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.

2000 March 17
See Explanation.  Clicking on the picture will download 
 the highest resolution version available.

Martian Dust Devil Trails
Credit: Malin Space Science Systems, MGS, JPL, NASA

Explanation: Who's been marking up Mars? This portion of a recent high-resolution picture from the orbiting Mars Global Surveyor spacecraft shows twisting dark trails criss-crossing a relatively flat rippled region about 3 kilometers wide on the martian surface. Newly formed trails like these presented researchers with a tantalizing martian mystery but have now been identified as likely the work of miniature wind vortices known to occur on the red planet - martian dust devils. Another example of wind processes on an active Mars, dust devils had been detected passing near the Viking and Mars Pathfinder landers. Such spinning columns of rising air heated by the warm surface are common in dry and desert areas on planet Earth. Typically lasting only a few minutes, they becoming visible as they pick up loose dust. On Mars, dust devils can be up to 8 kilometers high and leave dark trails as they disturb the bright, reflective surface dust.

Tomorrow's picture: A Wind From The Sun

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Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)
NASA Technical Rep.: Jay Norris. Specific rights apply.
A service of: LHEA at NASA/ GSFC
& Michigan Tech. U.