Humans have gazed at starry skies, in awe, for thousands of years, but as man-made light spills into the darkest hours of the night, it's getting harder to catch a glimpse of our galaxy. Can national parks preserve the experience?
By Anne Minard
For most of his life, Gordon Gower has been aiming telescopes at the night sky and has watched light pollution steadily obscure his clear view of the stars.
“I grew up in a city of 100,000 people in south Texas, and I could pick out constellations in my backyard,” he says. “But these days, fewer than 20 percent of Americans can see the Milky Way from their own homes.”
That’s a travesty, he says—but we can do something about it.
Gower, a visitor-use specialist at Natural Bridges National Monument in Utah—which boasts one of the darkest night skies in the country—is also the park’s unofficial “dark sky ranger,” pointing out planets and constellations to eager nighttime crowds.
Natural Bridges isn’t the only park encouraging people to stargaze. From night-sky festivals in Acadia National Park to Star Wars-themed programs in Bryce Canyon National Monument, parks across the country are reintroducing visitors to the wonders of the universe. But dark skies offer more than the chance to connect with something bigger than ourselves.
They’re a precious resource that affects some very Earthly matters, too, like the natural rhythms of wildlife and the health and well-being of humans.
National parks have emerged as celestial oases—the last places in America where people can experience a truly dark sky. And there’s a growing sense that protecting these nighttime vistas is every bit as important as protecting Yellowstone’s bison or Everglades’ wetlands.
“It’s our job,” says Chad Moore, who has been heading up the Park Service’s Night Sky Team for the past decade. “We want people to know the Park Service really cares about this stuff, and we guard night skies the same way we would elk in Rocky Mountain National Park or wolves in Yellowstone.”
But the reality outside park boundaries is different. Satellite maps of the United States show an eastern seaboard lit up like a Christmas tree every night. The West shows darker areas, but skies over even remote places have been getting brighter as the U.S. population grows.
Cities like Phoenix and Las Vegas cast domes of light as far as several hundred miles away; anyone within that range is forced to peer through a glow that obscures the heavens beyond. These days, they’re lucky to spot the Big Dipper.
Astronomers were the first to sound the alarm on light pollution, but the issue goes deeper than stargazing alone. On a basic level, Gower says, people lose something when they’re cut off from views into the universe.
“We are the first generation in the recorded history of the human race that’s lost our connection with the night sky,” he says. “Dark skies are our heritage. When we cut ourselves off from our heritage, we lose our roots—and to some degree, our healthiness. I think there’s a peacefulness that comes from being tied to nature and keeping a perspective that’s bigger than who’s on ‘American Idol.’”
Recent studies by Richard Stevens, a University of Connecticut epidemiologist, show a possible correlation between increased prostate and breast cancers and areas with high levels of artificial light. For the same reasons, the American Medical Association is advocating for light-pollution control and glare-reduction efforts around the country.
Wildlife suffers, too. Insects are lured to their deaths when artificial lights make them more visible to predators and easier to hunt. Owls and songbirds that migrate in the night collide with buildings, attracted by the man-made glare. Reptiles shy away from artificial lighting, which limits where they can forage for food. Sea turtle mothers and their hatchlings become disoriented by the glow of lights from beach communities, setting off on the wrong course as a result. If national parks are to remain refuges for wild species, Moore says, they must address the effects of light pollution on those residents.
In 1999, Moore and the Night Sky Team began tracking night skies over America’s parks. Since then, they’ve logged data from 64 parks, using specialized digital cameras that capture 360-degree views. Custom software measures grayness levels that set a baseline for the quality of the night skies. Meanwhile, they’ve begun posting the inventory data on a website—www.nature.nps.gov/air/lightscapes—to increase public awareness.
Eventually, Moore and his team hope to track the glow of park skies over a period of time, so they can begin to understand the changes. So far, there are no plans to track the change in light pollution over the parks; the efforts are still in the inventory phase. Moore says the program has subsisted on grants for 10 years, but funding is running out.
Thankfully, the Tucson, Arizona-based International Dark-Sky Association (IDA) is aiming to pick up where the Park Service survey left off. IDA secured a National Science Foundation grant in 2009 to set up 10 solar-powered dark-sky cameras in environmentally sensitive areas around the world. Five of those cameras have been built and are being tested, and IDA hopes to have up to 25 cameras recording data by the fall of 2011 in locations that range from Canada to Britain to national parks in the United States. The resulting data will provide the first continuous measurements of the world’s light pollution.
Since 2005, roughly 60 interpreters have participated in the Park Service’s Night Sky Program in locations like Bryce Canyon, Death Valley, and Badlands National Park. Rangers learn how to use telescopes, teach basic astronomy, lead effective constellation tours that weave in cultural and historic perspectives, and “communicate the message of light pollution without bumming people out,” Moore says. As a result, visitors are going on bat walks at Pinnacles National Monument in California and Carlsbad Caverns National Park in New Mexico, attending night-skies talks by the “dark rangers” at Bryce Canyon National Park in Utah, and witnessing an annual night-sky festival at Acadia National Park in Maine—an event so popular last year that visitors had to wait in hour-long lines at the telescopes.
“In numerous parks, especially in the Southwest, stargazing is the most popular ranger-led activity,” Moore says. “Visitors will ask about the best places to stargaze, but they aren’t amateur astronomers. They’re just parents who want their kids to be inspired by the cosmos just like they were.”
Even NASA employees are getting involved. Take Jane Houston Jones: By day, she’s a spokesperson for NASA’s Cassini Program, which operates a spacecraft orbiting Saturn and its moons. By night, she’s an “urban guerilla astronomer,” enticing random passersby on city streets and inside national parks to peer through her telescope. She’s spent countless weekends in parks like Yosemite, Death Valley, Crater Lake, Bryce Canyon, and the Grand Canyon.
To Jones, it’s like a religion. “People will look up and say, ‘Oh no, there are clouds! Does that mean it’s a bad night for viewing?’” she says. “And we say, ‘Actually, those clouds are our galaxy, the Milky Way.’ And then there’s just this shock, this amazement. Even the astronomers get lumps in their throats when they look up and see bunches and bunches of stars.”
A CALL TO ACTION
Outside the parks, Americans can help preserve night skies, starting with their homes. “There are a lot of big environmental issues that I can’t control,” Gower says. “But with light pollution, I can make a difference at my own house, tonight.”
Moore says Americans could cut roughly 2 percent of their power use by aiming and shielding outdoor lights so they point down instead of up, using slightly dimmer outdoor lamps, and turning lights off when they’re not needed or installing motion sensors. Two percent might not sound like much, but in the end, it amounts to about 44 million metric tons of carbon dioxide.
Despite its small size, Natural Bridges has made some big impacts of its own. The park was designated the world’s first International Dark-Sky Park in 2007, thanks to a complete overhaul of its lighting system, which included improving the aim of exterior lighting and putting other lights on timers that switch off after bedtime. The impact on the night sky wasn’t dramatic, because the park’s lights were relatively insignificant in relation to the wide, dark sky above them, but there’s no mistaking that those efforts have made a difference for park staff who live in and around Natural Bridges.
"If somebody accidentally leaves on their porch light all night long,” says Park Superintendent Corky Hays, “chances are that somebody will come by and mention it to them. The level of awareness has increased among us.”
In Big Bend National Park in western Texas, where the Milky Way shimmers over the park in intricate detail, people notice when something’s interfering with the view. In fact, early efforts to revamp inefficient lighting at Big Bend have been so popular that visitors are pressuring park staff to finish the job: Once the lights around park headquarters and the visitor center were replaced with high-efficiency LED fixtures, park visitors started complaining about bright lights around the park’s lodge and dining area that hadn’t been updated or replaced.
Grand Canyon National Park, Lava Beds National Monument, and Great Basin National Park are also seeking dark-sky designations—a distinction that serves to draw stargazing tourists and enhance awareness about night skies—awarded by the International Dark-Sky Association. Some of these have launched lighting inventories as a starting point.
The designation fosters a sense of pride not just inside park boundaries but in surrounding communities, often prompting them to join forces. Four towns near Acadia collaborate regularly with the Park Service on lighting ordinances that protect the night sky. Tucson, Arizona, has enforced strict lighting codes largely for the benefit of astronomers at several professional observatories there, and nearby Saguaro National Park is darker because of it. Flagstaff, Arizona—a hot spot for astronomy in its own right—was crowned the world’s first International Dark-Sky City in 2001. The Grand Canyon, just 75 miles north of Flagstaff, boasts a beautiful night sky, though it’s not as pristine as the one at Natural Bridges because of a glow from Las Vegas, 200 miles away.
“We don’t go a day without hearing about a community that has passed a new lighting ordinance,” says Kim Patten, programs director for IDA. “We’ve tried to keep up with statewide lighting ordinances, but we cannot keep up with the lighting ordinances in every small community.” She estimates that cities and townships have established 2,500 local ordinances since dark-skies efforts began.
As for Chad Moore, his quest for dark skies is partly personal, but his hopes of preserving them extend much farther. “I find perspective in my life when I wander out and look at the night sky and realize that the things I’m fretting about aren’t that important,” he says. “As a civilization, we learn more about ourselves when we look beyond our horizons.”