As early as 2019, Ding Hao, a professor at the School of Surveying and Mapping of Wuhan University, and members of his geophysical research team were conducting research on polar motion and discovered that the Earth’s inner core swings around its axis of rotation every 8.5 years.On December 8 last year, they further published a report on the causes of this movement in the journal Nature Communications.Research Papersbelieve that all this is caused by a slight misalignment between the earth’s inner core and the mantle (the lower layer of the earth’s crust, also known as the mantle).
The Earth’s core is composed of an outer core and an inner core. That is, the almost solid inner core is surrounded by a rotating liquid outer core. This subcrustal region, which begins 2,896 kilometers below the surface, is responsible for many of the Earth’s phenomena and activities related to geophysical dynamics, including the length of the day and the Earth’s magnetic field, which protects humans from solar radiation.
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In 2019, researchers discovered the “inner core wobble” after noticing a slight deviation in the polar shift that occurs every 8.5 years. Now, Ding Hao and other researchers have verified the core’s oscillation cycle every 8.5 years by measuring tiny changes in global day length and comparing it with deviations from the polar motion. They ultimately concluded that a 0.17-degree tilt between Earth’s core and mantle caused the wobble. Ding Hao emphasized that this rules out the traditional theory of Earth’s rotation, which “assumes that the rotation axis of the Earth’s core coincides with the rotation axis of the Earth’s mantle.”
John Vale, professor of earth sciences at the University of Southern California, pointed out that this new research helps to identify the differences in the metal composition of the inner and outer cores and estimate the direction and speed of the inner core’s swing. Although this study did not take into account atmospheric, oceanic and hydrological influences, it is undoubtedly a significant discovery and will help researchers in the future understand the dynamic relationship between the Earth’s inner core and natural events that affect humans.
(First image source: shutterstock)
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