The document provides an overview of the early history of astronomy from ancient Greeks to modern times. It discusses that ancient Greeks held an Earth-centered view but Aristarchus proposed a Sun-centered model. Later, Ptolemy developed an Earth-centered model using epicycles to explain planetary motions. In the 1500s-1600s, Copernicus, Kepler, Galileo and Newton helped establish the modern heliocentric model through observations and laws of planetary motion and gravity.