Polar auroras and radiation: NASA tells about the consequences of a record solar flare for Mars

In May 2024, the Sun produced a series of powerful flares that caused a record geomagnetic storm on Earth. Our planet was not the only one to be affected. According to NASA, the flares also reached Mars, causing auroras. 

Radiation burst on the surface

Scientists studying Mars have long awaited the peak of solar activity to see how it would affect the planet. On May 20 of this year, they got that opportunity. The Sun produced the most powerful flare of class X12. The X-rays, gamma rays, and coronal mass ejection produced by the flare headed straight for the Red Planet. The X-rays and gamma rays, traveling at the speed of light, reached Mars first, while the charged particles were a little behind and took only tens of minutes to reach Mars. 

“Snow” is caused by charged particles hitting the Curiosity rover’s Mars navigation camera. Source: NASA/JPL-Caltech

Data from the Mars rover Curiosity suggests that if astronauts had been standing next to it at that moment, they would have received a radiation dose of 8,100 micro-roentgens, the equivalent of 30 chest X-rays. Although not deadly, it was the largest burst of radiation Curiosity has recorded since the rover landed 12 years ago. The amount of radiation that reaches the surface of Mars is clearly demonstrated by the images taken that day from the rover’s navigation cameras. You can see “snow” on them: white streaks and spots caused by charged particles hitting the cameras.

Curiosity wasn’t the only Martian explorer to feel the full force of the flare. The Mars Odyssey spacecraft’s stellar sensor, used for orientation, became oversaturated with energy and went out for a while. It could have been worse, though. In 2003, charged particles from a flare that was eventually estimated to be X45 literally fried the Mars Odyssey radiation detector, which was specifically designed to measure such events. 

Auroras over Mars

NASA spacecraft in Martian orbit has captured another clear effect of recent solar activity. We’re talking about auroras. 

The mechanism of auroras on Mars is different from the way they appear on Earth. Our home planet is protected from charged particles by a strong magnetic field, which usually confines them to the pole region. Mars long ago lost its magnetic field, and it has no shield against charged particles. Therefore, when they enter its atmosphere, auroras cover the entire planet.

This is exactly what happened during the May flares. The instruments installed onboard MAVEN managed to record the light from the auroras that raged on the planet from May 14 to 20. 

Already this year, two ESCAPADE probes will be launched to Mars. They will study the planet’s magnetosphere and how it interacts with the solar wind. Their data will add to other spacecraft’s observations of how solar flares affect Mars.

According to NASA