Streetlights contribute less to nighttime light emissions in cities than expected

When satellites take pictures of Earth at night, how much of the light that they see comes from streetlights? A team of scientists from Germany, the USA, and Ireland have answered this question for the first time using the example of the U.S. city of Tucson, thanks to “smart city” lighting technology that allows dimming. The result: only around 20 percent of the light in the Tucson satellite images comes from streetlights.