NASA's "Blue Marble" series has introduced countless space lovers to impossibly beautiful, high-resolution photos of Earth's swirling clouds and oceans, as seen from far above. Now a joint venture between NASA and the NOAA has introduced "Black Marble," an unprecedented photo-stitch of our planet's haunting urban sprawl, as seen from space at night. "Nothing tells us more about the spread of humans across the Earth than city lights," said NOAA's Chris Elvidge. The nighttime photographs were taken from April to October aboard the Suomi NPP satellite, which is equipped with light-sensitive cameras capable of capturing every little flicker. "It's amazing what you can pick out," says Phil Plait at Slate

[M]y favorites are the Nile River, Hawaii all by its lonesome in the Pacific, and of course my hometown of Boulder (and Denver). It always amazes me how city lights in the United States just suddenly stop west of the central time zone. But when I look up at night and see my dark skies, I'm thankful for it.