Before the early Renaissance, most people thought the sun revolved around the Earth. Nicolaus Copernicus was an astronomer and the first person to state the opposite — that the Earth revolves around the sun.
Copernicus was born in 1473 in the province of Royal Prussia, then a kingdom of Poland. Like most learned men of the Renaissance, Copernicus studied various fields, spoke several languages and was knowledgeable about art.
Copernicus proposed that the planets have the sun as the fixed point around which they orbit. He also stated the Earth is a planet which, besides orbiting the sun annually, also turns once daily on its own axis.
His model was not a complete explanation of the solar system but the theory started the Copernican Revolution. This was a point in science when many began to move away from thinking about the Ptolemaic system of astronomy — the Earth at the center of the galaxy — to Copernicus’ heliocentric model.
Copernicus didn’t publish his major work, “On the Revolutions of the Celestial Spheres,” until he was very ill at the age of 70. His ideas didn’t reach most people until another astronomer, Galileo Galilei, further explained the theories and helped to popularize the heliocentric model. Today, both astronomers are credited for changing the landscape of modern astronomy.