I’m in eastern Nevada at Great Basin National Park, and it’s pitch black except for a startling sky above. Stars as bright as diamonds sparkle across the black cloth of space. The translucent band of the Milky Way arcs across the heavens, and Perseid meteors streak through the darkness, leaving fluorescent yellow tracers in their wake.
“At this time of night, the meteors will leave long trails just like an airplane,” says Tom Sevcik of the Salt Lake Astronomical Society, who is interpreting the night sky for our small band of stargazers.
But spectacular night skies like this one have become an endangered phenomenon. The culprit is light pollution -- the illumination and blanking out of the night sky by artificial light. Many people may be surprised to learn that two-thirds of Americans can’t see the Milky Way from their backyards, and 99 percent of American citizens now live in places afflicted with significant outdoor light pollution.
If we continue to increase outdoor lighting at the current rate, no dark skies will remain in the continental United States by 2025. Light pollution has already limited the number of visible stars in many cities to 150, but in an area with a pristine night sky, you should be able to see a crowd of 14,000 stars.
Cities and suburbs aren’t the only places with diminished views of the night sky. Although our national parks have some of the best stargazing in the United States, many are threatened by light pollution. The National Park Service’s Night Sky Team, responsible for monitoring light pollution in the national parks, found light pollution from cities affecting parks as far as 200 miles away. The neon glow from Las Vegas, for example, is visible at eight national parks, including Great Basin National Park and Death Valley National Park.
Light pollution is more than just a problem for stargazers and astronomers. It’s also a waste of ever-more expensive energy and poses a threat to nocturnal species. Thousands of migrating birds perish after colliding with brightly lit skyscrapers. Sea turtles swim inland, disoriented by the bright lights of malls and cities. Artificial light inhibits feeding bats, and evidence suggests that it discourages zooplankton from feeding on algae.
The good news is that light pollution, unlike many other forms of pollution, is completey reversible. If we begin to take action by replacing and reorienting outdoor lights in our cities, suburbs, rural areas and parks, we can reduce energy use, protect nocturnal animals and enhance the visibility of the night sky. Most buildings are lighted at night for safety and security, and we usually give little thought to turning off non-essential lights or directing light fixtures downward. Urging our schools, businesses, municipalities and lawmakers to take action will help ensure that our children will be able to marvel at the Milky Way.
Already, some states, cities and the National Park Service are leading the way to preserve dark skies. In 1999, New Mexico passed The Night Sky Protection Act, which eliminated high-powered mercury vapor bulbs for street lights, required park lighting to be shut off by 11 p.m., and stipulated that outdoor lighting be directed downward.
Tucson, Ariz., has retrofitted 22,000 street lamps with hoods, an action so successful that the Milky Way is once again visible from downtown. And after Utah’s Natural Bridges National Monument made significant changes to its outdoor light fixtures, the Tucson-based International Dark Sky Association designated the city as an International Dark Sky Park.
Standing in the darkness of Great Basin National Park, I feel wonder and humility as I crane my neck to stare up at the stars. The vastness of the night sky puts my daily struggles in perspective. As our guide identifies the constellations Cassiopeia and Scorpius with the help of a yellow laser pointer, it’s easy to understand why a night like this has captivated artists, poets and ancient cultures.
“I can’t imagine what it must have been like 200 years ago before light pollution,” marvels one dazzled stargazer.
“It must have been awesome,” exclaims another seated silhouette. ”No wonder people used to sit outside and look at the stars so much.”
Seth Shteir is a contributor to Writers on the Range, a service of High Country News (hcn.org). He teaches school in Sherman Oaks, California, and also serves as conservation chair of the San Fernando Valley Audubon Society.