Martian Sand Dunes Are Slowpokes

The sand dunes of Mars are in no rush to move across the red planet's surface, new research shows. It can take up to 1,000 years for dunes to move just a few meters on Mars, largely due to the planet's apparent lack of moving surface water, weak winds and thin atmosphere, said the study's author Eric Parteli. "Mars dunes move much slower than Earth's dunes," said Parteli, a researcher at the University if Stuttgart in Germany, in an e-mail interview. Parteli and colleague Hans Hermann, of Brazil's Federal University of Ceará, used computer simulations to reproduce actual Martian dunes observed by the Mars Orbiter Camera aboard NASA's Mars Global Surveyor spacecraft. The images were taken before Mars Global Surveyor went silent last year, ending its 10-year study of the red planet's surface.

The scientists found that a small Martian sand dune about 3-feet (1-meter) tall would need wind speeds 75 mph (120 kph) to move appreciably. Since such winds are extremely rare on the red planet, occurring just a few times each decade, the dunes of Mars are confined to their glacial pace, the researchers said.