NASA rover records first evidence of lightning on Mars

AFP | Paris

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A NASA rover has recorded evidence of lightning on Mars for the first time, its microphone picking up the sounds of tiny “zaps” whipped up by the dust storms constantly sweeping across the planet.

Scientists have long debated whether electrical discharges could be sparking in the dusty and little-known Martian climate -- but proof has been hard to come by.

It turns out that NASA’s Perseverance rover, which has been roaming the red planet since 2021, was inadvertently recording the sounds of lightning, according to a study published in Nature this week.

These are far from the thundering, kilometre-long lightning bolts we see on Earth. Instead, they are “little zaps” similar to “what you might feel in dry weather when you touch your car door and there’s a bit of static electricity,” lead author Baptiste Chide of France’s CNRS research centre told AFP.

While low in energy, these discharges are happening “absolutely all the time -- and everywhere” on Mars, the planetary scientist said.

The process starts when tiny grains of dust rub against each other. They become charged with electrons and release this energy in electrical arcs a few centimetres (inches) -- or even millimetres -- long, sending off an audible shock wave.

Here on Earth, dust storms and dust devils in desert areas also create electrical fields. But they rarely build up into electrical discharges.

However on Mars, “because of the very low pressure and the composition of the atmosphere, the amount of charge that needs to accumulate to generate a discharge is much smaller,” Chide explained.

This phenomenon has been theorised since Mars first started to be explored -- and has been reproduced in the laboratory.

Chide said it had been “such an important issue for Martian science” that an instrument on the European Space Agency’s Schiaparelli lander was dedicated to searching for it.

Unfortunately the spacecraft crashed while trying to land on Mars in 2016.