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

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       Introduction

       To Know the Dark

       Have you ever experienced Darkness, young man?

      —ISAAC ASIMOV (1941)

      At least when it comes to light pollution, what happens in Vegas does not stay in Vegas. What happens here seeps across the surrounding desert so that national parks in Nevada, California, Utah, and Arizona, tasked with conserving their features “unimpaired for the enjoyment of future generations,” report their horizons aglow, their dark skies tainted. It’s to one of those parks, Great Basin, that I am headed—two hundred fifty miles north on Nevada’s US Route 93, two lanes rising from I-15 toward Ely—to see for myself what’s left of the dark.

      The story is the same all over the country—dark places disappearing from the map. Computer images based on NASA photos show—from the 1950s to the 1970s to the 1990s—a steady spread of light across the land, and the projected view of 2025 imagines the entire country east of the Mississippi as one great rash of yellows and reds, the most intensely populated areas blisters of white; even west of the great river only scraps of black remain, each surrounded by a civilization gnawing at its ragged edges. Still, the eastern Nevada desert is some of the darkest geography left in the United States, and Great Basin National Park lies at its heart. So here I am, charging out of Las Vegas toward maybe the darkest spot in the nation.

      It’s the early evening, and all around the racing car the earth is changing, temperatures falling, animals and insects beginning to stretch and move, night-blooming plants feeling life surge again. All day the desert rocks have been gathering heat, expanding in sunlight, sending thermals skyward to soar hawks and bump descending planes. But at night the direction of energy flow reverses, the temperature drops thirty or forty degrees, and the desert rocks glow with warmth like a winter’s woodstove. In the natural rhythm of day and night, whole mountains swell and fall like the chest of a sleeper.

      To the east the mountain ranges still hold the rose color of the setting sun, while to the west already they are losing their definition, dissolving into silhouettes, the darkness sloping to the desert floor, long drapes hanging from mountainsides. We call this time “twilight,” and officially, there are three stages—civil, nautical, and astronomical—that correspond to the gradual gathering of darkness and fading of the sun’s light. In this twentieth-century classification, civil means the time when cars should use their headlights, nautical means dark enough that the stars needed for navigational purposes are visible, and astronomical means when the sky darkens nearly enough for the faintest stars. Unofficially, I love biologist Robin Wall Kimmerer’s name for twilight: “that long blue moment.”

      We like to think that darkness “falls,” as though it were like snow, but as the earth turns its back to the sun darkness actually rises from the east to wash and flood over land and sea. If you’ve ever stood at dusk and seen a gloaming on the eastern horizon, as though clouds were gathering, a thunderstorm brewing, that’s what you’re seeing—the earth’s shadow as we rotate into it. What we call “night” is the time when we are caught in that shadow, a shadow that extends into space like the cone to earth’s ice cream, a hundred times taller than it is wide, its vertex 860,000 miles above the earth. Dawn comes as we rotate out of that shadow into СКАЧАТЬ