Yesterday I learned about astronomy and my question today are we to be or not be heliocentric? Helios means sun and centric means to be in the center. Long ago everyone thought the earth was centric in the universe, but that theory or assumption was proved wrong by Nicolaus Copernicus. He was was an astronomer and mathematician in the Renaissance era who made a model of the universe and discovered that the earth in not the center of the universe but the sun is and that is called heliocentrism. Johannes Kepler is a mathematician and astronomer.  He was a very key figure in the 17th century and discovered and is known best for the eponymous laws of planetary motion. This means he discovered that the planets move in an oval orbit around the sun instead of a circle. He also provided the works for Isaac Newton's universal gravitation. Kepler also improved the refracting telescope, and mentioned his discoveries with Galileo Galilee.