Money Matters - Simplified

Fast-traveling martian sand dunes takes everyone by surprise

New images from NASA of shifting sand dunes on Mars prove that they are speedier than once thought. The new data contradict beliefs that the surface of Mars was static and unchanging.


This is unexpected because Mars has an atmosphere 100 times less dense than Earth's, and its high-speed winds are less frequent and weaker than Earth's. Scientists figured hurricane-force winds are needed to move sand around in the thin Martian air, and winds that high are rare.

For years, researchers debated whether sand dunes observed on Mars were mostly fossil features related to past climate, rather than whether they are currently active or not. In the past two years, researchers using images from Mars Reconnaissance Orbiter's High Resolution Imaging Science Experiment (HiRISE) camera have detected and reported sand movement. Now, scientists using HiRISE images have determined that entire dunes as thick as 200 feet (61 meters) are moving as coherent units across the Martian landscape.

This exciting discovery will further encourage scientists, who are trying their best to understand the changing surface conditions of Mars on a more global scale better," said Doug McCuistion, director, NASA's Mars Exploration Program, Washington. "This improved understanding of surface dynamics will provide vital information in planning future robotic and human Mars exploration missions."



The amount of sand moving around Nili Patera, for example, could fill up a children's sandbox each year, estimates Nathan Bridges, a planetary scientist with Johns Hopkins University. That may not sound like much, but it adds up over time. It also may explain why many landscapes on Mars are so eroded.

The research appeared in this week's journal Nature.