QUESTION:
How did the rings around Saturn get there?

ANSWER from Ted Dunham on May 9:
There is still some question about how Saturn got its rings.  The
most likely way is that a small moon got too close to Saturn and broke apart
because of the force of the tides.  The amount of material in the rings is
about the same as Saturn's small moon Mimas.  It is also possible that 
the rings are left over from the time when Saturn formed, but they don't
seem to be that old.