A NASA handout image of the continental United States at night shows a composite assembled from data acquired by the Suomi NPP satellite in April and October 2012 and released Dec 5, 2012. The image was made possible by the 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. [Photo/Agencies]