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Wednesday, 06 February 2013 14:20

Dark skies — and the stars that go with them — slowly disappearing

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coverAlthough the Great Smoky Mountains National Park is a protected expanse of land, all types of contamination — from air pollution to mercury contamination — manage to creep in. One of the more unusual suspects, but probably the most apparent, is light.

 

By day, the park gives visitors the illusion of being far from civilization. But at night, light pollution comes from all around, and even within.

The lighted billboards, streetlamps and security lights of nearby communities such as Gatlinburg, Pigeon Forge, Cherokee and Bryson City seep into the park’s airspace. Meanwhile, the metropolitan glow of cities as far away Asheville, Knoxville and Atlanta intrude on the Smokies’ nightscape. Even the park’s own visitor center, parking lot and campground lights have an affect on its pristine darkness.

“There are large blocks of light around the horizon that represent Knoxville and Atlanta,” said Paul Super, research coordinator for Appalachians Highlands Science Learning Center at Purchase Knob in Haywood County. “The bulk of lights from cities is significant — but even a light around a park building at night can potentially be a source of light pollution.”

Near and far, light pollution can have serious consequences. It not only makes bright stars dimmer and dim stars disappear. It can also wreak havoc on wildlife.

Super used to work near the coast and saw how artificial lights confused newly hatched sea turtles trying to orient themselves and navigate out to sea at night. In the mountains, light pollution disrupts the natural rhythms of nocturnal hunters like owls and confuses moths and bats, which may use stars and the moon to navigate. There is also concern over how extra light may affect breeding salamanders at night, Super said.

And the Smokies’ proximity to growing population centers makes it much more susceptible to light pollution than western parks such as Glacier, the Grand Canyon and Yellowstone — which are listed as some of the darker parks in the country. While many western parks have large buffers of uninhabited land between them and civilization, the light pollution problem for parks like the Smokies could become a lot worse before it gets better.

Some have already noticed significant changes. Ken Voorhis, the executive director of the educational nonprofit Great Smoky Mountains Institute at Tremont, has been living and working in the Smokies for nearly 30 years. He has noticed troubling changes in the nightscape as nearby population centers have become noticeably brighter to the detriment of the stars.

“The glow limits the stars you can see,” Voorhis said. “You used to be able to see the Milky Way pretty regularly, but it’s a rare night that you can see it now.”

Voorhis attributed the diminishing stars to population growth in Appalachian towns around the park and also to vacation homes that are multiplying on the hillsides. Many residents move to the region from cities where it is customary to have one, or several, outdoor lights for security — and they bring that custom with them to the mountains, Voorhis said.

Nonetheless, the location of the institute in the park provides for some of the best night sky experiences around. Voorhis said children who come from big cities look up into space at night and freak out when they realize how many stars are twinkling over their heads. However, that could change someday, as light pollution is often not taken as seriously as its counterparts, such as air and water contamination or deforestation.

“Light pollution is on the peripheral,” Voorhis said. “People have been aware of it for some time — but we don’t tend to deal with those problems until we recognize what we’ve lost.”

 

Night skies as a protected resource

The National Park Service has had an internal wing charged with monitoring and protecting night skies since 2001. Based in Fort Collins, Colo., the Night Skies Program shows an increased interest by the park service in protecting natural night sky conditions in America’s national parks.

“People say ‘I’m going camping, and I’m going to sleep beneath the stars,’” said Chad Moore, manager of the NPS program. “It’s an integral part of what people think about.” Stargazing programs are usually one of most popular events held at many national parks, he added.

Just as the park service inventories bird species or tracks changes in plant diversity, it has now placed an emphasis on documenting and protecting the nighttime resources.

Stars have also played an important part in American history: the constellations led black slaves from the South to North, following the northern star of the big dipper, or “drinking gourd” as the song goes. Stars appear on the country’s flag. And the USS Constellation was the last sail-only warship built and designed by the US Navy. There is a cultural importance in protecting the night skies and reducing night lights damaging to the stars, Moore said.

“Just as we don’t put a fast food restaurant next to a historic cabin,” Moore said. “We try to preserve the history and context of our heritage.”

Several years ago, the park service night skies team took some baseline measurements of light in the Smokies, using imaging equipment to capture light levels in the sky. Moore said the group plans to return this summer and collect further data, which will help them assemble a full report on the affects of light pollution in the park and how much its night skies have strayed from their natural conditions.

Moore said the Smokies are particularly vulnerable, given their proximity to population centers.

“Even though those small towns may think of themselves as more rural and less crowded, they’re so much closer to the park that they can have a greater impact than bigger cities,” Moore said.

There’s another deceiving aspect of light pollution: the changes tend to be gradual, slowly brightening the dark sky over a period of time until it becomes the new normal.

Susan Sachs, the education coordinator with the Appalachian Highlands Science Learning Center, hosts stargazing events each year at the learning center’s location at Purchase Knob near Maggie Valley. It’s one of the darker areas of the park, and a great reminder for how the natural night sky is supposed to look.

“We tend not even to realize when we lose it,” Sachs said. “Because we’re not as tuned in to the night and how dark it should be, we start to expect light pollution.”

However, other parts of the park, near the gateway communities, are not as dark as Purchase Knob.

Sachs recently attempted to host a statewide stargazing event, part of the state science festival in early April. But, at that time of year, the gravel road to Purchase Knob is not yet open, so Sachs looked for another site in the park with access, adequate parking and facilities to host such a large event.

But the alternative sites she identified, including Oconaluftee near Cherokee and Deep Creak near Bryson City, were simply not a good fit for a star-watching event.

“Everyplace we came up with was too bright,” Sachs said.

She said making people aware of light pollution can be the first step in combating it.

 

Reining it in

While national parks view their dark skies as a precious resource worth protecting, they are powerless to stop light pollution generated from the outside.

Population doesn’t have to be synonymous with light pollution, however, Moore said. Towns, cities and counties do have that power in the form of night lighting ordinances — reining in light from signs, parking lots and even their own street lights — and can significantly reduce the light footprint of a community.

Meanwhile, it may be a community’s best interest to protect the night skies of the Smokies, as many of the neighboring communities rely on tourism dollars brought by visitors to the park.

But few in the region have such rules.

Cherokee does not have a lighting ordinance, although many of the newer buildings constructed by the tribe may inadvertently reduce light pollution because of their energy efficient designs. Bryson City does not have a lighting ordinance either.

Bryson City’s Town Manager Larry Callicutt said lighting practices are left to the discretion of individuals living in the town limits.

“I’m not sure of why we’d be regulating things on it,” Callicutt said.

Many mountain counties near the park don’t regulate night lighting either, such as Haywood, Swain or Macon counties.

A handful of Western North Carolina communities have been proactive about reducing light pollution, however. Jackson County is one of the few with countywide light regulations, along with Buncombe.

Waynesville has had a dark sky ordinance in place for about a decade. It regulates maximum light output for commercial businesses, prohibits upward pointing lights, requires shields on light bulbs and limits the amount of light that trespasses onto an adjacent property.

Fred Baker, Waynesville’s Public Works director, said a more thoughtful approach to proper lighting not only protects night skies, but saves energy by using the right amount of light — but also directing it downward where it’s needed, instead of out and up.

“If you do it right, you can save money and get better nighttime environment,” Baker said.

And although a well-drafted local ordinance can help reduce nighttime light pollution in the area, and thus increase the amount of stars visible at night, Bernie Aghierre, president of the Asheville Astronomy Club, said all regulations aren’t created equal.

“Having a lighting ordinance alone doesn’t mean you’re there,” Aghierre said. “A good lighting ordinance would regulate all lights.”

A towns own streetlights are often exempt from an local ordinance, as is the case in Waynesville. However, Baker said Waynesville is gradually transitioning to a new street lights that reduce light waste as old streetlamps wear out.

Aghierre worked with Buncombe County and Asheville officials to draft their night sky ordinances and strengthen them during the years. He said a dark sky ordinance, in addition to protecting views of the stars, actually protect the rights of individuals, ensuring that their bedroom windows aren’t obnoxiously lit up at night by their neighbors’ floodlights.

“A lot of people don’t like regulation,” Aghierre said. “Many people don’t want to be told what to do on their property, but they’re not thinking about the neighbors.”

Another benefit of lighting regulation is added safety, Aghierre said. Lights without proper shielding or that are too bright can cause night blindness for drivers or residents taking a stroll after dark.

He identified security floodlights, sign lights pointing upward without shades and poorly designed street lights as the most damaging culprits.

But, one of the things that troubles Aghierre most about communities near the Smokies that don’t already have lighting regulations is that their night skies will most likely not become any darker, even if they took action today.

“When you put these ordinances in, you usually grandfather existing lights — so it’s not going to get better — you’re just going to stop it,” Aghierre said. “It could be a bigger problem in the future because the population is still growing.”

He said sunset clauses can be put written into lighting ordinances — requiring business to eventually phase out past lighting practices and transition to the new ones — but local governments are often hesitant to require that. And even with some of the most progressive lighting ordinances in the state, Aghierre and his astronomy club have to drive far away from Asheville for the best views of the night skies.

“The sky glow from a big city can go out for more than 100 miles. You have to go a long way to get away from that sky dome of light,” Aghierre said. “There are very few spots in the east where you can get a dark sky.”

 

Window to the universe

Star enthusiasts, local astronomy clubs and amateur night gazers depend the dark sky not only for diversion but also to further what mankind knows about the universe, and beyond.

One of darkest places in WNC is the site of the Pisgah Astronomical Research Institute, a nonprofit research station and education center. Tucked in the Pisgah National Forest in Transylvania County, it’s the site of an old NASA station that was used to communicate with the Apollo and Gemini spacecraft.

Michael Castelaz, the science director at the station, said the site was choice because of the astronomical infrastructure it has — housing two 300-ton radio telescopes and expansive laboratory space — as well as its dark skies that allow for star viewing with optical telescopes. Being within a National Forest protects the institute from encroaching development and the light brings.

Castelaz researches binary stars — pairs of stars that revolve around each other but are so close that they appear to be a single star when viewed from earth. To study this phenomenon, Castelaz must record subtle changes in the brightness of the set of stars. They are brightest when side by side but dimmer as one eclipses the other.

Light pollution could interfere with his research and reduce the contrast in the images he captures of the binary stars. Staff from the institute talk to its surrounding neighbors about proper lighting practices and negative affects of skyward glare.

As an example of the exquisite star views form PARI, hundreds of stars in the Orion constellation are visible from PARI while someone in the city may see just four.

“Here on a good dark night the Milky Way Galaxy just stands out and you’d never see that in a city somewhere,” Castelaz said.

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