Nicolaus Copernicus is celebrated for proposing the heliocentric model of the solar system, which positioned the sun at the center rather than the Earth. His groundbreaking work, "De revolutionibus orbium coelestium" (On the Revolutions of the Celestial Spheres), published in 1543, fundamentally changed the way we understand our solar system. This theory contradicted the long-accepted geocentric view, which held that the Earth was the center of the universe. Copernicus’ heliocentric model laid the foundation for future astronomers like Galileo and Kepler, ultimately paving the way for the Scientific Revolution and transforming humanity’s understanding of its place in the cosmos.