There are a number of hazards to consider on manned missions to Mars. Now, researchers have added lightning to the list. — Photo: esoc/ESA/dpa
Thunderstorms aren't just an earthly phenomenon. Scientists have long known that electrical discharges occur in the atmospheres of Jupiter and Saturn.
Now, for the first time, researchers have directly detected similar electrical activity on Mars.
Measurements from NASA's Perseverance rover show that swirling dust on the Red Planet can generate static charge through friction.
Last Wednesday, scientists reported in the journal Nature that lightning risks will need to be considered when planning future crewed missions.
On Earth, and likely on Jupiter and Saturn as well, thunderstorms form when water droplets and ice crystals collide, separating electrical charges. Mars is far too dry for that process.
Instead, scientists suspect that dust particles rubbing against each other in the planet's frequent whirlwinds, known as dust devils, could create electrical charges.
Massive dust storms, sometimes spanning thousands of kilometres, could also play a role.
The US rover Perseverance has recorded data showing that there is also lightening on Mars. Photo: NASA/JPL-Caltech/MSSS/dpa
Suspicions dating back years
"On Mars, the existence of electrical activity has long been suspected, but never directly demonstrated," Baptiste Chide and his colleagues from the University of Toulouse wrote.
But until now, the evidence was only indirect. In 2006, US researchers picked up unusual radio signals from Mars and later suggested they might be caused by lightning, though other explanations couldn't be ruled out.
Orbital missions also failed to detect clear signs of discharges.
To settle the question, Chide's team analysed data gathered on the ground by Perseverance, which has been exploring Jezero Crater since 2021.
Rover captures the rumble of Martian thunder
The breakthrough came from the rover's onboard microphone, which picked up 55 events consistent with electrical discharges near Perseverance.
Researchers said the device recorded not only the faint rumble of "thunder" on Mars, but also a brief, non-acoustic signal just beforehand - an electrical jolt triggered when the discharge's magnetic field briefly interfered with the microphone's electronics.
It also emerged that 54 of the events occurred during strong winds, showing that swirling dust plays a key role in generating electrical discharges on Mars.
Sixteen events were recorded during two close encounters of the rover with dust devils. Chide and his colleagues suspect that lightning is more likely to occur during such localized events than during large-scale dust storms.
The lightning could have a significant influence on the chemistry in the atmosphere and on the surface of Mars.
Electrical discharges, for example, promote the formation of highly oxidizing substances such as hydrogen peroxide. As such substances act as cytotoxins, they worsen the prospects of finding microorganisms on Mars. – dpa
