On Mars, it appears that you can wait a long time for a dust devil, and suddenly three appear at once. Fortunately, engineer Kevin M. Gill of NASA-JPL, who has the well-deserved title of Martian photographer, was able to discover them in photographs acquired by NASA’s Perseverance spacecraft. He didn’t simply detect them; he processed the raw photographs, increased the contrast, and combined them into a short animation that depicts the three small twisters sifting dust across Mars’ surface. Although the quality of the Navigational photos isn’t the finest (their goal isn’t thorough observations), Gill was able to create something captivating.
The photos were taken on Mars on the 372nd day of Perseverance. Or, in our case, March 7, 2022. Dust devils are rising air columns that move across the ground, and they’re rather abundant on Mars. The earth heats up faster than the air above it, causing it to rise and cooler air to descend. Vortices are formed as a result of this action, which can gather up sand and become apparent. The majority of them are little and only occur on occasion, but when the conditions are ideal, they may grow in number and size.
These dust devils can’t do much damage since the Martian atmosphere is 100 times thinner than Earth’s, but they do help move sand and sculpt the freezing desert climate that makes Mars what it is today. Perseverance is already sending back some intriguing data as it flexes and tests several pieces of equipment in readiness for the commencement of its research mission to explore and hunt for indications of ancient life on Mars.
Aside from incredible footage of Perseverance’s nerve-wracking landing and the first audio ever sent back from Mars, it’s also sent back a stunning 360° panorama of its new home, the first recording of a laser being fired on Mars (it’s a “snap!” not a “pew!”), shared its first test drive around Jezero Crater, and delivered its first science results while testing out its awesome SuperCam instrument.
Even when it wasn’t operating, it managed to take photographs and data from Mars’ surface, providing a lot of information to the rover crew on Earth about the desert planet’s environment. After only 26 sols, Perseverance has seen its first dust devil, captured swirling over the dusty terrain behind its robotic arm (Mars days). To put things in perspective, it took Opportunity seven years to catch its first fish. The result of the devil whirling into view from the right, causing whirlwinds of dust in its route, was sent back to Earth for some processing.
Dust devils arise when pockets of heated air rise to the surface. Due to contact with the warm earth heated by the Sun’s rays, the air closer to the ground might heat up. Warm air has a lower density than chilly air, therefore it rises above it and forms an updraft. That updraft may start to spin if the conditions are perfect. More air rushes in to replace the warm air ascending, creating a spinning vortex. Because the spinning produces forward motion when paired with surface friction, you’ll often witness them flying over the ground. Dust devils are more likely to arise when specific circumstances exist, and Mars possesses all of them.
Flat, arid terrain enhances the odds of hot air rising above ground, while dust aids visibility of the devil. The surface must be able to absorb a lot of the Sun’s heat in order to heat the ground, and Mars’ atmosphere is quite thin, so there isn’t much to shelter it from the Sun’s rays. Finally, a cold environment aids in the creation of a significant difference between surface-heated warm air and cool air.
