How Does Light Pollution Affect You?

'Artificial day' is when buildings, cars and streetlights produce so much light that the night sky doesn't even look that dark. . (Photo: Gavin Heffernan and Harun Mehmedinović)

When was the last time you had several nights in a row where you could see more than just the brightest stars in the sky? I spent a week in northern Vermont over Christmas, and that was the last time for me. Prior to that it was last summer in Vermont, and once in the mountains of Mexico. The brightest and most memorable stars I've ever seen were when I spent three months living off-grid on the Big Island of Hawaii. Not only was there little light pollution from the towns there, we were thousands of miles from any big city. In fact, the Big Island is isolated enough that it has a number of international observatories on its highest peak on Moana Kea. As you drive down the former volcano as you exit the observatory area, you are supposed to keep your headlights low, because even those small lights can disturb the careful measurements by the observatories there.

I used to go out most nights when I lived in Hawaii and look up, at least for a few minutes. I would make my way to the outdoor composting toilet where I was staying by starlight; it was so bright I didn't need a flashlight, even when the moon wasn't full. The incredible number, variety, depth and twinkliness of the stars left an indelible memory. They gave a feeling of a deep and complex universe outside our own. Seeing them night after night reminded me that the Earth is just one of many planets, the sun one of many stars.

This isn't a feeling I have much living in suburban Connecticut and New York City, where only a couple bright stars stand out due to light pollution. It's interesting to realize that throughout human history, we are the first couple generations of human beings that have grown up without regular views of the complete night sky. And our light pollution continues to grow with every new home, smartphone and additional car (with headlights, natch) that makes it on the road this year, and next, and the next. It's worth thinking about what we are losing.

If you haven't seen a star-filled night sky in you-don't-even-know how long, you are not alone; according to the video below, two-thirds of the Earth's people — 5 billion — do not really see the night sky once the sun sets, due to light pollution from our cars and cities.

"It's beautiful, from a distance, and blinding the rest of the time," says the narrator below, of human-created light. Exactly. And, yikes.

This awareness video was made with the International Dark Sky Organization, a group that's working to reduce the pollution that we all live with—and probably don't think about—too much. The nonprofit group is "fighting for the night"—and considering how our brightened nights hurt nocturnal and migrating animals as well as negatively affect our health, I'm a fan of the organization. I'd like to be able to see the gorgeous starry sky a little closer to home than Hawaii. Wouldn't you? Or are you lucky enough to live somewhere that gives you great night sky views?