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.