Santiago Andrés TrianaSep 1, 2023
The Earth's Free Core Nutation (#FCN) motion is essentially a slight misalignment between the mantle's spin axis and the fluid core spin axis (I greatly exaggerated it here for ease of visualization). The camera starts in an inertial reference frame and slowly moves to the mantle's frame. As seen from the mantle the core seems to wobble!
This is all caused by the Earth's slow #precession. The fluid core lags a bit resulting in a small misalignment.
#Earth #Core #Science #Geophysics #Nutation
Matt WillemsenAug 9, 2023
Mars is Spinning Faster and Faster
Earth is a geologically and biologically active world, so it’s only natural that Earth’s rotation rate is also dynamic. But a recent study shows that the rotation of Mars is also changing, which is a bit of a surprise.
https://www.universetoday.com/162710/mars-is-spinning-faster-and-faster/ #mars #spinning #faster #nutation
Mars is Spinning Faster and Faster

Before it retired, NASA's Mars Insight Lander sent home detailed data about the rotation of Mars. From these data, planetary scientists have discovered that the planet's rotation rate is accelerating by about four milliarcseconds per year, shortening its day by a fraction of a millisecond yearly. Scientists aren't exactly sure why it's happening, but it could be from ice accumulating at the polar caps, changing its center of mass, and increasing its rotation rate.

Universe Today