The Oort Cloud is a vast, spherical shell of icy bodies surrounding the Solar System, believed to be the source of long-period comets. It encompasses two regions: a disc-shaped inner Oort Cloud (also called Hills Cloud) and a spherical outer Oort Cloud.
It extends from about 2,000 AU to 100,000 AU from the Sun.
Alternatively known as the Öpik–Oort Cloud, it is named after Estonian astronomer Ernst Öpik and Dutch astronomer Jan Oort, who independently hypothesized its existence in the 1930s and 1950s to explain the origin of comets with long orbital periods.
Significant events include the theoretical proposal in 1950 by Jan Oort. Observations of comets like Hale-Bopp (1997) and Hyakutake (1996) are thought to originate from this region, providing insights into the early Solar System's composition.
