Weird Geological Features Spied On Mars

astroengine writes "The High-Resolution Imaging Science Experiment (HiRISE) camera carried by NASA's Mars Reconnaissance Orbiter has spotted a strange geological feature that, for now, defies an obvious explanation. Found at the southern edge of Acidalia Planitia, small pits with raised edges appear to hug a long ridge. So far, mission scientists have ruled out impact craters and wind as formation processes, but have pegged the most likely cause to be glacial in nature."