Saturday, January 10, 2009
Skyglow: When I dream about a sunset like this, it doesn't bode well, and this doesn't either
Know what I mean about a certain kind of dream sunset? The colors are garish and acrid and surrounded by amorphous figures of unknown provenance. It's usually a prelude to some sort of nightmare scenario.
I saw this one on the way home last night, driving toward Madison on Highway 12, about 10 miles out. It looked exactly like a real sunset, and stood out brightly against the dark, cloudy sky. The sunset glowed a bright orange above the horizon, beneath the low cloud ceiling, although the colors were a bit off. But I knew it couldn't be a sunset. It was 7:30 p.m. So what was it? That's when I realized it was the light from countless sodium vapor streetlights in Madison, along with all the other lights a city throws up at the night.
Every photon of light in this "sunset" is a photon representing wasted energy. It's the same kind of wasted light that results in those beautiful night maps shot from space that show urban centers as brightly illuminated nodes, connected by delicate networks of lesser lights crisscrossing the dark side of the planet. Much of it was generated by burning fossil fuels and adding to the greenhouse gases in the atmosphere. There are technologies for mitigating this atmospheric light pollution, which also harms migratory birds and makes it harder and harder to see the stars even on a clear night near any urban center. But we're slow to crack down on this extravagant and harmful form of pollution.
Maybe we need to rethink our relationship to darkness. "Better to light one candle than to curse the darkness," they say. But millions and millions of electric candles?