Heliocentricity



Heliocentricity is a reference system where the sun is at the center. Our planetary system is heliocentric wherein the ten known planets are orbiting the sun, and is therefore known as a "solar system".

Early astronomers such as Nicolas Copernicus, Galileo Galilei, and Johannes Kepler helped revolutionize the previously held view of geocentrism, which was supported by Aristotle's cosmology, and placed the Earth at the center. The Copernican theory proported that the sun was the center of the universe and the planets rotated around the sun each year. He also asserted that Earth had motion around its center, and a simple explanation for the retrograde motions of the planets.