Ionic thought's Influnce: Wheels and Bowls of Fire:
Xenophanes of Colophon (c. 570-490 BCE) migrated from Ionia to Italy fleeing the Medes' takeover, bringing Milesian theory with him. Although largely concerned with de-anthrophomorphizing god to make it infinite and all-encompassing, he propagates the view of heavenly bodies condensing into firey clouds from earth's exhalations (Aetius 2.20.3). His heavenly bodies, like Anaximines', follow circular courses (conceived as bands or zones) and are obscured behind high parts of the earth.
Heraclitus of Ephesus (c. 500 BCE), though criticizing his predecessors' work as data, not understanding, continues the idea of creation through balance of different substances and the process of condensation, this time, from fire. Night is formed of murkier exhalations from earth (as from Tartaros in Hesiod above) and day from exhalations ignited by the sun.
Sun, moon, and stars ae fire caught in bowls, which tip away to cause eclipses and lunar phases. The moon travels through the less purified air close to earth, so is dim, and the sun is the closest and thus brightest and hottest of stars.
Parmenides, Empedocles, and Pythagoreans: Paradoxes, Spheres, and Cycles:
The later of these "Presocratic" philosophers began to specialize, develop, and apply the systems of empirical observation and deduction which their predecessors had invented. Some, like Parmenides and Zeno, concentrated on exposing the fallacies and logical traps to which the first uses of analytical thinking often fell prey.
Others, like followers of the semi-legendary Pythagoras, used their theories about how the universe worked to develop new ideas of divinity, astronomy, universal harmony, and mathematics, and extended these ideas to dictate a proper, "harmonious" lifestyle. All these continued to refine and argue over the basic precepts put forth by the Milesian thinkers.
Parmenides (c 450 BCE): The Sphere of All, Wreaths of Fire:
Parmenides of Elea, in Italy, manages to demolish all physics by his proof that neither motion, change, nor differences in matter can exist. Having done this, he coyly outlines the "beliefs of mortals", which must in fact be his view of the"deceitful" physical world, a sort of Greek version of the Buddhists' maya. : His heavenly bodies, separating out with the heaviest matter towards the center, are again concentrations of fire-vapor, here regulated by "Necessity" to move them between an inner "wreath" of fire and an outer solid sphere.
It sounds like he conceived of the "wreath" as a belt like an asteroid belt, and the outer shell as a true sphere; whether or not his earth was flat is difficult to tell.
Empedocles and Anaxagoras: Reflections of Light:
Empedocles of Acragas (mid 5th cent. BCE) works on a system to reconcile the "unchanging" universe of Parmenides' sphere with chaotic, differentiated matter by having the universe in a state of flux (as in Heraclitus) between harmony and strife.
Along the way, he propounds an outer, hard universal sphere upon which the stars are fixed, and an inner sphere of double hemispheres, one of lighter fire for day, one of darker for night. The sun and moon are not physical bodies but concentrated, polished spots on this inner surface which reflect the outer fire.
Anaxagoras, friend of the Athenian statesmen Perikles and thus slightly younger than Empedocles, follows the usual theory of separation and condensation, but his heavenly bodies are again solid objects . His most important contribution to astronomy was the claim that the moon's light is a reflection of the sun and that eclipses of the moon were caused by earth's shadow, eclipses of the sun by the moon passing before it.
Pythagoreans: The Hearth of the Universe:
The Pythagoreans first proposed a non-geocentric system, perhaps partly on the basis of moral and religious grounds: to them, humanity and earth were imperfect, and only by sacrifice and a strict regimen of personal conduct could one strive to reach the divine.
Accordingly, they placed the divine, poetically called the "Hearth of the Universe" or "Throne of Zeus", at the center of a finite, spherical universe. The sun is a glass sphere which catches and reflects this hearth-light. A counter-earth, the "antichthon", had to be invented, supposedly to make the number of planetary spheres ten.
These include the five visible planets out through Saturn, earth, the moon, the sun, and the heavenly sphere on which were the stars. Heath, in outlining this system, suggests that the counter-earth was invented to account for the frequency of lunar eclipses.
The counter-earth also solves a major problem in this view, serving to eclipse the Hearth-Fire so that we never look God in the face, so to speak. The concepts of number, harmony, and music all influenced the Pythagoreans to invent this fully-realized version of the concentric celestial orbits, which resonate with "the music of the spheres".
The Socratics and beyond: A Geocentric System:
The atomists Leucippus and Democritus in the generation preceding Socrates refined the various pre-Pythagorean views of space: there is a drum-shaped earth (in Leucippus), condensation is the falling-together of atoms, and centrifugal force helps keep the earth and bodies of fire in place. Leucippus was probably from Miletus, and Democritus from Abdera; their development of atomic theory was a refinement of two centuries of Ionian scholarship.
After them, however, Socrates' pupil Plato and Plato's pupil Aristotle would espouse Pythagorean harmony and spheres and a geocentric system. Their many works analyze, refute, discuss, and expand on their successors; two of the passages representative of their views on astronomy are found in Plato's Timaeus 37dff and Aristotle's De Caelo 2,289a 11-291b 23.
In keeping with these theories now becoming prevelant, the early fourth century mathematician Eudoxis of Knidos mathematically described the idea of concentric spheres, anticipated by the "wreaths" and "zones" of many earlier scientists and probably assumed by the Pythagoreans.
Having discovered a theory of the solar, or rather, geo- system which accounted for all visible phenomenon (and was, moreover, aesthetically pleasing), subsequent astronomers and philosophers fine-tuned the idea for their particular fields.
The philosophers dwelt on harmony, cycle, and a new scheme of the divine; the mathematicians, a description of heaven in the marvellous language of geometry which was nowhere else in the physical world more eloquently expressed.
Sophisticated three-dimensional moving systems were worked out by various geometers to account for observed inconsistencies in their basic theory. It would take many centuries before anyone had accurate enough observations to realize that the theory could not account for all data.
By then, people would have even more difficulty letting go of their clockwork, geocentric, "divinely subsidized" universe than the Greeks, who had placed their version of a Bible, the Homeric and Hesiodic myth-cycle, into the realm of metaphor after executing only one gadfly of a philosopher.
