Copernicus believe in a Sun centered theory, that all planet's motion on it's orbit can be proved mathematically by putting the sun at the center. Galileo supported this theory and observation by creating his own telescope, based on the work of Hans Lippershey inventor of the telescope. While their Greek contemporaries may still be influence by ancient philosopher like Aristotle, who believe that that the earth is the center of the universe, they made elaborate explanation regarding this earth centered theory that lasted a thousand years.