The End of Night: Searching for Natural Darkness in an Age of Artificial Light

The temptation is to leave off the lights, to drive in the dark for more than these few moments. But while I’m happy to know the thrill of boldly going 100 mph through the desert at night, to feel catapulted from earth into space, I am also happy to be alive, and so I slow to 20 mph. It’s what seems now a trolling speed, and so I turn even the parking lights off and lean my head from the driver’s window. The warm dry air flows over, the asphalt rolls underneath, and I realize I am headed directly toward a meeting at the horizon with the Milky Way as it bends from one end to the other. As though on its own, the car slows to a stop in the middle of Route 93 in the middle of the Great Basin desert. Any car or truck coming from either direction will show long before I’d need to move. Unless, of course, they are driving with their lights off, too, staring up at this altogether other highway.

“To know the dark, go dark,” advises Wendell Berry. But seen from satellites at night, our planet’s continents burn as though on fire. Across the globe the collected glow from streetlights, parking lots, gas stations, shopping centers, sports stadiums, office buildings, and individual houses clearly details borders between land and water, sometimes spreading even into the sea on squid fishing boats, their spotlights built to mimic noonday sun. It would be one thing if all this light were beneficial. But while some does good work—guiding our way, offering a sense of security, adding beauty to our nightscape—most is waste. The light we see in photos from space, from an airplane window, from our fourteenth-floor hotel room, is light allowed to shine into the sky, into our eyes, illuminating little of what it was meant to, and costing us dearly. In ways we have long understood, in others we are just beginning to understand, night’s natural darkness has always been invaluable for our health and the health of the natural world, and every living creature suffers from its loss.

The earth at night, circa 2000. (C. Mayhew & R. Simmon (NASA/GSFC), NOAA/ NGDC, DMSP Digital Archive)

Our light-saturated age makes it difficult to imagine a time when night was actually dark, but not all that long ago it was. Until well into the twentieth century, what passed for outdoor lighting was simply one form or another of fire—torches, candles, or dim, stinking, unreliable lamps. And while these forms of lighting were an improvement on the earliest (skewering and burning oily fish or birds, gluing fireflies to your toes), how feeble this light was: A single 75-watt incandescent bulb burns one hundred times brighter than a candle. Historian E. Roger Ekirch reports that “pre-modern observers spoke sarcastically of candles that made ‘darkness visible,’” and a French proverb advised, “By candle-light a goat is lady-like.” Travelers considered moonlight to be the safest option for nighttime navigation, and lunar phases were watched far more closely than they are today. By the end of the seventeenth century, many European cities had some rudimentary form of public lighting, but not until the end of the nineteenth century did any system of electric lights—now so easily taken for granted—come into use. The darkness of our nights has been fading steadily ever since.

No continents burn brighter than North America and Europe. Already, some two-thirds of Americans and Europeans no longer experience real night—that is, real darkness—and nearly all of us live in areas considered polluted by light. In the United States, Henry Beston’s warning of “lights and ever more lights” from Cape Cod in 1928 may have seemed extreme for many of the 120 million Americans alive at the time, most of whom lived in rural areas without electricity, but fewer than ten years later he was well on his way to being proven right. With FDR’s signing into existence the Rural Electrification Administration in 1935, the old geography of night in the United States was certain to change. By the mid-1950s, whether in the city, the suburb, or the country, most Americans lived with electric light. In the half-century since, as the American population has risen past 300 million, those lights have continued their steady spread unabated and, for the most part, unnoticed. Could we jump from the dark of the 1930s (or 1950s, or even 1970s) to that of tonight, few of us would fail to be impressed by the dramatic increase in artificial light. But that increase has been gradual enough that it would be easy to imagine our nights are still as dark, or nearly so, as they ever were.

With this in mind, and knowing, as he says, “the extent to which ever-growing light pollution has sullied the heavens,” amateur astronomer John Bortle created in 2001 a scale on which he described various levels of dark skies, ranking them 9 to 1, brightest to darkest. He hoped his scale would “prove both enlightening and useful to observers,” though he knew it might stun or even horrify some. While Bortle’s distinctions can seem overly subtle, or inconsistent, they offer a language to help define what we mean when we talk about different shades of darkness, about what we have lost, what we still have, what we might regain.

Most of us are all too familiar with the brighter end of Bortle’s scale—his Class 9: Inner-city Sky, or Class 7: Suburban/Urban transition, or Class 5: Suburban Sky—for these are the levels most of us call normal, what we call “dark.” But Bortle’s scale shows us what we are missing. Indeed, most Americans and Europeans, especially the youngest among us, have rarely or never experienced—and perhaps can’t even imagine—a night dark enough to register 3 (“a rural sky” where only “some indication of light pollution is evident along the horizon”) or 2 (a “truly dark site”). As for Bortle’s Class 1, which he describes as a sky so dark that “the Milky Way casts obvious diffuse shadows on the ground,” many question if such darkness still exists in the Lower 48. While rumors arrive from the deserts of eastern Oregon and southern Utah, the Nebraska prairie and the Texas-Mexico border, there’s no denying that Bortle has described a level of darkness that for most of human history was common but for the modern Western world has become unreal.

From the moment I first encountered Bortle’s scale, I wondered about the places I had visited and lived and loved, like the lake in northern Minnesota where as a child I first experienced real darkness and began to learn about night. I wondered as well if there were any Bortle Class 1 places left in my country. Another way to phrase that question is this: In the Lower 48 states, are there any places left with natural darkness? Or, yet another way, Is every place in my country now tarnished by light?

I decided to find out. I would travel from our brightest nights to our darkest, from the intensely lit cities where public lighting as we know it began to the sites where darkness ranking a 1 might still remain. Along the way, I would chronicle how night has changed, what that means, what we might do about it, and whether we should do anything at all. I wanted to understand especially how artificial light can be both undeniably wonderful, beautiful even, and still pose a long list of costs and concerns. I would start in cities such as Las Vegas—in NASA photographs the brightest pixel in the world—and in Paris, the City of Light. I would travel to Spain to explore “the dark night of the soul” and to Walden Pond to check in with Thoreau. I would meet with scientists, physicians, activists, and writers working to raise awareness of the value of darkness and the threats from light pollution: the epidemiologist who first connected artificial light at night with increased rates of cancer, and the retired astronomer who founded the world’s first “dark sky” organization; the minister who preaches the necessity of the unknown, and the man whose work has saved countless nocturnal migrating songbirds in several major cities—it’s through people like these that I would tell this story.

My first move was to contact Chad Moore, a founder of the National Park Service’s Night Sky Team. For over a decade, Moore has been chronicling levels of darkness in the U.S. national parks, and I wanted to know what he thought I would find.

“Well,” he explained, “as you slide down this ramp from nine to one into darkness it’s not a smooth slide. It’s … bumpy.” Moore explained that with the Bortle scale, while the difference between 9 and 5, or between 5 and 2 would be obvious to anyone, the difference between 9 and 8 or between 2 and 1 can be difficult to discern. “There’s so much fuzziness that it’s prone to misinterpretation, and so if you’re grumpy you’ll give yourself a five, and if you’re optimistic you’ll give yourself a three … and it’s really a four,” he laughed.

That made sense, but are there still any Class 1 places left in the United States?

“There are rare places and rare moments where places in the U.S. compare with the rest of the world,” he said. “I would like to think that I’ve seen that, that I’ve glimpsed Class One. But it takes some diligence. It’s easier to get a plane ticket to Australia and drive out past Alice Springs … It could take a while before you find that combination here in the United States.”

Satellite photographs of the earth at night tell of two worlds—the illuminated civilization of developed (and developing) countries and the darkness of poor or uninhabited areas—and in some ways Moore is right; it would be easier to fly somewhere exotic and remote. But I wanted to know night closer to home. I wanted to know the darkness we experience in our daily life.

I decided to focus my journey on North America and western Europe. First, this is where the artificial lighting now sprawling over the world began and where it continues to evolve: It is Western thinking about darkness and light—and Western technology—that shapes the developed world’s night. Second, few of us will ever fly to Australia and drive out past Alice Springs, but we all experience night where we live and work and love.

And most of us, if we wanted, could get ourselves out to real darkness closer to home, like the darkness of a rural highway in eastern Nevada.

“Our sun is one star in a disk-shaped swarm of several hundred billion stars,” writes astronomer Chet Raymo. That disk-shaped swarm is our Milky Way Galaxy, and what arcs in three dimensions above this dark Nevada desert is the outer arm of that spiral, toward which we look from our inner-galaxy location. Raymo continues:

I have often constructed a model of the Milky Way Galaxy on a classroom floor by pouring a box of salt into a pinwheel pattern. The demonstration is impressive, but the scale is wrong. If a grain of salt were to accurately represent a typical star, then the separate grains should be thousands of feet apart; a numerically and dimensionally precise model of the Galaxy would require 10,000 boxes of salt scattered in a flat circle larger than the cross-section of the Earth.

This means that every star in our night sky, every individual star any human has ever seen with his or her naked eye, is part of our galaxy and its “several hundred billion stars.” Outside our galaxy exist innumerable other galaxies—one recent estimate put the number at 500 billion. At some quick point the size of the universe becomes overwhelming, its distances and numbers bending our brains as we try to comprehend the incomprehensible—that our night sky is but one tiny plot in a glowing garden too big to imagine.

But of course, for all of human history we have indeed imagined. Ancient civilizations from North America to Australia and Peru created constellations not only from groups of individual stars but even from the black shapes made by the gas and dust that lie between Earth and our view of the Milky Way’s smokelike stream. And for ages we imagined it might well be smoke, or steam, or even milk—not until 1609 did Galileo’s telescope confirm what he suspected, that the Milky Way’s glow was the gathered light of countless stars.

In these countless stars, in their clusters and colors and constellations, in the “shooting” showers of blazing dust and ice, we have always found beauty. And in this beauty, the overwhelming size of the universe has seemed less ominous, Earth’s own beauty more incredible. If indeed the numbers and distances of the night sky are so large that they become nearly meaningless, then let us find the meaning under our feet. There is no other place to go, the night sky makes this clear.

So let us go dark.

9 (#ulink_e93cc370-8260-522d-a4a4-f011bbcfaefa)

From a Starry Night to a Streetlight (#ulink_e93cc370-8260-522d-a4a4-f011bbcfaefa)

It often seems to me that the night is much more alive and richly colored than the day.

—VINCENT VAN GOGH (1888)

The growth of light pollution in the United States from the 1950s to the 1990s, and what light pollution might look like in 2025. (P. Cinzano, F. Falchi [University of Padova], C. D. Elvidge [NOAA National Geophysical Data Center, Boulder]. Copyright Royal Astronomical Society. Reproduced from the Monthly Notices of the Royal Astromical Society by permission of Blackwell Science.)

The brightest beam of light on Earth shoots from the apex of the Luxor casino’s black pyramid in Las Vegas, thirty-nine brilliant blended xenon lamps, each six feet tall and three feet wide (the greatest number of lamps they could fit in the space), reflecting off mirrors and marking, like a push-pin on the night map of the known world, the brightest city on earth. New York, London, and Paris, Tokyo, Madrid, and a slew of cities in China—with their larger geographies and populations—may send more light into space overall than this single desert city in the American Southwest. But the “overall” qualifier is important, for it would be foolish to think there is any brighter real estate in the world than the Las Vegas Strip.

Standing on the corner of Las Vegas Boulevard and Bellagio Drive, I am immersed in artificial light, subsumed in the accumulated glow from the city’s thousands of businesses and tens of thousands of homes, encased by peach-colored high-pressure sodium from the city’s fifty thousand streetlights, most of which I’d seen from the plane just an hour ago. From the airport the Strip is only a short drive—the Luxor’s beam on its south end meets you almost immediately—and in no time you are swallowed by light. Casinos rise bathed by floods, with ten million bulbs illuminating their glittering, flashing, changing signs. Digital screens and LED billboards call out from every corner, SEE OUR SHOWS! RENT OUR ROOMS! PLAY OUR SLOTS! Red lights, purple lights, green lights, blue—imported palm trees march past the illuminated iron footings of the Tour Eiffel of the Paris, Las Vegas casino, the tower drenched with gold-yellow light from base to tip-top, an exact replica of the real though half the size. A steady stream of headlights bob past, trailed by rafts of bright red tails. On a ruby-colored billboard truck, a blonde in a white bikini smiles. “HOT BABES, Direct to You.” Most of the lights want to sell you something, and the Strip has the feel of one big outdoor mall, with canned music piped in and the natural desert pushed out. Some signs are brighter than others, some buildings more brightly lit, but everything is illuminated: The ground at my feet, the clothing on my body, the bare skin of my hands and arms and face, no surface remains uncoated—even the air itself seems full of light—and I walk through its presence as though pushing through an invisible scentless mist. In these first decades of the new century we live in a world that is brighter than ever before in history and growing brighter every year. If any city reflects that fact, it’s Vegas.

Which is one reason I have come here to go stargazing. Rob Lambert, president of the Las Vegas Astronomical Society (there is such a thing, yes), has agreed to meet at the famous fountains in front of the Bellagio Hotel, saying, “I’ve got my telescopes in the back of my truck, so it will be no problem to bring them along.” We may not have any luck—there can’t be any better example than the Las Vegas Strip of Bortle Class 9, where “the entire sky is brightly lit, even at the zenith.” But it’s worth a try.

I wander over to the Bellagio, the tall curved casino set back from the reflecting pool housing the fountains, and when Lambert arrives we joke that we have chosen a popular spot, that we will be joined in our stargazing by hundreds of others—though they are here for comedians, magicians, musicians … and fountains—different stars than those we have come to see.

“People don’t think about Las Vegas as a place to come look at the stars,” Lambert tells me, “but we do quite a bit of outreach. Our slogan is, ‘The greatest stars of Las Vegas can’t be seen from the Strip.’ Our club membership is only about a hundred, but when we have our star parties we have anywhere from seventy-five to five hundred fifty public.”

Lambert takes out his laser pointer and cuts a thin green beam toward Orion—or, rather, the two bright stars from Orion we can see. “Okay, so that’s Rigel on the bottom and Betelgeuse on the top left.” He moves the laser lower to the left. “And there’s Sirius, the brightest star in the sky.” At first, I’m surprised we can see any stars tonight—this is my first visit to the Strip, and I had imagined the entire sky might be washed out by the lights. “Well, that’s almost true,” says Lambert. “When you consider that the stars we can see tonight are brighter than ninety-eight to ninety-nine percent of the stars our eyes could see, you start to realize what we’re missing.”

Behind us the water cannons begin going off, rumbling like distant thunder. The music changes to a kind of weird Italian carnival tune, coordinated with the booming cannons and joined by crashing cymbals. Someone nearby says, “I feel like breaking into song!” When I look to see who said this, I realize Lambert and I have turned so we face away from the fountain show, the only two in the crowd. “The winter Milky Way is actually over us,” says Lambert, still looking at the sky, “but you can’t see it …”

We agree to walk down the Strip to the Luxor, and as we start our trek south, Lambert tells me that he didn’t get started with astronomy until after he turned fifty, that he’d heard some people at work talking about “star parties” and wondered what they were. Next thing he knew he was watching a friend’s telescope at such a party, he says, and telling observers what they were seeing. “He had to go help someone with their scope and so he asked me to show people M13 through his telescope. So I said, sure, what’s M13? He quickly told me M13 is a globular cluster in the constellation Hercules that is twenty-five thousand light-years away and made up of about seven hundred fifty thousand stars. And so for ninety minutes I told people everything I knew about M13, and absolutely had a ball.”

We pass a man blasting solos on a cheap electric guitar, and further down the street the ghost of Keith Moon banging the hell out of a drum set, dozens of nude trading cards littering the sidewalk at our feet. On every block people are shouting into microphones, straining to be heard. Packs of partiers bump past, yelling their thoughts, half of them transfixed by cell phone screens, half staring, dazed at billboards pulsing light-emitting diodes (LEDs), and I’m reminded of how urban developers call signs like these “bug lights”—so bright they draw gawking crowds.

I ask Lambert about the appeal of looking at the night sky. “One of the things that I share with people is that, regardless of what your beliefs about creation are, it’s still happening, there are stars being born, there are planets being born, stuff is still going on. For example, our ‘challenge object’ this month was Hubble’s variable nebula, which changes all the time. You can look at it this year, look at it next year, and it’s going to be different. And so you actually see things happening up there.”

Not from downtown Las Vegas you don’t, nor from any downtown in the developed world. While the lights of the night sky are far brighter than anything humans have ever created, all save one are so far away we see them as faint, if we see them at all. Instead, at night, we see the lights of our own making. While few cities have a space as intensely lit as the Las Vegas Strip, it’s not just the Strip that makes Las Vegas bright. Here as in every city or suburb, it’s the accumulated glow from an array of different sources that has utterly changed our experience of night.

During a recent Earth Hour—the worldwide movement in which cities are encouraged to turn off some of their lighting for an hour to draw attention to energy use—Lambert says he was driving on US Route 95 and was surprised at what he saw. “I was on 95 basically going from the north side of town to the south side, and this is where 95 is elevated above the valley. But when they cut the lights on the Strip there were so many streetlights that it didn’t really affect the sky quality. You could tell that the Strip went dark because the hotels were no longer shining, but the quality of the sky didn’t change.”

In cities all over the world by far the greatest sources of light in our nights come from parking lots and streetlights (and, when in use, sports field lighting). While individually each streetlight might not seem so bright, it’s together that they make their mark—in the United States alone, some sixty million cobrahead streetlights blaze all night, every night, most still drop-lens high-pressure sodiums glaring their trademark pink-peach. We light our parking lots—think shopping centers, restaurants, hotels, stadiums, industrial areas, and the like—primarily with metal-halide lamps emitting intense white light. Add to these two sources a mix of auto dealerships, gas stations, convenience stores, driving ranges, sports practice fields, billboards, and residential neighborhoods and you have any given city’s recipe for bright.

In general, bright lights lead to more bright lights, as with one corner gas station trying to outdo another. If you imagine a single light in an otherwise dark room, then turning on other lights around it, you see how the first light—bright in the context of the dark room—is now swamped, and in order to be noticed would have to become brighter. In Las Vegas, the ironic truth is that were the city’s streetlights less numerous and less bright, the casino lights would actually appear more impressive.

Still, it’s hard not to be impressed by the Luxor’s beam, equal to the light of more than forty billion candles. In 1688, when the king of France decided to make a dramatic show of his power by illuminating Versailles, the Sun King shining in all his glory, all he could muster was twenty-four thousand candles. Granted, that is a lot of candles, and Versailles must have been beautiful—which is a word that at least for me is not so quickly applied to the Luxor’s beam. But the intensity of this casino light is undeniable, and I can’t help but stare. Though I’m staring too at what looks at first like sparkling confetti floating in the beam’s white column.

“Bats and birds,” Lambert says. “Feeding at their own buffet.”

He’s right. Dozens of bats and birds, drawn from desert roosts and caves, swooping and fluttering amid the casino’s buffet of insects and moths attracted to the light. And how convenient, yes? Maybe not. In addition to the destruction wrought on the insects and moths, the Luxor’s beam like a siren’s song draws the bats and birds from their natural feeding habitat, causing them to expend so much energy flying to the casino that by the time they return from the journey they have nothing left to feed their young.

The sight reminds me of Ellen Meloy’s essay “The Flora and Fauna of Las Vegas” and its concluding image: “Out from nowhere,” Meloy explains as she stands outside the Mirage watching the casino’s volcano erupt, “a single, frantic female mallard duck, her underside lit to molten gold by the tongues of flame, tries desperately to land in the volcano’s moat … Unable to land in this perilous jungle of people, lights, and fire, the duck veers down the block toward Caesars Palace. With a sudden ffzzt and a shower of sparks barely distinguishable from the ambient neon, the duck incinerates in the web of transmission line slicing through a seventy-foot gap in the Strip high-rises.”

So bright and so recent—in evolutionary terms the Las Vegas we know today appeared in a sudden flash. The Luxor beam has only been on since 1993, several of the largest, brightest casinos have been built even since then, and the city’s longest living residents were born before the first casino signs were illuminated in the mid-1940s. In less than a human lifetime what was almost an entirely dark place grew to the brightest place in the world, its population skipping from eight thousand in 1940 to sixty thousand in 1960 to more than two million today. “Welcome to Las Vegas,” reads the famous sign, but only since 1959. Meloy’s mallard, the bats and birds caught in the Luxor’s beam? In terms of time to adapt, they’ve never had a chance.

As early as the mid-nineteenth century, some European cities were experimenting with electric light on their streets. As I walk past the Paris, Las Vegas, I think of an 1844 drawing showing a demonstration of arc lighting in the Place de la Concorde of Paris, France, cutting like a train’s headlight through an otherwise jungle-dark night, catching in its glare the Place’s fountains and a crowd in evening gowns and suits, some grasping umbrellas as protection against the light. Arc lighting was simply too bright for many uses, the first type of lighting that could truly be mentioned in the same sentence as the sun. (And it wasn’t too bright simply because people had never seen anything like it. The moment I see a small arc light blazing away at the electricity museum in Christchurch, England, my immediate wish is for an arc welding mask—this was light that clearly could destroy your eyes.) As a result, it wasn’t until 1870 that several European capitals installed arc lights on some main thoroughfares. While the intensity of these lights was so great they had to be placed on towers high above the streets, their arrival was met with fascination and pleasure by most (many cities in the United States barged ahead with their installation, for example). They were, it seemed, an answer to our prayers.

The idea had always been to banish darkness from night. As far back as the early eighteenth century, proposals had been made to illuminate the entire city of Paris using some kind of artificial light set high on a tower. The most famous of these was the Sun Tower proposed by Jules Bourdais for the 1889 Paris Exposition that would stand at the city’s center near Pont Neuf and cover all of Paris with arc lights. Unfortunately for Bourdais (and fortunately for the rest of the world), his proposal was turned down in favor of one by a certain Gustave Eiffel. But even Eiffel’s tower now has spotlights on the top, to the delight of some and the disgust of others.

Understanding how bright arc lights were, it makes sense how ready the world was for the incandescent light bulb. A report from the 1881 International Exposition of Electricity in Paris reads: “we normally imagine electric light to be a blindingly bright light, whose harshness hurts the eyes … Here, however, we have a light source that has somehow been civilized.” The change affected not only street lighting, of course. Arc lights had been entirely impractical for domestic houses, but as Jill Jonnes explains in Empires of Light, when incandescent bulbs arrived,

wealthy, cultivated women in floor-length, rustling dresses delighted in showing their friends how if you just turned a knob on the wall, the room’s clear incandescent bulbs began almost magically to glow, casting an even, clear light. Unlike candles, the electric light did not burn down or become smoky. Unlike gaslight, there was no slight odor, no eating up of a room’s oxygen, no wick to trim or smoked-up glass globes to be cleaned.