The renowned scientist who proposed the heliocentric theory of the solar system is Nicolaus Copernicus. In the 16th century, Copernicus revolutionized astronomy by suggesting that the Sun, rather than the Earth, is at the center of the universe. His groundbreaking work, "De revolutionibus orbium coelestium," radically challenged prevailing geocentric views held for centuries. The heliocentric model provided a more accurate framework for understanding celestial movements and laid the groundwork for later astronomers like Galileo and Kepler. Copernicus's ideas marked the dawn of the Scientific Revolution, reshaping humanity's place in the cosmos.