(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
A roughly spherical region of space composed of comet-like bodies and other minor planets and asteroids that orbit distantly in planetary systems
A roughly spherical region of space from 50,000 to 100,000 astronomical units (approximately 1 light year) from the sun; supposedly the source of most comets around the Solar System.
Alternative form of Oort Cloud