A rover on Mars has detected a form of lightning : NPR

Mini-lightning strikes created by swirling dust devils on Mars have been accidentally detected by microphones mounted on the Perseverance rover.

In a report published in, researchers say this accidental discovery is direct evidence of a form of lightning on Mars NatureThey describe how the rover’s microphones picked up signals of electrical arcs just a few centimeters long, which were accompanied by audible shockwaves,

“There’s been a huge 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 in the United Kingdom, who was not part of the research team but wrote a commentary for the journal Nature.

“The key thing here,” he explains, “is that we actually have a rover on the surface of Mars that has detected something that matches our idea of ​​what lightning would look like on Mars.”

In addition to Earth, lightning has been observed in the atmospheres of Jupiter and Saturn, and has also been detected on Neptune and Uranus. But the discovery of lightning has proven more elusive on our nearest planetary neighbors – even though experimenters in the 1970s did laboratory work that suggested lightning should exist on Mars.

For example, when researchers poured volcanic sand into a flask and pumped it to Martian atmospheric pressure, rotating the sand in the flask produced a glow that could be seen in the dark, says Ralph Lorenz, a planetary scientist at the Johns Hopkins University Applied Physics Laboratory.

This glow came from electrical charges caused by friction between pieces of sand. If you have a large accumulation of electric charge, he says, it can produce a more sudden discharge, like what happens with a spark plug in a car, or on a larger scale, lightning strikes. After all, even on Earth, lightning can strike turbulent clouds of volcanic ash.

“So there’s no reason why dust or sand blown to Mars couldn’t become electrically charged,” Lorenz says.

Recently, he and some colleagues were reviewing audio picked up by the Perseverance rover, a car-sized robot that has been roaming the red planet since 2021. It has a microphone, and a few years ago scientists reported hearing the sound of a dust devil passing over the rover.

In addition to the hiss of wind and dust, Lorenz says, there was also a faint sound of a thump or crack in the middle of the encounter. “We just assumed it was a larger sand particle or smaller gravel particle, you know, hitting the structure,” he says.

But shortly afterward, a member of his team attended a science conference and overheard a discussion about atmospheric electricity. “I thought that if there were discharges, we could hear them. And then, I remembered this recording,” says Baptiste Chaide, who works with the Institut de Recherche en Astrophysique et Planetologie in Toulouse, France.

So they conducted some experiments using an electrostatic generator here on Earth to see how an electrical discharge would affect the microphone. What he saw were the same signals that had been captured on Mars; There was a specific pattern of a brief electrical interference followed by an acoustic signal of a shockwave.

Researchers say fifty-five such events were picked up by microphones over two years at Mars, and the sparks were typically associated with dust devils and dust storms.

Chide says the electrical arc will feel and sound like a spark of strong static electricity. If an astronaut were on Mars, it might be possible to see them, although “small discharges are difficult to see in bright sunlight, and it is the sunniest time of the day that has the most dust and probably the strongest discharge events. That said, some events were at night,” he says.

Researchers believe it is important to study this atmospheric electrical activity to understand whether it may pose a threat to future robotic or human missions. While most space hardware is designed to be robust, he noted that the Soviet Mars 3 mission landed during a dust storm and operated on the surface for only about 20 seconds and then suddenly and mysteriously ended its transmission.

“Something changed in 20 seconds,” Lorenz says. “Could it be an electrical discharge event? I don’t think we can rule it out.”