<P> Heliocentrism is the astronomical model in which the Earth and planets revolve around the Sun at the center of the Solar System . 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 BCE by Aristarchus of Samos, but at least in the medieval world, Aristarchus's Heliocentrism attracted little attention--possibly because of the loss of scientific works of the Hellenistic Era . </P> <P> It was not until the 16th century that a geometric mathematical model of a heliocentric system was presented, by the Renaissance mathematician, astronomer, and Catholic cleric Nicolaus Copernicus, leading to the Copernican Revolution . In the following century, Johannes Kepler elaborated upon and expanded this model to include elliptical orbits, and Galileo Galilei presented supporting observations made using a telescope . </P> <P> With the observations of William Herschel, Friedrich Bessel, and other astronomers, it was realized that the sun, while near the Barycenter of the solar system, was not the center of the universe . </P> <P> While the sphericity of the Earth was widely recognized in Greco - Roman astronomy from at least the 3rd century BCE, the Earth's daily rotation and yearly orbit around the Sun was never universally accepted until the Copernican Revolution . </P>

A simple sketch has been made of the earth's orbit about the sun