City lights of the U.S. in 2012

This image of the United States at night is a composite assembled from data acquired by the Suomi NPP satellite in April and October. 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.

See the full-sized version of the image here.