Johannes Kepler, Galileo Galilei, Robert Fludd, Giordano Bruno and Nicolaus Copernicus: in absentia arguments on ‘happy Earths’ and the infinity of the cosmos

The ideas within Nicolaus Copernicus’ De Revolutionibus Orbium Coelestium (1543) and Giordano Bruno’s De l’infinito, universo e mondi (1584) created a new heliocentric image of the universe.1 The concept of an infinite space without limits was beginning to appear in astronomy. Bruno was the first to break Aristotle’s sphere, producing a mass of arguments disclaiming its presence and verifying infinite space. Johannes Kepler was more careful in his treatment of the model of an infinite cosmos, mainly because of the contradictions in his own theory as expressed in his Mysterium cosmographicum (Prodromus dissertationum cosmographicarum, continens Mysterium cosmographicum de admirabili proportione orbium coelestium: deque causis coelorum numeri, magnitudinisy motuumque periodiconim genuinis et propriis, demonstratum per quinque regularia corpora Geometrica) (1596). Galileo Galilei, on the other hand, supported the idea of an infinite cosmos, describing ways in which to prove it, although it could not be verified because of a lack of adequate telescope observations. At the same time, Robert Fludd developed a radically different concept of the stages of creation, synthesising earlier ancient cosmological ideas and the biblical world outlook, and thus anticipating cosmological models of the first half of the twentieth century.