If you want to see the difference between night skies with and without light pollution, you can't do much better than the video above. The World at Night recently announced the winners of the 2012 Earth and Sky Photo Contest, and threw them into this six-minute Vimeo slideshow. Make it big and hit play.
More than 600 photographs taken during 2011 were submitted and judged in two categories. The first category was Beauty of the Night Sky. Photos were judged on the ability to show an amazing, unpolluted night sky in its natural color. The second category was Against the Lights. Photos were judged on their ability to show the negative affect of light pollution on the night sky. In each image, the photographer needed to capture the sky and a notable location or landmark.
The World at Night, Global Astronomy Month, and National Optical Astronomy Observatory held the contest for the third time. They picked five winners and 20 honorable mentions in each category. Winners received camera equipment, gift certificates, and subscriptions to Sky and Telescope magazine. The winning photo (the first one shown in the video above) is "Comet Lovejoy Over Australia," taken by Jia Hao on December 2011.
If you're interested in submitting your own photos for the 2013 contest, read this note from The World at Night director and founder Babek A. Tafreshi. He talks about how he picked and disqualified photos from the 2012 contest.