Mars has Auroras!

Auroras on Earth are caused by the ionization of atoms high in the atmosphere near the north and south magnetic poles.  The solar wind flies toward the Earth and this harmful radiation is blocked and funnelled by our magnetic field, creating harmless, beautiful glows that remind us how close we came to total destruction, but were saved by our planet.  Do other planets have auroras? Certainly! Jupiter and Saturn do, and even moons like Ganymede can have auroral activity.  It really depends on the magnetic field.  So how does a planet like Mars, with no magnetic field, have auroras? This is a surprising find to say the least.

Credit: University of Colorado

Mars does have sporadic, umbrella shaped magnetic fields pop up from time to time, a long lost remnant of a vast planet-wide field that disappeared millions of years ago when the planet’s core solidified.  But these are predominantly located in the southern hemisphere, so how do we find aurorae in the northern hemisphere of Mars?

Scientists aren’t sure, but it might be the magnetic fields of the solar wind itself that are guiding the particles into the atmosphere.  The thin atmosphere of Mars isn’t ionizing much, but when it does, the aurorae are seen very close to the surface, around 100 Km.  This is compared to Earthbound aurorae which lie much higher, up to 500 Km from the surface.

Whatever the origin, future Mars astronauts will likely see a faint green glow in the skies above, giving Mars a very eerie feel indeed.

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