Close up of the rings of Saturn, 1981.
© National Aeronautics & Space Administration / Science & Society
This picture, showing dozens of ringlets and divisions in Saturn's rings, was taken by one of the two Voyager spacecraft launched in 1977 to explore the planets in the outer solar system. Both flew past Jupiter in 1979 and reached Saturn in late 1980 (Voyager 1) and August 1981 (Voyager 2). The rings are composed of ice and ice-coated dust and rock. Their origin and formation are not precisely understood, but it seems that tidal effects caused by some of Saturn's moons play a role in maintaining their structure. The ring system is 250,000 kilometres in diameter, but les than 1 kilometre thick.