Even at night, our planet is never completely dark. Light pollution is something we try to get away from when viewing the night sky. Now imagine how the night side of Earth looks from space. One of NASA’s satellites took on the task to map out this scene in an attempt to help study human activity.
A new video released by NASA and the National Oceanic and Atmosphere Administration (NOAA) offers an unprecedented look at the entirety of the Earth's nighttime surface as seen from outer space.
The 30-second video stitches together 2.5 terabytes of image data taken during 312 orbits of the planet by NASA's Suomi NPP satellite, which was launched in October 2011.
The video opens with a view of the Asia-Pacific rim, with the city lights of Japan and the heavily populated areas of China's coastal regions near the center of the frame. The Earth's rotation then brings the lights of the Indian subcontinent and the Middle East into view, followed by Europe and the mostly-dark continent of Africa.
Finally, the Americas rotate into view, with the heavily-populated eastern United States outshining the western half of the country and the most densely populated areas of Central and South America.
Light from auroras, wildfires, and other stray light sources were filtered from the video in order to emphasize the city lights. “Nothing tells us more about the spread of humans across the Earth than city lights,” said NOAA scientist Chris Elvidge. “Even after 20 years, I'm always amazed at what city light images show us about human activity.”
Data from the Suomi NPP satellite is used to provide government weather authorities with advance notice of the potential for dangerous weather conditions.