Now just over seven months on Mars, NASA’s Curiosity rover has been exploring the region around its landing site, investigating the Martian surface with its impressive suite of scientific tools. Over the course of 208 Sols (Martian days), the rover has traveled nearly 500 meters (almost a third of a mile) across the pebbly terrain of Gale Crater toward its ultimate goal: Aeolis Mons, the crater’s 18,000-foot-high central peak. But in order to get there, Curiosity must first cross a wide swath of sand dunes that wrap around the mountain’s base — dark, windswept dunes that move.
While dunes here on Earth are known to be migratory landforms, sculpted and steered by a region’s prevailing winds, it wasn’t always known that dunes on Mars were also actively in motion. It wasn’t until long-term observations could be made with the Mars Reconnaissance Orbiter that scientists were able to see Mars’ dunes change over time, their fine grains gradually shifting and sliding under the faint but relentless force of the thin Martian wind.
Recently, researchers from the SETI Institute have discovered that the dunes that surround the base of Aeolis Mons are influenced by winds from both the east-northeast and northwest, causing the dunes in Curiosity’s path to move in a southwesterly direction at a rate of about 0.4 meters a year.
While a foot-and-a-half shift per year may not sound very dramatic, remember that it wasn’t known until recently if Martian dunes moved at all. So as Curiosity traverses Gale’s dune field it will have a chance to get a good look at these features up close, hopefully giving us our first close-up images of their ponderous shuffle across the crater floor.