De revolutionibus orbium coelestium De revolutionibus orbium coelestium De revolutionibus orbium coelestium ("On the Revolutions of the Heavenly Spheres") is the seminal work on the heliocentric theory of the Renaissance astronomer Nicolaus Copernicus (1473–1543). The book, first printed in 1543 in Nuremberg, Holy Roman Empire, offered an alternative model of the universe to Ptolemy's geocentric system, which had been widely accepted since ancient times. Copernicus initially outlined his system in a short, untitled, anonymous manuscript that he distributed to several friends, referred to as the "Commentariolus". A physician's library list dating to 1514 includes a manuscript whose description matches the "Commentariolus", so Copernicus must
History of the center of the Universe southern constellations rise higher above the horizon, and the shadow of Earth on the Moon during a lunar eclipse is round, and spheres cast circular shadows while discs generally do not. This understanding was accompanied by models of the Universe that depicted the Sun, Moon, stars, and naked eye planets circling the spherical Earth, including the noteworthy models of Aristotle (see Aristotelian physics) and Ptolemy. This geocentric model was the dominant model from the 4th century BCE until the 17th century CE. Heliocentrism, or heliocentricism, is the astronomical model in which the Earth and planets revolve around a relatively stationary