APOD: 2010 September 20 - Aurora Over Norway “Photographed above last weekend, flowing multi-colored auroras helped illuminate a busy sky above Tromsø, Norway. Besides the spectacular aurora pictured above, the photographer caught three satellites streaks, one airplane streak, and a friend trying to capture the same sight. … Called northern lights in the northern hemisphere, auroras are caused by collisions between charged particles from the magnetosphere and air molecules high in the Earth’s atmosphere.”