Prehistoric Astronomy

Prehistoric Astronomers

As one of the oldest sciences, astronomy flourished in prehistoric times. Hunter-gatherers realized the importance of recognizing seasons, moon phases, annular events, and the apparent movement of the Sun. The early peoples divided the skies into the North Celestial Pole, a single point about which stars move around in the sky, and the South Celestial Pole. The Celestial Equator is the half-way line between the Celestial Poles and also a projection of Earth’s equator into the sky. 3,000 years ago, the Babylonians discovered the 360° circle, which is a base 60 system that originated from 365 days in a year. The five ancient planets are Mercury, Venus, Mars, Jupiter, and Saturn. The North Star is the star closest to the North Celestial Pole— currently Polaris. Because of precession, or the wobble of Earth’s rotational axis that sweeps out a circle in 26,000 years, the extension of Earth’s North Pole points to a different North Star during the motion. Helical rising is the first day each year when a particular star can first be seen just before dawn; helical setting, then, is the last day of the year when the star can be seen at dusk.  The ecliptic is the apparent path of the Sun in the sky and the zodiac is the path of planets within a zone of 18 degrees wide-centered on the ecliptic. Hunter-gatherers and early settlers utilize knowledge of these ideas to farm, navigate, and survive.