3 of 8: This NASA image from a composite assembled from data acquired by the Suomi NPP satellite in April and October 2012 shows the earth's city lights at night. It took 312 orbits to get a clear shot of every parcel of Earth's land surface and islands at night.The new data was mapped over existing Blue Marble imagery of Earth to provide a realistic view of the planet. The image was made possible by the new satellite's "day-night band" of the Visible Infrared Imaging Radiometer Suite (VIIRS), which detects light in a range of wavelengths from green to near-infrared and uses filtering techniques to observe dim signals such as city lights, gas flares, auroras, wildfires and reflected moonlight. (AP Photo/NASA) (AP Photo/ Uncredited)

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