4. Which planets have rings? What are they made of?
It is now known that all of the outer planets except for Pluto (Jupiter, Saturn, Uranus and Neptune) possess varying numbers of rings. The most famous of all are the rings of Saturn, since they are so easily seen through even a small telescope. The rings of the other outer planets are much fainter and are only known to exist due to photographs sent back from the two Voyager spacecraft.
 |
 |
| Jupiter | Saturn |
 |
 |
| Uranus | Neptune |
Planetary rings are actually made up of thousands of small pieces of debris left over from the formation of the planets. When the giant gaseous planets formed during the early days of our solar system there was a certain amount of debris left over. This debris has spread out over time around the planets and has been orbiting them like small natural satellites ever since. At a great distance reflected sunlight makes them appear to be solid rings surrounding the planets.