Nicholas Copernicus was born into a well-to-do family on February 19, 1473. His father, a copper merchant, died when Copernicus was ten, and the boy was taken in by an uncle who was a prince and bishop.

Copernicus was well able to afford a good education. He entered the University of Cracow in 1491 and studied mathematics and painting. In 1496 he went to Italy for ten years where he studied medicine and religious law. Two things happened in the year 1500 that influenced Copernicus: he attended a conference in Rome dealing with calendar reform and, on November 6, 1500, witnessed a lunar eclipse.

The tables of planetary positions that were in use at the time were very complex and inaccurate. Predicting the positions of the planets over long periods of time was haphazard at best, and the seasons were out of step with the position of the Sun. Copernicus realized that tables of planetary...