Composite of images showing the varying angles presented by Saturn磗 rings. The ring angle changes from edge on not shown to the widest angle at the end of the sequence with a period of around 15 years, as seen from Earth. The rings are formed of small particles of water ice, and are only around 20 metres thick, thus they seem to disappear when seen edge on. Images taken by the Hubble Space Telescope.brRestrictions: