Satellite images capture fine details of planet’s night lights.

By Alexandra Witze

Web edition: December 6, 2012

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BLACK MARBLE

Lights from human activity ring the otherwise dark Atlantic Ocean in this new image, part of a collection showing Earth at night more clearly than ever before.

Credit: NASA, NOAA

SAN FRANCISCO — Lights from human activity shine brightly in a collection of new images showing Earth at night more clearly than ever before. Dubbed “Black Marble,” the high-resolution images were released December 5 at a meeting of the American Geophysical Union.

The pictures come from an instrument on board the Suomi satellite, a joint venture between NASA and NOAA. The instrument’s “day-night” band takes pictures in low-light conditions by adjusting the exposure so that bright pixels don’t oversaturate and dim ones don’t vanish into oblivion.

Scientists are using the resulting mosaic pictures to study patterns such as how Manhattan sank into semi-darkness after Hurricane Sandy and how geography forces people into settlement patterns, such as along the densely populated Nile in Egypt. Light-pollution experts also scrutinize such images to see where electricity is being wasted by shining light into the night sky.