NASA's MAVEN spacecraft (short for Mars Atmosphere and Volatile Evolution) spotted ultraviolet "Christmas light" auroras dancing in the Red Planet's atmosphere for five days leading up to Dec. 25, 2014.
"What's especially surprising about the aurora we saw is how deep in the atmosphere it occurs - much deeper than at Earth or elsewhere on Mars," Arnaud Stiepen, of the University of Colorado, a team member with MAVEN's Imaging Ultraviolet Spectrograph instrument, said in a NASA statement. "The electrons producing it must be really energetic."
Source: Space.com