The solar storms that produced the massively impressive auroras seen around the world on May 10 also hit Mars, igniting auroras over the Red Planet and flooding the surface with harmful radiation.
The primary source of solar storms was the active region, AR3664which was an intense node of magnetic flux in a sun populated by dozens sun spots which released a large number of powerful ones flare and coronal mass ejections (CMEs) first with us and later as they orbit the Sun, towards Mars.
The strongest eruption unleashed during this period occurred on May 20, 2024, when Earth he was on the other side of the Sun, but Mars was directly in the line of fire. Flooding gamma radiation and X-rays flew toward Mars at the speed of light, followed a few days later by the slower-moving charged particles of a coronal mass ejection.
On the surface, in Gale Crater on Mars, Mars rover Curiosity‘s Radiation Assessment Detector (RAD) typically records an average daily radiation dose of about 700 micrograys. During the solar storm, the radiation detected by the RAD shot up to 8,100 micrograys, the equivalent of 30 chest X-rays at once.
While still far from being immediately fatal, experiencing such exposure multiple times during any prolonged stay on the planet would drastically increase the health risks. On the other hand, this was the largest burst of radiation the RAD has picked up since Curiosity landed on Mars 12 years ago, so such high doses are not the norm.
Astronauts could potentially shelter in caves, such as those that may be associated with mine craters and lava tubes on the flanks of volcanoes, such as the recently orbited pit picture disseminated from NASA Mars Reconnaissance Orbiter.
Don Hassler of the Southwest Research Institute, who is RAD’s principal investigator, agrees with this safety measure.
“Cliff sides or lava tubes would provide additional shielding to the astronaut from such an event,” he said in a statement. declaration. However, it is not possible for everyone to hide in the cave, especially if you are not actually on the planet. “In Mars orbit or in deep space, the speed of the doe would be significantly higher.”
It really was. The radiation was so high that it knocked out orbit Mars Odyssey the spacecraft’s main star-finding camera, which it uses for orientation. Although the camera came back online after an hour, it was a reminder that spacecraft are vulnerable to sunlight. In October 2003, the Mars Odyssey radiation detector was fried by radiation from one of the largest solar flares in living memory.
Another spacecraft orbiting Mars, MAVEN (Mars Atmosphere and Volatile EvolutioN) fared better and was able to capture the Martian aurora from above Mars as charged particles from the CME rained down on the Red Planet.
MAVEN was able to image the aurora borealis on Mars from a high altitude, as well as capture a number of charged particles with its Solar Energetic Particle instrument. Black-and-white images taken by Curiosity’s navigation camera (Navcam) on the ground were speckled with “snow” — white spots and streaks caused by energetic particles hitting the camera’s sensor.
“This was the largest event of solar energetic particles that MAVEN has ever seen,” said Christina Lee of the University of California. Lee is the space weather lead on the MAVEN team. “There have been several solar events in recent weeks, so we’ve seen wave after wave of particles hitting Mars.”
In fact, it looks like a whole Solar System in May, the sun struck as its active regions spewed particles and radiation in all directions. The auroras seen on Earth and Mars could also be just a taste of things to come – p solar activity cycle approaching maximum in July 2025, we can expect many more solar storms in the coming months and the effects will be visible to us on an interplanetary scale.
On Earth, we have two things that protect us from this onslaught of radiation: our planet’s global magnetic field and a dense atmosphere that can deflect and absorb the radiation.
However, Mars lacks a global magnetic field, although it does have localized magnetic pockets that are thought to be remnants of an ancient planetary field. The atmosphere of Mars is also quite thin compared to Earth. Taken together, this means the red planet is bearing the full brunt of the solar storm.
The Earth’s magnetic field is channeled by the solar wind into a teardrop shape, called the magnetotail. When a CME strikes, charged particles become trapped in the magnetotail, which acts as a type of solar wind. The pressure from the CME pinches the magnetotail and separates it from Earth’s magnetic field. As the magnetotail is blown away from us by the solar wind (don’t worry, like a salamander regrowing a lost limb, the Earth regrows its magnetotail), the charged particles trapped within it are free to follow the magnetic field lines down to the magnetic the tail. poles.
On their way, the charged particles collide with atmospheric molecules, mainly oxygen, nitrogen and hydrogen, causing these molecules to glow in the colors of the aurora – green, red and blue. This is why we tend to see auroras closer to the poles and not the equator.
There is no magnetic field on Mars to trap charged particles and bring them to the poles, so when a CME hits, the charged particles simply go straight into the atmosphere all over the planet. Because Mars has some molecular oxygen in its atmosphere, its auroras tend to be colored green.