Oort cloud

[ awrt kloud, ohrt ]

noun

, Astronomy.

1. a region of our solar system far beyond the orbit of 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.

Oort cloud

/ ôrt /

1. 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.
2. Compare Kuiper belt

Word History and Origins

Origin of Oort cloud¹

First recorded in 1975–80; after Dutch astronomer Jan Hendrik Oort (1900–1992), who proposed its existence

Example Sentences

And when people are ogling the night sky this week, they should also keep an eye out for two additional celestial sightings — Saturn and the appearance of an ancient Oort cloud comet, she added.

From Los Angeles Times

But, the team calculated, it's slightly more likely that a rogue, Neptune-like planet from another solar system was snagged by the sun's gravity and came to rest somewhere in the Oort cloud.

From Scientific American

The object originates in the Oort cloud, a collection of icy bodies at the edge of the solar system, and its journey to our planet took about 50,000 years.

From BBC

The object originates in the Oort cloud, a collection of icy bodies at the edge of the Solar System.

From BBC

Those long-period comets compose the Oort cloud, or a band of cometary debris on the fringes of the solar system.

From Washington Post