| Themes > Science > Astronomy > The Stars > Stellar Motion > Stellar Motion |
The sky appears to turn once every 24 hours because of the daily rotation of the Earth (the diurnal motion), but the stars appear to be fixed in their relative positions on the celestial sphere. This is an illusion, however, caused by the very large distances to stars. In reality, the stars are in motion with respect to each other and that causes them to slowly change their relative positions. |
|
|