This image, taken by the High Resolution Stereo Camera (HRSC) on board ESA’s Mars Express spacecraft, show a patch of water ice sitting on the floor of an unnamed crater near the Martian north pole.The crater is 35 kilometres wide and has a maximum depth of approximately 2 kilometres beneath the crater rim. The circular patch of bright material located at the centre of the crater is residual water ice.
More news from Mars Express. Via Boing Boing.
Swopon 
