This movie clip shows several dust devils moving from right to left across
a plain inside Mars' Gusev Crater, as seen from the vantage point of
NASA's Mars Exploration Rover Spirit in hills rising from the plain. The
clip consists of frames taken by Spirit's navigation camera during the
rover's 543rd martian day, or sol (July 13, 2005). Unlike some other movie
clips of dust devils seen by Spirit, the images in this clip have not been
processed to enhance contrast of the dust devils. The total time elapsed
during the taking of these frames was 12 minutes, 17 seconds.
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.
