Polaris Wasn’t Always the North Star: How Earth’s Wobble Shifts the Celestial Pole
Polaris has been the constant guide for explorers and navigators in the northern hemisphere for thousands of years, hence its other name, the famous North Star. It is significant where it is located near the north rotational axis of Earth, and the whole sky appears to spin about it. But that’s not always been the case, and it won’t always be the case. The planet’s sluggish axial wobble, called precession, makes the pole trace a circle about every 26,000 years, bringing different stars into view over the ages. How Earth’s 26,000-Year Axial Precession Shifts the North Star Over Time As per NASA, gravitational forces from the sun and moon affect the rotation of Earth; these produce a bulge at the equator and axial precession. Every 26,000 years or so, this wobble makes a complete circle, and it makes the celestial pole move on a cycle, pointing to stars in sequence over time. Thuban, in the star constellation Draco, was the closest visible in the sky to the celestial pole some 4,700 years ago. The stars, such as Kochab and Pherkad, were …
