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NASA’s Perseverance rover has captured an aurora in the night sky from the Martian surface for the first time. Scientists have been aware for two decades that Mars hosts auroras, but these have only been detected in ultraviolet light, invisible to the human eye, until now. Previously, Martian auroras were observed from orbiters in space.
The resulting image, though grainy, is a significant achievement, according to Elise Wright Knutsen, the lead author of the research from the University of Oslo, Norway. A paper on this observation was published in the journal Science Advances on May 14.
Knutsen explained that the captured image was taken with an instrument not optimized for nighttime photography and lacks the spectacle of typical aurora images from Earth. The image’s softly glowing green sky, albeit pixelated, remains noteworthy.
The rover’s actual images were not as glamorous as artist renderings, but their detection is considered monumental, researchers stated. The phenomenon occurs when solar radiation from the sun reaches a planet, causing charged particles to travel along magnetic field lines and interact with atmospheric gases, creating glowing displays known as auroras.
On Earth, aurora colors vary based on atmospheric gases and altitude. Mars’ magnetic field differs from Earth’s, leading to unique aurora patterns. These auroras can appear in various locations, categorized into four types: localized discrete auroras, global diffuse auroras, proton auroras, and large wormlike auroras extending to Mars’ nightside. Some auroras emerge from the ground, likely forming around remnants of the ancient magnetic field in the planet’s crust.
Perseverance, while exploring the Jezero crater, identified the aurora on March 18, 2024. The sun had released energy expected to reach Mars, according to Rob Lillis from UC Berkeley, in a 2024 interview.
The rover used Mastcam-Z and SuperCam instruments to observe the faint green glow. Although the glow was dim, this discovery suggests that under better conditions, astronauts might see such phenomena with the naked eye in the future.
Studying these auroras is essential for developing navigation and communication systems for potential human missions to Mars. Accurate models of Mars’ ionosphere, the charged particle layer surrounding the planet, are necessary for these technologies to function effectively.
Further efforts to capture Martian auroras are planned. A NASA-funded mission, Escapade, aims to investigate how solar radiation strips Mars’ atmosphere. This mission will utilize two orbiters built by Rocket Lab to capture the first global snapshots of Martian auroras in visible light. The United Arab Emirates’ orbiter, Hope, has already obtained global images in ultraviolet light.
The rover’s recent detection was a breakthrough after several failed attempts, noted Knutsen, who aspires to explore space and previously applied to the European Space Agency’s astronaut program.
"I hope one day I can retire under a softly glowing green Martian sky," she expressed.
