Today, in and around cities like Atlanta, where population doubled in the past 30 years to 3.6 million, the cosmos has mostly vanished. Across the South, even in the Appalachian Mountains, night is being turned into day. Currently, only about 10 percent of the U.S. population can see the more than 15,000 stars that should be visible each night from Earth. Now, scientists say that our overlit world squanders resources, energy and money, and is taking a toll on the environment. Biologists have shown that light pollution harms animals.
Birds migrating at night use the constellations and moon as guides.
Bright lights blind or disorient, causing flocks to veer off course. And in 1981, more than 10,000 birds slammed into floodlit smokestacks at the Hydrox Generating Plant near Kingston, Ontario. Light pollution also endangers sea turtles. Bright lights near nesting beaches, like those along the South's Atlantic shores, discourage females from coming ashore to lay eggs. Hatchlings rely on celestial sightings to direct them back to the surf, but artificial lights behind beaches lure them to streets and parking lots.