Oort cloud
[ awrt, ohrt ]
/ ɔrt, oʊrt /
noun Astronomy.
a region of the solar system far beyond the orbit of the dwarf planet Pluto in which billions of comets move in nearly circular orbits unless one is pulled into a highly eccentric elliptical orbit by a passing star.
Compare Kuiper belt.
Origin of Oort cloud
1975–80; after Dutch astronomer Jan Hendrik
Oort (1900–1992), who proposed its existence
Scientific definitions for oort cloud
Oort cloud
[ ôrt ]
A sphere-shaped mass of more than 100 billion comets that makes up the outer edge of the solar system, surrounding the Kuiper belt and the planets. Some comets from this area are drawn into the inner solar system by passing stars and other forces and take more than 200 years to make one complete orbit of the Sun. Compare Kuiper belt.