The lesson was about precession.
Precession means movement. When anyone mentions precession as in ‘Precession of the Equinoxes’ or ‘Precession of the North Pole’ or ‘Precession of the Stars’, remember - Only the Earth Moves ......The Entire Earth!
The lesson started with precession of the equinoxes, every equinox was a little further west than the previous one.
This was accompanied by a corresponding movement of the North Pole.
The North Pole, we were told was moving very slowly away from pointing towards Polaris and would in time point towards another star.
Combined with the daily rotation of the earth, this precession meant that the North Pole was moving like a child’s spinning top.
Later I borrowed my kid brothers spinning top to see for myself what it looked like. I came to the conclusion that the precession effect occurred just before the top fell over and started rolling on the floor.
I decided that meant trouble for the Earth if it behaved liked that,- there’s no floor in space to stop it turning over.
