Why The Red Planet Could Turn Green This Week

Mars, the red planet, could be in for a global display of aurora this week after a huge cloud of charged particles left the sun in the direction of the red planet.

The prediction from solar scientists comes in the same week NASA’s Perseverance Mars rover made history by detecting visibly green auroras on Mars for the first time.

Mars In The ‘Strike Zone’

An X2.7 solar flare on Wednesday, May 14 — the strongest of the year so far — saw an intense burst of energy and electromagnetic radiation from the sun’s surface spread out across the system at light speed. An X-class solar flare is the most intense class, according to NASA. In its wake, there was a coronal mass ejection — a cloud of super-charged particles — that left the sun’s surface.

This CME, a surge in the solar wind — the ever-present stream of charged particles released from the sun that travels in all directions in the solar system — appears to be headed for Mars, according to Spaceweather.com. Data from NASA indicates that the CME will interact with the atmosphere of Mars on Monday, May 18, which could cause a global display of aurora. Earth is not in the “strike zone” of the CME.

Perseverance Spots Auroras On Mars

The forecast for powerful auroras on Mars comes on the same day NASA published stunning new images of such a display on the red planet last year. On March 15, 2024, a solar flare and an accompanying CME led to stunning auroras across the solar system, including on Mars. During that event, NASA’s Perseverance Mars rover made history by detecting auroras. It’s the first time that’s been done from the surface of another planet.

“This exciting discovery opens up new possibilities for auroral research and confirms that auroras could be visible to future astronauts on Mars’ surface,” said Elise Knutsen, a postdoctoral researcher at the University of Oslo in Norway and lead author of a paper published on May 15 in Science Advances.

Why Auroras On Mars Are Different

Aurora doesn’t come from the sun but results from how charged particles from our star interact with a planet’s magnetic field and react with particles in a planet’s atmosphere. Compared to Earth, Mars has almost no magnetic field and only a tenuous atmosphere. That makes the types of aurora on Mars slightly different, with so-called solar energetic particle auroras — super-energetic particles from the sun striking the Martian atmosphere — making the entire night sky glow.

Predicting Auroras On Mars

Until now, the only auroras on Mars have been detected at ultraviolet wavelengths by spacecraft orbiting the red planet. So, how were green auroras seen by Perseverance’s visible light cameras? “The trick was to pick a good CME, one that would accelerate and inject many charged particles into Mars’ atmosphere,” said Knutsen. “When we saw the strength of this one, we estimated it could trigger aurora bright enough for our instruments to detect.”

Thanks to a precise forecast of aurora three days after a huge CME left the sun in the direction of Mars, Perseverance’s SuperCam and Mastcam-Z instruments observed green aurora. The all-sky display was also detected by two orbiting spacecraft, NASA’s MAVEN ‚ which first saw aurora at Mars in 2014 — and the European Space Agency’s Mars Express.

Solar Maximum

The sun is now likely declining from the peak of solar maximum, the point of its roughly 11-year soar cycle when its magnetic activity is highest. NASA and NOAA’s Solar Cycle 25 Prediction Panel announced the arrival of solar maximum in October 2024, though the exact date won’t be obvious for a few years. The year or two after solar maximum is just as capable of producing major solar events.

Wishing you clear skies and wide eyes.