The publication of Nicolaus Copernicus's work in 1543 offered a mathematical alternative to the thousand-year-old model that took Earth as the motionless center of the universe. His proposal was that the planets — including Earth — revolve around the Sun. The model did not at first explain observations better than the old one and was still complex because it assumed circular orbits; its strength lay in proposing a simpler, more coherent order.

The revolution was not completed by a single book. Over later generations, Kepler's elliptical orbits, Galileo's telescopic observations, and Newton's law of gravitation turned this framework into a testable theory with strong predictive power. The process is an example of how observational evidence reshaped established authority.

Its impact was not confined to astronomy. The fact that an assumption about the place of humanity and Earth in the universe could be tested and changed strengthened the idea that knowledge is questionable and correctable. The term "Copernican turn" is therefore used beyond astronomy as well, to mean a fundamental displacement of an established point of view.