The hot centre of the Earth’s interior, composed mostly of nickel and iron. The core is divided into an outer part, which is liquid, and extends from 2,889 km to 5,150 km below the Earth’s surface. The inner, solid part has a radius of 1,220 km. The temperature of the inner core is estimated to be around 5,500 °C. The core is heated by the decay of radioactive elements. The movements of the liquid metal outer core probably generate the Earth’s magnetic field.