Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2009 October 21
See Explanation.  Clicking on the picture will download
 the highest resolution version available.

Martian Dust Devil Trails
Credit: HiRISE, MRO, LPL (U. Arizona), NASA

Explanation: Who's been marking up Mars? This portion of a recent high-resolution picture from the HiRISE camera on board the Mars Reconnaissance Orbiter shows twisting dark trails criss-crossing light colored terrain on the martian surface. Newly formed trails like these had presented researchers with a tantalizing martian mystery but are now known to be the work of miniature wind vortices known to occur on the red planet - martian dust devils. Such spinning columns of rising air heated by the warm surface are also common in dry and desert areas on planet Earth. Typically lasting only a few minutes, dust devils become visible as they pick up loose red-colored dust leaving the darker and heavier sand beneath intact. On Mars, dust devils can be up to 8 kilometers high. Dust devils have been credited with unexpected cleanings of mars rover solar panels.

Tomorrow's picture: open space

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Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
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