Copernicus, Nicolas

Copernicus, Nicolas (1473-1543), Polish astronomer.

In Copernicus's day, most people believed that the Earth was the center of the universe and did not move. This idea had been put forward 1,400 years earlier by a Greek astronomer named Ptolemy.

Copernicus believed that the sun was the center of the planetary system and that the Earth and the other planets revolved around it. He said that the Earth rotated on its axis every twenty-four hours and circled the sun once a year.

Copernicus set down his ideas in a book, On The Revolutions of Heavenly Spheres.

At the time some people laughed at these ideas and others thought them wicked. The Pope even forbade Christians to read Copernicus's book.