A planetary ring is a ring of cosmic dust and other small particles orbiting around a planet in a flat disc-shaped region. The most notable planetary rings known in the Solar System are those around Saturn, but the other three gas giants of the Solar System (Jupiter, Uranus and Neptune) also possess ring systems of their own.
Reports in March 2008 have suggested that the Saturnian moon Rhea may have its own tenuous ring system, which would make it the only moon known to possess a ring system. A later study published in 2010 revealed that imaging of Rhea from the Cassini mission was inconsistent with the predicted properties of the rings, suggesting that some other mechanism is responsible for the magnetic effects that had led to the ring hypothesis.
Read more about Planetary Ring: Overview
Famous quotes containing the words planetary and/or ring:
“We cannot cheat on DNA. We cannot get round photosynthesis. We cannot say I am not going to give a damn about phytoplankton. All these tiny mechanisms provide the preconditions of our planetary life. To say we do not care is to say in the most literal sense that “we choose death.””
—Barbara Ward (1914–1981)
“These words dropped into my childish mind as if you should accidentally drop a ring into a deep well. I did not think of them much at the time, but there came a day in my life when the ring was fished up out of the well, good as new.”
—Harriet Beecher Stowe (1811–1896)