An artist's conception shows what NASA's Mars Reconnaissance Orbiter has revealed, vast Martian glaciers of water ice under protective blankets of rocky debris at much lower latitudes than any ice previously identified on the Red Planet. Scientists analyzed data from the spacecraft's ground-penetrating radar and report in the November 21, 2008 issue of the journal Science that buried glaciers extend for dozens of miles from edges of mountains or cliffs. REUTERS/NASA/Handout  (UNITED STATES)  QUALITY FROM SOURCE.  FOR EDITORIAL USE ONLY. NOT FOR SALE FOR MARKETING OR ADVERTISING CAMPAIGNS.