Somnium, by Johannes Kepler

I’ve had an interest for a while in ridiculously old science fiction, such as Margaret Cavendish’s 1666 novel The Blazing World, as well as science fiction written by prominent scientists, such as Simon Newcomb’s His Wisdom the Defender (1900), Robert Williams Wood’s The Man Who Rocked the Earth (1915), and Fred Hoyle’s The Black Cloud (1957). But if I want to combine “ridiculously old” and “prominent scientist,” there’s no book that can beat Somnium, written by Johannes Kepler in 1608!

Often billed as the earliest science fiction novel, Somnium provides probably the earliest descriptions of a journey to the Moon and the beings that live there. But is it really science fiction? Let’s take a look at it more closely…

For those who are unfamiliar, Johannes Kepler (1571-1630) is a key figure in physics and astronomy.  He was witness to a number of astronomical events early in life, such as the Great Comet of 1577 and a lunar eclipse in 1580, that gave him a love of studying the cosmos.

Contemporary woodcut of the Great Comet of 1577, seen over Prague on November 12, 1577.

In 1589, he began a higher education at the Tübinger Stift, a religious hall of residence and teaching in Tübingen, Germany.  There he learned philosophy and theology, as well as the skill of astrology (which was intertwined with astronomy in that era).  Under the instruction of a mathematics professor, Kepler learned of competing theories of the solar system, the geocentric Ptolemaic system and the (more correct) heliocentric Copernican system, and he became a stout Copernican.

In 1594, Kepler accepted a position as a teacher of mathematics and astronomy in Graz, Austria; by 1596, he had published his first major astronomical work, Mysterium Cosmographicum (“The Cosmographic Mystery”), a strong defense of the Sun-centered Copernican system.  In it, Kepler attempted to explain the solar system in terms of the Platonic solids; through mathematical manipulation, he had found that the orbits of all the known planets could be placed on spheres nested within the various solids.  This theory was, of course, not accurate, and would be disproved with the discovery of later planets. But it did result in some cool images.

Kepler’s Platonic solar system.

Kepler sent his work to other astronomers, including Nicolaus Reimers Baer, the astronomer to the Holy Roman Emperor Rudolf II. Baer was a bitter rival of the Danish astronomer Tycho Brahe, and used Kepler’s letter as a weapon in one of their disputes.

In spite of this slight, however, Brahe and Kepler began to correspond, and in 1600 Kepler moved himself and his family to Prague to make collaboration easier.  This was not entirely voluntary; though he wanted to make the move, he was basically forced out of Graz due to religious and political turmoil and his refusal to convert to Catholicism.

1586 portrait of Tycho Brahe.

Brahe and Kepler would collaborate intensely through most of 1601, but the collaboration was short-lived: in October of that year, Brahe would die unexpectedly from some sort of bladder or kidney ailment. According to Kepler, the cause of death was social politeness! Brahe was attending a banquet in Prague and refused to excuse himself to use the bathroom when he needed to, as he considered it to be a breach of etiquette.  Apparently he did damage to his urinary tract, as he died 11 days later, on October 24.

Kepler took over Brahe’s role as imperial mathematician to Rudolf II, and had access to Brahe’s extensive astronomical observations, in particular measurements of the orbit of Mars.  At first, he attempted to continue Brahe’s work and fit the data to Brahe’s hybrid “Tychonic” model of the solar system, in which the Sun and Moon orbited the Earth but the other planets orbited around the Sun; the model was a hybrid of a geocentric and heliocentric system.

Kepler met with some success, but the Tychonic model did not fit the data perfectly, so he began to look for alternatives, focusing on Copernicus’ heliocentric system.  Keep in mind that, in this era, nobody had any idea what path the planets might take in their orbit around the Sun, nor what shape that path might form. After many failed guesses, Kepler finally tested the idea that Mars was traveling in an elliptical orbit, and he found that this hypothesis matched the data perfectly!  He then deduced that all planets must follow similar elliptical paths, and in 1609 he published his book Astronomia nova, the first ever to describe the planets as moving in this manner.  His work broke not only with the early Ptolemaic system and the Tychonic system, but also departed dramatically from Copernicus’ own model of the solar system; Copernicus had assumed that the planets rotated upon fixed spheres.

Cover page of Astronomia Nova (1609).

Astronomia nova was also the first mention of two of the three of what would later become known as Kepler’s laws of planetary motion.  The first law states that “all planets move in elliptical paths, with the Sun at one focus,” which describes the overall path of the planets. The second law states that “planets sweep out equal areas in equal times,” which describes how the speed of the planets depend on the position in their orbits.

It was during this period of intense intellectual activity that Kepler crafted his odd and groundbreaking “science fiction” work Somnium, which he apparently completed in 1608.  The book itself, however, had a much earlier genesis: it was based on a student dissertation he wrote while at the Tübinger Stift, defending the Copernican system.  In the dissertation, Kepler argued that the motion of the Earth would be as clear to observers on the Moon as the motion of the Moon is to observers on the Earth.  Evidently, while working on the Astronomia nova, Kepler dusted off his old paper as an additional defense of heliocentrism.

Portrait of Kepler, c. 1610.

Why write it as a fictional fantasy, though? Curiously, one imagines that Kepler had in mind very much the same argument presented in The Stories of Ibis, which I wrote about in my last blog post.   Fiction has a unique power: people are willing to listen to a story presented as fiction, even though they might reject the same story presented as fact. With an uphill battle to convince intellectuals of his new system, Kepler may have strategically thought that it would be easier to dress it up as a fun fantasy.

So what of the story¹ of Somnium? Clearly, Kepler was not a practiced storyteller: he begins with a set of layers upon layers that make the book’s beginning feel like an early attempt at ergodic literature.  We start with Kepler himself:

In the year 1608, when discord raged between the brothers Emperor Rudolph and Archduke Matthias, precedents for their actions were sought and commonly revived from Bohemian history. Excited by this public curiosity, I gave my attention to the legends of Bohemia.

So, Kepler himself isn’t going to be the main actor of the story; his role involves reading old legends of Bohemia.

When I came to the story of the heroine Libussa, so celebrated in the magical arts, something happened that night. After contemplating the stars and the moon, I settled into bed and fell into a deep sleep.

Okay, after reading about a sorceress, Kepler falls asleep. One would therefore expect that his fictional story is his dream, right? Well, not quite:

But in my dreams I seemed to be reading through a book that I had brought from the market.

To recap: Kepler’s story is something he read in a dream after falling asleep after reading other stories.

After that, things pick up a bit. The book Kepler is reading — in his dream — is about a 14 year old Icelandic boy named Duracotus.  Duracotus’ mother Fiolxhilde makes a living selling mysterious bags of herbs with mystical markings on them to ship captains for good luck.  One day, Duracotus cuts open one of the bags to see what is inside, and the contents spill out when the buyer collects it; angered at the loss of a sale, Fiolxhilde instead gives the young boy to the captain as payment, and Duracotus ends up on an ocean voyage heading to Denmark. When he becomes ill on the journey, the captain leaves him on land, with instructions to deliver a parcel of letters to the esteemed astronomer Tycho Brahe.

Yes, that Tycho Brahe.  Duracotus ends up becoming a student of the astronomer, and spends five years in his care learning how to observe the heavens.

It is rather clear that, in part, Duracotus represents Kepler himself.  So Somnium is a story about a fictional boyish Kepler, which Kepler reads about in a dream, after falling asleep after reading Bohemian stories.

Anyway, after five years with Brahe, Duracotus returns home to his mother. Fiolxhilde is so delighted to have him back, and so impressed with his scientific knowledge, that she explains her own supernatural powers: she can commune with spirits — or daemons — who can transport her anywhere in the world instantaneously and, even more amazing, can transport her or any other humans to their home world, the island of Levania. Aka the Moon!

The island of Levania is located fifty thousand German miles high up in the sky. The route to get to there from here, or back to this Earth, is rarely open. When it is open, it is easy for our kind, at least, to travel. But transporting humans is truly difficult, and risks the greatest dangers to life.

The actual Earth-Moon distance is 239,000 miles, but credit to Kepler for getting within the ballpark with the limited knowledge of his era!

At this point, the narrative is taken over by the mother’s favorite daemon, who describes the wonders of Levania — Duracotus himself does not go there.  So Somnium is a story about a fictional boyish Kepler hearing a story about a distant world. Kepler reads about fictional boyish Kepler in a dream, after falling asleep after reading Bohemian stories. Whew.

Here, though, Kepler’s imagination comes into full force.  He describes in detail the pains that the daemons must take in order to protect travelers from the incredible forces experienced on the journey. A sample:

First of all he experiences a strong pressure, not unlike an explosion of gunpowder, as he is hurled above the mountains and the seas.

For this reason, drugs and opium are consumed at the start, so that he falls asleep, and each of his limbs disentangled, so that his body is not torn from his legs, nor his head driven from his body, but so the shock will be distributed across all his limbs.

It’s a little unclear to me what “limbs disentangled” means: do the spirits actually remove a person’s limbs through supernatural powers? Or does it just mean that the unconscious person is more relaxed, and less likely to suffer injury. Hmm…

After describing the journey, Kepler describes the geography and astronomy of Levania.

Therefore, as geographers divide our sphere of the earth into five zones according to their celestial phenomena so is Levania divided into two hemispheres: one of these is the Subvolvan, the other is the Privolvan. The Subvolvans are forever blessed by the light from Volva which for them takes the place of our Moon. But the Privolvans are eternally deprived any sight of the Earth. The circle dividing their hemispheres, named the divisor, resembles the meridian passing through the solstices and the poles of our world.

Here Kepler is referring to what we often roughly refer to as the “light and dark sides of the Moon.” Because the Moon is tidal-locked to the Earth, the same face of the Moon is always facing it.

There is much discussion of the astronomy of Levania in the book, and a bit on the geography and even the creatures which live upon it²:

Whatever springs from the land or walks upon the land is of a monstrous size. Increases in size are very rapid. Life is of short duration because all living things grow to such an enormous bodily mass. The Privolvans have no fixed dwelling place. In the space of a single day, they traverse the whole of their world in hordes, following the receding waters either on legs that are longer than those of our camels, on wings, or in boats.

It is worth noting here that Kepler is apparently postulating about the existence of intelligent non-human life on another world. In his era, this would likely be considered heretical; with this in mind, it is understandable that Kepler framed his story as fiction.

The book is overall very short– my copy is 30 pages — and ends abruptly.  Kepler wakes from his dream, to find himself wrapped up in a blanket and head covering like the characters did in order to summon the daemon. So was it a dream, or not…?  Kepler leaves us with one last layer of confusion.

I don’t know if I would call Somnium science fiction.  It definitely contains elements of science fiction, but it is equally a fantasy story with its demons and magical spells. I might classify it as proto-science fiction, a tale that is clearly setting the stage for the genre to follow but has not yet fully realized it.

Incredibly, if you consider Somnium science fiction, it holds the distinction of being the only science fiction story that might have contributed to a person being put on trial as a witch! Kepler did not publish Somnium during his lifetime, but he circulated a copy among his friends in 1611. In 1615, a woman with a financial dispute with the Kepler family claimed that Kepler’s mother Katharina had made her sick with a potion. Katharina was officially accused of witchcraft in 1617, and went on trial in 1620.  Kepler himself provided her defense, however, and had proven her innocence and secured her release by 1621.  It has been suggested that word of Somnium may have been used as a motivation for her trial — as Duracotus clearly represents Kepler, it was easy for enemies to extrapolate and argue that Fiolxhilde represented Katherina and her magical powers.  Kepler evidently thought this himself, and after his mother passed away he added many explanatory notes to his text, including one in which he more or less accuses his enemies of using Somnium against him.  It is worth noting that Somnium was not mentioned at all in Katherina’s trial, however; a full discussion can be found at The Renaissance Mathematicus.

If Kepler’s enemies tried to destroy him by attacking his mother, however, they failed.  Kepler’s most famous work, the three volume Epitome astronomiae Copernicanae, was finished and published between 1615 and 1621, the same era in which his mother was being persecuted.  His masterwork would contain all three of Kepler’s laws of planetary motion, and these laws would later be key in the acceptance of Isaac Newton’s theory of gravity, as Newton could derive them using his new physics.

Somnium would only be officially published in 1634, four years after Kepler’s death, by his son Ludwig.  Though it is a short book, and not a particularly well-written one, it is a fascinating footnote both in the history of science as well as the history of science fiction, and it is well worth checking out for this reason.

(Note: post updated with more context on the witch trial and its relationship to Somnium.)


¹ The quotes for this post came from The Somnium Project, which unfortunately doesn’t have a complete translation.

² I drew this quote from my personal copy, from the 2017 “Vintage Collection” edition of Somnium. Thanks to my niece Ceci for getting it for me for Christmas!

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3 Responses to Somnium, by Johannes Kepler

  1. Blake Stacey says:

    Fascinating, as Mr. Spock always sez! To my shame, I’d known of Kepler’s Somnium for years, but I’ve never taken the time to read it myself.

  2. kaleberg says:

    It sounds like this is a real curio. I know Rabelais, in the previous century, had a visitor to the “coast of Mars” in one of his novels, but I wouldn’t count Gargantua and Pantagruel as science fiction. It’s interesting, though, how attitudes towards intelligent life on other worlds reflect the times. When the Scholastics at the Sorbonne were rediscovering the classics, they argued that there could only be intelligent life on earth and on no other world. The bishop of Paris dissented and called this blasphemy since it denied God’s power to create intelligent life wherever he wanted. Whether he could have also sacrificed his only begotten son on one of those other worlds was a question left best unanswered.

  3. Tom Metcalfe says:

    Reblogged this on The Somnium Project and commented:
    With translations from the Somnium Project:

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