The Lights of Earth: United States

The Lights of Earth can be seen from space. Human-made lights highlight particularly developed or populated areas of the Earth's surface, including the seaboards of Europe, the eastern United States, and Japan. Many large cities are located near rivers or oceans so that they can exchange goods cheaply by boat. Particularly dark areas include the central parts of South America, Africa, Asia, and Australia. The above image is actually a composite of hundreds of pictures made by the Defense Meteorological Satellite Program (DMSP) currently operates four satellites carrying the Operational Linescan System (OLS) in low-altitude polar orbits. Three of these satellites record nighttime data. The DMSP-OLS has a unique capability to detect low levels of visible-near infrared (VNIR) radiance at night. With the OLS 'VIS' band data it is possible to detect clouds illuminated by moonlight, plus lights from cities, towns, industrial sites, gas flares, and ephemeral events such as fires and lightning-illuminated clouds. The Nighttime Lights of the World data set is compiled from the October 1994 - March 1995 DMSP nighttime data collected when moonlight was low. Using the OLS thermal infrared band, areas containing clouds were removed and the remaining area used in the time series.

See http://visibleearth.nasa.gov/cgi-bin/viewrecord?5826