Nicolaus Copernicus was an astronomer and mathematician who lived during the Renaissance period, and is most known for his heliocentric model, which proposes that the Earth rotates upon its axis each day, while also revolving around the Sun over the course of the year. Putting forth his points in his seminal work, De revolutionibus orbium coelestium, Copernicus’s findings challenged the then millennium-held belief that the Earth was central to the universe. His work would serve as a springboard for future astronomers to further refine this idea of non-Earth-centricity and planetary movements.
According to Thomas Kuhn, a scientific revolution occurs when prevailing paradigms are replaced. A paradigm shift is not when new knowledge is simply added to collective thought, but instead occurs when a new framework is put in place, inspiring scientists to think in a new way, which he did accomplish. While Copernicus’s model still relied on circular orbits and did not predict planetary movement vastly better than the existing Ptolemaic system, he can be seen as existing on the cusp between old world knowledge and the revolution he is often attributed to starting. Many astronomers first adopted his mathematical techniques yet did not fully embrace the notion of heliocentrism, though this would be expounded more fully in the later work of Kepler and Galileo.