This image acquired on October 30, 2020 by NASAs Mars Reconnaissance Orbiter, shows a dust devil forming by rising and rotating warm air pockets.

February 26, 2021

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Dust devils form by rising and rotating warm air pockets. Air near the soil surface can become heated by contact with the warmer ground during the day. The warm air is less dense and rises through the cooler air above it.

As additional air moves inward along the surface to replace the rising pocket, it begins to rotate driven by Coriolis forces, and forms a vortex of spinning air. When the incoming air rises into the column, its rotation picks up speed like a spinning ice skater bring their arms closer to their body. This faster moving air near the soil surface can cause sand grains to bounce and kick up dust which easily rises up into the growing vortex. In this way a dust devil is born.

The study of dust devils is important because they indicate atmospheric conditions such prevailing wind directions and speed. They also periodically cleanse the surface of the dust that gradually settles from the atmosphere. This is something that can be extremely helpful to robotic missions like InSight and Curiosity to keep their solar panels from getting too dusty.

The map is projected here at a scale of 25 centimeters (9.8 inches) per pixel. (The original image scale is 26.5 centimeters [10.4 inches] per pixel [with 1 x 1 binning]; objects on the order of 79 centimeters [31.1 inches] across are resolved.) North is up.

The University of Arizona, in Tucson, operates HiRISE, which was built by Ball Aerospace & Technologies Corp., 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.


NASA/JPL-Caltech/University of Arizona


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