NASA has just released the first new Earth at night map since 2012. This nighttime global composite map of our home planet, dubbed the Black Marble, provides researchers with a unique perspective of human activities worldwide. By studying Earth at night, researchers can investigate how cities expand, monitor light intensity to estimate energy use and economic activity, and aid in disaster response.
NASA scientists examined the different ways that light is radiated, scattered and reflected by land, atmospheric and ocean surfaces. Scientists say that the principal challenge in the nighttime satellite imaging was accounting for the phases of the moon, which constantly varies the amount of light shining on Earth, though in predictable ways. Likewise, seasonal vegetation, clouds, aerosols, snow and ice cover, and even faint atmospheric emissions (such as airglow and auroras) change the way light is observed in different parts of the world. The new maps were produced with data from all months of each year. The research team led by Earth scientist Miguel Román of NASA’s Goddard Space Flight Center in Greenbelt, Maryland wrote code that picked the clearest night views each month, ultimately combining moonlight-free and moonlight-corrected data.
You can zoom into any place on Earth using NASA's "Earth at Night Map" online.
Photo credit: NASA Earth Observatory images by Joshua Stevens, using Suomi NPP VIIRS data from Miguel Román, NASA's Goddard Space Flight Center
Video credit: NASA’s Goddard Space Flight Center