The molten core, which swirls about 2200 km beneath our feet, generates Earth’s geomagnetic field as it moves. By measuring small changes in the magnetic field, scientists have historically observed the core flowing mainly westwards. But in 2010, it unexpectedly changed direction deep beneath the Pacific Ocean and started moving strongly eastwards. The reasons for this unexplained reversal in the flow of molten material are still a mystery but satellites, including ESA’s Swarm and CryoSat, provided data that has now been analysed and published.

The study, published in the Journal Studies of Earth’s Deep Interior, analyses both ground observations and satellite data between 1997 and 2025. The video shows the large scale of flow in the molten core between 1997 and 2025. The overturn of the flow below the Pacific and the main stable structures of the flow have been isolated. Each arrow indicates the movement of the core liquid horizontal to Earth’s surface.

Read full story: Insights into Earth’s molten outer core from space