GERLACH, Nev. — Here in the desert, the Earth boils and stars fill the sky. By day, you can see plumes of geothermal steam rising in every direction, pouring from vents in the ground and disappearing into the crisp, dry air. At night, you can see distant galaxies with the naked eye, their light much older than our species.

Five years ago, NASA launched a satellite that’s roughly the size of a minivan and that circles our planet 14 times a day. Its largest instrument collects information from across the electromagnetic spectrum over land, ice and ocean. Scientists analyzed its data and combined that with measurements taken on the ground to map our planet’s light pollution. Only a few small areas in the U.S. remain mostly untouched.

“As you see, the largest dark area is in northwest Nevada. Maybe at the center of this area we can have the darkest places,” said Fabio Falchi, a researcher at the Light Pollution Science and Technology Institute and author of “The World Atlas of Light Pollution.” Over 100 miles from Reno, 240 miles from Sacramento, and hundreds of miles from anywhere else I’d ever been lies one of the darkest places in the country, tucked away from the bleeding glow of civilization.

So that’s where I went. I wanted to feel what it was like in the dark. The human population is somewhere north of 7 billion, and light tends to follow our species wherever it goes. I wanted, in a way, to go back in time.

I was swimming in a desert hot spring, the water warmed by radioactive decay deep in the Earth’s crust, when the storm rolled in. It barreled down on me as fast as a truck, over the mountains and into the flat where the hot spring lay. And then there was nothing but the storm — the cold rain and the hot pool and the dark-gray clouds. The steam melted into the fog as the gale kicked up miniature waves that raced across the water. I wondered if I would ever see the stars.

In 2008, an assistant principal in Hambleton, West Virginia, arrived at work one morning to discover hundreds of birds — mostly yellow warblers but also thrushes, cuckoos and sparrows — dead in his school’s parking lot. They’d been swarming the school during the night, crashing into its windows. In 2011, 27 hatchling sea turtles were scraped off the pavement of A1A Boulevard in Fort Lauderdale, Florida, yards from the beach. Firefighters were able to save four others from a nearby storm drain. And in 2015, in Columbia, Pennsylvania, the state’s department of transportation cleared two-foot-high piles of countless dead mayflies from a bridge above the Susquehanna River. The swarming insects caused three motorcycle accidents before their demise, and their putrid corpses forced pedestrians to walk in the street.

It was light killed the beasts, they say.

The school’s lights had been left on overnight and the birds, possibly disoriented by foggy conditions, flew toward the light source, smashing into the windows. The turtles mistook the glow from a bar and an ice cream shop for the light of the moon glistening off the ocean. The mayflies hatched on the river and couldn’t resist the streetlights’ inviting glow.

In an 1887 letter to the editor of Science, one G. Thompson observed that “some disadvantage or evil appears to be attendant upon every invention, and the electric light is not an exception in this respect.” His hometown, Washington, D.C., had recently installed outdoor electric lighting — and spiders followed. Their prey was plentiful in the new light, Thompson reasoned, but their webs blocked views and dirtied surroundings. And, he noticed, the spiders seemed to “take possession of the portion of the ceiling of any room which receives the illumination.”

That letter may be the earliest public acknowledgement of what we now call light pollution. As human civilization has advanced, one of its innocuous-seeming byproducts — light — has seeped into the natural nocturnal world. And some humans have come to believe that light is wreaking havoc.

It began with the astronomers. The effect of light pollution on their field is obvious enough: Astronomers need darkness to collect and examine the unfathomably distant light of deep-space objects. Going into space to do that work is very expensive, after all.

The astronomers were joined by others in what can collectively be called the dark-sky movement. The ecologically-minded resent the effects light may have on our flora and fauna. Those more focused on humans are concerned about what they worry could be carcinogenic effects. And then there are those whose concerns center on a lost heritage: the notion that if we look up at night and see no stars, we are poorer for it, missing out on some nourishing, mystical, ancestral connection.

Those concerns have led to attempts to beat back the light. In 1958, the city of Flagstaff, Arizona, passed the country’s first dark-sky ordinance. To protect the darkness for research at its Lowell Observatory, the city banned the use of commercial searchlights. Scofflaws could be punished with a $300 fine, 90 days in the city jail, or both.

The struggle has continued ever since, in city halls, in state assemblies, on op-ed pages and on the internet. The dark-sky movement is quick to tell you that they are not Luddites who want to turn off the world’s lights. Rather, they advocate for well-considered lighting that serves its purpose without excess illumination. Too often, they say, lights are too bright, point too far up, are on too often, or are the wrong color. (Blue, they say, is especially bad.)

At noon on a bright fall day, I met Susan Harder, the New York state representative for the International Dark-Sky Association (IDA) and an outspoken apostle for the movement, at a cafe on Manhattan’s Upper East Side. In and around one of the brightest megalopolises in the world, she’s taken this fight to the New York State Assembly; the New York City Council and the city’s Department of Transportation; the towns of East Hampton and Riverhead; and the village of Sagaponack. The IDA she represents is one of the most prominent activist groups in the movement, employing full-time staff, educating the public and lawmakers, and bestowing its certified blessing on what it calls “dark sky places.” (Flagstaff and Borrego Springs, California, for example, have made the list.)

Harder had just arrived in the city from the Hamptons; she splits her time between the beach community and Manhattan. Bad luck drove her to join this crusade. Church lights across the street from her East Village apartment tortured her, despite painted-over windows and blackout curtains. Her house in East Hampton is “lit up” at night by a neighboring home, despite the fact that her house sits on a “fairly sizeable property.”

She works full time for the cause these days, giving lectures, lobbying policymakers and meeting with people like me. “Creatures, great and small, are negatively affected,” she told me, citing reading she had done about the issue. “Humans are dramatically affected by night lighting.” Ever vigilant, she has a blue-light-blocking screen on her cellphone. Going dark is also more fiscally responsible, she said — excess lighting wastes billions of dollars worth of energy each year. And the mystical element motivates her advocacy too. “The emotional, spiritual connection with the universe,” Harder said. “If it’s gone, what else do we have? We just have our Earth-borne environment. I think it also could cut off our feeling of curiosity. It’s hard to measure these things, but psychically, I think they’re quite dramatic.”

The evidence of that connection is all around us — in the star-heavy designs in jewelry, in clothing, in children’s bedsheets, Harder said. The design house Valentino even put out a collection of high-fashion clothes depicting celestial objects, she explained, and she regretted not wearing a piece from it to our interview. She was, however, sporting a sparkling star-shaped brooch.

In her experience, a combination of these arguments can appeal to folks across the spectrum. “Rabid, crazy Trump supporters are into this, and then my most ardent environmentalists are very seriously into it,” she said.

But convincing laypeople that light pollution is harmful to humans is one thing; convincing scientists of it is quite another.

On some fronts, the IDA’s concerns are in line with the evidence. In June, the American Medical Association adopted guidelines for streetlights meant “to minimize potential harmful human and environmental effects” from LED lighting, especially the blue-heavy varieties. There are two big problems with blue light, according to the AMA. First, it produces glare and discomfort for drivers, creating a “road hazard.” Second, blue light is on the “wavelength that most adversely suppresses melatonin during night” — it’s a sleep hazard.

All those lights could have effects that ripple far beyond bedtime, but this is where the science gets more complicated. We know that older, nonelectric light isn’t that bad for us, said Richard Stevens, a professor in the School of Medicine at the University of Connecticut. But what of the new variety? “We evolved for billions of years as life on the planet with the reliable cycle of bright sunlight and dark,” Stevens said. “Humans figured out fire a long time ago, and we started making candles about 5,000 years ago, but that kind of light does not affect our physiology much at all.”

Modern electric lighting might. Circadian disruption can alter not only sleep cycles but also core body temperature, hormone levels and gene expression — scientists have observed this in animal studies and Stevens has argued that the same disruption affects humans. He has explored the links between electric light and some of the so-called diseases of modern life: obesity, diabetes, depression and cancer. “The disruption to our circadian rhythmicity is a very big deal,” he said.

Stevens hypothesized a link between electric light and breast cancer as early as 1987. The genesis of his idea, and the reason it remains intriguing, is that while scientists understand some of the common causes of many types of cancer fairly well (lung cancer and smoking, liver cancer and hepatitis viruses, cervical cancer and human papillomavirus) the causes of breast cancer remain mysterious. A 2010 paper by Stevens and three Israeli scientists — “Nighttime light level co-distributes with breast cancer incidence worldwide” — was cited by nearly every dark-sky advocate I spoke with.

But even the author admits that these claims are debatable. “If you took 100 researchers who know this area, there would be no consensus on a cause for breast cancer,” Stevens said.

One such researcher, Karla Kerlikowske, studies risk-prediction models for breast cancer at the University of California San Francisco. “I have not heard of this theory before,” she told me. “So I would say it is not mainstream.” Another, Lisa Schwartz, is a professor of medicine at the Dartmouth Institute, where she researches the quality of medical communication to the public. She pointed out that neither the Physician Data Query nor the International Agency for Research on Cancer, two major organizations that assess cancer risks, consider light a standard risk factor. “They do mention other environmental factors with ‘inadequate evidence,’ but this one isn’t even on their lists,” Schwartz said. “I think this is a fringe idea.”

Thus far, there’s not much research showing any widespread negative ecological or health effects related to light pollution, as John Barentine, the program manager for the IDA, admits. (Barentine has a Ph.D. in astronomy and an asteroid named after him.) In its list of “five appalling facts about light pollution,” the IDA devotes a spot to the claim that “artificial light at night disrupts the seasonal cycle of trees.” In an envelope of news clippings and documents Harder gave me at the cafe (“I’ve got billions of articles,” she said), there was a handout that showed a photo of a tree in Amagansett, New York. It still had about a third of its autumn leaves in winter thanks, the document said, to a streetlight above it, which the handout claimed caused the tree stress.

Members of the movement remain convinced that urgent action is needed. “Wasteful artificial light has to be the most toxic and damaging pollutant that humankind knows!” reads one prominent website devoted to chronicling its ill effects. The site also hosts a photo of that very same tree in the Hamptons that’s sporting, supposedly, too many golden fall leaves.

There’s no research suggesting that light is a public health crisis, Barentine said. “It’s interesting, and it appears to be suggestive, but it’s not conclusive.” Nevertheless, he made grand comparisons, hoping that the dark-sky movement could create and benefit from sweeping changes in public opinion, much like the same-sex marriage movement or antismoking campaigns. (The research gets even more conflicted when you consider the benefits of light, which, in big cities especially, is often thought to deter crime.)

At times, though, Barentine sounded more like an evangelical darkness missionary, invoking the importance of our dimming heritage. “Human beings could use a little bit of humility now and then,” he said. “Does it add something, like art or literature or music? I’m convinced it does.”

Gerlach, Nevada, was settled in 1906 and named for the Gerlach Land and Cattle Company. The company was one of the biggest operations in the Black Rock Desert basin, and Louis Gerlach, its founder, was one of the richest cattlemen in the West. In the early 1900s, the story goes, on a visit to survey a ranch he’d acquired, Louis was bitten by a tick. Tick fever was going around that year, and he was rushed by stagecoach to a doctor 110 miles south, in Reno. Louis Gerlach never returned to the town that bears his name.

Over a century later, I traveled those same 110 miles, in the opposite direction, in a rented Jeep, to see what life is like in what may be the darkest town in the United States.

You don’t need directions to get to Gerlach from Reno; there’s really just one way to go. Nevada state Route 447 is a two-lane blacktop ribbon unfurling up the state, through the sagebrush, past Pyramid Lake, around and through the mountains. Travellers who follow Gerlach’s Main Street out of town will find that the pavement quickly gives way to gravel.

You could be forgiven for driving right through the town without noticing it. For darkness seekers, though, Gerlach is perfect — it’s five hours from Redding, California; five from Medford, Oregon; seven and a half from Twin Falls, Idaho; eight from Boise, Idaho; and eight from Salt Lake City — hundreds of miles removed from trespassing city light in any direction.

I pulled into Gerlach with a Unihedron sky-quality meter in my pocket. It’s a chunky black plastic box about the size of a pack of cigarettes. When I point its lens toward the sky’s zenith (that is, straight up) and press a button, the meter displays the darkness of the night sky, measured in something called magnitudes per square arcsecond (mag/arcsec²). The higher the number, the darker the sky. The night before I left for Nevada, outside my apartment in the arcadian (by Brooklyn standards) neighborhood of Ditmas Park, my meter was getting readings of around 15.9 — not good, and close to the bottom of the range shown on the meter’s pictorial legend, which starts with a streetlight and depicts skies getting darker further from the lamp’s glow. From my apartment windows, I can occasionally see a single star — a dim Polaris. My hopes for a more rewarding stargazing experience in the desert were running high.

Gerlach’s welcome sign reads both “Center of the Known Universe” and “Population Wanted.” It was a mining town and a railroad town. Gerlach “can be rough and tough on a Saturday pay night,” read a Desert Magazine feature in 1960, and “every passing train jiggles it like a bowl of tapioca.” In 1909, the Western Pacific Railroad began operating in the town. In 1970, the original California Zephyr ran its final trip, and passenger rail service to Gerlach came to an end. In 1975, the residents bought the town from the railroad for $18,000. With the railroad gone, the railroad workers left too, and today the town is home to fewer than 200 people.

There is one motel in Gerlach — Bruno’s — located behind Gerlach’s one restaurant — also Bruno’s. At the restaurant, you can book a room, sip a beer and order a meal, all at the bar. But to get even further into the nighttime darkness, I stayed 25 miles north at the Iveson Ranch. Jeff Barker, who goes by JB, is the owner, but he prefers to be called “activity director.” “The owner is God and all the people who are here,” he told me. A sign at the ranch entrance warns: “No county official beyond this point without a warrant and sheriff.”

Even before Barker showed up, there was a ranch here, owned by the Ivesons. “Those people were lyin’, cheatin’, cattle-thievin’ motherfuckers,” Barker recalled Gerlachers saying. Barker thought they sounded cool. So, not one for vanity, he called his new property Iveson Ranch.

The ranch, about 350 acres, lies snug between the Granite Range and the Calico Mountains, in the shadow of mountaintop cairns that the “ancient people,” as Barker called them, once used to drive antelope into the Hualapai Flat for the hunt. This topography, with vast rises on either side, evokes the slitted opening of a telescope dome. Wind turbines, along with a solar array of Barker’s construction, help shoulder the burden of being off the grid. When I arrived around midafternoon, the ranch was full of life. Magpies and quails, chickens and wild horses, deer, and a succession of dirty, friendly dogs — one of which, I later learned, was called Little Trump — seemed to be in charge.

Barker, 55, has a baby face that conceals a rancher’s hard-won know-how. He was well aware that he lived under extraordinarily dark skies, and he said so when we first exchanged emails. In fact, he’d built a runway — 3,300 feet by 60 feet, perfectly flat — meant to accommodate both planes and the RVs and sensitive equipment of serious stargazers. It was empty when we drove by, but past visitors had influenced Barker’s outlook.

“We’re just a little dot in what exists,” he told me. “Whether humanity lives or dies doesn’t matter. We better start taking care of ourselves and our planet.” The stargazers and their five-figure telescopes had brought a perspective that reinforced his own sustainable, leave-no-trace view. All very rural Nevada. “We’re gonna have to quit being so damn greedy — about money, about the way we use our resources,” he said.

Late that afternoon, I met Will Roger Peterson at his home back in Gerlach. It was the nicest house I’d seen in town, sitting on two acres and boasting a wraparound deck, a sauna and a bat house.

Peterson, 68, is the vice president of Friends of Black Rock-High Rock, a conservation and education group devoted to 1.2 million acres of “northwestern Nevada’s extraordinary landscapes.” He’s also a co-founder of the company that now runs the annual Burning Man festival, which is held on the playa. A white beard softened his handsome, desert-battered face. Peterson first came up to Gerlach in 1994, but in the winters he stays at his home in Oakland. “I didn’t think I’d like the desert, but it ended up mesmerizing me,” he told me.

“Gerlach is kind of unique considering dark skies because there’s very few streetlights here, so there’s very few lights shining upward,” he said. I asked him if that was on purpose, the result of some local, grassroots dark-sky movement. Peterson laughed. “No. As you can see, this is a poor, unincorporated town. There’s not a lot of money spent in Gerlach on things like streetlights.”

“It’s a challenge to live here,” he said. “So most people who live here are dealing with that challenge. They’re not out looking at the sky much.”

But Peterson is. Each night, he performs his own stargazing ritual on his second-floor balcony: He won’t go to bed until he sees three shooting stars. He said he usually sees them within 15 minutes.

To describe the significance of dark skies, Peterson invoked Carl Jung. “The things that are repeated — the symbols, the signs, the rituals that we’ve repeated for 2 million years as humans — are the things that are most collective in our unconscious. Looking at fire instead of television. Looking at the sky. Every culture known to us throughout our history has created constellations and has read the sky as a way to deal with the mystical.”

I asked Peterson if he thought there was any hope for a dark-sky movement in a place like New York City. He skipped right over the question, telling me to get out of the city as often as I could in search of a “mystical moment.” (There was also some talk of my being a sheep and a slave to contemporary culture.) Even being at the ranch for a couple of days would be good for me; he said he could see it in my eyes.

Outside the house, in an adjoining lot, is his home’s pièce de résistance, a testament to Peterson’s devotion to ritual: the labyrinth. Two-thirds of a mile long and constructed of thousands of rocks arrayed along the ground, it’s modeled after the one in the 12th-century Chartres Cathedral in France. Most walk that labyrinth praying to a Christian God, but when Peterson walks his each night at sunset, his focus is on more mystical forces. “There’s a lot of energy in there,” he said.

I walked it. The winding path took about 20 minutes to complete. For the first 15 minutes, I was too busy thinking about the weird desert insects that were biting me to notice any energy in the labyrinth. But for the last five, as the clouds lifted and each rock cast a sharp sundial shadow on the desert ground, I thought about the light, and the dark, and all I wanted to do was see the stars.

On my way out, Peterson handed me a packet of information about the Fly Geyser, which sits on Fly Ranch, which Burning Man had just bought for $6.5 million. The geyser is about midway between Gerlach and the Iveson Ranch and it’s not to be missed, Peterson told me, so we made vague plans to meet there the next day and swim in the hot spring next to the geyser. What Peterson’s packet didn’t mention was that Burning Man’s acquisition of Fly Ranch was funded in part by a co-founder of Airbnb, and by the CEO of Cirque du Soleil. “The future of Gerlach looks bright,” Peterson said. For selfish reasons, I hoped that wasn’t literally true — at least for the next couple of days.

When I showed up at Fly Ranch the next day, there was no sign of Peterson or his motorcycle. In fact, there was no sign of another human for miles in any direction. I hopped the roadside gate, passed a Burning Man “No Trespassing” sign, and walked a half-mile or so into the ranch to the geyser. It’s a spewing, alien structure, shimmering red, green and gold, five feet high and rising, built up over decades by mineral deposits from an uncapped well. Nearby is the natural pool it has created, where the water is around 100 degrees Fahrenheit. I swam back and forth a few times, both exhilarated and relaxed, trying to etch the surreal experience into my brain.

And then, over the mountain, the storm rolled in. Needles of cold rain sliced sideways into my top half, while my bottom half was comfortably submerged in the natural hot tub. My gear — phone, notepad, digital voice recorder — was perched precariously on the side of the pool, barely protected from the weather, and I could think only two things: There go my interviews, and I’m never going to see the stars. Gusts that day at a weather station in nearby (by the standards of northwest Nevada) Lovelock were measured at 53 miles per hour, on the high end of the “severe gale” category. As I drove back to the ranch, desert crows flew backwards.

Back in the tack room where I was staying, as my soaked clothes hung on hooks and the whipping wind carried trash cans and tree limbs past my small window, the power went out. And yes, it was dark in the tack room. Left with little to do and anxious that I might have come all this way to look at nothing but murky nighttime clouds, I lit a candle and opened the leather-bound guest book sitting in the corner. Years ago, one guest, Julie, had written: “So peaceful, and so many stars!”

“Fucking hipsters got too much time on their hands. Light pollution?” someone scoffed.

A party had broken out on my first night at the ranch. The Burning Man burnouts and self-described semi-organized vagrants who seemed to orbit the place had come together for some impromptu revelry. JB had invited me over to the main house and its fire pit for dinner (pork and potatoes) and cocktails (vodka and cranberry juice). As partygoers played “fire Jenga” with logs and a “Come on Eileen”-centric playlist blared at deafening volume, I found myself struggling to explain to the assemblage that I was there because it was dark. In retrospect, I can well understand their bemusement.

There was general agreement that, yes, indeed, it’s dark there. (“No shit, Sherlock,” was the subtext I received.) But when I said I badly wanted to lay eyes on the Milky Way, responses were more mixed. Some in the crowd lauded its majesty while others seemed not quite sure what the Milky Way was.

Later, in the main house, I was able to pin down James DiGiorgio, who was staying somewhere near the geodesic dome on the property. He splits his time between the desert and the Bay Area, constructing buildings out of recycled shipping containers (“grownup Legos”) and making art cars for Burning Man. DiGiorgio didn’t have much patience for the dark-sky movement, which he considered a risk, a drag on the real environmental work that needed to be done. “We’re already trying to fight people who don’t think global warming is real, who say solar and wind is useless,” he said. “Let’s not create another batch of loony hippies. I mean, I love my brethren, but some of us are nuts.” He had heard, however, of the turtles being killed. The turtles being killed, that’s real, man.

To my surprise and delight, the sky had cleared considerably while we were talking indoors. It was still cold and damp, but, followed by a loyal coterie of dogs — my coyote protection squad — I headed up the gravel road into the pitch-black night to get a better look.

I took my final measurement of the trip. The sky meter read 22.2 mag/arcsec². The number was the highest I’d seen, so high it doesn’t even show up on the legend on the front of the meter, and it meant that my view of the night sky was tempered only by natural airglow and zodiacal light. I was well into Class 1 on the Bortle Scale — the dark-sky bigtime. At this level of darkness, not only is the Milky Way visible in great detail, but you can also see the Andromeda Galaxy (2.5 million light-years away) and the Pinwheel Galaxy (25 million light-years) with the naked human eye.

A domed, inky tent of dark stretched above me, from mountain range to mountain range, with me squarely at its center. It’s hard to blame the ancient philosophers, like Anaximander, who thought the stars were tiny holes in the wheel of the sky through which a great fire could be seen. So it seemed to me then. To look up was to get lost. And to look up was to be found.

So peaceful. And so many stars.

As I headed back south down highway 447, a country song came on KLAP, one of Gerlach’s two radio stations. (The Burning Man organization runs the other, but it was off-air thanks to a power outage.)

Chains of this town

Broken me free

Shakin’ the dust off of my coat

Clearin’ the blur out of my eyes

I drove the Jeep the three hours back to Reno, lost $30 at the Eldorado, and caught a red-eye home. I landed just as the sun was rising.