As is well known, speculations about the structure of the universe were always contained in the cosmogonic models and philosophical systems developed by ancient civilizations. In Asia, in Africa, in Latin America, superb achievements were obtained by ancient societies – in their mythical approach to the study of nature, in their cultural monuments, in their artistic and technological ingenuity, in their astronomical observations, in the philosophies on space, time, matter, and life that they were led to create and which reflected their forms of interaction with the world
It was, as everyone knows, the atomistic philosophers of ancient Greece who exercised perhaps the greatest influence on the modern conception of the universe. Before the Greeks, the Babylonians and the Egyptians had already made observations, during many centuries, on the motions of the sun and of the moon with respect to the fixed stars, and knew how to predict lunar and solar eclipses.
In spite of the fact that the Greeks identified the celestial bodies with gods, Anexagoras stated that the sun was like a red hot stone and that the moon was made like the earth. The Pythagoreans, at the end of the fifth century B. C. , stated that the earth is spherical, Aristarchus of Samos, in the third century B. C. , discovered the complete Copernican system, and Eratosthenes, in the year 200 B. C. , calculated, according to Claudius Ptolemaeus, the maximum distance of the moon from the earth and the minimum distance between the sun and the earth.