APOD 2.5: Sand Cascades on Mars

The photo, courtesy of NASA (taken by the Mars Reconnaissance Orbiter in 2008) displays odd, pinkish brown chasms, dunes and streaks. The lighter, blueish areas show frost on the dark sand. The spring Sun melted most of the carbon dioxide ice, but some remains at the top of these Mars hills. When dark sand cascades down the dune, it leaves the dark streaks, and it looks like patches of trees growing. The objects are only about 25 centimeters across in reality. The billowy plumes show that the sand was sliding even as the picture was taken. The picture was taken near Mars' north pole!