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A swarm of comets orbiting the sun at a distance of one to two light years, proposed as a source of comets that pass near the sun.
[After Jan Hendrix Oort (1900-1992), Dutch astronomer.]
Oort cloud(ôrt, ōrt)
A sphere-shaped mass of comets that makes up the outer edge of the solar system, surrounding the Kuiper belt and the planets. The more than 100 billion comets in this region orbit the sun at a distance of one to two light-years. Comets from this area that come into the inner solar system take more than 200 years to make one complete orbit. Compare Kuiper belt.
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|Noun||1.||Oort cloud - (astronomy) a hypothetical huge collection of comets orbiting the sun far beyond the orbit of Pluto; perturbations (as by other stars) can upset a comet's orbit and may send it tumbling toward the sun|
astronomy, uranology - the branch of physics that studies celestial bodies and the universe as a whole