Last Sunday, eruptions shook the surface of the Sun and sent two blasts of magnetic plasma streaming out into space. They barreled toward Earth, where our planets magnetosphere picked up charged particles and funneled them toward the poles. Electron flux entering the atmosphere excited oxygen and nitrogen molecules, which sent out flares of green, orange and red.
On the Earth’s surface, viewers watched the rippling aurora borealis dance as far south as New York State and across Britain. In a counterpoint, pink and purple streams of the aurora australis light up Christchurch, New Zealand.
The results of this solar storm were ours, but had it occurred elsewhere on the Sun, other planets could have had their own displays. Auroras do actually happen on most of the other planets in our solar system and some moons. They’ve been spotted by astronomers before, but little is known about extraterrestrial auroras. So when NASA’s Maven mission was able to watch five days of northern lights on Mars this past Christmas, astronomers were excited.
The preliminary results of MAVEN’s observations, including the presence of an usual dust cloud in at orbital altitudes, were presented at the 46th Lunar and Planetary Science Conference.
Although Martian auroras have been seen before by Europe's Mars Express spacecraft, what surprised scientists was how deep in the atmosphere this occurred - much deeper than at Earth or elsewhere on Mars.
But the finding makes a degree of sense because while Earth retains a global protective magnetic field, Mars lost its one billions of years ago. This means that the high energy particles streaming in from the Sun make direct strikes, penetrating deep into the atmosphere.
“The electrons producing it must be really energetic," says Arnaud Stiepen, of the University of Colorado, in a NASA press statement. The Martian aurora, dubbed 'the Christmas lights' was a bright ultraviolet glow spanning much of the Red Planet’s northern hemisphere. While Martians probably didn’t ooh and aw, our own satellites and rovers may have enjoyed the show.