September 07, 2004
The above photo of this captivating green aurora was taken on July 25, 2004 at 2:20 a.m. (local time) from Houghton, Michigan. Houghton is on Michigan's Upper Peninsula (UP) -- the lights of Hancock, Michigan, are in the foreground and the view is toward the northeast. I was in Houghton attending a great workshop for middle and high school teachers at Michigan Tech University, and as an unexpected bonus, was treated to my first show of the northern lights. Over a two-hour period, from approximately 1:00 a.m. to 3:00 a.m., the shapes and dimensions of the aurora changed constantly, but the bright green color remained dominant. When charged particles from the Sun collide with atoms in the Earth's upper atmosphere, oxygen and nitrogen atoms become excited and emit light -- green light is the color most commonly observed.
Photo details: Canon Powershot A80, 15-second exposure, at f2.8, ISO 400.