Origin of Oort cloud
1975–80; after Dutch astronomer Jan Hendrik Oort (1900–1992), who proposed its existence
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
in reference to the hypothetical cloud of small objects beyond Pluto that become comets, proposed 1949 by Dutch astronomer Jan Hendrick Oort (1900-1992), and named for him by 1968.
Online Etymology Dictionary, © 2010 Douglas Harper
- 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.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.