On vacation in Bryce Canyon—one of the few truly dark places left in the United States—a visiting astronomer said that in 25 years, if trends in light pollution don’t abate, no child in the United States will be able to see the Milky Way. Living for forty years in the New York-D.C. corridor, I have seen it only once, in far rural Virginia. In too many places now, the Milky Way and all except the brightest stars are “vanishing in a yellow haze,” says the International Dark-Sky Association (IDA).
Light pollution may sound at first like a problem that isn’t much of a problem, but it has consequences, disrupting the natural patterns of animals (many of which are nocturnal), migrating birds, and humans’ sleep patterns. Not only are sleep disorders a problem for many people, some research suggests these disrupted circadian rhythms raise the risk for chronic diseases: obesity, diabetes, and cancer.
Some years ago, the city of Tucson tackled the problem, when its expansion and night-glare threatened the operation of the night-observation telescope array at the nearby Kitt Peak National Observatory. In Tucson, night lighting must be shielded so that the light is directed down, not allowed to spread in all directions. IDA’s conservation program is attempting to designate dark sites that can preserve the starry night skies for future generations. (Proper lighting also conserves resources, given that 22% of U.S. energy use is for lighting.)
Many businesses—car lots and gas stations are an example—are lit much too brightly at night, in the mistaken assumption that this makes them safer. We referred to the parking lot of a movie theater in Florida where we visited as the “brain surgery parking lot,” it was so brightly lit. Too much light creates glare that actually makes it harder to see. Having lights outfitted with correctly calibrated motion detectors indicate an intruder more easily than lights burning at full power all night. According to light pollution expert Paul Bogard, whose book is The End of Night: Searching for Natural Darkness in an Age of Artificial Light, “the best lighting is uniform, low-level lighting.” In other words, light when and where it is needed, not attempts to recreate High Noon.