The devils on Mars


When I was a boy, we lived for a time at the edge of farmland — acres and acres of lettuce and corn. My brother and I would often wander those fields, looking for entertainment. We’d scan for anything, whether it was a chance to skip stones across a pond, or climb a tree, or poke a stick at a skeletonized dead animal, or find an opportunity for a dirt clod fight, or just whatever. One of the things we would do when the season was right was dust devil chasing. The right season was late spring before the planting or the fall after the heads had been plucked and the corn reduced to stubble, after at least a week of dryth, so there was dust, and then we’d see the dust devils skirling about. What else would a couple of 12 year olds do but try to run and catch them? We rarely succeeded, and when we did it accomplished little more than tousle our hair and get grit in our eyes.

I thought of this because there was a strategy we didn’t try, which was to stop and wait for one to spawn nearby and fortuitously run over us. That’s never an option for 12 year old boys, but that’s what NASA’s Perseverance rover on Mars did. They just waited for a Martian dust devil to happen on them, and recorded it.

Murdoch said the team’s success in capturing a dust devil’s sound reflects both luck and preparation. The rover’s microphone takes recordings lasting a little under three minutes, and it does that only eight times a month. But the recordings are timed for when dust devils are most likely to occur, and the rover cameras are pointed in the direction where they are most likely to be seen.

“Then we have to just cross our fingers,” she said.

That clearly did the trick, because Perseverance managed to capture the dust devil through multiple instruments, registering the drop in air pressure, changes in temperature, the sound of grains making impact, all topped off with images that show the size and shape of the vortex.

And now we can hear it!

That’s the sound of lonely ghosts on a dead planet.

Comments

  1. wzrd1 says

    One of the Spirit and Opportunity rover design team was curious and concerned if dust devils generated significant electrostatic charges that could potentially damage the rovers.
    Conventional wisdom at the time suggested that such couldn’t be an issue, but science likes to poke conventional wisdom in a presenting orifice to ensure reality and said wisdom coincide.
    So, off to the desert he went, observing and measuring dust devils. All were surprised to learn that up to 12 kv was measured within the dust devils, necessitating some important design changes in the rovers.
    Amazing what one finds when ignoring convention and actually measuring while observing!

  2. moonslicer says

    If a dust devil hits a rover on Mars but there are no instruments to record it, does it make a sound?

  3. JimB says

    If a dust devil hits a rover on Mars but there are no instruments to record it, does it make a sound?

    And does a chihuahua start barking a whole planet away?

  4. StevoR says

    @ ^ Was @ JimB of course. Disclaimer no actual chihuahua present here (my current dog is a real mixture but doubt any chihuahua involved) but know what you mean. They do -ogs generally – have aastoundingly sensitive hearing as well as smell so very probly pick up on things we don’t hear but. dust devils on the red planet probly not among them!

    As for the dust clearing usefulness of dust devils -maybe dust angels would be a better term for them? – see :

    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6350794/

    &

    “Gusev (crater – ed.) was alive with dust devils,” explained one scientist familiar with rover operations.

    But suddenly Spirit’s available energy rocketed to a high level. The plus-up in power, team members believe, was due to a whirlwind passing right over the robot, removing the dust that had collected on its solar cells.

    Martian squeegee men

    The impact of the devilish dust-off was significant.

    “The noon solar output from the panels went from a 40 percent loss to just 7 percent,” said rover science team member, Larry Crumpler, a research curator in volcanology and space sciences at the New Mexico Museum of Natural History and Science in Albuquerque.

    Images of the panels taken later showed “beautiful dark panels,” Crumpler explained. “And all the wires and edges on the [rover] deck have little dust tails. I think it might have been the Martian squeegee men. Either that or one heck of a buffeting by a dust devil,” he said.

    Source : https://www.space.com/861-spirit-dust-devil.html

    Plus the images at the top of this news item :

    https://www.businessinsider.com/nasa-ending-insight-mars-mission-early-dusty-solar-panels-2022-5

    Showing the dramatic diffrence a bit of Martian dust makes!

  5. simplicio says

    It sounds like most of your readers have never experienced a dust devil. We and about a dozen others were lucky enough to have been in a large one as it passed over the pavement in a parking lot.

    It was strong enough to remove the hats of those who didn’t hang onto them and it carried one for a quarter mile. Besides the drop in pressure, it makes a memorable low-pitched buzzing or roaring sound (at least here on earth). We were fortunate to be in a parking lot, so we missed the fun of having to take a shower afterward.

    How many have you been through?

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