500 to AD
(2503 years ago) |
- The Pythagoreans teach that Earth is a sphere and not in the shape of a disk
- Pythagorean philosopher, Philolaus, suggests that there is a central fire around which the Earth, sun, moon, and planets revolve; he also believes that Earth rotates
- Democritus, Greek philosopher, he recognizes that the Milky Way consists of numerous stars, and the moon is similar to Earth.
- Greek philosopher, Aristotle, founded the Peripatetic School. Aristotle study all natural phenomena. In Aristotelian cosmology, Aristotle stated Earth was imperfect and situated in the center of the Universe. All other celestial bodies (Sun, moon and stars) rotated around the earth on concentric spheres.
- Aristarchus of Samos, challenges Aristotle's teachings by asserting that the sun is the center of the solar system and that the planets revolve around the sun.
- Seleucus, he is the last known astronomer to champion the heliocentric theory of the solar system until Copernicus
- Ptolemaic System: a model of planetary motion in which Earth is the center of the universe and the sun and moon move around the Earth in perfect circles. Because the planets seem to move backwards some of the time, however, their observed motion cannot be explained by perfect circles. Ptolemy adopted a solution to this problem that had been devised by Apollonius: each planet moves on a small circle, called an epicycle. The epicycle has as its center a point called deferent, and the deferent itself moves on a circle around Earth.
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