Our Place in the Universe

Since the beginning of civilization, our ancestors have been careful observers of the heavens.  They knew that the Sun, the Moon and the stars have regular, repeating motions, but their patterns of motions are complicated.  By 500 B.C., ancient astronomers have found that the Earth was round, and understood the cause of the phases of the Moon.  Using simple measurements and mathematics, Greek astronomers could accurately determine the sizes of the Earth and Moon, and the distance to the Moon 2000 years ago.

The ancient Greeks created a sophisticated model of the cosmos which could predict the times and directions of sunrise and sunset on any day of the year, and at any place on Earth.  The model could account for the unequal lengths of the seasons and the precession of the equinox.  They could also predict the positions of planets hundreds of years into the future.  This system of cosmology was later integrated into the Christian theology that dominated European thinking for over 1000 years.  It was not until that 16th century that an obscure clergyman developed a new cosmological theory that destroyed the philosophical foundation of European system of church and state. The philosophical implications of the Copernican revolution will be discussed.