Earth’s inner core may be reversing its rotation

Amazing stuff!

Perhaps, geology has more to do with climate change than humans! 😊 The two popular science articles below omit to mention this entirely! You wonder why!

"Earth’s inner core may have temporarily stopped rotating relative to the mantle and surface, researchers report in the January 23 Nature Geoscience. Now, the direction of the inner core’s rotation may be reversing — part of what could be a roughly 70-year-long cycle that may influence the length of Earth’s days and its magnetic field — though some researchers are skeptical.

“We see strong evidence that the inner core has been rotating faster than the surface, [but] by around 2009 it nearly stopped,” says geophysicist Xiaodong Song of Peking University in Beijing. “Now it is gradually mov[ing] in the opposite direction.”"

From the abstract:

"Differential rotation of Earth’s inner core relative to the mantle is thought to occur under the effects of the geodynamo on core dynamics and gravitational core–mantle coupling. This rotation has been inferred from temporal changes between repeated seismic waves that should traverse the same path through the inner core. Here we analyse repeated seismic waves from the early 1990s and show that all of the paths that previously showed significant temporal changes have exhibited little change over the past decade. This globally consistent pattern suggests that inner-core rotation has recently paused. We compared this recent pattern to the Alaskan seismic records of South Sandwich Islands doublets going back to 1964 and it seems to be associated with a gradual turning-back of the inner core as a part of an approximately seven-decade oscillation, with another turning point in the early 1970s. This multidecadal periodicity coincides with changes in several other geophysical observations, especially the length of day and magnetic field. These observations provide evidence for dynamic interactions between the Earth’s layers, from the deepest interior to the surface, potentially due to gravitational coupling and the exchange of angular momentum from the core and mantle to the surface."

From the research article:

"... Interestingly, the same multidecadal periodicity is also well observed in the Earth’s climate system, especially the global mean temperature and sea level rise. An ultimate explanation for the multidecadal climate oscillations is still being sought that includes extraterrestrial origins. On the other hand, high correlations are also found recently, at zero lag, between global mean temperature and −ΔLOD46 and between global mean sea level and magnetic dipole changes. In addition, both vertical and horizontal displacements at the Earth surface can be excited by an oscillating inner core and torsional outer-core flows under gravitational coupling. Consequently, the multidecadal periodicity of the climate system might also originate from the oscillating core–mantle system, through the surface deformations and the exchange of angular momentum from the core and mantle to the surface. As such, our finding"

Earth’s inner core may be reversing its rotation Such a turnaround might sound bizarre, but isn’t likely to have profound effects on life

The Spin of Earth’s Inner Core May Be Changing, Scientists Say (article contains a link to the PDF file) A new study finds our planet’s iron center shifts between spinning slightly faster and slightly slower than the surface—but not all experts agree

Multidecadal variation of the Earth’s inner-core rotation (no public access, but article above contains a link to the PDF file)