April 12, 2019 | Feature
on light pollution and how to see in the dark
I saw stars, and I mean really saw stars, for the first time when I was 18 years old. And no, I’m not from New York City or Hong Kong or some other neon-lit “City That Never Sleeps,” but a suburb in Maryland where a cursory glance at a clear night sky reveals Orion’s belt, a flickering yellow dot I squint at before realizing it’s an airplane, and little else. The background of the night’s sky is not the inky pitch it should be, but rather a warm, diluted glow, on most nights a dull orange, on others a pallid green. It’s light pollution: that ubiquitous yet little-discussed phenomenon keeping some of us up at night. Literally.
My case is in no way unique—two-thirds of humanity lives in these conditions; one-fifth can’t see any evidence of the Milky Way at all. On the long list of environmental problems, light pollution is a relative newcomer. For most of human history, a lack of electricity meant no night lights, and so no light pollution. To give some further perspective: If you stood two or three miles outside of London on a typical night in 1800s (at the time the world’s largest city with around one million residents), you wouldn’t be able to see any evidence of the city at all. Tonight, you could drive 100 miles away from Salt Lake City (also home to around one million) to a desolate salt marsh in the middle of nowhere and still see the city’s lights grazing the night’s horizon.
What happened in between? Let’s start by giving a hearty thanks to Thomas Edison. Contrary to popular belief, Edison did not invent the first light bulb. That would’ve been, depending on how you define the device, Alessandro Volta in 1800, Humphry Davy in 1802, any number of British inventors of the 1840s and 1850s, or perhaps even Canadians Henry Woodward and Mathew Evans a few decades later. Nevertheless, in 1879 Edison finally made the light bulb practical (i.e. commercial), using a carbon filament to create a relatively long-lasting incandescent bulb, and the technology exploded from there. As Alex Goody put it, it was “a transformation of culture at a fundamental level.”
A century later, the crew of Apollo 17 took the first full image of a daylit Earth from space and dubbed it the Blue Marble. But those crewmembers and today’s astronauts no longer see a Black Marble by night; the East Coast of the United States, like a string of Christmas lights, is an unbroken chain of glowing cities tracing I-95’s path. The whole of Europe is awash in a firefly-like twinkle. There’s also no night in Japan—the California-sized island is entirely covered by an incandescent sheet. Lights aren’t confined to cities, either. According to “Our Vanishing Night,” a popular 2008 National Geographic article, “In the south Atlantic the glow from a single fishing fleet—squid fishermen luring their prey with metal halide lamps—can be seen from space, burning brighter, in fact, than Buenos Aires or Rio de Janeiro.” Darkness, apparently, is only left in a few far-off places, less urbanized countries like the Central African Republic, often cited as the world’s darkest nation.
Jackson Hole, Wyoming, is not quite so dark, but with the exception of a few spots in Arizona, it’s pretty good for the continental United States I’m 17, out West on summer vacation, and I’ve just realized that my entire knowledge of astronomy is based on pictures I’ve marveled at in nature magazines, the same way I only know what a T. rex looks like because I’ve seen its fossils and artistic renderings.
Each night I’m there I check the sky with the help of an astronomical map telling me where to focus to find the glittering arc of the Milky Way. Each night I charge my camera in the hopes of capturing the constellations. Outside, it’s cloudy: back to bed. Wake. Vacation. Check for stars: cloudy. Repeat.
For a week I stumble onto the inn balcony to find Jackson’s lights bouncing off the accumulated gray ceiling so the whole valley is illuminated from above and below. But the night I fly home into Reagan National Airport, the sky is clear, and I see Pierre L’Enfant’s city plan spelled out in boulevards of glaring office buildings and the pinpricks of light that mark traffic circles. An alternating pulse of green and red leaps out from the top of the Washington Monument.
Some cities have made attempts to counteract this nighttime brightening. In Flagstaff, Arizona, the only irregular flashes of light come from shooting stars. In 2001, the International Dark-Sky Association recognized Flagstaff as the world’s first International Dark Sky City. In an effort to protect the scientific integrity of the city’s Lowell Observatory from seeping light during the middle of the 20th century, the city enacted sensible regulations: Offices had to shut lights off at night, and reflectors bounced excess streetlamp wattage toward the ground.
This was back when scientists thought light pollution only affected astronomers, and the public had never even heard of the phenomenon. But most cities in 2019 are nothing like Flagstaff. In Chicago, for example, thousands of Victorian-style street lamps spill their contents upward where the light waves mix with the halogens, floodlights, and LEDs of countless skyscrapers. The result is a nebulous beacon sprawling across Lake Michigan.
Fourteen thousand years ago, when the Ice Age’s glaciers retreated and left the Great Lakes sitting in their wake, when there were no compact fluorescent bulbs or gas lamps or campfires (only bioluminescence), the view of the night sky would have been that of the unadulterated cosmos. In fact, this was how it was up until the last century or so. Consequently, for the last 3.8 billion years, excluding this recent change (which is a mere sliver in the timeline of the history of the Earth), life on this planet has evolved in concert with natural patterns of day and night. In nearly every biological process and activity necessary for survival—feeding, mating, migrating, hunting, spawning—the animal is dependent on the cues of light and darkness.
Already beleaguered by humanity in the forms of habitat loss, ocean acidification, and global warming, species around the world have found their circadian rhythms disrupted by light pollution. Over 100 species of coral in the Great Barrier Reef that normally spawn after each October or November’s full moon are now producing their sperm and eggs too late—or not at all—because of overflowing lights from Australia’s urban coastal cities. This mistimed spawning results in perpetually fewer offspring.
For newborn sea turtles, which are hatched high up on beaches, light pollution proves especially confounding. The hatchling turtles are biologically coded to crack out of their eggs and seek the bar of shining light low on the horizon—what used to be the moon’s reflection on the ocean’s waves. Unfortunately, that glowing horizon line is now often the nearby boardwalk. Vulnerable hatchlings march off in the wrong direction of the water and are prone to exhaustion and, unless they fancy margaritas, dehydration. Those that survive make an easier meal for predators.
Light pollution also negatively affects species of zooplankton, countless bugs, and migratory birds. What you probably didn’t realize—maybe because you don’t look in the mirror every morning and process your reflection as a Great Ape in business attire—is that light pollution is probably adversely affecting your own health, too. Just like any other animal, be they loggerheads or sapsuckers or single-celled microscopic organisms floating helplessly in lakes, your body is designed to operate under the pretense of light days and dark nights. Alter that balance, and your internal clock gets out of sync, causing hormone levels to shift to irregular marks. Specifically, current research (of which there isn’t much yet) shows significant influence on melatonin production, which can in turn harm nerve tissue.
I couldn’t tell you exactly when or why I became interested in the night sky. Maybe it was when my elementary school class went to a planetarium. Maybe it was when Pluto was demoted, and I started reading about what the heck a dwarf planet was. Maybe it was when I first saw a Hubble photograph of the corner of the galaxy we live in. In my mind, though, it’s none of these. I’m hardwired to look up at the stars in awe the same way we all are; it’s the same reason nearly every religion’s gods come down from the sky, and even if the ether doesn’t determine our horoscopal fate, it still holds a power over us.
Flick off the lights, or find a dark spot, and the night sky I stare at is the same one my ancestors saw from a boat crossing the Atlantic. The same one my ancestors’ ancestors prayed and worked and ate and shat and fought and loved under—and so on before them all the way back to the first homo sapiens, an ordinary species who by some fluke of evolutionary roulette distinguished itself from all the other animals under the moon and stars by assigning patterns and meaning and stories to those far-away-but-oh-so-close celestial balls of gas and dust.
Light pollution is not like other types of pollution. Litter takes time to be picked up and shipped off to become litter elsewhere. Chemicals need to be cleaned up from ecosystems or given thousands of years to radioactively break down. The magic of light pollution is that it can disappear instantly; all we need to do is be more mindful, throw on a lampshade, and dim the lights. I can tell you now, the view won’t disappoint if we do.
I saw stars for the first time in my life—I mean, finally saw the Milky Way—a few Augusts ago from a pullover on the road in southeastern Maine. The best stargazing in the world is in Chile’s Atacama Desert, where high elevations, cool temperatures with no humidity, and few people combine to make the perfect recipe for clear skies. This, a gravel parking lot by one of Maine’s well-trafficked coastal summer campsites, was not. Car headlights poked their way through knobby pine trunks to shine periodically into my eyes. A distant sentinel lighthouse blinked its formal hello every five seconds, which the black ripples of the North Atlantic scattered peacefully. And the white beam of my dad’s headlamp bounced sporadically downward as he picked his way over sea-sculpted rocks. I had kept him up that night in my ongoing effort to see stars, and while every other vacationer in Vacationland was probably long asleep, we left our rental and drove to the most remote peninsula we could find.
If, on this stretch of road by the sea in Maine, you crane your neck back until you hear your vertebrae uncomfortably protest and then look up at the night sky, this is what you see: a Jackson Pollock splattering of brilliant whites and yellows and reds and blues against the blackness. Then—if, like me, you let the black hole in the middle of your eyes dilate ever wider—you see those glowing dots start to unhinge themselves from their assigned seats, and the whole canvas does a flickering shimmy. And if, like me, you’ve lived your whole still-short life without ever seeing this universal show of electromagnetic radiation, you stand there gazing up for a while without noticing the mosquito dessert-ing on your bicep or hearing the tractor-trailer on the nearby highway, because all those little things on Earth don’t matter when you get to look beyond.