New research reveals Earth’s inner core “paused” and now reversing
According to NASA, the inner core of the Earth is located deep inside and extends for about 746 miles. It is mostly made of pure, solid iron. Perhaps while it has been widely assumed and verified via studies that the inner core rotates, a new study reveals it may have “paused” its spin and even reversed.
The Earth’s magnetic field is caused by the liquid outer core that encases the inner core. NASA claims that the magnetic field is produced by the movement of molten iron and nickel in the outer core, which generates electrical currents. According to Nature, the outer core also permits the inner core to rotate independently.
Though scientists lack a direct method of monitoring the core, they may study the effects of earthquakes and nuclear testing from the Cold War era on seismic waves that reach the centre of the Earth. Scientists Yi Yang and Xiaodong Song from Beijing’s Peking University used this method in their latest study, which was released Monday in the journal Nature Geoscience.
The inner core’s rotation appears to have “paused” between 2009 and 2020, according to Yang and Song’s examination of seismic waves created by comparable earthquakes dating back to the 1960s, and may even be reversing “by a small amount.”
This must be alarming to you. It’s probably not the first time our inner core has stopped. However, they now believe that the shift is “associated with a gradual turning-back of the inner core as part of an approximately seven-decade oscillation.”
Study findings from Yang and Song point to “another overturn or a slowdown of the rotation around the early 1970s.”
Seismologists have shown that variations in the speed at which seismic waves travel through the inner core correlate with “with changes in several other geophysical observations, especially the length of day and magnetic field,” both of which are affected by the motion of the inner core.
Although the shifts are “valid,” the findings of Yang and Song may not represent what’s actually occurring deep within our globe. A professor of earth sciences at the University of Southern California who was not involved in the study, John Vidale, told The Wall Street Journal that there are “several competing ideas” concerning the Earth’s core.
These include the ideas that the inner core’s rotation stops in the early 2000s and that it reverses more frequently than the 70 years Yang and Song determined.
Vidale told The New York Times that “No matter which model you like, there’s some data that disagrees with it,”
Vidale recently co-authored a paper showing that the inner core’s spin shifted between 1969 and 1974, and that it appears to oscillate “a couple of kilometers every six years.”