The Oort Cloud is a vast, spherical region of icy bodies that surrounds our solar system, extending from about 2,000 to 100,000 astronomical units from the Sun. It is named after the Dutch astronomer Jan Oort, who proposed its existence in 1950. The Oort Cloud is believed to be the source of long-period comets that enter the inner solar system. The Oort Cloud is not directly observable, as it is too far away and its objects are too small and faint. However, scientists infer its presence through the study of comet orbits and other celestial phenomena. Understanding the Oort Cloud helps astronomers learn more about the formation and evolution of our solar system.