Planetary Rings  

 

Saturn's rings were discovered by Galileo in 1610 (although he didn't realize what they were).

 
(view from Cassini orbiter, not Galileo's telescope!)

notice gaps and different rings
 

 
 
But in fact all the gas giants have rings:
Backlit picture of Jupiter from Voyager 2

notice how thin they are!



 
 
Image of Uranus & rings from Hubble Space Telescope:

 
 
 
 
Neptune's rings...
...and ring arcs


So what are they? Not solid objects: Instead they are vast sheets of small water ice particles (few cm to a few meters in size) all moving individually. Schematically:


Where'd they come from?

More work is needed...