Something strange has been going on beneath our feet. The rotation of Earth’s inner core is not in sync with the rotation of the mantle, creating wobbles that affect the movement of the poles and even the length of the days Earth experiences.
The fluctuations are small, so they are not responsible for how quickly the weekend passes, but they do create a visible effect. This is an effect that is difficult to explain without internal core displacement or movement.
The inner core is the very center of the Earth, a 2,440-kilometer (1,520-mile) diameter sphere made primarily of iron and nickel. Surrounding it is an outer core of molten liquid metal that is 2,260 kilometers (1,400 miles) thick. The outer core is the main source of the planet’s magnetic field and lies beneath a thick mantle. The new study suggests that the axis of rotation of the inner core is offset by 0.17 degrees compared to the rotation of the mantle.
The researchers say this value is much smaller than the previous assumption of 10 degrees used in some geodynamic models. Interestingly, the tilt is now pointing west, suggesting that the northwestern hemisphere of the inner core may be slightly denser than the rest. The tilt between the mantle and the core is static. It doesn’t change over time.
Polar motion and variations in day length were key data that led researchers to explore the strange behavior between the core and mantle. There are approximately 24 hours in a day, but there is some variation depending on a variety of factors. The atmosphere, the tides, the movement of continents, and the melting of glaciers are some of the influences that can create change.
Since the late 1980s, researchers i doubt it The coupling between the inner core and the mantle may be the cause of the 10-year periodic fluctuations. The study estimates the wobble to be 8.5 years plus or minus 75 days. Signals of polar motion were discovered in 2018, and when combined with photoperiod fluctuations, researchers concluded that they were caused by the same process: small shifts.
The wobble and misalignment suggest that the outer and inner cores are not only in different states, but also solid and liquid. There is also a difference in density between the two.
This study nature communications.