Dust devils (convective vortices laden with dust) are common on the Martian surface, particularly in the Jezero crater, the landing site of the Perseverance rover. They are indicators of atmospheric turbulence and are an essential lifting mechanism for the Martian dust cycle.
When the Perseverance rover landed on Mars, it was equipped with the first working microphone on Earth’s surface. Now scientists have used it to create the first-ever audio recording of an alien whirlwind.
Roger Wiens, professor of earth, atmospheric and planetary sciences in Purdue University’s College of Science, said: “We can learn a lot more with sound than with other tools. They take measurements at regular intervals. The microphone lets us hear a sample, not quite at the speed of sound, but almost 100,000 times per second. It helps us get a better idea of what Mars is like.”
Every few days the microphone will record for about three minutes instead of being on all the time. Wiens claimed that while not necessarily unexpected, it was lucky to get the whirlwind shot. Since Perseverance’s landing in Jezero crater, the crew has found evidence of about 100 dust devils — small dust and grit tornadoes. The microphone was first turned on when the rover was driven over.
Together with barometric pressure measurements and time-lapse photos, the dust devil sound recording helps understand the weather and atmosphere on Mars.
Whose said, “We could see the pressure drop, listen to the wind, then have a little bit of calm, which is the eye of the little storm, and then hear the wind again and see the pressure rise. It all happened in a few seconds. The wind is fast – about 25 miles per hour, but about what you’d see in a dust devil on Earth. The difference is that the air pressure on Mars is so much lower than the wind while it is just as fast, pushing at about 1% of the pressure that the same wind speed would have on Earth. It’s not a strong wind, but enough to blow grit into the air to make a dust devil.”
According to the information, future astronauts won’t have to worry about gale-force winds knocking down antennas or habitats, meaning no Mark Watneys left behind. However, the wind may even have certain advantages. Other rovers, especially Opportunity and Spirit, may have held out longer as the breeze blew grit off their solar panels.
Whose said, “Those rover teams would see a slow drop in power over a number of days to weeks, then a jump. That was when the wind pulled off the solar panels.”
“Just like on Earth, there is different weather in different areas of Mars. By using all our instruments and tools, especially the microphone, we get a concrete idea of what it would be like to be on Mars.”
- Murdoch, N., Stott, AE, Gillier, M. et al. The sound of a Martian dust devil. Nat Commun 13, 7505 (2022). DOI: 10.1038/s41467-022-35100-z