ANCIENT ASTRONOMY

People have been fascinated by the vast sky ever since. As early as the 1300's B.C., Chinese scholars recorded the eclipses of the sun and the moon. By about 700 B.C., the Babylonians and the Egyptians had made great advances in the knowledge of the sky and the bodies in it. They recorded their observations, which are of great interest for scholars indeed. The ancient buildings in Babylonia and Egypt are based on the facts related to the heavenly bodies-the sun, the moon and a few stars.

GREEK ASTRONOMY

Astronomy is the science that studies the heavenly bodies. It was developed by Greek philosophers around 600 B.C. Pythagoras (500 B.C.'s) held that the earth was round. He also attempted to explain the nature and structure of the universe as a whole.

About 370 B.C., Eudoxus observed the motions of the heavenly bodies and held that all of them revolved round the earth. Philosophers like Aristotle accepted this theory. About the same time, Heraclides proposed two facts:

1. That heavenly bodies look moving to the west across the sky because the earth spins from west to east about its axis.

2. That Mercury and Venus revolve round the sun, not round the earth.

About a hundred years later, Aristarchus suggested that all the planets including the earth revolve round the sun.

PTOLEMY'S VIEW

Ptolemy was a Greek philosopher and scientist who lived in Alexandria (Egypt) during 100's A.D. He wrote a book entitled Almagest in which he supported the view that the earth was at the center of the heavenly system. This theory is known as geo-centric theory. It came to be accepted by most of the scientists of that period. As a result, the theory of Aristarchus (sun-centered theory) came to be rejected by most of the astronomers.