Jakarta –
Scientists in China recently made new discoveries about the heart of our planet. Every 8.5 years, the Earth’s core vibrates on its rotation axis.
This shift is most likely caused by a small misalignment between the Earth’s inner core and mantle to the layers beneath the Earth’s crust, according to a new study by researchers.
Starting about 2,896 km below the surface, Earth’s core divides into a swirling liquid outer boundary and a mostly solid inner layer. This region is partly responsible for a number of our planet’s geophysical dynamics, from the length of each day to the Earth’s magnetic field which helps protect humanity from the harmful rays emitted by the Sun.
This newly discovered tilt of the inner core could ultimately cause changes in the shape and motion of the liquid core leading to potential shifts in Earth’s magnetic field, according to research published December 8, 2023 in the journal Nature Communications.
To better understand how the Earth’s core works, geophysics researchers led by Hao Ding of Wuhan University, in 2019 analyzed the movement of the Earth’s rotation axis relative to its crust, known as polar rotation.
They detected slight deviations in polar motion that occur approximately every 8.5 years, indicating the potential for a wobble of the inner core, similar to the wobble of a spinning top.
In their latest study, Ding and his co-authors further confirmed this cycle by measuring small shifts in day length across the globe controlled by periodic movements of Earth’s rotational axis and comparing them to variations in polar motion they had previously observed.
“Their data shows that this wobble is most likely due to the 0.17 degree tilt between the Earth’s inner core and the mantle, which contradicts the traditional Earth rotation theory which assumes that the rotation axis of the Earth’s inner core and the rotation axis of the Earth’s mantle coincide,” Ding said as quoted by Live Science, Tuesday (9/1/2024).
This tilt may indicate that the Earth’s northwest hemisphere of the inner core may be slightly denser than the other layers, and that there is also a difference in density between the Earth’s inner and outer core.
“This new study helps distinguish the composition between the metals in the solid inner core and the liquid outer core and estimates the direction and speed of the inner core wobble,” said John Vidale, professor of Earth sciences at the University of Southern California.
“There is nothing here that can save humanity. But this effort adds to the basic foundation for understanding our planet,” he continued.
The research team ruled out atmospheric, oceanic and hydrological influences that might cause deviations in polar motion other than inner core wobbles. However, it is difficult to ensure that these sources did not play a role because many experts were required to compile the analysis conducted in this study,” according to Vidale.
In the future, this discovery could help researchers understand the dynamics of the Earth’s core and the processes that impact humanity, from earthquakes to changes in the magnetic field.
Watch the video “Study: The Earth’s Core May Start Rotating in the Opposite Direction”
(rns/fay)
2024-01-09 05:15:29
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