Under a Dark Night Sky

“If one is able to see only a dozen or so stars, all rather evenly distributed across the sky…if that wide expanse of hazy starlight we call the milky way is invisible, then how can the casual observer possibly gain an intuitive feel for the earth as a part of this greater whole?”Dr. Tony Mezzacappa, astrophysicist at Oak Ridge National Laboratories 


Photograph from NASA

Think about the word “pollution.” What images form in your mind? Smoggy, gray air that makes you cough? An ocean with an island made of plastic? A landfill of unwanted things? Or maybe just a plastic cup thrown carelessly to the ground in a public park? But there is another polluter that is growing in prevalence – light. I would guess that most people do not immediately consider light when they think of pollution. After all, light is a positive thing, right? Light helps us find our way, makes us safer, makes us happy, and literally guides us through darkness. And dark is bad – dark is a depravation of senses and we must endeavor to avoid it.

I want to change these attitudes. I want to posit a fairly new idea (but one with the support of many people already involved): that all light is not always good and all dark is not always bad. We don’t need this strong dichotomy. Diminishing and preventing light pollution is not about turning off all your lights every night or day, it’s about making informed choices concerning when and where to use light and how to be comfortable with natural darkness.

Light pollution is an up and coming topic among many researchers – astronomers, biologists, doctors, architects and city planners, conservationists, and others. There are both short-term and long-term effects relating to biodiversity and wildlife health, human health and safety, and astronomy.

When I first started seeing doctors about my myriad of sleep problems, one of the suggested treatments involved light. I was to set a strict sleep-wake schedule (something I am not very diligent about now as a busy grad student) and try to simulate natural light conditions at night and in the morning. Before going to sleep, I was supposed to be in very dim light (as close to candlelight level as possible) for an hour. Upon waking, I was to be in very bright light (bright like sunlight) for an hour. I bought an alarm clock with a light that would gradually get bright like the sun – 10,000 lux – to simulate being in full daylight. When I followed this regimen closely for a few months, I slept better and felt more alert during my days.

Our attitude towards needing to light the night has completely thrown off the natural day and night cycles that our bodies have known for hundreds of thousands of years. At one point in time the word “midnight” must truly have meant the middle of the night to English speakers – now many of us are barely headed to bed then, surrounded by city lights, street lights, and our computer screens. Unfortunately, this is not an ideal situation for a human body that has evolved to be a part of the natural world, not to alter it to fit our new desires. Light when our bodies do not expect is can disrupt the production of melatonin, a hormone very important to the rhythm of restfulness and alertness. Disruption in melatonin production can lead to certain types of cancer – most commonly breast, colorectal and prostate cancer. There also seems to be a possible correlation with early-onset diabetes. It’s blue light that is the worst offender – the wavelengths emitted by most things with a screen. Too many of us live half our lives in a virtual world now, forgetting that we don’t need that harsh, blue glow to survive the night.

Animals are suffering for our obsession with light, as well. Last year, I wrote a research paper on fireflies, looking at our relationship with these flying, luminescent beetles. Recently, firefly populations in many species have been severely declining. Fireflies thrive in moist, dark areas. There, they light up – a distinctive color and pattern for each species. This alerts potential mates of the same species to their location. Without darkness, fireflies will not flash. When they don’t flash, they don’t mate, and numbers go down. We’re developing away many of their last dark spots as we light places that probably don’t need it.

I’ve also personally observed the effects of light pollution on sea turtles. A few years ago, I spent a couple of weeks volunteering in St. Croix to help some biologists with leatherback sea turtle conservation. As beaches become more and more developed, sea turtles are building their nests in dangerous places. Female leatherbacks will return to the same beach year after year. We had to move some nests because human activities put them in a precarious place. I watched a few nests hatch and sometimes upwards of one hundred hatchlings clawed their way out – a frantic, heaving pile. These hatchlings need to go straight to the sea – 90% are not expected to survive their first night out anyway due to predation. But I watched them move as one large group towards the distant city lights. We’d place them in the water and they’d turn around immediately, desperately and fatally attracted to the bright area in the distance.

Birds are perhaps the most affected wildlife. Some species use moon and starlight to navigate, and are confused by brighter lights below them. The Fatal Light Awareness Program conducts extensive studies on this and works to educate people on how to help. Birds and other wildlife everywhere are affected. Check out this photograph by Jim Richardson of Salt Lake City glowing all the way from the Bonneville Salt Flats.

And what of the astronomer’s viewpoint? Astronomers know that light and dark are resources. Yet when we direct a light where it is not needed, leave it on when we’re not using it, or make it much brighter than necessary we’re being wasteful. Think of any other precious, natural resource – many people at least understand that stronger efforts towards conservation are needed. But even a simple yard lamp that lets light point upwards and creates dark shadows is wasting light and energy. We don’t need it there, we’re just used to it there.

Nearly all cultures of humans have found some sort of connection to the sky. Look up and you can find a story. Look up and you can find many stories – your history, humanity’s history, and the history of something much, much greater. Stars connect us to our larger home, our past, stories long forgotten. They are literally lights in the darkness, and we need to learn how to use and appreciate that natural light again.

I recently spent a night at the Willard L. Eccles Observatory, owned and operated by the University of Utah, near Milford, UT. At 9500 feet under cold, dark skies, the stories and connections being created above me were magnificent. The Milky Way, our neighborhood, clearly streaked across the sky in bright whites and light purples. Jupiter rose, a hot reddish orange demanding attention.  The Pleiades huddled close, brilliant in blue. And the farm below us had a total of three lights.

We could see the skyglow from Las Vegas as a dull dome peaking up from the horizon. I tried to ignore it, and watched the black outlines of mountains reach out and touch a silvery sky. What happens on Earth is not disconnected from what happens above it.

But there is hope and there are things we all can do to reduce our part in this startling form of pollution. Make conscious decisions about your outdoor lighting. Do you need to light the sky and empty space, or would just lighting the ground and objects people need to see suffice? Follow the IDA’s guide for outdoor lighting and especially look for fixtures with full cutoff shielding that point downwards. This ensures that light goes where it is needed, not where it is superfluous. And remember that we don’t need extremely bright light to see or be safe. You can conserve energy and our dark skies at the same time – look for long lasting LED bulbs. LEDs are becoming more popular and easier to find in bulb shapes that fit into regular household fixtures. They are also finally being manufactured in several different colors so you can get a “warm white” look instead of that harsh, blue light. You can also look out for fixtures with the IDA Fixture Seal of Approval, which ensures that these standards have been met.

Most of all, don’t forget to look up. Whether you’re in a bright city or a less-bright rural area, don’t forget about the beauty of the nighttime environment. Don’t forget that darkness just brings different things, not necessarily bad things. And remember there are always tiny points of light above us all to guide us when we need it.

If you’re interested in more information, check out the International Dark Sky Association and our local chapter, the Colorado Plateau IDA.

Annie Gilliland is an Environmental Humanities Master’s student at the University of Utah completing a fellowship with the Office of Sustainability and researching light pollution.

2 responses to “Under a Dark Night Sky

  1. Pingback: Heritage Starfest | Stars Over Slickrock·

  2. Pingback: Join the Conversation About Light Pollution in Salt Lake City | sustainableUTAH·

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