New Scientist reports that Spirit, one of
the two rovers on the Martian surface, captured two images of dust
devils, miniature tornadoes possibly caused by surface heating or
eddies and columns caused by turbulent wind over craters.
Martian dust
devils finally caught on camera. NASA has the images at
Spirit
Captures Two Dust Devils On the Move,
Spirit
Captures Two Dust Devils On the Move (Unlabeled),
Dust
Devils Seen by Spirit, and
Dust
Devils Seen by Spirit (Unlabeled).
Electric power limits both rover's effective lives, and the solar
panels have a year of accumulated dust. But on March 9, Spirit's
electric output abruptly increased to 93% of its initial level,
raising the tantalizing possibility that wind might have cleaned
off its solar panels.
'The team is still figuring out exactly when the power
boost occurred, and whether it was a single event or not. Science
team member Geoffrey Landis told New Scientist that the cleaning of
the solar panels may have taken place at night. But dust devils
occur only in the midday sunlight, he notes, so it may have simply
been a strong breeze that cleaned the rover.'
On a late night drive back from Florida, I first heard on this
story in the interview of Dr David Grinspoon on
John Batchelor's radio show.