NASA's "Perseverance" rover directly recorded lightning-like electrical discharge signals on Mars for the first time. It captured a total of 55 times during the two-Mars-year observation period, which is related to strong dusty weather such as sandstorms and "dust devils" on Mars.
The research team pointed out that these discharges occur in areas near the surface of Mars where dust is highly concentrated, and usually occur in about the first three percent of the strongest wind speed, indicating that strong winds picking up and rubbing dust particles are key conditions for generating charges.
The SuperCam microphone on Perseverance can record sound data and electromagnetic interference signals. Researchers screened out 55 suspected electrical discharge events from about 28 hours of recordings, of which 7 were completely recorded with the characteristic waveform of "electronic pulse + attenuated ringing + tiny sonic boom".
According to the acoustic analysis of six of the events, most of the discharge energy was very weak, only about 0.1 to 150 nanojoules; the other one had a larger energy, about 40 millijoules. It is speculated that the rover may have accumulated electric charge and then discharged it to the ground.
This micro-discharge phenomenon on Mars is different from the common cloud-to-ground lightning on Earth. The energy of a typical lightning bolt on Earth is about one billion joules, which is much larger than the nanojoule to millijoule-level small discharges observed on Mars.
Although the energy gap is huge, this result shows that in the thin, dry and carbon dioxide-dominated atmosphere of Mars, dust activity can also effectively generate and release charges, thus confirming the previous theoretical model about "Mars has electrical activity/lightning-like".
Researchers believe that this discovery will affect the engineering design of future Mars probes and residential facilities, because the risks and interference that dust-induced electrical discharges may bring to equipment and personnel need to be considered.
From the perspective of planetary science and astrobiology, these electrical discharges will also participate in chemical reactions in the Martian atmosphere. Some hypotheses about "lightning promoting primitive geochemistry and helping the origin of life" can now be included in the evaluation in the Martian environment, providing new constraints for judging whether Mars has chemical conditions suitable for life in the past or present.