Martian Aurora Is One of a Kind

Join Our Community of Science Lovers!

On supporting science journalism

If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.

The impressive display known as the northern lights is one example of Earth's auroras, which occur around the planet's poles. Now scientists have discovered that the Red Planet puts on its own dazzling light show--one that is powered in a unique manner.

Auroras on Earth and four other planets (Jupiter, Saturn, Uranus and Neptune) result from the interaction between charged particles from the solar wind with the planets' magnetic fields, which subsequently excites atmospheric molecules. On Venus, which lacks a magnetic field, auroras arise from atmospheric molecules energized directly by solar wind particles. Using the ultraviolet spectrometer (SPICAM) on board the Mars Express satellite, Jean-Loup Bertaux of the Service d'Aeronomie du CNRS in France and his colleagues observed a Martian aurora. Unlike the other large planets' celestial shows, which occur near the poles, the light show above the Red Planet manifests around areas of magnetized rock in the planet's crust. "Mars has no internally generated, planetary-scale magnetic field," explains study co-author Bill Sandel of the University of Arizona. "It has what are called 'crustal magnetic anomalies' scattered around the Martian surface, remnants of what presumably was Mars's planetary-scale magnetic field that was active when the planet was younger."

The aurora measured some 30 kilometers across and appeared about 130 kilometers above the surface, according to a report published today in the journal Nature. Note the authors: "It corresponds to a distinct type of aurora not seen before in the solar system."

It’s Time to Stand Up for Science

If you enjoyed this article, I’d like to ask for your support. Scientific American has served as an advocate for science and industry for 180 years, and right now may be the most critical moment in that two-century history.

I’ve been a Scientific American subscriber since I was 12 years old, and it helped shape the way I look at the world. SciAm always educates and delights me, and inspires a sense of awe for our vast, beautiful universe. I hope it does that for you, too.

If you subscribe to Scientific American, you help ensure that our coverage is centered on meaningful research and discovery; that we have the resources to report on the decisions that threaten labs across the U.S.; and that we support both budding and working scientists at a time when the value of science itself too often goes unrecognized.

In return, you get essential news, captivating podcasts, brilliant infographics, can't-miss newsletters, must-watch videos, challenging games, and the science world's best writing and reporting. You can even gift someone a subscription.

There has never been a more important time for us to stand up and show why science matters. I hope you’ll support us in that mission.

Thank you,

David M. Ewalt, Editor in Chief, Scientific American