A spacecraft orbiting the planet Mars captured contrasting images of Martian sand dunes – from the years 2007 and 2010 – indicating that sand dunes on Mars shift and move at about the same rate of earthly dunes in Antarctica. We knew the sands on Mars were shifting, but the rate of the shift is surprising because the atmosphere of Mars is thin. The air on Mars is only about one percent as dense as on Earth. So, although the winds on Mars can be fast, they are much weaker than earthly winds.
These researchers analyzed images from Mars Reconnaissance Orbiter’s High Resolution Imaging Science Experiment (HiRISE) camera. They published their analysis in the journal Nature on May 9, 2012.
The blinking image above shows the movement of a sand dune on Mars. The before-and-after images were taken nearly three Earth years apart. The images show a dark, rippled sand dune overlying bright-toned rock. Lighting effects cause some of the differences between the two images. The arrow near the lower-left corner shows an actual advance of sand on the dune’s lee (downwind) front between the years 2007 and 2010. Other arrows indicate places where the edge of the dune has moved.
For years, researchers debated whether sand dunes observed on Mars were mostly fossil features related to past climate, rather than currently active. Spacecraft have revealed much more activity in Mars’ shifting sands than anyone would have imagined just a few decades ago.
Bottom line: Researchers analyzed images from Mars Reconnaissance Orbiter’s High Resolution Imaging Science Experiment (HiRISE) camera to find that sand dunes on Mars are shifting at about the same rate as dune in Antarctica on Earth. They published their analysis in the journal Nature on May 9, 2012.