As the antarctic winter on Mars comes to a close, sunshine has begun to fall on the dunes in Russell Crater. When that happens, carbon dioxide ice sublimates (turns directly from a solid into a gas) and dislodges material that flows downhill. In this false-color image, the green spots might look like some kind of alien vegetation, but they are just places where frost has sublimated away in the sun.

Sent by: Mars Reconnaissance Orbiter | From: Mars | Released: November, 2008 | Credit: NASA/JPL/UA | Image source