The Vikings (and the same was true for the Irish monks) could never, therefore, have sailed from Spain to Central America, as Columbus would later do. But the picture changes if we imagine they first took a route from Iceland to Greenland, and from there to the Canadian coast. Looking at a map, we can easily see how skilled mariners in longships could succeed (with who knows how many shipwrecks along the way) in reaching the far north of the American continent and perhaps the coast of Labrador.
THE SHAPE OF THE SKY
But let us leave the Earth and look at the sky. Aristarchus of Samos had advanced a heliocentric theory between the fourth and third centuries B.C.E., as Copernicus recorded. Plutarch tells us that Aristarchus was accused of impiety precisely because he had put the Earth in movement so as to explain, through earthly rotation, astronomical phenomena that could not otherwise be accounted for. Plutarch did not agree with this theory and Ptolemy later judged it “ridiculous.” Aristarchus was way ahead of his time, and perhaps he reached his conclusion for the wrong reasons. There again, the history of astronomy is curious. A great materialist such as Epicurus developed an idea that survived for so long that it was still being discussed by Gassendi in the seventeenth century, as well as appearing in Lucretius’s De rerum natura. He suggested that the sun, the moon, and the stars (for many very serious reasons) can be neither larger nor smaller than how they appear to our senses. So Epicurus judged the sun to have a diameter of about thirty centimeters.
Copernicus’s De revolutionibus orbium coelestium was published in 1543. We imagine the world was suddenly turned upside-down and we talk about the Copernican revolution. But Galileo’s Dialogo sopra i due massimi sistemi was published in 1632 (eighty-nine years later) and we know what opposition this met. There again, the astronomies of both Copernicus and Galileo were imaginary, since they were wrong about the nature of planetary orbits.
But the most rigorous of imaginary astronomies was that of Tycho Brahe, a great astronomer and Kepler’s teacher, who admitted that planets rotate around the sun—otherwise many astronomical phenomena could not be explained—but claimed that the sun and planets rotate around the Earth, which remains immobile at the center of the universe.
Brahe’s theory was taken seriously, for example, by the Jesuits and especially by Athanasius Kircher. Kircher was a cultured man and could no longer accept the Ptolemaic system. In an illustration of solar systems in his Iter extaticum coeleste (1660 edition), alongside the Platonic system and the Egyptian system he shows us the Copernican system, explaining it accurately, but adding this note: quem deinde secuti sunt pene omnes Mathematici Acatholici et nonnulli ex Catholicis, quibus nimirum ingenium et calamus prurit ad nova venditanda. This was later accepted by almost all non-Catholic and some Catholic mathematicians, namely those who evidently had a craving to peddle new ideas in their writings. Not being of that accursed breed, Kircher thus prefers Brahe.
There were, however, very strong arguments against the idea of an Earth that moves around the sun. In his Utriusque cosmi historia of 1617, Robert Fludd uses mechanical arguments to show that if you have to turn a wheel, like that of the celestial wheel, it is easier to make it turn by exercising a force around the circumference—the point among the spheres where the primum mobile was—than by acting on the center, where the foolish Copernicans would place the sun and every generating force of life and motion. Alessandro Tassoni, in his Dieci libri di pensieri diversi of 1627, lists a range of reasons why the movement of the Earth seemed inconceivable. I will quote two of them.
Argument of the Eclipse. By removing the Earth from the center of the universe, it has to be placed either below or above the moon. If we place it below, there will never be an eclipse of the sun since the moon, being above the sun and above the Earth, will never come between the Earth and the sun. If we place it above, there will never be an eclipse of the moon, since the Earth will never be able to come between it and the sun. And what is more, astronomy could no longer predict eclipses, since it bases its calculations on the movements of the sun, and if the sun does not move, such calculations would be in vain.
Argument of the Birds. If the Earth moves, birds flying westward would never be able to keep up with its rotation and would never go forward.
Descartes, who favored Galileo’s hypothesis but never had the courage to publish his opinions about it, had developed quite an interesting theory involving vortexes, or tourbillons, in Principia philosophiae (1644). He imagined that the heavens were liquid matter, like a sea, swirling about, forming eddies or whirlpools. These vortexes carry planets with them, and the Earth is carried in a vortex around the sun. But it is the vortex that moves. The Earth remains immobile in the vortex that carries it. Descartes was shrewd in setting out these astonishing explanations—a way of getting out of the impasse between the geocentric and heliocentric arguments—as a mere hypothesis, without having to dispute the truth recognized by the church.
As Apollinaire said, Pitié, pitié pour nous qui combattons aux frontières de l’illimité et de l’avenir, pitié pour nos péchés, pitié pour nos erreurs . . . These were times when the astronomer could still commit many serious mistakes, as happened to Galileo when, through his telescope, he discovered the rings of Saturn but could not work out what they were.
First of all he declares he has seen not one single star but three joined together in a straight line parallel to the equinoctial, and represents what he has seen as three small circles. In his later writing he suggests that Saturn may appear in the shape of an olive, and finally he no longer describes three bodies or an olive, but “two semi-ellipses with two very dark little triangles in the middle of the said figures” and draws Saturn to look very much like Mickey Mouse.
Only later would Huygens describe a ring.
AN INFINITY OF WORLDS
Roaming among worlds constructed by the imagination, the imaginary astronomy of our forebears, shaded with hints of the occult, was able to create a revolutionary idea: that of the plurality of worlds. It was an idea already present among the ancient atomists—in Democritus, Leucippus, Epicurus, and Lucretius. As Hippolytus tells us in his Philosophumena, if atoms are in continuous movement in the void, they cannot but produce infinite worlds, each different from the other; and some have neither sun nor moon, for others the stars appear larger than they do for us, and from others many more stars are seen. For Epicurus, it was a hypothesis that, since it could not be contradicted, had to be taken as true until shown to be false. In the words of Lucretius (De rerum natura, book II, lines 1050–51), “Nulla est finis: uti docui, res ipsaque per se / vociferatur, et elucet natura profundi” (“There is no limit; I have shown this, the facts speak for themselves, and the nature of the void is evident”). And he continues: “Thus it is increasingly necessary you recognize that other congregations of material bodies exist elsewhere in the universe, like this of our world, which the ether encircles in eager embrace” (lines 1064–66).
Both the void and the plurality of worlds were disputed by Aristotle and, as well as Aristotle, by great scholars such as Thomas Aquinas and Roger Bacon. But when it came to the debate over the infinita potentia Dei, suspicions about the plurality of worlds would be expressed by William of Ockham, Buridan, Nicole Oresme, and others. Nicholas of Cusa spoke about an infinity of worlds in the fifteenth century, and Giordano Bruno in the sixteenth century.
The deadly poison contained in this hypothesis would emerge more clearly when it gained support from the new epicureans, the seventeenth-century freethinkers. The idea of visiting other worlds, of finding other inhabitants there, was a far more dangerous heresy than the notion of heliocentricity. The infinity of worlds casts doubt on the uniqueness of redemption: Adam’s sin and Christ’s passion are either just minor episodes relevant to our world but not to other divine creatures, or else Golgotha would have to be repeated an infinite number of times on endless planets, removing the sublime uniqueness of the sacrifice of the Son of Man.
As Fontenelle would recall in his Entretiens sur la pluralité des mondes (1686), the suggestion was already there in the Cartesian theory of vortexes, because if every star sweeps its planets into a vortex, and the star is swept away by a larger vortex, it was possible to imagine in the sky an infinity of vortexes carrying an infinity of planetary systems.
The idea of the plurality of worlds heralded the beginning of modern science fiction in the seventeenth century, from the travels of Cyrano di Bergerac in the empires of the sun and of the moon, to Francis Godwin’s The Man in the Moone and
