Earth’s molten core suddenly reversed direction — and scientists don’t know why

Scientists have observed a sudden, unexplained reversal in the flow of molten iron within Earth's outer core beneath the Pacific Ocean, which occurred in 2010. Data from satellite missions like Swarm and CryoSat helped researchers track this shift, which influences the planet's geomagnetic field.
Why it matters
Changes in the Earth's core dynamics are critical for understanding the generation of the geomagnetic field, which protects the planet from solar radiation.
Liquid iron in Earth's outer core can behave in surprising ways. Scientists discovered that a large flow of molten material deep beneath the Pacific Ocean changed direction for reasons that remain unclear. Data from ESA satellites helped researchers trace the shift and build a more detailed picture of what is happening near the center of the planet.
Earth's molten outer core lies about 2200 km below the surface. As this electrically conducting liquid iron moves, it helps generate the planet's geomagnetic field. For many years, scientists studying small variations in that field concluded that much of the outer core was flowing mainly westward.
That pattern changed dramatically in 2010. Beneath the Pacific Ocean, a large region of molten material began moving strongly eastward instead of continuing its weaker westward flow. Scientists still do not know what caused the reversal.
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