The sky's the limit: light pollution is making the night sky increasingly difficult to see.

Have you ever stood under a star-filled sky and wondered at the inspiring nature of our Milky Wily galaxy as it arches overhead head on a cool, clear summer or autumn evening? From parks located away from cities, constellations and planets shine as brightly as they have for millions of years. But for the average person today, the opportunity does not exist to simply look up at the night sky and experience the vastness of space.

Until recently, light pollution has been an environmental problem little known to the general public. But it is now becoming more recognized because not only does light pollution destroy our view of star-filled night skies; it also interferes with the feeding, mating, and migratory habits of many forms of nocturnal wildlife. And recent research also indicates that artificial night lighting may have serious impacts on human health by aiding the growth of breast cancer cells.

Light pollution stems from poorly designed outdoor lighting that creates glare, light trespass and energy waste. For all too many people, the only hope of enjoying our night skies is to visit a park.

A report by the National Parks and Conservation Association (NCPA), Vanishing Night Skies, states that under ideal conditions, national park observers may be able to see more than 2,500 stars plus the Milky Way. But for most observers in the suburbs, only 200 to 300 stars are visible. And in the larger cities, it may only be a few dozen. In fact, perhaps as little as 10 percent of the U.S. population is able to view a pristine night sky.

What is Light Pollution?

There are many reasons for lighting at night. We need visibility, security, safety; and we want an attractive nighttime environment around us. But not all lighting is good lighting. There are a number of components that lead to bad lighting.

Glare is the blinding ball of light that we want to turn our eyes away from. Glare is very common, never helps visibility and often creates dangerous safety problems. Glare also presents a special problem for the aging eye. When lighting an area, an agency should strive for a glare-free environment.

Another problem of light pollution is light trespass. This is defined as the invading light that shines into yards and windows at night. Have you ever tried to sleep at night with a bright light shining in your bedroom? This problem is worsened by excessive lighting practices too often employed by shopping markets, convenience stores and service stations.

Energy waste is an alarming byproduct of needlessly lighting the night. In the United States alone, at least $2 billion is wasted annually by shining light when and where it is not needed, and by using light sources that are energy-inefficient.

A common lighting myth that encourages wasteful energy habits is the idea that bright light makes the area safe. Most crime actually occurs during the day and night lighting by itself does not ensure safety. A recent U.S. Department of Justice report to Congress concluded, "We can have little confidence that lighting prevents crime, particularly since we do not know if offenders use lighting to their advantage.... In short, the effectiveness of lighting is unknown."

An earlier Justice Department study stated, " ... while there is no statistically significant evidence that street lighting impacts the level of crime, there is a strong indication that increased lighting--perhaps lighting uniformity--decreases the fear of crime."

The Effects of Light Pollution

As numerous studies have already shown, light pollution doesn't just affect people. Florida's sea turtles face a major threat from bright lights. Every nesting season, endangered sea turtles emerge from the surf to deposit eggs in sand nests; and later, tiny hatchlings struggle return to the ocean. For this activity to be successful, it must take place in darkness.

But all too often, bright lights cause the hatchlings to get disoriented, lose their direction, and die of exhaustion or become easy prey to predators. Many species of birds, especially the small insect-eaters, migrate thousands of miles at night. Guided in part by the starlight of constellations, they are now often attracted to lights shining from skyscrapers, broadcast towers, lighthouses, monuments and other tall structures. In their confusion, the birds either flutter about until they drop from exhaustion, or they actually hit the lighted structure and die.

Another consequence of light pollution and the resulting urban sky glow is the loss of the night sky as a viewing experience. Sky glow is caused by light that is not directed properly downward and that is too bright for the area it is illuminating. Its eminence into the night sky creates a pinkish veil that destroys the view of the universe. Can you recall the times you have traveled to a park far from sky glow and looked up in awe at the brilliant, star-filled sky?

Younger generations are losing contact with this grand picture of the universe and the heritage it brings--the stories of the constellations and the important lessons they taught our ancestors. Today, bright and glaring lights create such an overpowering sky glow that only the very brightest stars can be seen. However, this tragedy can be reversed.

Dark Skies in Parks

What can be done to protect and promote the night sky experience in our parks? Establishing dark sky preserves is one way. One of the very first dark sky parks was established in Michigan in 1995. In 2002, then Michigan Governor John Engler signed a law that permanently designated Lake Hudson State Park as a "Dark Sky Preserve." This permanent designation was the result of the efforts of the Amateur Astronomers of Jackson, local politicians and other dark sky enthusiasts from around the state of Michigan.

Just more than two years ago, an Indiana state resolution was signed, designating the Potawatomi Wildlife Park as Indiana's first dark sky preserve. Rurally located in north central Indiana, Potawatomi Wildlife Park is uniquely positioned to offer relatively dark skies for the region. This preserve is comprised of 320 acres of upland woods, wetland areas and river bottom and is surrounded by farm land. The property is a not-for-profit nature park managed as a wildlife refuge.

Potawatomi Wildlife Park is open dawn to dusk year-round, with the exception of youth group camping on the property and amateur astronomers observing after dark. Because of the absence of individual campers, the property is optimal for observing at night because it lacks such intrusions as vehicle headlights, campfires and other light sources that would interfere with night vision adaptation.

Other examples of dark sky preserves come from our neighbor to the north. In Ontario, Canada, the Torrance Barrens Conservation Reserve was established by Canada's parliament a few years ago. In 1997, efforts to preserve the night skies culminated from a grassroots community effort to have it legally protected. The area's unrestricted night skies, rugged rocky barrens scenery, nationally and provincially rare plants and wildlife, and a contiguous peaceful wilderness were all worth preserving. The Reserve is a fully preserved oasis in central Ontario, Canada, just a two-hour drive from Toronto.

Another Canadian dark sky preserve was established in late 2004 at Cypress Hills Interprovencial Park's West Block Ranger's Station in Saskatchewan, Canada. At 97,800 acres, it is the largest dark sky preserve in Canada. The historical dedication took place as part of the Canadian Parks Council Conference with 70 park managers from across Canada and the northwest United States in attendance.

Park staff were delighted with the declaration to protect their natural dark skies environmentally, historically and culturally. With a nearby observatory suffering from major light pollution and to make the property observer friendly, all barnyard style security lights were removed. Other steps were also taken to make the property more dark sky friendly: The park uses curfews, sets maximum levels for lighting and shields all lighting to protect the night skies and wildlife.

Light pollution plagues national parks, too. If you are planning to visit one of America's national parks expecting to see a starry night sky, you may be disappointed. Vanishing Night Skies claims that light pollution is a growing problem in nearly two-thirds of those National Park System units where overnight visitation is permitted. It states that light pollution "from highways, homes, office buildings and other developments can affect national parks that are more than 100 miles away. In addition, some National Park Service and private park concession facilities add unnecessary glare to the night sky."

"Like clean air and water, wildlife, or the sounds of nature," the report continues, "a clear, dark night sky is an intrinsic part of the national park experience that must be protected for present and future generations."

"In addition to obscuring the stars, excessive light pollution can seriously compromise the educational story presented in many national parks. Observing the night sky has been a crucial human activity since the Pleistocene era, inspiring wonder and curiosity, shaping religious beliefs, propelling scientific inquiry, and motivating and guiding global exploration to the present day. From the builders of celestial calendars at Chaco Culture National Historical Park in New Mexico to the builders of rockets at Canaveral National Seashore in Florida, the mission of our national parks could not be complete without dark night skies to help tell their stories."

There is much we can do to preserve the pristine night skies at our parks. If we use just the right amount of light only when and where we need it, we could see better, save energy and protect the nighttime environment.

Help is available from the International Dark-Sky Association (IDA), a non-profit educational organization with thousands of members from more than 70 countries. Visit IDA's web site at www.darksky.org. IDA has developed dozens of tools to help everyone preserve the beauty of our night skies through better quality lighting. The site also links to additional scientific studies on the subject of light pollution.

National Park Service Aims for Darker Skies

The Night Sky Team of the National Park Service (NPS) recently reported a higher level of funding to protect dark skies in parks. Originally established to inventory night sky quality in parks, the team has collected over 200 datasets from over 40 national parks. With a new grant of $900,000, originating from park entrance fees, the team will be able to expand its efforts. The majority of this new grant will be directed to retrofitting and replacing outdoor lights in parks.

The team will start with smaller parks, including Agate Fossil Beds National Monument in Nebraska and Natural Bridges National Monument in Utah. This work will be done alongside a partnership effort with Musco lighting, which is tackling lighting in another 24 parks.

Additional efforts have already begun to train park "interpretive" rangers in providing public astronomy programs and communicating the message of light pollution and nocturnal habitat. Many parks are seeing a sharp increase in visitor interest in stargazing and an appreciation of dark night skies. Whereas four years ago few visitors were aware of the light pollution issue, now many Americans come to national parks to witness starry nights.

The Night Sky Team is partnering with the Urban Wildlands Group and other organizations to develop lighting guidelines for parks. The team is already assisting many parks with the recently approved International Dark-Sky Association Dark Sky Park certification process. The team will also be able to continue making sky brightness assessments with the photometric CCD (charge-coupled device) camera system it developed in another 20 parks. The NPS is a leader on this issue, but other agencies are on board too. The NPS has received requests from the U.S. Forest Service and New Mexico State Parks to collect sky brightness data on those lands.--written by Chad Moore, NPS Night Sky Team program manager

For more information, visit www2.nature.nps.gov/airllightscapes.

Preserving the Night Sky

Park and recreation facilities can eliminate glare and light trespass.

* When using lighting, be sure the fixture shines light down and only where it is truly needed.

* Use time controls to insure that lighting is on only when needed.

* Design and install lighting to insure that glare is minimized. Most glare comes from poorly designed fixtures or poor installations.

* Use the right amount of light for the task--don't overkill.

* Use only energy-efficient light sources.