Free Astronomy Magazine March-April 2024

8 MARCH-APRIL 2024 ASTRO PUBLISHING the same space. In a certain sense, Origen was a forerunner of the Sil- urian hypothesis and of those who consider the contemporaneity of different civilizations on different planets almost impossible. About a century later, another reli- gious man (rather famous in the Western world), Augustine of Hippo, returned to discuss the plu- rality of worlds. Unlike many other thinkers of his era, Augustine be- lieved in the infinity of time and space, and in the possibility that the Creator had not limited himself to generating a single world. Throughout the Middle Ages, other thinkers countered the worldview of Plato and Aristotle. Among them, Thomas Aquinas, Henry of Ghent, Richard of Middleton and Nicole Oresme (just to name a few) stated that from the theological point of view the plurality of inhabited worlds was not impossible, although in those times any position was still heavily conditioned by Aristotelian by Michele Ferrara revised by Damian G. Allis NASA Solar System Ambassador T he possible existence of life on other planets is a topic that has intrigued humans for mil- lennia. The first writings in this sense were attributed to the two pre-Socratic philosophers of Ancient Greece Leucippus and Democritus in the fifth century BC, who both sup- ported the existence of other inhab- ited worlds. This view was chal- lenged in the fourth century BC by Plato and Aristotle, supporters of the idea that if the Demiurge had created the world in his image, being only one, he would have only created a single world. The au- thority of Plato and Aristotle was enough to crystallize that belief for several centuries, although from time to time, the antagonistic idea resurfaced thanks to other philoso- phers and theologians. This is the case for the Alexandrian Origen, who in the third century AD sup- ported the principle of the succes- sion of worlds in time, where at the end of one world another began in From how far can we be observed?