1-153-660 - Ann Ronan Picture Library/Heritage-Images

Nicolas Copernicus, Polish astronomer, 16th century. Copernicus (1473-1543) is considered to be the father of modern astronomy and founder of heliocentric cosmology. Prior to the work of Copernicus, the Earth was considered to be the stationary centre of the universe, a notion first advocated by the Egyptian astronomer Ptolemy. Copernicus' pioneering work The Revolutions of Celestial Spheres (1543) describes his idea of a Sun-centred universe, in which the Earth is merely one of the planets revolving around the Sun and rotating on its axis. Anonymous 16th century portrait.