The northern lights fill the sky over the south shore of Lake Superior east of Superior, Wis. above Duluth, Minn., early Sunday, July 15, 2012. A solar storm sparked the spectacular northern lights display in the skies over the Upper Midwest. (AP Photo/The Duluth News-Tribune, Andrew Krueger)
The northern lights fill the sky over the south shore of Lake Superior east of Superior, Wis. above Duluth, Minn., early Sunday, July 15, 2012. A solar storm sparked the spectacular northern lights display in the skies over the Upper Midwest. (AP Photo/The Duluth News-Tribune, Andrew Krueger)
Massive solar flares contributed to spectacular light shows in the skies above central Minnesota over the weekend. July 16, 2012.