Mars has auroras, and new research shows they form through the same physical mechanism that lights up Earth’s polar skies.
Scientists working with data from NASA’s MAVEN orbiter have found that certain auroras on the Red Planet are produced by a miniature version of the Dungey cycle, the magnetic reconnection process that drives Earth’s Northern and Southern Lights. The finding, published in Nature Communications, answers a long-standing question about how electrons become energized to create Martian auroral displays.
Magnets on a Smaller Scale
Earth’s auroras depend on the planet’s global magnetic field, generated by its churning iron core. When the solar wind’s magnetic field lines reconnect with Earth’s magnetosphere, energy and charged particles pour into the upper atmosphere, producing the familiar curtains of green and red light.
Mars has no such global field. Instead, it holds localized crustal magnetic fields, fossilized remnants of a global field that existed roughly four billion years ago, frozen into the rock as ancient lava cooled. These crustal fields act as numerous miniature magnetospheres scattered across the Martian surface.
The MAVEN team found that magnetic reconnection within these localized fields operates on the same principle as the Dungey cycle on Earth, just at a much smaller scale.
“We knew that magnetic reconnection was happening at Mars but did not expect it to be like the Dungey cycle,” said Shaosui Xu, lead author of the study and a researcher at the University of California, Berkeley.
The Final Puzzle Piece
The discovery used multiple instruments aboard MAVEN to build a complete picture: the magnetometer mapped the magnetic configuration, the Solar Wind Electron Analyzer tracked electrical currents, and the STATIC instrument measured plasma flows in the ionosphere.
“We really pushed the limit of STATIC to get the data we needed,” Xu said. “It was the final piece to the puzzle in understanding these localized auroras.”
The result demonstrates that a Dungey-like reconnection mechanism can operate at vastly different scales, from Earth’s global magnetosphere to Mars’s patchwork of crustal fields.
“This is a remarkable result that changes how we think of Martian auroras,” said Shannon Curry, MAVEN principal investigator at the University of Colorado Boulder. “And it is another important step toward understanding why Mars and Earth have evolved so differently despite being governed by the same underlying physics.”
A Mission’s Final Gift
MAVEN launched in 2013 and spent more than a decade studying the Martian upper atmosphere. The spacecraft was declared unrecoverable on June 3, 2026, six months after losing contact with Earth. This discovery, drawn from data gathered before the loss, adds to the mission’s legacy of transforming our understanding of the Martian atmosphere and its interaction with the solar wind.