-Caltech/University of Rome/Southwest Research Institute shows a recently discovered underground deposit of carbon dioxide ice in the Martian south pole. Scientists say Mars was stormier and dustier 600,000 years ago because there was more carbon dioxide in the atmosphere. The researchers findings are based on the discovery of a huge underground reservoir of dry ice in the Martian south pole. (Credit: NASA/JPL-Caltech/University of Rome/Southwest Research Institute) less 
1 / 1
Associated Press
Thu, Apr 21, 2011 3:41 PM EDT