The rings of Saturn, 1980.
© National Aeronautics & Space Administration / Science & Society
Saturn was first observed through a telescope by Galileo in 1610, but its rings were not identified until 1659, by Christiaan Huygens. This is a view of the rings taken from the dark side of the planet, a view never seen from Earth. It was taken by one of the two Voyager spacecraft launched by NASA 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, which are composed of ice and ice-coated dust and rock, are 250,000 kilometres in diameter, but les than 1 kilometre thick. 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.