City lights at night are a fairly reliable indicator of where people live. But this isn’t always the case, and the Korean Peninsula shows why. As of July 2012, South Korea’s population was estimated at roughly 49 million people, and North Korea’s population was estimated at about half that number. But where South Korea is gleaming with city lights, North Korea has hardly any lights at all—just a faint glimmer around Pyongyang.
On September 24, 2012, the Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi NPP satellite captured this nighttime view of the Korean Peninsula. This imagery is from the VIIRS “day-night band,” which detects light in a range of wavelengths from green to near-infrared and uses filtering techniques to observe signals such as city lights, gas flares, auroras, wildfires, and reflected moonlight.
The top, wide-area image shows the Korean Peninsula, parts of China and Japan, the Yellow Sea, and the Sea of Japan (also known as the East Sea). The white inset box shows the lights of fishing boats in the Yellow Sea, and many of the boats appear to form a line, as if marking a watery boundary between nations.
Following the 1953 armistice ending the Korean War, per-capita income in South Korea rose to about 17 times the per-capital income level of North Korea, according to the U.S. Central Intelligence Agency. Worldwide, South Korea ranks 12th in electricity production, and 10th in electricity consumption, per 2011 estimates. North Korea ranks 71st in electricity production, and 73rd in electricity consumption, per 2009 estimates.
NASA Earth Observatory image by Jesse Allen and Robert Simmon, using VIIRS Day-Night Band data from the Suomi National Polar-orbiting Partnership. Suomi NPP is the result of a partnership between NASA, the National Oceanic and Atmospheric Administration, and the Department of Defense. Caption by Michon Scott.
While city lights at night serve as a good proxy for population density, North Korea provides a dark exception.
Satellite images of Earth at night have been a curiosity for the public and a tool of fundamental research for at least 25 years. They have provided a broad, beautiful picture, showing how humans have shaped the planet and lit up the darkness.