... All Christians, for centuries, believed that Earth is flat and in the center of the universe until Copernicus and Galileo showed them that it is not the case. ...
That is a common misconception. While the Church believed that the Earth is the center of the solar system and the Universe, it did not claim that the Earth is flat. The Ptolemaic model that the Church endorsed included a globular Earth. It is interesting to note that Ptolemy did not put the Earth at the exact center and that this slight discrepancy was generally ignored.