For many centuries, people believed that the earth was the center of the universe and that the sun revolved around it. Then here came along a Polish astronomer named Copernicus, who held on to a different theory. He believed that the sun was the center of our solar system, and that the earth and all other planets within the system were revolving around the sun. Almost no one agreed with him. His theory was so unpopular and revolutionary that he was afraid to release it. But shortly before his death in the sixteenth century, he published a book. Very soon his […]