> In historic times astronomers invented crystalline spheres [1] that carried stars to save the stationary earth doctrine. My understanding is that the ancient

> In historic times astronomers invented crystalline spheres [1] that carried stars to save the stationary earth doctrine. My understanding is that the ancients used the celestial spheres to explain the movements of the planets around the Earth - the spheres themselves moved relative to each other hence the different speeds and courses of the planets. The spheres could be made to work regardless of whether the Earth spins or not. If the Earth is static, then the spheres can still use their relative motions to explain the motion of the planets. In contrast, if the Earth is spinning, you add its spin to that of the spheres and an observer on Earth couldn't tell the difference.