translate English to French: If you now imagine the room to be a sphere, and the that you are moving around the light at a constant speed, you can see how there is a smooth transition of stars from season to season, and that the changing sky is due purely to the motion of the Earth around the Sun.
Vous comprendrez pourquoi les étoiles se succèdent si uniformément d'une saison à l'autre. La métamorphose du ciel résulte entièrement du voyage de la Terre autour du soleil.