Nightskyline New York City's gilttering night skyline is an iconic symbol of the city. But it's also becoming a thing of the past, as environmental concerns are prompting more and more commercial buildings to turn off the lights, according to the New York Times:

Motion sensors ensure that unoccupied offices, storerooms and canteens go dark after workers and cleaning crews leave at night. Dimmers soften overhead lights that once could burn only bright or not at all. Timers guarantee that buildings fade to black while the city sleeps.

Gone are the days when cheap electricity, primitive lighting technology and landlords' desire to showcase their skyscrapers kept floor after floor of the city's highest towers glowing into the night. Now, rising energy costs, conservationism, stricter building codes and sophisticated lighting systems have conspired to slowly, often imperceptibly, transform Manhattan's venerable nightscape into one with a gentler glow.

It's a really interesting read, and the NYT also has a cool video tour that accompanies the story.

I was thinking about that article when I recently read this month's National Geographic cover story, "The End of Night." Urban light pollution, the story says, has done a lot more than obliterate our view of the stars. It's had several adverse biological effects, as well, from disrupting the migratory patterns of birds to altering the breeding patterns of sea turtles, toads and frogs.

Our bright night skies are even affecting human biology: One study, according to National Geographic, suggests "a direct correlation between higher rates of breast cancer in women and the nighttime brightness of their neighborhoods."

And light pollution is likely the most preventable kind of pollution that humans produce.

Of course cities like New York aren't ever going to completely turn off the lights at night. There are plenty of good reasons -- crime prevention, economic development, public safety -- to keep buildings lit.

But as energy costs and environmental impact become bigger concerns, it seems the era of the all-night blazingly bright office tower is coming to a close.