The aurora borealis, or northern lights, fill the sky above the Takotna, Alaska checkpoint during the Iditarod Trail Sled Dog Race on March 9, 2011. (Bob Hallinen/The Anchorage Daily News/AP) #

The aurora borealis, or northern lights, fill the sky above the Takotna, Alaska checkpoint during the Iditarod Trail Sled Dog Race on March 9, 2011. (Bob Hallinen/The Anchorage Daily News/AP) #