Saturn

Saturn's most striking feature is its system of rings. Other planets in our Solar System also have rings, but none are as spectacular as Saturn's. Galileo Galilei discovered the ring system in 1610, and Giovanni Domenico Cassini described the Cassini Division in 1675. This refers to a large gap between the rings in which the moon Mimas orbits.

Saturn is the second largest planet after Jupiter, but its weight is only about 30% of Jupiter's. As a gaseous planet consisting mainly of hydrogen and helium, Saturn has a very low density. At 0.687g/cm3, this is even lower than that of water under normal conditions and the lowest density of all the planets in our Solar System. Due to the gaseous structure, the equatorial regions of the planet rotate significantly faster than the polar regions.

Saturn's hydrogen-heavy atmosphere becomes liquid towards the centre due to high pressure. The hydrogen takes on a metallic form farther in. A very hot rock core lies underneath. This causes Saturn to radiate more energy than it receives from the Sun. The radiated heat creates winds and moves the clouds in the gaseous part of the planet.

Four different probes have carried out measurements to date on Saturn: Pioneer in 1979 and Voyager 1 and 2 in 1980 and 1981 respectively. In 2014, the Cassini-Huygens space probe also flew past Phoebe, one of Saturn's moons. It burnt up as planned in Saturn's atmosphere in 2017.