Good questions. Real sources.

Each number is tied to an independently published source and a reference period. Open a measure to see its definition and provenance.

The planet behind the data

Earth surface and clouds by Solar System Scope, licensed CC BY 4.0. Night lights use NASA’s 2016 Black Marble, by NASA Earth Observatory / Joshua Stevens, using Suomi NPP VIIRS data from Miguel Román, NASA GSFC. The grayscale composite is resized and given a warm tint for this view. Regional zoom loads more detailed night imagery and daytime tiles from NASA GIBS Blue Marble Next Generation. These are historical composites, not live satellite images. Country boundaries use Natural Earth public-domain geometry. Flags use the MIT-licensed flag-icons package. Cloud and city-light textures are illustrative composites, not current satellite observations.