This is what a dust storm on Mars sounds like
In “The Martian,” dust storms are quite unpleasant and downright dangerous. This is one of the few scientific inconsistencies of the film and book. In fact, they even seem to be very practical, as researchers have often discovered, because they clean solar panels of the dust that settles over time. But what does a dust devil like this even sound like? When the Perseverance rover landed on Mars, it was equipped with the first working microphone on the planet’s surface. Scientists used it to make the first-ever audio recording of an extraterrestrial whirlwind.
The study was published in Nature Communications by planetary scientist Naomi Murdoch and a team of researchers from the National Higher French Institute of Aeronautics and Space and NASA. Roger Wiens, professor of Earth, atmospheric and planetary sciences in Purdue University’s College of Science, leads the instrument team that made the discovery. He is the principal investigator of Perseverance’s SuperCam, a suite of instruments that form the rover’s “head” and include advanced remote sensing instruments with a wide range of spectrometers, cameras and the aforementioned microphone.
“We can learn a lot more using sound than we can with some of the other instruments,” Wiens says. “With the microphone, we can take samples, not quite at the speed of sound, but almost 100,000 times per second. That helps us get a better sense of what it’s like on Mars.”
The microphone is not on all the time, but records for about three minutes every few days. The whirlwind recording, Wiens said, was a stroke of luck, though not necessarily unexpected. In Jezero Crater, where Perseverance landed, the team has observed nearly 100 dust devils – tiny whirlwinds of dust and sand – since the rover landed. This is the first time the microphone was on when one of the dust devils passed over the rover. The sound recording of the dust devils, along with air pressure measurements and time-lapse recordings, helps scientists understand the Martian atmosphere and weather.
“We could watch the pressure drop, then there was a little bit of silence, the eye of the little storm, and then we heard the wind again and saw the pressure rise,” Wiens explains. It all happened in a matter of seconds. “The wind is fast – about 40 kilometers per hour, which is about the same as 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 are just as fast, but only at about one percent of the pressure that the same wind speed would be on Earth. That’s not a strong wind, but it’s enough to throw sand particles into the air and create a dust devil.”
The information suggests that future astronauts won’t have to worry about hurricane-force gusts blowing away antennas or habitats – so future Mark Watneys won’t be left behind – but the wind could have some benefits. The breezes that blow sand off the solar arrays of other rovers – Opportunity and Spirit in particular – may have helped them last so much longer. “Those rover teams experienced a slow drop in performance over several days to weeks, then a jump. That was when the wind cleared the solar panels,” Wiens says. The lack of such wind and dust devils in Elysium Planitia, where the InSIght mission landed, may help explain why that mission is now being phased out. “Just like on Earth, there are different weather conditions in different areas on Mars,” Wiens said.