Privileged Planet: core movements (Introduction)

by David Turell , Sunday, January 07, 2024, 16:19 (322 days ago) @ David Turell

Makes the life-saving magnetic field:

https://www.popularmechanics.com/science/environment/a46191284/why-earths-core-mysterio...

"Few things are more vital to our existence—yet less understood—than the Earth’s inner core. Surrounded by a cocoon of liquid metal (aka the outer core), this solid mass of nickel and iron at the planet’s heart is what creates the Earth’s magnetic field, which protects all life from harmful solar radiation. Despite this essential, life-sustaining function, the inner core remains a huge mystery for geologists eager to understand the deep workings of the world.

***

"Their study, published this month in the journal Nature Communications, argues that this “Inner Core Wobble” (ICW) occurs every 8.5 years and implies that the static tilt of the core is 0.17 degrees different from the rotation axis of the mantle. The team came to this conclusion by studying polar motion (PM) and length-of-day changes (ΔLOD).

“'This implies a potential eastward differential rotation angle of the inner core of less than 1 degree and misalignment in the symmetry axes of the lower mantle/core-mantle boundary layer with the upper mantle,” Wuhan University research and study co-author Hao Ding said in an interview with Phys.org. “These deviations offer valuable constraints for the 3D density model of the mantle and question assumptions in the liquidity-core oblate, highlighting potential deviations from a perfectly spherical form calculated using traditional theories.”

"In another study from 2018, Ding first discovered evidence of the 8.5-year harmonious signal while studying the subtle movement of Earth’s poles over time. The core’s tilt, as compared to the mantle, goes against the typical hypothesis that the tilt of those two layers are in sync. Ding also thinks that the origin of this “signal” could explain why the Earth’s magnetic field changes over time.

***

"While this theory explains some of the mysterious oddities surrounding the Earth’s inner core, it’s only one theory among several. As Vice notes, one idea points the finger instead at the push-and-pull forces between the Earth’s magnetic field and its gravitational field. Another focuses on the irregular shape of the core itself."

Comment: without the magnetic field we would be open to various killing rays from the universe. Our Earth's core is designed to produce the field.