The Darkest Sky We Have Left

There is a moment, about forty minutes after the last daylight has drained out of the west, when your eyes finish adjusting and the sky stops being a ceiling and becomes a depth. I felt it happen. The stars I could see at dusk — a respectable scatter, the ones that survive in most places — were suddenly the loud minority, and behind them, filling in every gap, came thousands more, and behind those a soft grey river of uncountable others, until the black between the stars was not really black at all but crowded. I have looked up my whole life. I had never actually seen the sky.

I was standing on a gravel flat two hours from the nearest town with a woman named Sena Ortiz, who has spent the better part of a decade fighting to keep this particular patch of darkness dark. She runs a small volunteer watch — a handful of neighbors, an astronomer or two, a retired pilot — that measures the night sky's brightness on a regular schedule and lobbies, endlessly, patiently, to keep new light from creeping over the horizon.

What we lose when we light everything

"Most people my age grew up able to see the galaxy from their backyard," Ortiz told me, setting up a meter that reads the sky's brightness in numbers. "Their grandchildren can't see it from anywhere within a day's drive. We didn't decide to give that up. It just leaked away, one porch light, one parking lot, one billboard at a time. Nobody voted for it."

Nobody voted to lose the stars. It just leaked away, one porch light at a time. — Sena Ortiz, dark-sky volunteer

The loss is not only aesthetic, though the aesthetic loss alone should shame us. Excess light at night disorients migrating birds, pulls hatchling turtles away from the sea, scrambles the internal clocks of nearly everything that evolved under a genuinely dark night — ourselves included. A wasted upward-pointing light is, quite literally, energy spent making the world worse. The remedy is almost insultingly simple: point light down, use only as much as you need, and turn it off when no one is there. Darkness, unlike almost every other thing we have ruined, can be restored the same night you decide to restore it.

The long watch

We stayed out past two. Ortiz read her meter, wrote the number in a weatherproof notebook by red flashlight, and we talked in the low voices the dark seems to ask for. A meteor cut a long silent line and we both said nothing, which felt correct. Somewhere a fox complained. The temperature dropped until our breath showed against the star-glow.

What struck me, driving out at last with the heater running, was how ordinary the whole effort was. No grand technology, no dramatic campaign — just a few people who decided that a thing worth keeping was worth the boring, repeated work of measuring it and speaking up for it. The darkest sky we have left is not protected by law or fortune. It is protected by attention. And attention, unlike the stars, is something any of us can still choose to give.