The Copernican Revolution refers to the transformation in cosmological thought, spanning roughly the mid-16th through mid-17th centuries, in which the dominant geocentric model of the universe - placing Earth at the center of celestial motion - was displaced by a heliocentric model placing the Sun at or near the center. The term derives from Nicolaus Copernicus, whose work De revolutionibus orbium coelestium (1543) initiated the shift, though the full revolution encompassed the contributions of Tycho Brahe, Johannes Kepler, Galileo Galilei, and Isaac Newton. The phrase is also used more broadly as a metaphor for any fundamental reorientation of a conceptual framework - most notably in Immanuel Kant's description of his own epistemological project.
Ancient and medieval European astronomy inherited a geocentric cosmos, most systematically expressed in Ptolemy's Almagest (c. 150 CE), which used a system of deferents, epicycles, and equants to predict planetary positions with practical accuracy. This framework was integrated into scholastic natural philosophy and carried theological weight within Latin Christendom, though geocentrism was not universally held across all intellectual traditions. Copernicus, working within the Catholic Church as a canon, proposed a heliocentric arrangement primarily on grounds of what he took to be greater mathematical simplicity and coherence, not on the basis of new observational data. The subsequent century saw Brahe's systematic naked-eye observations, Kepler's derivation of elliptical planetary orbits (1609-1619), and Galileo's telescopic evidence - including the phases of Venus and the moons of Jupiter - that challenged the specific predictions of geocentric models. Newton's Principia Mathematica (1687) provided a unified gravitational mechanics that subsumed Kepler's laws and established the physical basis for heliocentric motion. A fuller account of these developments is at Copernican Revolution - History.
Historians and philosophers of science have examined the Copernican Revolution as a case study in large-scale conceptual change. The transition involved not only a change in the assigned position of Earth but also the dissolution of the Aristotelian distinction between terrestrial and celestial physics, the removal of a finite celestial sphere, and the demotion of humanity's cosmic location from a position of centrality to one of contingency. The degree to which these implications were recognized contemporaneously, and the degree to which ecclesiastical opposition was primarily theological versus institutional or political, remains a subject of historiographical discussion. Thomas Kuhn's 1957 monograph The Copernican Revolution and his later The Structure of Scientific Revolutions (1962) framed the episode as a paradigm case of a scientific paradigm shift, an interpretation that has been both influential and contested.
There is a strong consensus across astronomy, physics, and history of science that heliocentrism - more precisely, the Sun-centered model as refined into a solar-system framework within a larger universe - correctly describes planetary motion and has been confirmed by centuries of observation, space exploration, and physical theory. The astronomical consensus on the structure of the solar system is not in active scientific dispute. Separate from the empirical question, interpretive claims about the revolution's causes, pace, meaning, and implications for religion, philosophy, and the nature of science remain open topics in history and philosophy of science.