Planets & Solar System
Saturn inside and out Saturn is often compared with Jupiter, but it can hold its own
Saturn is a gas giant as it has no solid surface and is mostly composed of gas. But it does have a rocky core, which is similar in composition to the Earth’s. Comprising iron, nickel and silicate rock, it is estimated to be between 10 and 20 times the size of the Earth’s core. Surrounding the core, there’s a layer of ice made of ammonia and other elements, then a layer of highly pressurised metallic hydrogen, and finally molecular hydrogen that changes from a liquid to a gas. The outer layers of the planet are different types of ice, including ammonia, ammonium hydrosulphide and water. The cloud cover is coloured yellow by ammonia. Density, pressure and temperature all increase as you pass through the atmosphere and into the core, resulting in a very hot interior at about 11,700°C (21,000°F). Saturn sends out more than twice the energy it receives from the Sun. Some of this is due to gravitational compression, but we aren’t sure if that can account for such a huge energy output. One possibility is an interaction between helium and hydrogen in the atmosphere, which may put out heat in the form of friction. Saturn has a magnetic field 578 times stronger than Earth’s. Scientists believe that the metallic hydrogen layer generates an electric current that is responsible for the magnetic field, called a metallic-hydrogen dynamo. The magnetic field is a dipole, with north and south poles. Aside from the rings, one of the most interesting features of Saturn is its auroras. These beautiful light displays have been captured at both the north and south pole regions by the Hubble Space Telescope and the Cassini probe, and appear as circles of light around each pole.
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Molecular hydrogen Liquid metallic hydrogen Ice Rocky core
