Mars: Tiny Lightning Strikes Detected by Perseverance Rover

Mars is full of surprises. The Perseverance rover, which has been exploring the red planet since 2021, recently made an unexpected discovery. Its microphone picked up signs of small lightning strikes caused by dust devils. These tiny electrical arcs, just a few centimeters long, were accompanied by audible shockwaves. This finding is a big deal because it provides direct evidence of lightning on Mars, something scientists have been curious about for a long time. Lightning is not uncommon in our solar system. It has been observed on Jupiter, Saturn, Neptune, and Uranus. However, detecting it on Mars has been a challenge. Back in the 1970s, scientists conducted experiments that suggested lightning should exist on Mars. They created a glow by swirling volcanic sand in a flask under Martian atmospheric conditions. This glow was caused by electrical charges from the friction between the sand particles. If there's a significant buildup of electric charge, it could lead to a sudden discharge, similar to a spark plug or lightning. The Perseverance rover's microphone captured the sounds of a dust devil passing over it a few years ago. Among the wind and dust, there was a brief snap or crack sound. Initially, scientists thought it was just a grain of sand or gravel hitting the rover. But later, one of the team members attended a science conference and heard a talk about atmospheric electricity. This sparked his curiosity, and he decided to investigate further. He conducted experiments on Earth using an electrostatic generator to see how electric discharges would affect the microphone. The results matched the signals captured on Mars: a brief electrical interference followed by the acoustic signal of a shockwave. Over two Martian years, the microphone picked up 55 such events, usually associated with dust devils and dust storm fronts. These electrical arcs would feel and sound like strong static electricity sparks. If an astronaut were on Mars, they might be able to see them, although it would be difficult in strong sunlight. The researchers believe it's crucial to study this atmospheric electrical activity to understand the potential hazards it could pose to future robotic or human missions. After all, the Soviet Mars 3 mission landed during a dust storm and only operated for about 20 seconds before mysteriously ending its transmission. Could an electrical discharge event have been the cause? It's a possibility that scientists can't rule out.