Light Pollution

A little more on light pollution. I was never sure of the reasons to limit lights except for the energy consumption, this says it well.

http://ngm.nationalgeographic.com/2008/11/light-pollution/klinkenborg-text/1

Unlike astronomers, most of us may not need an undiminished view of the night sky for our work, but like most other creatures we do need darkness. Darkness is as essential to our biological welfare, to our internal clockwork, as light itself. The regular oscillation of waking and sleep in our lives—one of our circadian rhythms—is nothing less than a biological expression of the regular oscillation of light on Earth. So fundamental are these rhythms to our being that altering them is like altering gravity.