planetary rings


Also found in: Dictionary.

planetary rings

Flat rings of material – consisting of numerous small bodies and particles of rock and ice – known to surround the four giant planets. Saturn's rings were discovered in 1610 by Galileo but not recognized for what they were until Christiaan Huygens correctly described them in 1659. NASA's Pioneer and Voyager spacecraft confirmed that the rings were indeed made up of innumerable smaller bodies ranging in size from a fraction of a millimeter to 30 meters across. The two Voyager spacecraft confirmed the existence of Jupiter's rings, Uranus' rings, and Neptune's rings, which are all much fainter than those of Saturn, All these ring systems probably came into being either because a satellite was shattered to fragments through collision with an asteroid or comet or because a satellite or captured interplanetary body came too close to the planet concerned and was torn apart by gravitational tidal forces. See also Roche limit.
References in periodicals archive ?
Planetary Rings Larry Esposito (Cambridge University Press, 2006).
WHENEVER I talk to solar-system experts, they point to the University of Arizona Press title Planetary Rings as one of their bibles.
Other than Saturn's E ring, whose tiny water-ice particles are supplied by geysers on the moon Enceladus (see page 19), all other planetary rings are reddish.
Mechanisms of such clustering may play a role in natural phenomena such as the formation of planetary rings and movement of sea-ice floes.
Many of the processes going on in planetary rings are very similar - though different in detail - to the processes that likely occurred in the formation of the solar system.
These putative bands have been modeled theoretically for decades--they have the distinction of being the longest-studied planetary rings whose existence has yet to be verified
Synnott notes that the pictures have yielded "not a hint" of the short, comma-shaped arcs that may be Neptune's odd version of planetary rings.
Nicholson, a Cornell University specialist in planetary rings and the dynamics of natural satellites, is a member of the Visual-Infrared Mapping Spectrometer science team on the Cassini mission to Saturn.
After all, the Pioneer and Voyager spacecraft that went to Jupiter, Saturn and Uranus passed through the asteroid belt, planetary rings and radiation belts with little or no damage.