Nicolaus Copernicus made significant discoveries that fundamentally altered our understanding of the universe. His central proposition was the heliocentric model, which argued that the Earth and planets revolve around the Sun, contrary to the prevailing geocentric model. This revolutionary idea, detailed in his seminal work, De revolutionibus orbium coelestium, laid the groundwork for the Scientific Revolution and influenced later astronomers like Galileo and Kepler. Copernicus's concept challenged longstanding beliefs about humanity's position in the cosmos, marking a pivotal shift in scientific thought and paving the way for modern astronomy and physics.