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| Illustration from La Sphere du Monde by Oronce Fine (1549) (the sublunary elements are fire, air, water and earth; above the moon is aether) |
In most ancient Greek and Roman minds the distant stars were not thought to be suns capable of supporting a family of orbiting planets, and our own sun was not thought to be the central hearth-fire of our familial solar system. Their view of the cosmos was fundamentally different to our own.
“The Greeks, by about 500 BC, were trying to explain the movements of the planets by first assuming the earth to be the centre of the universe. ( … practically everyone before modern times assumed that it was.) A philosopher named Anaximenes about 550 BC suggested that the stars were fixed in a huge hollow sphere that enclosed the earth, the sun, the moon and the planets … This sphere might be motionless while the earth turned, or vice versa. Later Greeks argued both ways.
The sun, moon and planets could not be fixed to this sphere of the stars, because they did not move along with the stars at the same speed. They must therefore exist in space between the sphere of the stars and the central earth … each must be fixed in a special sphere of its own [Asimov at 25-27].”
