FIG. 1. COPERNICUS' HELIOCENTRIC THEORY, as illustrated
in his De revolutionibus orbium coelestium ("On the
Revolutions of Heavenly Bodies"), 1543. Although suggested
by Greek philosophers, the heliocentric theory was not
adopted until the Ptolemaic geocentric view proved incapable
of explaining observed motions of the heavenly bodies.
Copernicus' work was carried on by Kepler and Galileo.