Copernicus’ Revolution: 1543–1609

“It’s the duty of an astronomer to compose the history of the celestial motions through careful and expert study,” said the introduction to Copernicus’ great book, De Revolutionibus. Regarded in retrospect as a great astronomer who started the revision of the Ptolemaic system, Copernicus was not so well appreciated in his own lifetime. Nominally holding a position in the Church (administrative rather than as a member of the clergy), he began to work on astronomy on his own. He developed his theory over three decades, initially writing it up in a private commentary, and finally publishing it only at his death. The theory did not make a great impact among astronomers of the period. Viewed in its era more as a matter of technical adjustment, Copernicus’ move to place the Sun at the center of the universe was only recognized as an epochal turning point in the following century. In the same year that Copernicus published on astronomy, 1543, the great physician Andreas Vesalius published his work in anatomy, De Humani Corporis Fabrica Libri Septem. Also that year, Petrus Ramus, a philosopher in Paris, published a book, Animadversions on Aristotle. The publications in 1543 set in train the decline of Aristotle’s influence. In the following century, the Scientific Revolution made major advances in medicine and biology as well as in astronomy and physics.