Many of the weather events we experience here on Earth can be found on other planets too, and that includes whirlwinds. Several missions have observed small whirlwinds called dust devils on Mars, and the Perseverance rover recently captured footage of one such dust devil in action as it rolled across the martian surface.
The footage was captured by one of Perseverance’s black-and-white navigation cameras, called Navcams, and shows a dust devil moving at a speed of around 12 mph across a regions known as the Thorofare Ridge. You can clearly see the dust devil as a white column moving across the top of the ridge in an animation posted by NASA’s Jet Propulsion Laboratory, which manages the rover.
Dust devils are common on Mars due to the atmospheric conditions there. It has a thin atmosphere that is just 1% the density of the atmosphere on Earth. When the planet’s surface heats up due to the sun, but the atmosphere around it is still cool, this causes air to rise, which can then start to rotate and form a dust devil. A similar process happens on Earth too, but on Mars, these dust devils can grow large and dust storms can even become global events that blanket the entire planet.
In the recent observations, the dust devil that Perseverance spotted was located around 2.5 miles away and was calculated to be around 200 feet wide. The footage shows just the bottom of the dust devil; scientists were able to work out an estimate for its 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 Perseverance science team member Mark Lemmon of the Space Science Institute in a statement. “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.”
As dust devils are related to atmospheric conditions, how often they appear varies by season. It is currently summer, which is peak dust devil season, in the northern hemisphere of Mars, where Perseverance is currently located, so it’s expected that more of these events will be occurring. However, it’s impossible to predict exactly when and where a particular event will be visible, so the efficient black-and-white cameras used by the rover for navigation make a handy tool for monitoring the surrounding area in the hopes of catching an event like this.
