On March 18, 2024, a powerful coronal mass ejection from the Sun hit Mars, causing a bright atmospheric phenomenon – aurora in the visible spectrum. For the first time in history, a greenish shimmer in the Martian sky was recorded by NASA’s Perseverance rover. The discovery, published in the journal Science, reveals new details about the Sun’s interaction with the atmosphere of a neighboring planet.
Martian charm
Researchers from the University of Oslo used the rover’s SuperCam spectrometer and Mastcam-Z to record the glow in the Red Planet’s upper atmosphere. Previous observations had recorded only ultraviolet flashes, but this time the glow appeared to be in the range visible to the human eye – like a diffuse green “haze” that evenly covered the sky.
“It was exactly what we expected: a gentle green light, similar to Earth’s auroras but with Martian charm,” said Elise Knutsen, the study’s leader.
Auroras occur when charged particles from the Sun hit the planet’s magnetosphere and atmosphere. On Mars, which has a weak magnetic field, this process is different from on Earth. Studying the auroras helps us understand how solar activity affects Martian climate and the possibility of colonization.
Hunting for aurora
Attempts to record the phenomenon continued for three years. For the fourth time, scientists were able to synchronize the rover with NASA models that predicted the effects of the solar storm. The coronal mass ejection reached Mars in three days, activating carbon ions in the atmosphere – they produced a distinctive green hue.
This discovery proved that Martian auroras could not only be predicted, but also studied in detail. The next step will be to analyze the luminosity spectra to determine the chemical composition of the atmosphere and its response to solar activity, which peaked this year. This data will be critical for future manned missions, as radiation storms are a major threat to future colonists.
Earlier we reported on how a new type of aurora on Mars stunned scientists.
