Oort Cloud

A spherical shell around most stars containing numerous small bodies of cometary material. A typical Oort Cloud is about 0.5 to 1 light year from its primary and has an aggregate mass about that of Terra ( Sol / Solomani Rim 1827); density is thus extremely low. The main constituents of cometary bodies are ice and dust ("dirty snowballs"). Bodies in the Oort Cloud are occasionally perturbed by collisions or by the influence of nearby stars into orbits which pass near the star; these form the visible comets.

The Oort Cloud is named after its discoveror, Terran astronomer Jan Oort.

(MT-ENCYC, 1120)

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