[DB 1507 (36); OAB 77] Like the question of Titan's methane, the question of the instability of Saturn's rings is an Unexplained Mystery that arises primarily as a result of insufficient data. Saturn's ring system is extremely complex, and we have had very few opporunities to study it up close (Pioneer 11 and the two Voyager spacecraft were all brief flybys with limited instrumentation). At our present state of knowledge, it is true that we do not know how Saturn's rings could have remained stable for longer than 10 to 100 million years. There are two main possible solutions to this problem: either the secret of the rings' stability is yet to be discovered, or the ring system is in fact much younger than Saturn itself. The second possibility is intriguing: the rings of giant planets may be cyclical, being regenerated by material that strays to near and is pulled apart by the planet's gravity, and then dissipating again over time. In fact, if Saturn's rings are due to a relatively recent such event, it would explain why Saturn is the only one of the four giant planets to have such a large ring system. Whatever the solution to this problem may be, we should learn a great deal about it from the Cassini spacecraft, due to arrive at Saturn in 2004. And in any case, even if it does turn out that Saturn's rings are relatively young, there is no reason why such a discovery should have any implication for the age of Saturn itself, much less the age of the Solar System or the Universe.