Precession of the Equinoxes

This is a phenomenon that happens to Earth. It is like the behaviour of a spinning top. This results in Earth's axis pointing at slightly different directions over time. The North Star, Polaris in the constellation Ursa Major, would no longer be the polar star in 26 000 years, when Vega, the brightest star in the constellation Lyra becomes the star closest to the North Pole.

The bright star Vega (26 light years away) in the constellation Lyra, the harp.

Video clips on Celestial Precession

The Earth spins on a tilted axis like a top.

Celestial geography | Celestial compass| Celestial ecliptic | Celestial precession | Celestial sphere