Who was Copernicus?
(Marc from San Francisco, CA) A: Nicolaus Copernicus was a Polish astronomer who lived from 1473 to 1543. Copernicus was the first person to challenge the belief the earth was the center of the universe. In 1543, Copernicus published his book, On the Revolutions of the Heavenly Spheres. It established the theory the earth revolved around the sun. This theory was called the Heliocentric theory. Heliocentric means “sun-centered.” It is also known as the Copernican theory, after Copernicus.