Using satellite data, researchers have discovered that our planet’s outer core – which usually flows round the inner core in a westerly direction – rapidly changed course in 2010.
Unexpected changes
The reason for this surprising reversal in movement, from west to east, is still a mystery. However, scientists believe it could hold the key to understanding Earth’s magnetic field, which protects our planet from harmful cosmic radiation.
Scientists from the School of GeoSciences and the British Geological Survey analysed data from the European Space Agency’s (ESA) Swarm and CryoSat-2 satellite missions between 1997 and 2025 to map the magnetic field with exceptional precision.
By flying in carefully coordinated orbits, the satellites can distinguish magnetic signals originating from earth’s core from those produced by the world’s crust, oceans and upper atmosphere.
Magnetic field
Through measuring changes in the magnetic field, the team detected an irregular flow of iron-rich liquid rock beneath the Pacific Ocean. This changed from moving weakly westward to flowing strongly to the east around 2010, before weakening again in 2020.
Our planet's magnetic field is generated from electric currents produced by the movement of molten iron and nickel found in the outer core.
Previous research has shown the magnetic field is not fixed and slowly changes over time as the core flow evolves. This can affect everything from navigation systems to spacecraft operations.
Significant findings
Understanding how and why the earth’s core changes is crucial for gaining new insights into how our planet works, experts say.
The study, published in the Journal of Studies of Earth’s Deep Interior, incorporated data from Germany’s CHAMP mission and Denmark’s Ørsted mission.