Mini-lightning strikes created by whirling dust devils on Mars were detected accidentally by the microphone on board the Perseverance rover. The chance discovery is direct evidence of a form of lightning on Mars, researchers report in Nature. The rover’s microphone picked up signs of electrical arcs just a few centimeters long, accompanied by audible shockwaves.
“There’s been a very big mystery about lightning on Mars for a long time. It’s probably one of the biggest mysteries about Mars,” says Daniel Mitchard, a lightning researcher at Cardiff University who wrote an accompanying commentary for the journal. “The key thing here is that we actually have a rover on the surface of Mars that appears to have detected something that fits our idea of what we think lightning on Mars would look like.”
Besides Earth, flashes of lightning have been seen in the atmospheres of Jupiter and Saturn, and lightning has also been detected on Neptune and Uranus. But finding lightning on Mars has proved elusive, even though lab work in the 1970s suggested it should exist there. In experiments that mimicked Martian atmospheric pressures, swirling volcanic sand produced a visible glow from electrical charges created by friction between grains. With a larger buildup of charge, sudden discharges—analogous to spark plugs or lightning—could occur. “So there’s no reason that blowing dust or sand on Mars shouldn’t become electrically charged,” says Ralph Lorenz, a planetary scientist with the Johns Hopkins University Applied Physics Laboratory.
Researchers reviewing audio from Perseverance — which has been operating on Mars since 2021 — had earlier reported hearing the sounds of a whirling dust devil passing over the rover. In that recording, besides wind and dust hiss, there was a brief snap or crack during the encounter. Initially assumed to be a grain of sand hitting the rover, the sound was reconsidered after a team member attended a conference on atmospheric electricity.
Baptiste Chide of the Institut de Recherche en Astrophysique et Planétologie recreated electrical discharges in Earth lab experiments using an electrostatic generator to see how they would affect a microphone. The signals matched those captured on Mars: a distinctive pattern of brief electrical interference followed by an acoustic shockwave. Over two Martian years, the team identified 55 such events recorded by the rover’s microphone, primarily associated with dust devils and the leading edges of dust storms.
The electrical arcs resemble strong static electricity sparks. Chide says an astronaut might be able to see them, though small discharges are hard to spot in bright sunlight, and many strong discharge events occur in the sunniest parts of the day; some events did occur at night.
Studying this atmospheric electrical activity matters for understanding hazards to future robotic and human missions. Most space hardware is designed to be robust, but electrical discharges could still affect systems. Lorenz notes the Soviet Mars 3 mission landed during a dust storm and stopped transmitting after about 20 seconds. “Something changed in 20 seconds,” he says. “Could it have been an electrical discharge event? I don’t think we can rule that out.”