While earlier Greek thinkers like Aristarchus of Samos had proposed a heliocentric model, it was Copernicus's work, "De Revolutionibus Orbium Coelestium" (On the Revolutions of the Heavenly Spheres), published in 1543, that laid the groundwork for the modern understanding of the solar system.
Copernicus's model, though not perfect and still using circular orbits, challenged the prevailing geocentric model of Ptolemy and provided a more accurate representation of planetary motions. This paved the way for later astronomers like Galileo Galilei and Johannes Kepler to further refine the model and lead to the development of the modern heliocentric system.
