The scientist famous for proposing the heliocentric model of the solar system is Nicolaus Copernicus. In the 16th century, Copernicus challenged the prevailing geocentric model, which placed Earth at the center. He argued that the sun, rather than the Earth, is at the center of the universe, with planets, including Earth, orbiting around it. This revolutionary idea, published in his work "De revolutionibus orbium coelestium," laid the groundwork for modern astronomy, ultimately leading to greater understanding by later astronomers such as Galileo Galilei and Johannes Kepler.