Copernicus, Nicolaus

Nicolaus Copernicus, Polish Mikołaj Kopernik, German Nikolaus Kopernikus, (born February 19, 1473, Toruń, Royal Prussia, Poland—died May 24, 1543, Frauenburg, East Prussia [now Frombork, Poland]), Polish astronomer who proposed that the planets have the Sun as the fixed point to which their motions are to be referred; that Earth is a planet which, besides orbiting the Sun annually, also turns once daily on its own axis; and that very slow long-term changes in the direction of this axis account for the precession of the equinoxes. This representation of the heavens is usually called the heliocentric, or “Sun-centred,” system—derived from the Greek helios, meaning “Sun.” Copernicus’s theory had important consequences for later thinkers of the Scientific Revolution, including such major figures as Galileo, Kepler, Descartes, and Newton. Copernicus probably hit upon his main idea sometime between 1508 and 1514, and during those years he wrote a manuscript usually called the Commentariolus (“Little Commentary”). However, the book that contains the final version of his theory, De revolutionibus orbium coelestium libri vi (“Six Books Concerning the Revolutions of the Heavenly Orbs”), did not appear in print until 1543, the year of his death.