While it wasn't a completely new idea (some ancient Greek philosophers had proposed similar theories), Copernicus's book "De Revolutionibus Orbium Coelestium" (On the Revolutions of the Heavenly Spheres), published in 1543, was a major turning point in astronomy. He presented a comprehensive and mathematically sound model for a heliocentric (Sun-centered) solar system, which challenged the prevailing geocentric (Earth-centered) model that had been accepted for centuries.
Copernicus's work faced strong opposition from the Church and many scientists of his time. However, it laid the groundwork for later astronomical discoveries and ultimately revolutionized our understanding of the universe.
