Back to Blog
Credit: Virginia State Parks
923 words / 4 minute read
The natural night sky looms large over humanity's past, present and future. Once a province only of the gods, the night sky is now our portal to understanding the universe. Light pollution, a phenomenon of only the last two centuries, now threatens to separate much of humanity from the starry heavens. Should access to a night sky unspoiled by light pollution be reserved only to those who live, or can travel to, rural places? Or should we aspire to a world that affords such access to all?
Under one sky
There are many reasons why people work toward preserving dark night skies. As our window on the cosmos, the night sky is the source of information that fuels astronomy. "Astrotourists" travel around the world unique experiences under the stars. Closer to home, casual stargazers find recreation opportunities under almost any skies.
We know that actions taken to protect the night sky have myriad benefits on the ground, too. Light pollution has negative effects on most wildlife species. Darker places, on the other hand, offer refuge to plants and animals already stressed by habitat loss and climate change. Better outdoor lighting can also improve public safety while using less energy. Taken altogether, these are powerful reasons for reducing light pollution.
But if we set all that aside, there's an equally strong argument that access to the night sky has a prominent place in what it means to be human. Dark night skies were once accessible to all people in the world, and they inspired great works of art, literature and music. The sky is part of the cultural heritage of all humanity. It's one of the few aspects of the natural world that we all share.
As such, it may be true that all people should have equal access to the stars. If so, then light pollution is more than an environmental threat. It interferes with access to an important cultural resource.
Cheomseongdae, an astronomical observatory in Gyeongju, South Korea. Built in around the 7th century CE, it may be the oldest surviving such structure in the world. Photo by Flickr user ecodallaluna.
An international view
To date there is little recognition in law for these ideas. Many of the assertions about humanity's rights come from the United Nations. A few UN-sponsored activities have either implied a right to access the night sky or called for it outright. For example, Article 1 of the the La Laguna Declaration of 1994 asserts that “persons belonging to future generations have the right to an uncontaminated and undamaged Earth, including pure skies.”
The United Nations Educational, Scientific and Cultural Organization (UNESCO) held a conference on these ideas in 2007. The resulting "Declaration in Defense of the Night Sky and the Right to Starlight" considers "an unpolluted night sky" to be "an inalienable right of humankind". The Declaration elevates the right to starlight to a place alongside "all other environmental, social, and cultural rights".
Another relevant UN statement is the 1972 UNESCO Convention for the Protection of the World Cultural and Natural Heritage. This action established the UNESCO World Heritage Programme. It has applied the label to astronomy sites, both ancient (e.g, the Chankillo Archaeoastronomical Complex, Peru) and modern (e.g., Jodrell Bank Observatory, UK). But so far it has resisted designating the night sky, or nighttime landscapes.
The night sky is both cultural and natural heritage. It transcends national boundaries; there is, for instance, no "American sky" or "Chinese sky" belonging to those cultures alone. And it’s not a problem that the night sky, or space, is an “intangible” thing. UNESCO already recognizes such forms of cultural heritage. Under the existing framework, the night sky could receive the same kind of recognition and protection as any object the UN recognizes.
The uses of outer space are now beginning to affect the quality of night skies on Earth. The space over our heads is increasingly crowded, with the planned launch of hundreds of thousands of new satellites in the 2020s. These satellite "megaconstellations" are gradually transforming the appearance of the night sky. And yet the main international treaty governing the use of space is silent on the subject. When the nations of the world signed the Outer Space Treaty in 1967, these concerns were on no one's radar.
Photo by Warwick University
Stars for all humankind
Threats to human health from the pollution of air, water and soil can dictate measures to reduce those pollutants. There is an emerging consensus among researchers that nighttime darkness is key to our health and wellbeing. Reasons exist suggesting that regular access to nature is good for us. And there's even evidence of disparities in the way light at night affects poor neighborhoods and communities of color.
Does nature itself have some say in all this? Nations have begun to recognize certain "rights of nature" that can lead to rehabilitation of environmental harms. That's true even when no real person has suffered any obvious injury. Touted as a legal means to combat climate change, it's possible the same principles apply to night-sky conservation.
In an era when so much divides us, whether neighbor versus neighbor of culture versus culture, the night sky is something we all share. Over time, we may come to realize that seeing the stars is not only something of value to people who can afford to escape the nighttime glow of the world's cities. Rather, it's an integral part of the human experience that should be available to all. Solving the global problem of light pollution is simple and cost effective. And it just might make all of our nights a little better.
There are many ways to bring back the stars to the places where we live, work and play. Contact us today to find out how we can help.
Back to Blog
742 words / 3 minute read
Got a railroad ticket,
As a musical genre, the origin of the blues is clear: it emerged from the the Deep South of the United States in around the 1860s. The source of its name refers to melancholy and sadness, the lyrical topics of many blues songs. According to the African American anti-slavery activist Charlotte Forten Grimké (1837-1914), blues songs "can't be sung without a full heart and a troubled spirit."
There are lots of influences around us that may give us the blues. Short-wavelength, or "blue", light at night is one of them. Many modern light sources are blue-rich, which can lead to a host of problems. As light-emitting diode (LED) technology continues to displace earlier ways of making light at night, these problems become more common.
How much blue?
The amount of blue light a lamp or light source emits depends on many factors. We can compare sources by determining how much of their light they emit over some range we call "blue". For our purposes here, we define "blue" wavelengths to be in the range 380 to 520 nanometers. Using information about many common lamp types, we can arrange the sources according to what percentage of their light emissions fall within this range.
Note that natural sources of light in the outdoor environment, such as the Sun and Moon, are remarkably blue. Because blue light scatters more in our atmosphere than other colors, our sky is blue during the day rather than some other color.
Blues in the night
Much of Earth's biology has evolved to expect lots of blue-rich light during the daytime and little or none of it at night. As a result, many species are very sensitive to blue light exposure at night. Consider, for example, that blue light exposure changes the balance of food webs in rivers and streams. In the lab, researchers find blue light stresses or even kills both human and primate cells.
The effect that makes the sky blue during the daytime can make the nighttime glow of cities worse, especially at large distances. If one holds the light output of a city constant but shifts the colors of its lights toward the blue, the night sky over the city gets brighter. White LEDs replacing earlier sodium lamps can add up to 10-20% to skyglow.
Blue light can also change how people perceive light on the ground. As lighting shifts toward more blue, it tends to cause more perceived glare that may, in turn, cause traffic safety problems. This is especially true for older drivers, as light scattering in the aging eye becomes important.
How to kick the blues
Despite these concerns, it's not all bad news. People need blue light exposure at certain times of day to ensure good health. It helps maintain a healthy circadian rhythm and contributes to sleep quality. At night, there should be little blue light in our environments.
At night, a small amount of blue light supports seeing colors correctly and distinct from one another. This important for public safety as well as for the benefit of law enforcement. But, again, the blue light content of outdoor lighting should be kept low to avoid disadvantaging older drivers. It will also benefit nocturnal wildlife and improve our views of the stars.
The solution is to give careful consideration to the spectrum of light and ask tough questions about whether blue is really necessary. If we don't need it, we shouldn't use it. In some cases, it makes the most sense to use light sources such as amber LED that emit very little blue light. In other instances, lighting isn't necessary in the first place. Alternatives such as reflective tape or self-luminous paint can help with wayfinding and mark the presence of obstacles.
Lastly, keep in mind that the potential harm associated with lighting is a function of many variables, not color alone. We should give equal consideration to the duration of lighting as well as its intensity. Choose dimmer lamps when possible, and match light levels to needs. Timers and motion-sensing switches can effectively reduce blue light emission by simply limiting the time that lighting is switched on.
With some mindful thinking about outdoor lighting, we too can cast our blues aside. Contact us today to find out how we can help.
Back to Blog
Credit: RAB Lighting
685 words / 3-minute read
Few issues make for more unpleasant relations between neighbors like outdoor lighting disputes. On one side of the street, a homeowner blasts light into the darkness beyond. On the other side, a neighbor spends another sleepless night as that light floods into a bedroom. They may exchange some angry words. Responses sometimes escalate to the level of civil lawsuits.
Can neighbors stop these problems before they ever start? And can lighting actually promote neighborliness? Here, we briefly examine why conflicts arise, how the careless application of lighting contributes, and ways property owners can tread more lightly on those around them.
Why people light — and why they fight
People have plenty of good reasons to light their property at night, whether for aesthetics or safety. Yet outdoor light at night is often used indiscriminately. Homeowners may prefer extensive lighting of architectural details and landscaping. Some believe that brightly lighting outdoor spaces deters criminal behavior. Others don't realize the impacts of their lighting on neighbors, having added lights one by one over many years. A few assert authority to light their property as they please, a right that supersedes their neighbors' right to the peaceful enjoyment of their properties.
In rural places where large distances separate homes, this may not be much of an issue. But in higher-density settings like suburbs, there isn't much of a buffer or setback between and among homes. In city centers, where commercial and residential land uses commingle, there may be no separation.
Most neighbor disputes involve light trespass, a condition in which light emitted on one property falls on another. Often the trespass is unintentional. The root of the problem is a lack of mindfulness about the responsibilities neighbors have to one another. Simple consideration of the "off-site impacts" of lighting is usually enough to prevent quarrels before they start.
Think of others when lighting
"Good-neighbor lighting" respects property rights and prevents disagreements from the start. For new installations, think about where light goes after leaving fixtures where you're considering placing them. What message does it send? Is the light too bright? Remember color, too; in many parts of the world, people consider blue-rich white light harsh.
And don't forget that there may be certain legal requirements in your jurisdiction. New lighting installations, and even some replacements, may need municipal permits. Sometimes those installations require professional installation, such as by certified electricians.
There are many ways to address neighbor complaints after installing lighting on your property. Adding shielding to lights may be enough to prevent light trespass. In other cases, adjusting the orientation of fixtures is enough. Installing timers or motion-sensing switches can resolve complaints about lighting that is on all night.
Each of these interventions allows the property owner to continue using the lighting as desired. In other cases, on further reflection, property owners may decide the offending lighting isn't necessary. Simple removal of an unneeded fixture can solve the problem.
Keep it civil
When discord arises, don't lose your cool. Try to keep relations friendly and constructive. No one wants to force an issue to come before a court. Bear in mind that many lighting feuds involve grievances well beyond actual lighting concerns.
The key is to act in good faith. Take neighbor complaints seriously and try to make requested changes. Consider how you would feel if a neighbor's light intruded into your home every night. We all want to live in safe communities where people act with some consideration toward each other. The way we light our exterior spaces at night is no exception.
As urbanization continues around the world, people find themselves living closer to others than ever before. High-density residential situations tend to exacerbate conflicts and disagreements. But where outdoor lighting is concerned, these outcomes aren't inevitable.
When done right, residential lighting can be a win-win prospect. But to do that, we have to think in different ways about how we approach the issue in general.
Neighbor disputes about lighting can be difficult to navigate, but we can help. Contact us today.
Back to Blog
Credit: Y. Beletsky (LCO)/ESO
1,215 words / 5-minute read
My friend, Dr. Al Grauer, is an astronomer with the Catalina Sky Survey in Arizona. The project aims to find many of the thousands of small asteroids that may one day collide with our planet. It relies on convenient access to dark night skies to see these faint interlopers.
As part of his work, Al became interested in what factors contribute to the brightness of the night sky. In turn, that determines how sensitive the Survey is. It's therefore important to understand those factors to know how effective the Survey can be at achieving its mission.
In studying this subject, Al made an observation that has stuck with me ever since I first heard him say it: "The natural night sky is alive with its own light." To understand the significance of dark skies and what we stand to lose to light pollution, Al argues, we need to understand the night sky as nature alone influences it.
Here, we review those sources and what we know about them. The results are important in framing what we mean when we talk about "dark skies".
As night falls
A remarkable transformation happens each day on Earth. Day becomes night and night becomes day again with a perfect predictability. This 24-hour, light-dark-light-dark cycle is the basis for one of the most basic of all biological rhythms. It also sets up a convenient way to record the passage of time.
Each day, the main event begins as the sun sets and the transition to night begins. From sunset until the onset of nighttime darkness, the brightness of the night sky decreases by about one million times. Once the Sun is about 18 degrees below the horizon, its direct light misses the top of the atmosphere and the observer is fully immersed in the Earth's shadow. This is "night".
The three phases of twilight from sunset to night. Graphic by T.W. Carlson, licensed under CC BY-SA 3.0.
Until that time, direct or scattered sunlight determines the brightness of the sky in any direction. As that light fades away, the stars begin to appear. After some time the sky gets no darker until several hours later as morning approaches. Then the process repeats, but in reverse order.
Sources of natural light in the night sky
Say you're outside at night in the most remote corner of the world. What would you see in the sky at night?
Absent light pollution, the sky is not black at night from anywhere on Earth. It's not even completely black as seen from space. Instead, natural light sources brighten the night sky in an understandable way. Once we know what those sources are, we can figure out how much light they contribute.
There are two main sources of natural light that we see in the night sky. One kind originates in our own atmosphere. The main component, called "airglow", originates over 100 kilometers overhead. In the upper atmosphere, atoms and molecules interact with each other in ways that causes the emission of light. This light is always present, but it can vary in brightness and distribution over minutes to hours.
Layers of airglow in the Earth's atmosphere seen from low orbit. The colors come from neutral sodium (yellow; 80-100 km) and oxygen (green, 100 km; and red, 200-300 km) atoms. NASA photo ISS042-E-037847, made by European Space Agency astronaut Samantha Cristoforetti. Public domain.
Toward the Earth's poles, near where its magnetic field emerges from inside our planet, a different effect can be seen. This is the "aurora". Energetic particles from the outer atmosphere of the Sun interact with the Earth's magnetic field. The resulting light is often very bright and seen as shimmering curtains of bright green and pink known as the Northern or Southern Lights.
The other source of natural light can be called "astronomical" and refers to light originating above our atmosphere. The most familiar variety is moonlight, which varies in brightness throughout the 29-day cycle of lunar phases. At its brightest, the Moon is still vastly fainter than most artificial light sources.
Some astronomical light comes from within the Solar System. Dust shed by comets and colliding asteroids fills space near the inner planets. The dust scatters sunlight toward us, lighting up the twilight and night sky as a ghostly, cone-shaped glow called the zodiacal light.
Fainter light sources are further away still. Masses of stars in our Milky Way blend together in the familiar glowing clouds seen from dark-sky sites. Dust elsewhere in our galaxy scatters starlight toward us. Even distant galaxies themselves contribute a tiny amount of light to our night skies.
What light pollution adds
Putting together all these sources, one comes up with a number that represents the typical brightness of the natural night sky. That represents a point of comparison for describing a light polluted night sky. Calling that amount of light one "unit" allows us to describe city skies in multiples. Rural areas might be around 2-5 units in brightness. The most light-polluted cities can exceed 1,000 units.
Light pollution isn't very much like those natural sources. Its spectrum often looks very different. When artificial light is directed into the night sky, it scatters in the atmosphere and forms "skyglow". This is the washed-out appearance of the night sky familiar to city dwellers that makes the stars difficult to see. Because bluer colors of light scatter more in the atmosphere, white light in particular makes this problem worse.
It also contributes to light received on the ground, which can be harmful to wildlife. Biology is tuned to natural brightnesses and rhythms like the lunar cycle. Some species, like the dung beetle, use the night sky to navigate. Others need nighttime darkness to avoid predators and find both food and mates.
Setting all that aside, skyglow robs us of our heritage as humans. The night sky is one of the few things that all humans share in common. For thousands of years it inspired great and enduring works of art, music and literature. Still today, seeing the Milky Way at night evokes a sense of awe and wonder. But now, more than ever, many people can no longer see the Milky Way from where they live.
Protecting an important resource
The Senegalese conservationist Baba Dioum once said "In the end we will conserve only what we love; we will love only what we understand; and we will understand only what we are taught." He emphasized the importance of understanding and learning from nature as the keys to protecting it.
The night sky at night is not perfectly devoid of light, like a dark canvas waiting for paint. Rather, as Al Grauer puts it, it's alive with its own light. Besides benefitting the ecology, natural darkness is worth preserving for its own values. Understanding that darkness to be imperfect establishes an important frame of reference.
What is "darkness"? And where does "night" begin and end? These questions still lack definitive answers. It may be that there are only literal shades of gray contributed by both natural and artificial light at night. The absolutes of light and dark we imagine may not be so absolute after all.
Effective conservation the resource of the night benefits from deep understanding and experience. We can contribute both to the pursuit your own dark-sky goals. Contact us today to find out how we can help.
Back to Blog
750 words / 3-minute read
People pursue dark skies for many reasons. For some, it's about protecting the nighttime environment for wildlife. For others, saving energy and reducing greenhouse gas emissions is important. But in recent years, dark skies has come to mean something else important to many people: their way of earning a living.
"Astrotourism" is an unfamiliar word to many because the idea behind it is still new. It is an unusual type of tourism in which people travel to dark locations to view and enjoy the night sky. Along with the rise of the dark-sky movement in general, astrotourism is quickly gaining an audience. Consider some of these news headlines of the past year:
The Amazing Race To Space: Why ‘Astrotourism’ Is The Current Buzz Word For The Travel Industry
Seeing the Stars: Small Towns and Rural Parks Pursue Dark Sky Goals
Dark skies offer a new travel frontier, and perspective in our own dark days
Astro-Tourism is the Next Big Travel Trend
Dark sky tourism is on the rise across the U.S.
A dark-sky adventure awaits
What is so appealing about this new kind of 'adventure tourism'? For many, it is the chance to experience something brand new to them, particularly those who live in light-polluted cities. Astrotourism means a quiet night under the stars, reconnecting with nature. It stokes a sense of curiosity about the universe, and brings participants closer to the sights and sounds of the natural night.
It's also big business. According to a 2019 study, one dark-sky region in the western U.S. alone may see astroutourism revenues of nearly $6 billion in the 2020s. In other places, it is such a new idea that no one can yet estimate its value. But many agree that astrotourism is a growth industry.
Nighttime tourism has an outsized economic impact compared to other, more traditional forms of tourism. Unlike most tourists, astrotourists can't simply "drive through" dark skies in a day. The nature of their activity requires an overnight stay. This creates opportunities for other businesses, such as resorts and restaurants, to add value to their visits. And it complements daytime tourism in traditional venues like national parks, with the reminder that "Half The Park Is After Dark".
Fair tourism development for a post-COVID world
As the global COVID-19 pandemic continues to curtail plans for many people, they look ahead to resuming their travels. Tourism professionals expect that post-COVID tourists will prefer new, exciting and unconventional experiences. Some will find that astrotourism fits the bill nicely, and they are willing to spend big to visit the world's darker places.
But there are concerns about how to develop this industry in a way that is fair and sustainable. Because astrotourism focuses on rural and often underdeveloped places, it is crucial to include locals in tourism enterprises. This is especially true in places where the local economy was based on extractive activities in the past. As industries such as mining and logging leave, locals are left with many fewer opportunities to earn a good living.
We already have some examples of success. For instance, native people operate lodges in the !Ae!Hai Kalahari Heritage Park of South Africa, which the International Dark-Sky Associated designated an International Dark Sky Sanctuary in 2019. Their revenues are making a difference in the nearby ‡Khomani San and Mier communities. Done right, this outcome is a win-win proposition for locals and tourists alike.
Keeping skies dark for tourists of the future
At the same time, this sense of endless economic promise is balanced by a need to protect the resource that tourists come to see. The development of astrotourism requires infrastructure to cater to tourists' needs. That means new hotels, restaurants, and other supporting businesses, which in turn means new outdoor lighting.
A key challenge is creating this infrastructure while avoiding significant, new light pollution. But this problem is at least solved in part already. We have new evidence that dark-sky designations may reduce light pollution in certain regions, even as astrotourism grows. Modern outdoor lighting best practices also offer enhanced educational elements for visitors. They can see examples of good lighting firsthand, while astrotourism operators can explain how that lighting helps preserve dark skies.
Will 2022 be astrotourism's big year? While no one yet knows the answer, there are good signs that it will be is best year so far. There are many ways that people and organizations can become involved in this emerging tourism sector. We can offer advice to places seeking dark-sky certifications, or help prospective astrotourism companies launch their businesses to the stars. Contact us today to find out how.