The purple color in this image shows auroras on Mars’ nightside as detected by the ultraviolet ... [+]
NASA’s Curiosity rover gazed out over the Gale Crater on May 20 and saw something spectacular: the effects of an epic solar storm that blasted Mars. “This science bonanza has offered an unprecedented opportunity to study how such events unfold in deep space, as well as how much radiation exposure the first astronauts on Mars could encounter,” NASA said in a statement on June 10.
Curiosity sometimes uses its cameras to monitor the crater for dust devils and wind activity. That’s what it was doing when the sun spit out an X12 solar flare in the direction of Mars. X-class flares are the most intense type and an X12 denotes an exceptionally strong flare. “The biggest X-class flares are by far the largest explosions in the solar system and are awesome to watch,” said NASA in an explainer. Curiosity captured views of the flare’s impact on Mars. The images are grainy due to processing, but are also filled with streaks and snow-like specks.
The specks in the sequence of images in this video were caused by charged particles from a solar ... [+]
The streaks and specks aren’t from flying dust, though. They’re artifacts from the sun’s tantrum. “Recently, my routine dust monitoring coincided with a major solar event hitting the red planet, and the charged particles that hit my camera caused distortions,” the Curiosity team explained on X. “It's the biggest radiation surge I've detected since landing in 2012.” NASA did the math and worked out that an astronaut standing beside Curiosity would have been bathed in an 8,100-microgray dose of radiation, which is equivalent to getting 30 chest X-rays. Fortunately, that’s not a killer dose.
Streaks and specks caused by charged particles from a solar storm appeared in images captured by the ... [+]
The measurement came from Curiosity’s Radiation Assessment Detector. NASA is planning ahead to one day sending humans to Mars, but the agency will need to work out ways to protect astronauts from radiation. Seeking shelter from solar storms might help. “Cliffsides or lava tubes would provide additional shielding for an astronaut from such an event,” said RAD principal investigator Don Hassler. “In Mars orbit or deep space, the dose rate would be significantly more.”
The sun is having a moment. Activity is up and it’s been coughing up flares and coronal mass ejections. The National Oceanic and Atmospheric Administration Space Weather Prediction Center describes CMEs as “large expulsions of plasma and magnetic field from the sun’s corona” that can eject billions of tons of material. When those blasts reach Earth, we get vivid auroras. Auroras in May were some of the strongest displays on record, according to NASA.
Flares travel fast. “Moving at the speed of light, the X-rays and gamma rays from the flare arrived first, while the charged particles trailed slightly behind, reaching Mars in just tens of minutes,” NASA said.
Curiosity wasn’t the only explorer to witness the scene. NASA’s MAVEN (Mars Atmosphere and Volatile EvolutioN) orbiter caught sight of Martian auroras. Mars doesn’t have the same protections Earth does from the sun’s bursts. Earth auroras are concentrated at the poles. Mars auroras cover the whole planet. MAVEN’s Solar Energetic Particle instrument tracked the event and NASA created an aurora video with data from the orbiter’s ultraviolet instrument.
The purple color in the video represents auroras on the nightside of Mars for a week starting on May 14. Brighter purple indicates more auroras. “This was the largest solar energetic particle event that MAVEN has ever seen,” said Christina Lee, MAVEN Space Weather Lead.
The sun isn’t done. We can expect more outbursts as it lingers in a phase of high activity. That means the potential for more light shows on Earth and more data on how the sun interacts with Mars. Curiosity and MAVEN will be ready.
