The Heliocentric Model is a scientific theory that places the Sun at the center of the solar system, with the Earth and other planets orbiting around it. This model was first proposed by the ancient Greek philosopher Aristarchus of Samos but gained prominence in the 16th century through the work of Nicolaus Copernicus. The Heliocentric Model challenged the earlier Geocentric Model, which suggested that the Earth was the center of the universe. The acceptance of the Heliocentric Model laid the groundwork for modern astronomy and was further supported by the observations of Galileo Galilei and Johannes Kepler.