Scientists have spotted a two-kilometer-high “devil” on Mars. The amazing spectacle observed by NASA’s Perseverance rover was revealed to be a dust devil moving across the Martian landscape.
A dust devil is a small, rotating column of air that is made visible by the dust, dirt, and debris it picks up from the ground. It is a weather phenomenon similar to a tornado, but typically much weaker and less destructive. Dust devils usually form on clear, sunny days when the ground is heating up, and they often occur in desert or arid regions, although they can occur anywhere under the right conditions.
On Mars, dust devils interest NASA scientists because they help them learn about the planet’s weather and atmosphere. Perseverance, NASA’s six-wheeled geologist robot, documented the lower portion of the twister as part of an atmospheric exploration of Jezero Crater. The whirlwind was seen moving east to west about 12 mph along “Thorofare Ridge” on August 30.
Using data from the imagery, mission researchers determined that this particular dust devil was about four kilometers (2.5 miles) away.
They calculated its width to be about 60 meters (200 ft). And while only the bottom 118 meters (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,” says 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 kilometers) in height.”
Scientists says dust devils on Mars can be significantly bigger than ones on Earth. Though they’re unpredictable, they happen most often during spring and summer on the Red Planet. “Mars’ northern hemisphere, where Perseverance is located, is currently in summer,” NASA notes in their media release. “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.”