Earth’s molten outer core behaves in chaotic and unexpected ways

Scientists are working to solve the mystery of Earth’s molten outer core, which lies more than 2,000 kilometers beneath our feet.

By Claire Cameron edited by Lee Billings

Earth’s molten outer core is essential for life on our planet. Extending some 2,900 kilometers below the surface, it is a vast “sea” of liquid iron that swirls around the solid planet. inner core. This movement generates the Earth magnetic fieldwhich protects our planet from harmful cosmic radiation.

The measurements show that the inner core spins eastward, just like Earth itself, but molten metal from the outer core tends to flow westward. But now, a new analysis of data from European Space Agency (ESA) satellites and other sources reveals something astonishing: Starting in 2010, this flow abruptly changed direction eastward in an outer core region beneath the Pacific Ocean. The exact reason for this remains a mystery, but researchers are gradually gleaning clues.

Using archival observations collected between 1997 and 2025 by sources such as ESA’s Swarm and CryoSat-2 missions, which study Earth magnetic field and polar ice caps, respectively, scientists identified the anomalous flow of a ball of iron-rich liquid rock beneath the Pacific that changed direction, flowing strongly eastward rather than westward for about a decade before weakening again in 2020. studyrecently published in the Journal of Studies on the Deep Interior of the Earth, also incorporated data from Germany’s CHAMP mission and Denmark’s Ørsted mission, as well as ground-based observatories.

On supporting science journalism

If you enjoy this article, please consider supporting our award-winning journalism by subscribe. By purchasing a subscription, you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.

The results suggest that the large-scale movements of the outer core are much less stable than previously thought. They also indicate that the outer core can be influenced by hidden changes occurring within the inner core.

“Large-scale flow reversals beneath the Pacific raise new questions about the behavior of Earth’s depths,” said doctoral student Frederik Dahl Madsen. student at the University of Edinburgh and lead author of the study, in a statement.

Other data suggest that something was indeed happening in the inner core that may have influenced the change in direction in the outer core, he said.

“Scientists now want to understand whether the reversal represents a short-lived fluctuation, part of a repeated oscillation or a new stable equilibrium for the central circulation,” he said. “Continued monitoring will be essential to determine flow trends in the years to come.”

Understanding what is happening so deep inside the Earth is crucial to understanding how our planet works, how it changes over time, and how these changes affect its protective magnetic field. It turns out that protecting our satellites and even Earth’s biosphere from radiation from space sometimes requires looking deeper within.

“This research raises fascinating questions about how Earth’s deepest layers are dynamically connected,” said Elisabetta Iorfida, ESA Swarm mission scientist, in the same statement.

“As the magnetic field continues to evolve,” she added, “satellite missions provide an increasingly detailed view of the dynamic processes occurring deep within our planet, revealing that the Earth’s core may be far more variable and complex than once thought.”