NASA's Mars Reconnaissance Orbiter's high-resolution camera snapped up this picture of a dust devil in the Amazonis Planitia region of northern Mars on March 14, 2012. The whirl of martian dust is only about 70 meters wide, but it reaches some 12 miles high. Dust devils, unlike tornadoes, tend to form on clear days when the sun has heated the ground and warmed the air just above it. As the heated air rises through the cooler air above it, it can begin to swirl. This picture from Mars was taken late in the northern spring, when the sun's rays would have been warming the martian ground. Some 22,000 images taken by the camera, the High Resolution Imaging Science Experiment, are available on the operating team's website.
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