The Divine Comedy by Dante Alighieri is the story of a journey across the Universe as it was known in the Middle Ages, a work of science fiction ante litteram. Dante had an encyclopedic mind, no doubt, and his poem is the most widely read book after the Bible. He was a master of the astronomical knowledge of his time, and used astronomy in his work to indicate places, to measure time, and to exemplify beauty. Indeed, in the Convivio, he wrote that...