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Dust tornadoes over 387feet (118m) tall are skimming along the surface of Mars, scientists have found.
Known as ‘dust devils’, these whirlwinds swirl around at speeds of 25mph (40kph), blowing up grit and particles as they go.
NASA’s Perseverance rover took the first ever audio recording of the phenomenon, which provides insight into the atmosphere and weather on the Red Planet.
This could help engineers as they design future Mars missions, as bombardment from the dust has implications on the hardware we send up.
Recording of a ‘dust devil’ on Mars. Two periods of the low frequency wind can be heard as the dust devil leading and trailing walls pass over the rover. Grains impacting the rover can also be heard.
Dust tornadoes over 387feet (118m) tall are skimming along the surface of Mars, scientists have found. Pictured: A 70-yard-wide Martian dust devil
This is a spectrogram of the microphone sound showing the wind noise, grain impacts and also the rover pump harmonic at 760 Hz. A large grain impact causes an acoustic echo at approximately 6kHz due to sound reflections from the base of the microphone
Perseverance landed in the Jezero Crater on Mars on 18 February 2021, after a nearly seven-month journey through space.
Since then, the car-sized robot has been searching for ancient biomarkers in the Martian clay, which could indicate if alien life ever existed there.
It is equipped with 23 cameras that help it navigate, assess its safety and collect visual data on near and distant objects.
One of those cameras is the ‘Supercam’ – a suite of tools located on Perseverance’s ‘head’ that contains scientific instruments, cameras and a microphone.
Sensors on other landers and rovers have been able to pick up vibrations on Mars in the past, however this microphone is the first to ever grace its surface.
It records samples at nearly 100,000 times a second, which gives researchers a stronger sense of the environmental conditions on Mars.
‘We can learn a lot more using sound than we can with some of the other tools,’ said Dr Roger Wiens, the principal investigator of Perseverance’s SuperCam.
Scientists at NASA and the National Higher French Institute of Aeronautics and Space have used the microphone to make the first ever recording of an extraterrestrial dust devil.
Dust devils are common on Mars, and indicate areas of atmospheric turbulence.
They lift dust into the atmosphere – an important step in the planet’s dust cycle, which helps regulate its climate.
This particular one was about 82 feet (25 m) wide, which is about ten times wider than the rover itself.
Perseverance (pictured) landed in the Jezero Crater on Mars on February 18 2021, after a nearly seven-month journey through space
Dust devils (pictured) are common on Mars, and indicate areas of atmospheric turbulence. They lift dust into the atmosphere – an important step in the planet’s dust cycle
Prior to this recording, data collected by Perseverance’s other sensors showed that over a hundred of these tornadoes have passed over the rover since it landed.
However, since the microphone is only on for about three minutes every day, it wasn’t until 27 September 2021 that the sound of a dust devil was picked up for the first time.
You can clearly hear the blowing winds, with a faint pattering of grains bouncing off the rover’s exterior.
As well as the audio recording, Perseverance took air pressure readings and time-lapse photos during this encounter.
Dr Roger Wiens, the principal investigator of Perseverance’s SuperCam, said that all this enabled the researchers to follow the dust devil.
He said: ‘We could watch the pressure drop, listen to the wind, then have a little bit of silence that is the eye of the tiny storm, and then hear the wind again and watch the pressure rise.’
This figure shows the relative size of the dust devil with respect to the Perseverance rover. The dust devil diameter (white circles) is 25 m. The blue dashed arrow shows the dust devil trajectory direction. The rover Navigation camera (Navcam) field of view is indicated by the pale triangle. At t1, Perseverance is in the leading vortex wall. At t2, Perseverance is inside the eye of the vortex. At t3, Perseverance is in the tailing vortex wall. The orange arrows indicate the clockwise rotational direction of the vortex winds
These are images taken of the direct dust devil encounter by the rover’s Navigation Camera (Navcam). The images have been processed to show the quantity of dust. The colour scale ranges from lowest dust content (blue) to highest dust content (yellow)
The team analysed all the data Perseverance collected together, and their findings were published today in Nature Communications.
They revealed that this tornado of dust and grit isn’t quite as menacing as some of those we’ve experienced on our home planet.
He said: ‘The wind is fast, about 25 miles per hour, but about what you would see in a dust devil on Earth.
‘The difference is that the air pressure on Mars is so much lower that the winds, while just as fast, push with about one per cent of the pressure the same speed of wind would have back on Earth.
‘It’s not a powerful wind, but clearly enough to loft particles of grit into the air to make a dust devil.’
This will come as a relief to future astronauts, who can be confident that they won’t have to face gale force winds while exploring the planet.
The dust devils may also have blown off grit that settled on the solar panels of previous rovers, helping them to survive on Mars for longer than they otherwise would have.
The Spirit rover lasted for six years, and the Opportunity rover remained active for nearly 15 years.
Dr Wiens said: ‘Those rover teams would see a slow decline in power over a number of days to weeks, then a jump. That was when wind cleared off the solar panels.’
This could explain why the InSight lander, which currently sits in the less windy Elysium Planitia, is winding down its mission after only four years.
Scientists at NASA and the National Higher French Institute of Aeronautics and Space have used Perseverance’s microphone to make the first ever recording of an extraterrestrial dust devil. Pictured: A dust devil photographed by NASA’s Curiosity Rover
Prior to this recording, data collected by Perseverance’s other sensors showed that over a hundred of these tornadoes have passed over the rover since it landed. Pictured: Three dust devils photographed by NASA’s Mars Reconnaissance Orbiter
The researchers hope the microphone will be able to pick up the sound of dust devils that appear in different geological locations on Mars.
This will allow them to compare data from the different recordings to find out how the Martian landscape affects their properties.
‘Just like Earth, there is different weather in different areas on Mars,’ Dr Wiens added.
‘Using all of our instruments and tools, especially the microphone, helps us get a concrete sense of what it would be like to be on Mars.’
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