This movie clip shows dust devils moving across the plain inside Mars'
Gusev Crater, as seen with a hazard-identification camera on NASA's Mars
Exploration Rover Spirit. The clip consists of consists of frames taken
by that camera during a span of 8 minutes, 26 seconds on the rover's
559th martian day, or sol (July 29, 2005). Contrast has been enhanced for
anything in the images that changes from frame to frame, that is, for the
dust moved by wind.
Spirit began seeing dust devil activity around the beginning of Mars'
spring season. Activity increased as spring continued, but fell off again
for about two weeks during a dust storm. As the dust storm faded away,
dust devil activity came back. In the mid-afternoons as the summer
solstice approached, dust devils were a very common occurrence on the
floor of Gusev crater. The early-spring dust devils tended to move
southwest-to-northeast, across the dust devil streaks in Gusev seen from
orbit. Increasingly as the season progresses, the dust devils are seen
moving northwest-to-southeast, in the same direction as the streaks.
Scientists are watching for the big dust devils that leave those streaks.
