An aurora borealis visible in the northern sky over Merritt Reservoir in Valentine, Neb. The colors captured in this 30 second photograph, which was taken by amateur astronomer Howard Edin, were not visible to the naked eye. When the photo was taken, the low intensity of the aurora appeared as an arc of gray clouds across the northern sky. Read more about Edin's experience viewing the aurora Here. (Date of Image: July 2009) Credit: Howard Edin