PART ONE
AN HISTORICAL SKETCH OF THE HELIOCENTRIC THEORY OF THE UNIVERSE.
CHAPTER I.
The Development of Astronomical Thought to 1400 A. D.
A Preliminary Sketch of Early Theories as a Background.
THE appearances in the heavens have from earliest historic ages filled men with wonder and awe; then they gradually became a source of questioning, and thinkers sought for explanations of the daily and nightly phenomena of sun, moon and stars. Scientific astronomy, however, was an impossibility until an exact system of chronology was devised.[1] Meanwhile men puzzled over the shape of the earth, its position in the universe, what the stars were and why the positions of some shifted, and what those fiery comets were that now and again appeared and struck terror to their hearts.
In answer to such questions, the Chaldean thinkers, slightly before the rise of the Greek schools of philosophy, developed the idea of the seven heavens in their crystalline spheres encircling the earth as their center.[2] This conception seems to lie back of both the later Egyptian and Hebraic cosmologies, as well as of the Ptolemaic. Through the visits of Greek philosophers to Egyptian shores this conception helped to shape Greek thought and so indirectly affected western civilization.
- ↑ The earliest observation Ptolemy uses is an Egyptian one of an eclipse occurring March 21, 721 B. C. (Cumont: 7). [In these references, the Roman numerals refer to the volume, the Arabic to the page, except as stated otherwise. The full title is given in the bibliography at the back under the author's name.]
- ↑ Warren: 40. See "Calendar" in Hastings: Ency. of Religion and Ethics.
