Completion of Tycho Brahe's subterranean observatory at Stjerneborg.
Giordano Bruno, in England, publishes his " Italian Dialogues", including the cosmological tracts La Cena de le Ceneri ("The Ash Wednesday Supper"), De la Causa, Principio et Uno ("On Cause, Principle and Unity") and De l'Infinito Universo et Mondi ("On the Infinite Universe and Worlds").