How the Milky Way Shows Up Over Manhattan

NASA's Astronomy Picture of the Day is a photograph of the Milky Way over Manhattan, a sky where, as the accompanying explanation notes, the city lights outshine the stars.

The picture works because of the band it is taken in. The astrophotographer's setup blocks most of the city's light pollution, and the explanation offers a pleasingly specific reason why: old incandescent bulbs and some neon lights are still bright in the near-infrared, but fluorescent and LED bulbs are not.

That makes light pollution less like a single dimmer switch than like a set of bulbs. It depends on the wavelength you're looking at and on what the fixtures are made of, which means the same city glow that hides the sky from one camera may barely register in another.