The movement of molten metals in Earth's outer core generates a vast magnetic field that protects the planet from potentially harmful space weather. Throughout Earth's history, the structure of the magnetic field has fluctuated. However, data suggest that averaged over sufficient time, the field may be accurately approximated by a geocentric axial dipole (GAD) field—the magnetic field that would result from a bar magnet centered within Earth and aligned along its axis of rotation.
source https://phys.org/news/2021-02-antarctic-lava-yields-clues-earth.html
