Friday, September 12, 2008

Dust devils around Phoenix

Recently, with temperatures around the Phoenix Mars Lander changing as Winter on Mars approaches, dust devils have started forming.  Scientists working on the Phoenix mission have noticed that they are steadily increasing in number.  They believe this is caused by the growing difference of day and night temperatures which are currently around -30C and -90C, respectively.  The following animated image is composed of 10 images taken during a Martian night and clearly illustrates the moving clouds that are swirling in the night sky and moves in a westerly direction.  Just click the image below to see the animated image.

Phoenix has photographed several of these dust devils (below image, click for animated image) and has even recorded a drop in air pressure as one passed over the Lander .

One of these dust devils had recorded wind speeds that exceeded 5 meters per second (about 11 miles per hour) and range in size from 2 meters (7 feet) to 5 meters (16 feet).  This was recorded with the telltale during the Martian night and is shown in the below image (those blurs moving in the background are clouds, click for animated image).

The winds from these dust devils are now strong enough to stir up dust and shake the solar panels on the Phoenix lander, moving them up about half a centimeter (0.19 in).  In the below image this effect is shown well as you will see on part of the panel, it was blurred in the image as it moved during an exposure in the image below (the white spikey patch is caused by a few overexposed pixels in the camera, it may be a reflection from the sun).

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