Why does Saturn have such spectacular rings?

The answer

Saturn's rings are composed of countless particles of water ice and rocky debris, ranging from microscopic grains to chunks as large as houses. They span 282,000 kilometers in diameter but are astonishingly thin - only about 10 meters thick in most places. The rings may be the remains of a shattered moon, a captured comet, or primordial material that never coalesced into a moon. Surprisingly, Cassini data suggests the rings may be only 10 to 100 million years old - meaning dinosaurs may have looked up at a ringless Saturn. They are also slowly fading and may disappear within 300 million years.