On March 18, 2024, the Sun swung a large bubble of plasma toward the direction of Mars. The eruption of the solar storm led to an auroral display across the Martian sky, which glowed with a greenish hue. A group of scientists used the Perseverance rover to look up at the sky and capture Mars’ visible aurora for the first time.
Scientists used Perseverance’s SuperCam spectrometer and Mastcam-Z camera to observe a visible aurora on Mars, identifying the exact spectral line causing the green emission. Although scientists have detected Martian auroras before, they appeared in ultraviolet wavelengths. The new discovery, however, marks the first time an aurora on Mars has appeared in wavelengths visible to the naked eye.
“It took three unsuccessful attempts before we got it right, but when we did, it appeared exactly as we had imagined it; as a diffuse green haze, uniform in all directions,” Elise Knutsen, a researcher at the University of Oslo, and lead author of a new paper published today in the journal Science, told Gizmodo.
Auroras take place when energetic particles from the Sun (in the form of a coronal mass ejection) interact with the planet’s magnetic field and its atmosphere, creating shimmering displays of light across the skies. On Earth, auroral displays appear when solar storms and charged particles impact the atmosphere. Knowing exactly when the aurora will appear in Earth’s skies is tricky, but it is so much trickier on Mars.
“Aurora forecasting at Mars is even more challenging than on Earth,” Knutsen said. “We spent a lot of time developing the exact instrument settings, and fine-tuning the timing of our observations.”
In March 2024, a coronal mass ejection (CME) was observed heading toward Mars. The team behind the new study used simulations published online by NASA’s Community Coordinated Modeling Center to evaluate whether the CME was likely to trigger an aurora bright enough for Perseverance’s instruments to detect. The team was successful on the fourth attempt, capturing Mars’ glowing skies for the first time. The observations proved that auroral forecasting on Mars is possible, and scientists can make the proper arrangements to prepare for the light display.
The aurora appeared on Mars on March 18, 2024, three days after the solar storm took place. “Auroras are the visible manifestations of how our Sun affects planetary atmospheres,” Knutsen said. “So far, we have only reported our very first detection of this green emission, but observations of aurora can tell us a lot about how the Sun’s particles are interacting with Mars’s magnetosphere and upper atmosphere.”
