Illustration showing the Earth's magnetic field. This magnetic field (white lines) generated by the eddies (blue spirals) set up in the liquid core. The mantle (solid and semi-molten rock, orange) extends downwards for 2855 kilometres from below the crust. The outer core (yellow-orange) is a liquid layer of iron and nickel, extending downwards for another 2210 kilometres. The inner core (centre) is a solid sphere of iron-nickel alloy, with a radius of around 1278 kilometres. The Earth's magnetic field extends outwards into space for tens of thousands of kilometres, protecting the planet from high-energy radiation from the Sun.