ABCTE World History Practice Exam 2026 - Free World History Practice Questions and Study Guide

The heliocentric theory, which posits that the Sun is at the center of the solar system and that the Earth and other planets orbit around it, was proposed by Nicolaus Copernicus. This revolutionary idea was detailed in his work "De revolutionibus orbium coelestium" published in 1543. The acceptance of this theory marked a significant shift from the geocentric model, which placed the Earth at the center of the universe. Copernicus's approach laid the groundwork for modern astronomy, challenging long-held beliefs and paving the way for future astronomers, such as Galileo and Kepler, who built upon his ideas with their own observations and theories.