Who is credited with proposing the heliocentric model of the universe?

The proposal of the heliocentric model of the universe is primarily attributed to Nicolaus Copernicus. In the early 16th century, Copernicus challenged the prevailing geocentric model, which placed Earth at the center of the universe, by suggesting that the Sun, rather than the Earth, is at the center of our solar system. His groundbreaking work, "De revolutionibus orbium coelestium" (On the Revolutions of the Celestial Spheres), published in 1543, laid the foundation for modern astronomy by introducing the idea that planets, including Earth, orbit around the Sun.

Copernicus' theory marked a significant shift in scientific thought by proposing that the stars and planets moved in circular orbits around a stationary Sun, thereby transforming the understanding of celestial mechanics. His heliocentric model was a pivotal moment in the Renaissance, corresponding with the broader humanist movement that emphasized observation and inquiry. This theory eventually led to further developments in astronomy, as later figures such as Galileo, Kepler, and Newton built upon Copernicus' ideas, refining our understanding of the solar system and gravity.