Saturn interior, cutaway illustration. The interior of Saturn includes its core of heavy elements (orange), a liquid metallic hydrogen layer (grey), and a gaseous molecular hydrogen envelope (brown). The planet's magnetic field (shown by pink lines) is thought to originate from the top of the metallic hydrogen layer. The interaction of charged particles from the Sun with Saturn's magnetic field and upper atmosphere result in auroras (purple rings) in the planet's polar regions. Saturn, a ringed gas giant planet, is 120,000 kilometres across. Image published in 2017.