Inspired by an ancient Greek theory that placed the sun at the center of the universe, Copernicus spent twenty-five years studying planetary movement before proposing his heliocentric (sun-centered) theory. Copernicus did not publish his theory until the last years of his life because he knew that his ideas contradicted the Church and would likely cause his own persecution. Following Copernicus' death, other scientists such as Tycho Brahe, Johannes Kepler, and Galileo built upon his ideas. Using Brahe's data, Kepler developed a series of accurate laws which mathematically showed Copernicus' ideas to be true. Galileo built his own telescope and discovered that Jupiter had multiple moons, the sun had dark spots, and the moon was rough and uneven. After publicly defending Copernicus' ideas, the Church threatened Galileo before ultimately forcing him to concede that the Church was correct, after which he lived under house