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These Martian dunes in Mars' northern hemisphere were captured from above by NASA's Mars Reconnaissance Orbiter using its High-Resolution Imaging Science Experiment (HiRISE) camera on Sept. 8, 2022. Scientists use such images to track the amount of frost that settles on the landforms and then disappears as the weather warms in spring.
Martian dunes migrate just like dunes on Earth, with wind blowing away sand on one side of the dune and building up on another. Recent research has shown that winter frost stops the movement of sand grains, locking the dunes in place until the spring thaw.
The University of Arizona, in Tucson, operates HiRISE, which was built by BAE Systems in Boulder, Colorado. NASA's Jet Propulsion Laboratory, a division of Caltech in Pasadena, California, manages the Mars Reconnaissance Orbiter Project for NASA's Science Mission Directorate, Washington.
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