Light Pollution - 5/12/15
Today, little of our planet’s land is dark at night. The starry hubs of cities and ports and vein-like outgrowths of the well-lit suburbs cover the surface of the Earth. The planet may be "a pale blue dot," as Carl Sagan has said; but at night, we're bright. Too bright.
Over thousands of years, Earth’s animals have evolved to have circadian rhythms and internal clocks maintained by the daily light/dark cycle that is disrupted today by light pollution.