The Oort cloud, named after the Dutch astronomer Jan Oort, sometimes called the Öpik–Oort cloud, is a theoretical cloud of predominantly icy planetesimals proposed to surround the Sun at distances ranging from 2,000 to 200,000 AU.

Discovered: 1950

Discoverer: Jan Oort

Did you know: The Oort Cloud travels the Astronomical Unit; the distance between the Sun and Earth.