Tall boulder rolls down martian hill, lands upright
Thursday, August 14, 2014 - 05:30
in Astronomy & Space
(Phys.org) —A track about one-third of a mile (500 meters) long on Mars shows where an irregularly shaped boulder careened downhill to its current upright position, seen in a July 3, 2014, image from the High Resolution Imaging Science Experiment (HiRISE) camera aboard NASA's Mars Reconnaissance Orbiter.