Mini Lightning Discovered on Mars, Offering Clues to Planet’s Chemistry and potential for Life
PASADENA, CA – NASA’s Perseverance rover has detected frequent, small-scale electrical discharges – a form of “mini lightning” – occurring within Martian dust storms and vortices, a discovery that could reshape our understanding of the planet’s atmospheric chemistry and its implications for the search for past or present life. The findings, published recently, offer a potential explanation for the long-observed presence of oxidants on Mars and provide valuable data for future mission design.
Unlike Earth’s lightning,which is generated by friction between ice particles in clouds,Martian “lightning” arises from friction between dust particles. Mars’ thin atmosphere lacks the water vapor necessary for conventional thunderstorms. Researchers analyzed 29 hours of audio recordings captured by Perseverance’s microphone over two Martian years, identifying 55 distinct electrical events ranging from static bursts to small shock waves - the sound of the discharges themselves.
“This is very exciting… This opens up a new field of investigation for Mars,” said Baptiste Chide of the institut de Recherche en Astrophysique et Planélogie in Toulouse, in a statement to Space.com.
The discovery also sheds light on the origin of oxidants like hydrogen peroxide, first detected on Mars in 2003. while oxidants can break down organic molecules – perhaps destroying evidence of life (biosignatures) – the electrical discharges can also create new organic molecules through chemical reactions. This duality is crucial in assessing mars’ habitability.
Daniel Mitchard from Cardiff University explained the difference in electrical discharge thresholds between Earth and Mars. “The threshold for electrical discharges is higher on Earth than on Mars… So we can expect lightning on Mars to be weaker than on earth,” he stated.
The majority of the 55 events (54) coincided with winds reaching 30% of their peak strength during the recording period, and 16 occurred as dust devils passed near the rover. Interestingly, some discharges originated from the rover itself, as it accumulated a charge of several kilovolts from dust particle impacts before releasing it to the ground.
While Perseverance’s instruments are designed to withstand these discharges, Chide speculated that the failure of the Soviet Union’s Mars 3 mission in 1971 - which ceased operating just 20 seconds after landing – may have been caused by a similar electrical event.
The data gathered by Perseverance’s microphone will inform the design of future Mars missions. “Now that we have quantitative data on electrical discharge energy, we can adjust the specifications of electronic equipment and perhaps put new constraints on spacesuit design,” chide noted.
Looking ahead, Chide’s team plans to measure the amount of oxidant produced by these discharges through laboratory experiments and modeling, further refining our understanding of Mars’ complex atmospheric processes and their impact on the search for life.
