“SICUT NODUS IN TABULA”: DE LA ROTATION PROPRE DU SOLEIL AU SEIZIÈME SIÈCLE

Abstract

Taking as his starting point a passage by G. B. Riccioli (1598–1671), the author investigates those writers in the sixteenth century who postulated that the Sun rotates—that is, prior to the observational proof by Galileo. The idea of the axial rotation of the Sun was proposed in Antiquity by Plato but strongly resisted by Aristotle. It reappears in the writings of the anti-Aristotelean philosopher Bernardino Telesio (1509–88), for whom it was a necessary consequence of his conception of a Sun formed of fire. But other pre-telescopic authors, such as Cesalpino, Bruno, Campanella, and Kepler, likewise proposed the rotation of the Sun as required for one reason or another, although at the close of the sixteenth century Tycho Brahe (who of course had no telescope) rejected such a rotation as an optical illusion.