The Earth’s magnetic field is generated deep down the Earth’s core. The flow of liquid iron at the centre of the Earth generates an electric current that produces magnetic fields. Charged metals passing through these fields create electric currents of their own, so the cycle continues. This self-sustaining loop is known as the geodynamo. The spiralling caused by the Coriolis force aligns separate magnetic fields in the same direction. The combined effect of magnetic fields produces one vast magnetic field engulfing the planet.