From the March 2010 issue

Why didn’t any of the other gas giants (Jupiter, Uranus, or Neptune) develop a large ring system like Saturn?

Aykut Altug, Los Angeles
By | Published: March 29, 2010
Saturn and its ring system.
European Southern Observatory

Saturn’s ring system, however, is unusual in two ways. So the mystery is not why the other three planets didn’t develop large, bright, icy ring systems, but why Saturn did!