The Cassini Division Splits Saturn's Rings
The Cassini Division is named for Giovanni Cassini, an astronomer who discovered the gap in 1675. The division exists because of the gravitational pull from Saturn's moon Mimas, which keeps the area clear of many small particles. However, the division is home to some ring material-it simply has much less than its surroundings.
Key Facts In This Video
Jupiter has 3 faint rings, Neptune has 5, and Uranus has 13. (0:23)
Saturn's rings may have formed after a comet or moon entered its Roche limit. (1:05)
Saturn's rings are almost entirely made of water ice. (1:34)