My name is Duracotus. My country is Iceland, called Thule by the ancients. The recent death of my mother Fiolxhilde has freed me to write this, as I have long wished. But while my mother lived she would not let me write. Indeed, she said, there were many evil people who hated any arts their dull minds could not grasp – so they misrepresented those arts and made laws harmful to the human race…

Around the beginning of the 17th Century, the German astronomer Johannes Kepler wrote one of the first science fiction stories: In Somnium Astronomicum, or An Astronomical Dream. The short story in Latin relates the tale of an astronomy student who learns about voyages to the surface of the moon during a lunar eclipse, propelled by moon-dwelling creatures who can travel between the earth and the moon on the bridge of darkness.


After the introductory adventure, Kepler’s Somnium surveys the peculiar conditions on the lunar surface: Kepler imagined the moon – known as Levania in the lunar language – as a populated world, with an atmosphere, exotic life, and alien cities. Kepler reasoned that the near side of the moon, which always faces the earth, is a temperate land warmed and illuminated during the lunar nights by earthshine. The far side of the moon, which never sees the earth and only sees the sun for two weeks every month, is in turns a scorching desert and a landscape of ice riven by storms, its inhabitants oppressed by the burning rays of the sun and the harsh night of empty space.


This was more than just a tall tale. Kepler’s Somnium may be both the earliest example of a “hard” science fiction story, and a remarkable document of a pivotal stage of scientific history. Kepler’s descriptions of the lunar landscape and conditions contain elements of a radical new theory of nature that placed the sun – not the earth – at the center of the known universe. In the course of a few decades, the heliocentric model championed by Nicholas Copernicus, Giordano Bruno, Galileo Galilei, and Kepler dislodged the geocentric Ptolemaic model of the heavens and challenged the authority of powerful Catholic and Protestant churchmen. Kepler’s analysis of the motions of the planets around the sun inspired Isaac Newton’s work on gravity, and were a step towards the modern understanding of the universe. The Somnium may have also put Kepler’s family in danger: he wrote that his story of magical arts and “daemons” was twisted to accuse his elderly mother of witchcraft.