The discovery of rings around Jupiter, as well as those around Uranus and Neptune, was another in the long list of surprises that the Voyager missions sent back as they made their journey through the outer solar system. The rings of Jupiter are far too thin to be seen from Earth and are even too thin for the powerful Hubble Space Telescope to see.
This image of Jupiter and its rings was taken by the Galileo mission and should give you a good idea of just how thin the rings really are.

The sight of one of Jupiter's Galilean moons above the rings makes for a very impressive image as you can see from the picture at the right. The Galileo spacecraft took this very impressive image of the icy moon Europa apparently hovering just above Jupiter's ring system.
Information sent back by the Galileo spacecraft have enabled scientists to determine that the rings are made up of dust particles from Jupiter's moons. The current explanation for this is that Jupiter's moons have been hit by comets and other bodies and the dust resulting from these impacts have formed into the planet's ring system.