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

It was in order to supply domestic customers like these that Thomas Edison in 1882 opened his first power station in lower Manhattan. By 1920 in America, electric service reached 35 percent of urban and suburban homes, and by World War II more than 90 percent of Americans had electric light. Still, it wasn’t until FDR’s insistence on the Rural Electrification Act of 1936 that electric light began to reach many areas of the rural United States, and not until well into the 1950s could one reasonably say most Americans enjoyed the benefits of electricity. Since that time, we have simply turned that knob on the wall farther and farther to the right, spreading electric light from city to city, town to town, up onto mountaintops and down into hollers, across the plains and into the desert, from coast to coast.

I sometimes try to imagine living in a city before electricity. How quiet pre-electric nights would have been without cars or trucks or taxis, without any internal combustion engines at all. No radios, televisions, or computers. No cell phones, no headphones, nor anything to plug those headphones into if you had them. How deserted the city with most of the population locked inside their homes, the night left to fears of crime, sickness, and immorality, and best avoided if one could. Finally, and most strangely—the biggest difference from that time to ours—not one single, solitary electric light.

How dark it would have been—imagine leaning out your door and, on the darkest nights, not being able to see more than a few feet in any direction. Historian Peter Baldwin describes as “downright perilous” the streets in early American cities, with few paved and then those only with cobblestones. On nights of clouds and no moon, he writes, “travel was obstructed along the sidewalks and street edges by an obstacle course of encroachments: cellar doors, stoops, stacks of cordwood, rubbish heaps, posts for awnings, and piles of construction material … In 1830 a New York watchman running down a dark street toward the sound of a disturbance was killed when he collided blindly with a post.” What lights did exist were intended only as beacons or guides rather than to illuminate the night. The New York street lanterns burning whale oil were in 1761 merely “yellow specks engulfed by darkness,” and even more than a hundred years later its gas lamps were still “faint as a row of invalid glow-worms.”

In Brilliant, Jane Brox tells of how American farm families, after they first got electric light, would turn on all the lamps in their house and drive out a ways just to watch it glow. Who can blame them? To go from the stink and dark and danger of kerosene to the clean well-lighted place brought by electricity—at the speed of light, no less. I would back away to admire the view as well. But soon it will be the rare person in the Western world who hasn’t spent his or her entire life bathed in electric light, and no one will remember what night was like without it.

In the United States, our bright nights began with the first electric streetlight in Cleveland, April 29, 1879. But it was in New York City that the “possibilities of nighttime lighting first entered American consciousness,” writes John A. Jackle in City Lights: Illuminating the American Night. “Once adopted there, its acceptance was assured almost everywhere.” Thomas Edison returned to New York after a trip in 1891 to Europe proclaiming, “Paris impresses me favorably as the city of beautiful prospects, but not as a city of lights. New York is far more impressive at night.” Broadway was always the first, always led the way. It was the city’s first street to be fully lit at night, first with whale oil lamps, then gas (1827), then finally electricity (1880). In a drawing from City Lights of Madison Square in 1881, arc lights on a tall pole shed light on an otherwise dark city scene of strolling couples, a horse-drawn carriage, telegraph poles and wires, and—in this famously windy part of the city—a man in the foreground who seems about to be blown over by the light as he crosses the street, cane in hand. By the 1890s, Broadway from Twenty-third Street to Thirty-fourth Street was so brightly illuminated by electric billboards that people began calling it The Great White Way.

These days, walking from lower Manhattan, it’s not until I get to Thirty-first Street that I reach anything close to the bright white streetlights I had expected. Until then I’m in what feels, at least late on a summer Sunday, like a forgotten part of the city. With the theater district and advertising lights moved far up the street, the once bright Way is far more mild than Great, much less White than gray.

But once in Times Square, all that changes. Flashing digital signs, billboards, colored lights—from Forty-second to Forty-seventh is the brightest—and there is no night sky. I don’t mean I can’t see many stars, or even that I can’t see any stars, I mean there appears to be no sky. Yes, above me, there is a blackish color—but with no points of light or any other indication of being alive. Instead, I feel as though I’m in a domed stadium. The light from the digital billboards simply drowns the white streetlights that lower on Broadway seemed so bright. I can honestly say it feels as bright as day. Maybe a cloudy day, but day nonetheless. Certainly, it no longer feels like night.

And by that I mean it no longer feels dark.

In fact, at least in terms of darkness, “real night” no longer exists in New York City, or in Las Vegas, or in hundreds of cities across the world. According to the World Atlas of the Artificial Night Sky Brightness, created in 2001 by Italians Pierantonio Cinzano and Fabio Falchi, two-thirds of the world’s population—including 99 percent of people living in the continental United States and western Europe—no longer experience a truly dark night, a night untouched by artificial electric light. Satellite photographs of the earth at night show the dramatic spread of electric light over the globe—even without a map to show political boundaries, many cities, rivers, coastlines, and country borders are easily identifiable. But as impressive as these photographs are, they don’t show the true extent of light pollution. Cinzano and Falchi took NASA data from the mid-1990s and, using computer calculations and imaging, showed that while in the photographs many areas outside cities appeared dark, they were actually flooded by pools of light spreading from the cities and towns around them. On the Atlas, levels of brightness are indicated by color, with white the brightest, and descending from there: red-orange-yellow-green-purple-gray-black. Like the NASA photographs before it, the World Atlas of the Artificial Night Sky Brightness has a certain beauty, but in truth it is a tale of pollution.

Light pollution is the reason Rob Lambert and I could see only a handful of stars from the Las Vegas Strip, and the reason I don’t see any stars from Times Square. It’s the reason why in the night skies under which the vast majority of us live, we can often count the stars we see on two hands (in the cities) or four (suburbs), rather than quickly losing count amid the more than twenty-five hundred stars otherwise visible on a clear night. It’s the reason why even from the observatory deck of the Empire State Building we now see 1 percent of the stars those in 1700s-era Manhattan would have seen.

The International Dark-Sky Association (IDA) defines light pollution as “any adverse effect of artificial light, including sky glow, glare, light trespass, light clutter, decreased visibility at night, and energy waste.” Sky glow—on display nightly over any city of any size—is that pink-orange glow alighting the clouds. It’s tramping through a two-foot snowfall with the whole town bathed in push-pop orange. It’s that dome of light on the horizon ahead though the sign says you’ve still got fifty miles to go. Glare is that bright light shining in your eyes that you raise your hand to block. Trespass is light allowed to cross from one property onto another. It’s your neighbor’s security light shining through your bedroom window. It’s the lights on the brand-new science building that also illuminate the sororities across the street. It’s all over every neighborhood in America, land of the free and the home of property rights. And clutter? A catchword for the confused lighting shining this way and that in any and every modern city.

A long exposure shows birds and bats hunting moths and insects amid the Luxor Casino’s beam in Las Vegas. (Tracy Byrnes)

The bad news? All mean wasted light, energy, and money. The good news? All are caused by poorly designed or installed light fixtures and our using more light than we need, and all could be significantly and—compared to other challenges we face—easily remedied.

When I think of how light pollution keeps us from knowing real darkness, real night, I think of Henry David Thoreau wondering in 1856, “Is it not a maimed and imperfect nature that I am conversant with?” He was writing about the woods around Walden Pond and how the “nobler” animals such as wolf and moose had been killed or scared away. “I hear that it is but an imperfect copy that I possess,” he explained, “that my ancestors have torn out many of the first leaves and grandest passages, and mutilated it in many places. I should not like to think that some demigod had come before me and picked out some of the best of the stars.” Some 150 years later, this is exactly what we have allowed our lights to do. “I wish to know an entire heaven and an entire earth,” Thoreau concluded. Every time I read this I think, Me, too.

Bob Berman lives in a small town in upstate New York that has no streetlights. “I could never live in a place with streetlights,” he tells me as we wind along a dark two-lane road, joined by a rising moon cast over the ruffled lakes and through bare spring trees, the songs of peepers audible over the sound of the car. We are on the way to the observatory he built by himself. Once described as the country’s most popular astronomer, Berman has written a number of books, wrote the “Night Watchman” column for Discover magazine and the “Skyman” column for Astronomy magazine, and is known especially for his humorous writing style. Which is not the easiest thing to pull off when you’re writing about astronomy, he says. “Science isn’t inherently funny. What’s funny about Pluto? What’s funny about galaxies, and the cosmos, and the expanding universe? This is not social satire. When I was able to do a column on stupid questions, that was a gift from God.”

“What was your favorite?”

“It’s hard to top, ‘If a solar eclipse is so dangerous, why are they having it.’”

But of course the “stupid questions” column had a serious point to make, that most Americans don’t know much about the night sky.

I used to count myself among that number. I was always drawn to it, but I’d never known its names and numbers, its secret lives. In fact, here is what I did know: planets don’t twinkle and therefore I could supposedly tell them from stars, and two prominent constellations—the Big Dipper (which technically is only part of a constellation) and Orion.

“That’s not bad,” Berman tells me. “The only thing most people know is the moon.”

That I know more than I used to has a lot to do with Bob Berman, and especially his book Secrets of the Night Sky. Here’s some of what I learned: One of the stars in Orion, Betelgeuse is “the largest single thing most of us will ever see.” Sure, a galaxy is bigger, but a galaxy is a collection of stars rather than a single thing. Anyway, no galaxy is bright enough to shine through the light pollution that covers most of the developed world’s skies. “Betelgeuse, on the other hand,” writes Berman, “is brilliant enough to bulldoze its way through the milkiest urban conditions.” Or how about this: Rigel, another brilliant star in Orion, “shines with the same light as fifty-eight thousand suns.” Rigel is much farther away than the other stars making up the constellation, and, as Berman explains, if Rigel “were as close to us as the others, our nocturnal landscape would tingle with sharp, alien Rigel shadows, and the night sky would always be as bright as when a full moon is out. Most of the universe would disappear from view.”

The moon tonight, a waning gibbous a few days past full, is bright enough that our view at the observatory won’t be as great as it otherwise might be. When, during its twenty-nine-day cycle, the moon is big enough and therefore bright enough to wipe so many stars from view, most astronomers are not excited to see it. But Berman seems genuinely delighted to roll back the roof of his DIY observatory (which he built, he says, “crazy and wrong”) and point his telescope at the moon. (“Did you make the telescope yourself?” I ask. “No, no, no,” he says. “I wanted a good one.”)

“Here, take a look at this,” he says, and invites me to step up to the eyepiece.

I am not prepared for what I see: the gray-white moon in a sea of black, its surface in crisp relief, brighter than ever before. I am struck, too, by the scene’s absolute silence. It is clearer, yes, brilliantly so, but this moon seems cold, antiseptic—alone in the unfathomable expanse of space. I learned a lot about the moon from Berman’s writing (“it’s more brilliant when it’s higher, when it’s nearer, and in winter when sunlight striking it is seven percent stronger”), and I appreciate this kind of information. But I think our relationship with the moon has more to it than simply astronomical facts. With my naked eye, on nights the moon climbs slowly, sometimes so dusted with rust and rose, brown, and gold tones that it nearly drips dirt colors and seems intimately braided with Earth, it feels close, part of this world, a friend. But through the telescope the moon seems—ironically—farther away.

“So now we’ll go to Saturn,” Berman says. Using both arms, he moves the large white telescope as though leading a dancing partner, turning it slightly to the east, then steps up the ladder and adjusts the view. “Now we’re talking,” he says. When I look through the scope, though, the bright tiny object is dancing around, and the image is blurry. Berman takes another look and makes some more adjustments, explaining as he does the key elements for viewing the night sky: transparency, darkness, and “seeing.” Yes, that’s what they call it. “You would think astronomers would come up with a more technical term,” he chuckles, “but no, all around the world astronomers are saying, ‘The seeing is a three point five tonight.’” Seeing reflects the effect of turbulence in the earth’s atmosphere on the sharpness and steadiness of images—good seeing if the atmosphere is steady and calm, bad seeing if it is especially turbulent. A quick way to check seeing is how strongly stars twinkle: The more the twinkling, the worse the seeing. Berman tells me that bad seeing is one reason why no major observatories have been built east of the Mississippi for more than a century. The good “seeing” atop mountains in the desert has drawn astronomers west.

“Take a look at that,” says Berman, climbing down. “Wait for the moments of good seeing—when it steadies up.” Waiting for that—for good seeing—is exactly what an experienced observer will always do, he says. “I remember once when I was about twenty-four, and it was thirteen below zero, and my beard was frozen, I just stood there for three straight hours waiting for those moments when there would be steadiness and you could see ring within ring, detail that even photographs don’t show. That’s what observers have done for centuries.”

As I wait for good seeing, I think about what Berman’s just said. While humans have always watched the sky, modern astronomy has its origins in the lands we know as Egypt and Babylon, in the third and second millennia before Christ. People then were looking to the sky for signs and omens (though of course they were looking in other places, too; “the entrails of sheep were of special interest,” writes historian Michael Hoskin). Eventually, the cosmology that developed—the classic Earth-centered Greek model of the universe—would dominate Greek, Islamic, and Latin thought for two thousand years. During the Middle Ages, astronomy in Europe was truly in the Dark, and not in the way modern astronomers would like—we have Islamic astronomers to thank for keeping the craft alive. That’s the reason so many stars have Arabic names; one Islamic prince named Ulugh Beg, who lived from 1394 to 1449 in Samarkand in central Asia, catalogued over a thousand individual stars himself. And when, in 1609, Galileo Galilei (1564–1642) turned his handmade telescopes toward the sky, human observation of the cosmos changed forever.

When the “seeing” settles and Saturn comes into view, I can’t help but say, “Oh my God!” To the naked eye Saturn is simply a bright starlike object—interesting, perhaps, but nothing more. But seen through a telescope it’s a soft yellow marble with wide, striated rings—exactly as in photographs, but this time alive.

“Over the years more than a thousand people have looked through that telescope,” Berman says. “And with Saturn, people always say one of two things. They either say, ‘Oh my God!’ or they say, ‘That’s not real!’”

That’s not real—what a curious response. I’ve had other astronomers tell me the same thing, or say that people will question whether the astronomer hasn’t placed an image of the planet into the telescope somehow. The fact that people are seeing something with their own eyes has incredible power—you can see photographs of Saturn a thousand times and be somewhat impressed, but see it for yourself and you don’t soon forget.

The most beautiful starry night I have ever seen was more than twenty years ago, when I was backpacking through Europe as an eighteen-year-old high school graduate. I had traveled south from Spain into Morocco and from there south to the Atlas Mountains, at the edge of the Sahara desert, to a place where nomadic tribes came in from the desert to barter and trade, a place that when I look on a map I can no longer find. One night, in a youth hostel that was more like a stable, I woke and walked out into a snowstorm. But it wasn’t the snow I was used to in Minnesota, or anywhere else I had been. Standing bare chest to cool night, wearing flip-flops and shorts, I let a storm of stars swirl around me. I remember no light pollution—heck, I remember no lights. But I remember the light around me—the sense of being lit by starlight—and that I could see the ground to which the stars seemed to be floating down. I saw the sky that night in three dimensions—the sky had depth, some stars seemingly close and some much farther away, the Milky Way so well defined it had what astronomers call “structure,” that sense of its twisting depths. I remember stars from one horizon to the other, stars stranger in their numbers than the wooden cart full of severed goat heads I had seen that morning, or the poverty of the rag-clad children that afternoon, making a night sky so plush it still seems like a dream.

So much was right about that night. It was a time of my life when I was every day experiencing something new (food, people, places). I felt open to everything, as though I was made of clay, and the world was imprinting upon me its breathtaking beauty (and terrible reality). Standing nearly naked under that Moroccan sky, skin against the air, the dark, the stars, the night pressed its impression, and my lifelong connection was sealed.

When I tell Berman about Morocco he says, “A sad corollary to that story is when my wife’s mom visited us once. And she had spent her life living in either Long Island or Florida, light-polluted places. We heard the car drive up, heard the trunk close, heard her wheel her luggage to the house, and when she came in she said to Marcy, ‘What are all those white dots in the sky?’ And of course Marcy said, ‘Those are called stars, Mom.’”

“I’ve heard people say such things,” I laugh, “but I can’t believe they’re true.”

Berman leans back and calls, “Marcy, do you remember when your mom said what are those white dots in the sky?”

“Yep.”

“Do you think she was kidding?”

“Nope.”

Seeing stars is something Bob Berman has done all his life. And here in upstate New York, the sky still offers a wonderful view.

“We get down to about magnitude five point eight, five point nine, where you see a good twenty-five hundred stars,” he says, referring to the scale astronomers use to describe the brightness of individual stars. “Theoretically, three thousand stars are visible to the naked eye at one time, but, in truth, since the overwhelming bulk of stars are fifth and sixth magnitude—the fainter you go, by far the more stars there are—and because extinction near the horizon is so great, the truth is faint stars stop at about ten degrees from the horizon and you lose a swath.”

We adopted the idea of magnitude from the ancient Greeks, who called the brightest stars “first magnitude” and the dimmest “sixth magnitude.” When modern astronomy put precise measurement to the Greek magnitude idea, a few of the brightest stars actually turned out to have minus numbers, such as Sirius (-1.5). But these values are all relative, reflecting only how we see these stars from Earth. The brightest star in the history of the universe could be fainter than faint if it’s far enough from our view.

It’s commonly accepted that the naked-eye limit is magnitude 6.5, though some observers report magnitude 7.0 or better. As Berman writes,

There are few brilliant stars, many more medium ones, and a flood of faint stars. This hierarchy continues with a vengeance below the threshold of human vision. Recent advances have allowed telescopes to detect stars of magnitude 29—more than a billion times fainter than anything the unaided eye can perceive! This is very faint indeed: The light from such a star equals the glow of a single cigarette seen from 125,000 miles away.

But a light-polluted sky renders all this meaningless, of course, as the greatest wealth of stars lie in the larger values of magnitude, exactly the magnitudes erased by artificial light.

“My feeling,” says Berman, “is that an observer needs to see four hundred fifty stars at a time to get that feeling of infinitude, and be swept away, and go, ‘Oh, isn’t that beautiful.’ And I didn’t make that number up arbitrarily—that’s the number of stars that are available once you get dimmer than third magnitude. So in the city you see a dozen stars, a handful, and it’s attractive to no one. In the city you say, ‘Oh, there’s Vega, who cares?’ And if there’s a hundred stars in the sky it still doesn’t do it. There’s a certain tipping point where people will look and there will be that planetarium view. And now you’re touching that ancient core, whether it’s collective memories or genetic memories or something else from way back before we were even human. So you gotta get that, and anything short of that doesn’t do it.”

Humans have long found in stars like these the familiar shapes that reflect our lives. For modern viewers these shapes sometimes make absolute sense, as with the scorpion of Scorpius, or the hunter Orion. The same is true of an asterism like the Summer Triangle, a shape made of bright stars from separate constellations: Vega from Lyra, the Lyre; Deneb from Cygnus, the Swan; and Altair from Aquila, the Eagle. But then there are the many constellations that puzzle us with their amorphous shapes and illogical identities, as though they are the eternal result of some ancient Greek joke. A good example is Auriga, with its bright star Capella, which lies just above Orion, readily apparent to any stargazer. How many of us would identify this shape as a charioteer? And Auriga is one of the easy constellations; try identifying Monoceros, the Unicorn, or Cetus, the Sea Monster, which both lie near Orion as well. With an image in mind (a good astronomy book or smartphone app helps), some of the ancient figures like Cassiopeia and Perseus may appear, but others (Ophiuchus, the Serpent Holder—which is hard to say, let alone see) are almost surely never to register.

Still, things could be worse, or at least more complicated. In 1627, the German astronomer Julius Schiller attempted to Christianize the sky by replacing the names of the constellations with the names of characters from the Bible. Thus the twelve constellations of the zodiac became the twelve disciples, and the constellations from the Northern Hemisphere were replaced by characters from the New Testament and those in the Southern Hemisphere with characters from the Old Testament. For better or worse, his idea never caught on. Not so lucky were the southern skies, where many of the constellations reflect the fascination of European explorers from the sixteenth, seventeenth, and eighteenth century for the practical new inventions of their time. Such inspirational constellations as the Air Pump, the Draftsman’s Compass, and the Chemical Furnace live on today, as do the creatively named Telescopium and Microscopium. But not all is lost in the Southern Hemisphere, at least for children and those childlike at heart, all of whom can forever delight in pointing to the nautically inspired Puppis, the Poop Deck.

In order for us to see the stars in anything close to their possibilities—whether the awe-inspiring numbers Berman talks about, or in constellations both familiar and ridiculous—we need darkness. But how dark is dark? My hunch is that for most of us there are basically three levels. First, there is dark as in, “It’s night, so it’s dark.” This is the standard notion of night’s darkness, and it corresponds to around Bortle 8 down through Bortle 5. Next, at least for anyone lucky enough to find him-or herself in an area that would correspond to Bortle 4 or 3 or 2 (or, certainly 1), there is really dark, as in, “It’s really dark out here.” And finally, there is for some people a level of “darkness” that equates to “Vegas, baby!”

The reality, though, is far more complex. This is the message from Bortle’s scale and the World Atlas of the Artificial Night Sky Brightness—we don’t know what real darkness looks like, because we seldom ever see it.

One place to see real darkness in Manhattan is at the Museum of Modern Art, in Vincent van Gogh’s The Starry Night. Unless Van Gogh’s oil on canvas from 1889 is traveling as part of an exhibition, it hangs at home on its MoMA wall as fifty million people pass by every year. On a Saturday morning I stand near Van Gogh’s scene of stars and moon and sleeping town, talking with its guardian for the day, Joseph, as he repeats, “No flash, no flash,” “Two feet away,” and “Too close, too close” again and again as people from around the world crowd near. “What’s the appeal of this painting?” I ask. “It’s beautiful,” he says. “What more can you say than that?”