Scientists have spotted a 1.2-mile-high dust devil on Mars.
The whirlwind was observed by NASA’s Perseverance rover moving across the Martian landscape.
The six-wheeled geologist robot documented the lower portion of the dust devil as part of an atmospheric exploration of Jezero Crater.
It was seen moving east to west at about 12 mph along Thorofare Ridge on August 30.
“Much weaker and generally smaller than Earth’s tornadoes, dust devils are one of the mechanisms that move and redistribute dust around Mars,” explained NASA’s Jet Propulsion Laboratory (JPL), a robotic space exploration research and development centre in California.
“Scientists study them to better understand the Martian atmosphere and improve their weather models.”
Using data from the imagery, mission researchers determined that this particular dust devil was about four kilometres (2.5 miles) away.
They calculated its width to be about 60 metres (200 ft). While only the bottom 118 metres (387 feet) of the swirling vortex are visible in the camera frame, the scientists could also estimate its full height.
“We don’t see the top of the dust devil, but the shadow it throws gives us a good indication of its height,” said Mark Lemmon, a planetary scientist at the Space Science Institute in Boulder, Colorado, and a member of the Perseverance science team.
“Most are vertical columns. If this dust devil were configured that way, its shadow would indicate it is about 1.2 miles (2 kilometres) in height.”
Dust devils, which also occur on Earth, form when rising cells of warm air mix with descending columns of cooler air.
JPL added: “The Martian versions can grow to be much larger than those found on Earth. While they are most prominent during the spring and summer months (Mars’ northern hemisphere, where Perseverance is located, is currently in summer), scientists can’t predict when they’ll appear at a specific location.
“So Perseverance and its fellow NASA Mars rover Curiosity routinely monitor in all directions for them, taking images in black-and-white to reduce the amount of data sent to Earth.”