Earth's Core Stopped Spinning | UPSC Current Affairs

Description

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Context:

According to a new research, published in the journal ‘Nature Geoscience’, the inner core of Earth seems to have stopped spinning in the same direction as the rest of the planet.

Important Article: https://www.iasgyan.in/blogs/discontinuities-inside-the-earth

Background:

With a radius of almost 2,200 miles, Earth’s core is about the size of Mars. It consists mostly of iron and nickel, and contains about one-third of Earth’s mass.
At the center of Earth is the core, a ball with a mean radius of 3480 kilometres that is composed mostly of iron.
The outer core is liquid while the inner core, with a radius of 1220 km, is solid.
Because the outer core has a low viscosity, it could be rotating at a different rate from the mantle and crust. This possibility was first proposed in 1975 to explain a phenomenon of Earth's magnetic field called westward drift: some parts of the field rotate about 0.2 degrees per year westward relative to Earth's surface.
In 1981, David Gubbinsof Leeds University predicted that a differential rotation of the inner and outer core could generate a large toroidal magnetic field near the shared boundary, accelerating the inner core to the rate of westward drift. This would be in opposition to the Earth's rotation, which is eastwards, so the overall rotation would be slower.

Note: The spinning of the Earth’s core is by the magnetic field that is generated in the outer core that is regulated by the gravitational effects.

New Findings and implications:

Earth’s inner core, seems to have been spinning in the opposite direction in comparison to the rest of the planet.
The rotation of the inner core that is the hot iron ball, which is around the size of Pluto "came to near halt around 2009 and then turned in an opposite direction.

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TRIVIA

According to Researchers, the inner core rotates, relative to the Earth's surface, back and forth, just like a swing.

One cycle of the swing is of around seven decades. This means that it changes direction after every 35 years, the researchers added.

It changed its direction earlier in the early 1970s and the same may happen again in the mid-2040s.

This rotation lines up with changes in what is called the "length of day", the small variations in the exact time it takes the Earth to rotate on its axis.