The planet is continually being observed and imaged by satellites.
Before 1972, satellites weren’t designed to study or monitor Earth’s surface. Instead, they were mainly used for military missions. Imagery was commercialized in 1984.
Earth observation satellites specifically intended for non-military applications were designed for long-term global observations of the land surface, oceans, biosphere, and atmosphere.
Satellite instruments became equipped to measure vegetation coverage, sea-ice fluctuation, sea level and sea surface temperatures, concentrations of atmospheric gases, and many others. These observations are applied to meteorological forecasting, environmental monitoring, disaster monitoring, and cartographic purposes.