Web Sites
The five-hundredth anniversary of Copernicus's birth was celebrated throughout the world in 1973. Various governments issued commemorative stamps in his honor; the last of the two orbiting astronomical observatories, launched by NASA in 1972, was named OAO-Copernicus, and historians of science met to eulogize the accomplishments of the man who revolutionized astronomy with his heliocentric system.
After the death of his father when Copernicus was 10 years old, an uncle, a churchman who later became a bishop, raised him and saw to it that he had an excellent education. Copernicus studied mathematics, philosophy, astronomy, and astrology at the University of Cracow, and he studied law and medicine at the Universities of Bologna and Padua. When he returned to Poland, he lived for a while in his uncle's castle. There he spent time as a physician, engaged in diplomatic activities, and undertook various administrative duties. After he was elected a canon through his uncle's influence, he had sufficient income to devote more of his time to astronomy, his first love.
Beginning in 1512, Copernicus set himself the task of examining critically the various systems of the world that had been proposed in the past. Becoming dissatisfied with the complexity and improbability he found in the Ptolemaic system, he revived Aristarchus's heliocentric concept sometime before 1514. Placing the Sun at the center of the Solar System simplified matters, as wrote Copernicus: "In the center of everything the Sun must reside;...there is the place which awaits him where he can give light to all the planets." In his development of the heliocentric system, Copernicus also retained the notion of uniform circular motion. He was thereby compelled to introduce a number of epicycles and eccentrics in order to account for the variable movements of the planets.
Sometime before 1514 Copernicus circulated a summary of his ideas among his friends. Knowledge of it spread to others. However, the full fruits of his labor, On the Revolutions of the Heavenly Orbs, did not appear until 1543, nearly three decades later. To a cardinal friend who had inquired about his theory Copernicus wrote: "Although I know the thoughts of a philosopher do not depend on the judgment of the many, yet when I considered how absurd my doctrine would appear, I long hesitated whether I should publish my book."