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The phenomenon could be part of a natural cycle in the iron flows that give Earth its protective magnetic field.
The cast-iron river that runs about 2250 kilometers deep beneath the Pacific Ocean, in the Earth’s outer core, left scientists surprised when change direction.
The observation offers new data on the behavior of the liquid outer core, which plays an essential role in the formation of Earth’s magnetic field. Without this magnetic shield, the planet would be dangerously exposed to solar radiation.
Researchers at the University of Edinburgh analyzed ground-based observations and satellite data collected between 1997 and 2025.
In a recently published The Journal of Studies of Earth’s Deep Interiorreport that, in 2010, a vast region of iron-rich fluid under the equatorial Pacific Ocean stopped moving slowly westward and began to move quickly east.
A video released by the study authors shows large-scale flow in the molten core between 1997 and 2025.
“Large-scale flow reversal beneath the Pacific raises new questions about the behavior of Earth’s deep interior,” said the study’s lead author, Frederik Dahl Madsenfrom the university’s School of Geosciences, at ESA.
“Scientists now want to understand whether this inversion represents a short-lived fluctuation, part of a repetitive oscillation or a new stable equilibrium in the circulation of the core”, he added.
Second Elisabetta Iorfidaa European Space Agency scientist specializing in Earth’s inner and outer fields, the reversal now observed beneath the Pacific calls into question the idea that the outer core is dominated by a stable westward circulation.
“This study shows that regional changes can emerge quicklyin just a decade,” he said. “The findings could also help scientists investigate possible interactions between the Earth’s outer core, inner core and lower mantle and, in this way, offer new data about the boundary between the core and the mantle, a critical region for the deep dynamics of the planet.”
The latest ESA data suggests that the eastward flow may now be weaken again, after reaching a peak several years ago. This raises the possibility that the phenomenon represents a temporary oscillation or causes part of a longer natural cycle in core dynamics.
These changes occur far below the Earth’s surface, explains , and do not pose any immediate danger for people or the climate. But scientists consider them fundamental to understanding the functioning of the planet and the way in which the outer core generates the Earth’s protective magnetic field.
The magnetic field is not fixed. It slowly changes over time as flows in the core evolve, with effects on areas as diverse as navigation systems, spacecraft operations and space weather models near Earth.
