An eternal electric day is creeping across the globe, but our brains and bodies cannot cope in a world without darkness.
Sound dominated my senses as we left the village of San Pedro de Atacama and walked into the desert night. The crunch of shoes on gravel underlay our voices, which were hushed to avoid waking any households or street dogs. Our small group of astronomy writers was escaping from light and, without any flashlights or streetlamps, we struggled to see, so our other senses were heightened. Land that looked red by day was now monochromatic, the rods in our retinas serving as our only visual input.
After about 15 minutes of hiking, we stopped to take some pictures of the sky. I fumbled with my gear and tried to get my bearings, but everything was alien. I was horribly jet-lagged after 10 hours hunched against the window of a 757, another two-hour flight north from Santiago and a two-hour bus ride, and it wan’t just my oxygen-hungry brain that put me out of sorts.
The Atacama Desert looked like Mars as drawn by Dr Seuss; I was surrounded by wrong-coloured cliffs and swirling rock formations. But I was determined to photograph something even more bizarre: the Large Magellanic Cloud, a dwarf galaxy you can see only from the southern hemisphere. I perched my camera on a rock and aimed at the sky, but the cosmic smudge would not resolve in my viewfinder. I stood, brushed dirt from my jeans, and looked up.
The unfamiliar sky momentarily took away what little breath I had left at 8,000 feet in elevation. Above the horizon was the conspicuous Southern Cross. Orion was there, too, but looked as disoriented as I felt, upside down to the world. And there were so many constellations I’d never seen, with hopeful, Latinate names such as Dorado and Reticulum. Countless stars blazed into view as I stared into the smear of the Milky Way.
To most people who have travelled outside the developed world – whether to camp or to meditate or to hunt – such bright and plentiful stars are a glorious sight. But this beauty instilled in me a creeping sense of guilt. At home, 1,500 miles north, I wouldn’t recognise such spangled heavens.
From where I live in the American Midwest, the stars might as well not exist. After journeying millions of years, their light is swallowed by city glare and my porch lantern. Those that make it through will still fail: not even bright Betelgeuse can outshine my iPhone. Yet I am an astronomy writer, a person who thinks about stars and planets all the time. What does my neglect of the night sky say about the rest of humanity?
‘We are all descended from astronomers,’ the astrophysicist Neil deGrasse Tyson intones in the rebooted version of the TV show Cosmos. This is as poetic as it is true. Everyone owns the night sky; it was the one natural realm all our ancestors could see and know intimately. No river, no grand mountain or canyon, not even the oceans can claim that. But since Edison’s light bulbs colonised our cities, the vast majority of humans has ceased to see those skies.
More than 60 per cent of the world, and fully 99 per cent of the US and Europe, lives under a yellowy sky polluted with light. For many of us, the only place to see the milky backbone of our own galaxy is on the ceiling of a planetarium. Although humans are diurnal, factories and Twitter and hospitals and CNN are not, so we must conquer the darkness. As a result, almost everything industrialised people build is lit up at night. Malls, hospitals, car dealerships. Streets, bridges, air and sea ports. Buildings on a skyline. These artificial lights identify our cities all the way from the moon. If aliens ever do drop by, this might be their first sign that someone is home.
But cosmology, the study and interpretation of the universe, has always depended on a star-choked dark sky. Ancient civilisations from the Greeks to the Pawnee looked to the stars and saw not only creation tales, but active participants in their lives. Christians, who invest great meaning in the good of light and the evil of darkness, spread a starry message, too: the star of Bethlehem as a beacon to salvation.
A millennium and a half later, Galileo looked up and saw a new version of the cosmos, breaking the dawn of modern science. And Edwin Hubble discovered the expansion of the universe by the candlelight of supernovas. All of this happened under virginal skies and, by any measure, we don’t have those anymore. We look at our glowing rectangles, and we opt out of that shared heritage.
Nowhere is light pollution more apparent, almost achingly so, than in satellite images of the Earth from space. The continental United States seems to split in half: the eastern side is brighter than the west, except for the klieg lights of Las Vegas. Highways innervate America, connecting luminous dots of small towns and big cities. Across the Atlantic, Europe shimmers. Moscow is a radiant nine-pointed star. The Nile Delta glows like a dandelion sprouting from mostly indigo Africa. Farther east, Hong Kong and Shanghai are ablaze, and the demilitarised zone separates dark North Korea from South Korea more cleanly than if the peninsula had been cleft in two. Developed society, it’s clear, is where the light is.