Copernicus argued that the earth and all the other planets revolved around the sun. Before Copernicus, people thought the earth was at the center of the universe, with the sun, the planets, and all other starts revolving around it.
People were upset by Copernicus's theory because they believed that God would never design the universe with the earth anywhere but the center. They thought that removing the earth from the center of the universe was a way of acknowledging that earth wasn't the center of God's attention. For evidence, they pointed to the story of Joshua, who the Bible says made the sun stand still in the sky. They argued that the Bible could never be wrong, but that if the earth rotated around the sun, and if the sun were therefore not in motion, then Joshua could not have made the sun stand still in the sky.
