The Perseverance rover has detected evidence of mini-lightning strikes on Mars, a finding published in Nature. The discovery was made through the rover's microphone, which recorded signs of electrical arcs accompanied by audible shockwaves.
Researchers have long speculated about the presence of lightning on Mars. Daniel Mitchard, a lightning researcher at Cardiff University, noted the significance of direct detection, stating it aligns with existing hypotheses about Martian lightning. While lightning has been observed in the atmospheres of Jupiter, Saturn, Neptune, and Uranus, its detection on Mars and other inner planets has been challenging.
Earlier laboratory experiments in the 1970s simulated Martian atmospheric conditions, showing that swirling volcanic sand could generate electrical charges and a visible glow, suggesting the potential for larger electrical discharges like lightning.
The discovery stemmed from a re-evaluation of audio collected by the Perseverance rover, which has been operational on Mars since 2021. Initial recordings of a dust devil passing over the rover included a brief "snap or crack" sound, which was initially attributed to sand or gravel impact. Baptiste Chide from the Institut de Recherche en Astrophysique et Planétologie later hypothesized that the sound might indicate an electrical discharge. Earth-based experiments using an electrostatic generator confirmed that similar electrical interference followed by an acoustic shockwave matched the Martian recordings.
Fifty-five such events were identified by the microphone over two Martian years. These electrical arcs were predominantly associated with dust devils and the leading edges of dust storms. The electrical discharges are described as comparable to strong static electricity sparks.
Researchers emphasize the importance of studying this atmospheric electrical activity to assess potential hazards for future robotic and human missions. The sudden termination of the Soviet Mars 3 mission, which landed during a dust storm and ceased transmissions after approximately 20 seconds, is cited as an example where an electrical discharge event cannot be definitively ruled out as a contributing factor.