Heliocentrism, or heliocentricism, is the astronomical model in which the Earth and planets revolve around a stationary Sun at the center of the solar system. The word comes from the Greek (ἥλιος helios "sun" and κέντρον kentron "center"). Historically, heliocentrism was opposed to geocentrism, which placed the Earth at the center. The notion that the Earth revolves around the Sun had been proposed as early as the 3rd century BC by Aristarchus of Samos, but had received no support from most other ancient astronomers.

It was not until the 16th century that a fully predictive mathematical model of a heliocentric system was presented, by the Renaissance mathematician and astronomer Nicolaus Copernicus, leading to the Copernican Revolution. In the following century, this model was elaborated and expanded by Johannes Kepler and supporting observations made using a telescope were presented by Galileo Galilei. (wikipedia)