Saturn
Saturn is second planet in size and mass after Jupiter and is the only one with a ring system visible from Earth. The equatorial and polar diameters are respectively 120,536 and 108,728 km. This effect is produced by the quick rotation of the planet, its fluid nature and its relatively low gravity. Saturn is the only planet in the solar system with a lower density than water (690 kg / m³) The planet is formed about 90% of hydrogen and 5% of helium. Saturn's interior is hot (12000 K at the core) and it radiates more energy into space than it receives from the Sun. Though they look continuous from the Earth, the rings are actually composed of innumerable small particles each in an independent orbit. The ring particles seem to be composed primarily of water ice, but they may also include rocky particles with icy coatings. Like the other jovian planets (called jovian due to its similarity with Jupiter), Saturn has a significant magnetic field.
Saturn rings
The main rings (A and B) and one faint ring (C) can be seen from the Earth. The gap between the A and B rings is known as the Cassini division. In the region inside the ring B there is another ring (C) and one faint ring fine (D). Outside we can distinguish a thin and weak ring called ring F.