Johannes Kepler: Servo-Controlled Planets Orbiting a Sun-God

Abstract

If there are globes in the Heaven similar to our Earth, do we vie with them over who occupies the better portion of the Universe? For if their globes are nobler, we are not the noblest of rational creatures. Then how can all things be for mans’ sake? How can we be the masters of God’s handiwork? … This system of planets, on one of which we human dwell, is located in the very bosom of the World, around the heart of the Universe, that is, the Sun… We humans live on the globe which by right belongs to the primary rational creature, the noblest of the corporeal creatures.

Appendix: Two Pre-Keplerian Moon Voyages

Here are two very-brief accounts of Moon-voyages that had long preceded Kepler. They are intended merely to show how modern and scientific Somnium looks by comparison; and so does De Facie.

Lucian of Samosata (125–180 AD): A True Story

Despite its title, no part of this little tale is intended to be taken seriously, which is not surprising, the author being a Skeptic; still, it has the distinction of being the first imaginary moon-voyage. The story is pure fancy, much closer to fairy tales or the Arabian Nights than to science-fiction; also, many passages are intended as parodies of now lost works, hence their point is equally lost. The astronomical information Lucian makes use of is scarce, and there would be no excuse for presenting even a brief discussion if Kepler had not been clearly interested: he even used that True Story, together with a German translation, in order to learn Greek at Tübingen. Later, when writing Somnium, he intended at first to add his own translation but gave it up. The tale had remained popular; many manuscripts are still extant, and the first printed edition is from Florence in 1496; such is the power of wit, even when supported by little substance.

The narration begins by a sea-voyage; all of a sudden the ship is caught up by a whirlwind, raised in the air and

…for seven days and nights we sailed the air, and on the eighth day, we saw a great country in it, resembling an island, bright and round and shining with a great light. Running in there and anchoring we went ashore, and on investigating, found that the land was inhabited and cultivated. By day, nothing was in sight from the place, but as night came on we began to see many other islands hard by, some larger, some smaller, and they were like fire in color. We also saw another country below with cities in it and rivers and seas and forests and mountains. This we inferred to be our own world.

The key world is that “below” (κατω). Despite the land being inhabited, cultivated etc.… (otherwise, there would be no story at all), Lucian does not conceive of Moon as an Earth-like place, with a firm ground underneath and a sky above. The obvious inherent difficulties are elegantly solved: the inhabitants, many of them human-like, move (and fight) mounted on birds, or on giant creatures similar to fleas or ants, capable of creeping upside-down and caring little about gravity. Predictably, Endymion is found to be the local king. Soon the voyagers witness a great battle (no doubt, to make them feel thoroughly at home), and

…so much blood dripped down to the Earth that I wonder if something of the sort did not take place in the sky long ago, when Homer supposed that Zeus had sent a rain of blood on account of the death of Sarpedon.

Both the great war and the peace treaty that follow are spoofs of the Athenian-Spartan wars as described by Thucydides. However, which way exactly is this “below”? Lucian appears a little confused since

…I saw another marvel. A very large looking-glass [κατοπτροσ μεγιστοσ] is fixed above a well…and if a man looks into the looking-glass, he sees every city… we saw that the country was green and fertile and well watered… and every country [of the Earth] just as if he were standing over it. When I tried it, I saw my family and my whole native land…

Later on the travellers proceed to the Morning Star: “… we landed there and procured water”, next to the Sun. Here, Phaeton, none the worse for his ancient mishaps, is the ruler; then

sailing the next night, we reached Lamptown [Λυγνοπολισ] toward evening, already being on our downward way. This city lies in the air, midway between the Pleiades and the Hyades, though much lower than the Zodiac.

Such is all the astronomical substance of the tale. The voyage goes on and on, getting more and more like Arabian Nights, but turns again into a mere sea passage, as the author forgets that his ship is supposed to navigate the Heavens. Altogether, no great loss occurred when Kepler dropped his projected translation: De Facie was to prove far richer.

Ariosto (1474–1533): Orlando Furioso

The theme of the moon-voyage had been taken up again by Ariosto and occupies a small part of his 1516 Orlando Furioso. By the time, it had become thoroughly christianized, and also given that most peculiar fairy-tale atmosphere of the chivalry novel. The hero, Astolpho, is a perfect knight and a most proper Englishman to boot; to perform his trip to the Moon, the one and essential commodity required is spiritual guidance, which soon becomes indistinguishable from actual piloting. This is sought for in highest and most orthodox circles: no less an authority than Saint John the Evangelist is induced to leave Patmos, and drive the knight to his goal. No one is greatly worried by technical details, and a pack of geese harnessed to a flying carriage proves adequate. A single piece of astronomical information seems to be given anywhere: the two travellers have to pass though the sphere of fire on their way, which means strictly orthodox Aristotelian surroundings. However, they do not meet the scriptural Waters Above (which would have greatly pleased John); even so, not a feather gets singed, and an easy lunar landing is accomplished. Nothing relevant to Plurality warrants a description; still, one notes that the Moon functions mostly as a convenient storage-place for everything lost on Earth, particularly the minds of madmen, a hill-sized pile of which is found. If ever the Moon is turned into a garbage-dump by humans, this should be code-named ARIOSTO, inventor of that dreadful proposal. Incidentally, these geese will be put to work again, at least within seventeenth-century fiction.