Roughly 3,000 kilometres beneath our feet lies Earth’s molten outer core — a churning ocean of liquid metal whose motion generates the magnetic field that shields our planet. And according to scientists, something unexpected has been happening down there.
A reversal beneath the Pacific
For a long time the flow of molten metal moved mostly westward. But around 2010, deep under the Pacific Ocean, it suddenly changed direction and began moving east. Researchers still can’t fully explain the flip.
How we can even know this
Nobody sees the core’s movement directly. Scientists infer it from tiny changes in Earth’s magnetic field, measured by satellites — among them the European Space Agency’s Swarm and CryoSat missions. A new analysis combined surface observations and orbital data spanning 1997 to 2025.
Why it matters
The outer core acts as the invisible engine driving Earth’s geomagnetic field. Any change in its flow draws attention, because it is tied to the stability of the magnetic shield that protects us from charged particles streaming off the Sun.
A mystery that is fading
The eastward flow beneath the Pacific strengthened and peaked around 2020. Since then, the latest data shows it has been weakening. What triggered the shift — and why it is now retreating — nobody yet knows for sure. The study was published in spring 2026.
Photo: NASA / Wikimedia Commons (public domain)