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South America, night-day satellite image. This composite image of the Earth is set against a background of stars, and is centred on South America. North is at top. The left-hand half of the globe is at night, and city lights (yellow) show areas of dense population. The right-hand half of the globe is lit by sunlight and shows clouds (white), seas and oceans (blue), and land cover: vegetation (green) and arid areas (brown). This day-night line is the dawn terminator. This image, from 2001, combines data from a variety of satellite sensors (AVHRR, SeaWiFS, MODIS) for the sunlit areas. Night-time data is from the Defense Meteorological Satellite Program (DMSP). For the separate images, see E074/086 and E050/684. (KEYSTONE/SCIENCE PHOTO LIBRARY/NASA/NOAA)