Earth Axial Precession + Nutation 3D

A lit 3D Earth, tilted at its 23.4-degree obliquity, with the spin axis drawn out into space. Because the planet bulges at the equator, the gravity of the Sun and Moon pulls on the bulge and torques the axis sideways, so instead of toppling it sweeps a slow circle, the axial precession, completing one cone every ~25,772 years at 50.29 arcseconds per year. That is why Polaris is only temporarily the North Star. A second, faster effect, the 18.6-year nutation tied to the Moon's orbital-node cycle, adds a small nod of amplitude 17.2 arcsec in ecliptic longitude and 9.2 arcsec in obliquity. The axis position follows the standard closed-form IAU precession-nutation series, which is why the identity of the pole star drifts over the millennia. Drag to orbit the camera, scroll to zoom; the readout shows the simulated year and the current axis angles.