|Publisher:||Smithsonian Institution Press|
|Edition description:||New Edition|
|Product dimensions:||5.90(w) x 8.90(h) x 1.00(d)|
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A Plurality of Worlds
There will certainly be no lack of human pioneers when we have mastered the art of flight. Who would have thought that navigation across the vast ocean is less dangerous and quieter than in the narrow, threatening gulfs of the Adriatic, or Baltic, or the British straits? Let us create vessels and sails adjusted to the heavenly ether, and there will plenty of people unafraid of the empty wastes. In the meantime, we shall prepare, for the brave sky-travelers, maps of the celestial bodiesI shall do it for the moon, you Galileo, for Jupiter. Johannes Kepler (1571-1630)
The man who can fairly be regarded as the first significant figure of the space age was only a babe in arms when Pedro Menéndez de Avilés encountered the Ay people on the beach at Cape Canaveral. Born at Weil der Start, Württemburg, on 27 December 1571, Johannes Kepler was one of the most remarkable citizens of an extraordinary age. Slowly and painfully a new Europe was emerging from an era of chaos, confusion, and change. During the century before Kepler's birth, a Renaissance of art and literature had swept across Italy and France, the Protestant Reformation had shattered the unity of medieval Christendom, and mariners had planted their respective flags on the shores of two continents whose very existence they had not suspected.
It was a time of profound contradictions. Bigotry, intolerance, and persecution flourished while geographic and intellectual horizons were undergoing an enormous expansion. As Europeans struggled to deal with theconsequences of religious wars, unprecedented social and economic upheaval, and shifting international rivalries, they also were growing accustomed to the excitement of change and the thrill of new discovery.
Johannes Kepler, a major contributor to one of the most significant intellectual revolutions in history, involving nothing less than a rearrangement of the cosmos, personified the ironies and contradictions of his age. The philosopher Immanuel Kant, surely a creditable judge of such matters, regarded him as "the most acute thinker ever born." Yet for all of that, Kepler's life was deeply rooted in a world of darkness, superstition, and violence.
His father, an alcoholic mercenary soldier with a criminal record and a penchant for wife beating, deserted the family when Kepler was seventeen. His great aunt was burned as a witch. His mother was accused of the same crime, apparently with some justification, and barely escaped the stake. Giordano Bruno, a contemporary of Kepler's, was less fortunate. He was burned alive as a heretic at the Campo di Fiori in Rome on 17 February 1600 for insisting that the stars in the night sky were suns warming "a plurality of worlds," some of which, like Earth, might shelter life.
Kepler, an aloof and unpopular neurotic who admitted to a "dog-like loathing of baths," was not a particularly pleasant fellow. The man who laid the foundation for the science of celestial mechanics was best known in his own time as a mystic, an astrologer, and a numerologist. Although he acknowledged that astrology was but "the foolish step-daughter" of astronomy, he cast horoscopes for Duke Albrecht von Wallenstein, the preeminent military commander of the time, and cheerfully predicted everything from the weather to the outcome of battles based on his observations of the heavens.
Yet if Kepler lived his life with one foot firmly planted in the past, his eyes were most certainly turned toward the future, and his mind ranged much further afield than any of the great explorers of his day. Christopher Columbus, and those who followed him, crossed oceans and began the process of exploiting the wealth of new continents while Kepler dreamed of journeys into the cosmos and the exploration of entirely new worlds. Kepler, in fact, was among the first to honestly believe that men and women might one day voyage into space.
You can scarcely dream of traveling to a place until you know it exists. For the common folk of Kepler's age, as for their ancestors, the possibility of a journey beyond Earth was unthinkable. There was no place beyond Earth. The stars were pinpricks in a black velvet dome, revealing the light of some mysterious fire that was beyond knowing. The heavens hung very low overhead, and the notion that someone looking up into the night sky might be gazing across a billion-mile gulf or responding to light generated some ten thousand years earlier by a distant Sun was simply inconceivable.
The more educated members of society were aware of a theory, originally proposed by Parmenides, a Greek scholar of the fifth century B.C., which described the universe as a nest of spherical shells with Earth at the center, the Sun, the Moon, and planets on intermediary spheres, and the stars on the outer shell, or primum mobile. Over the centuries, this simple model grew increasingly complex as additional shells were added to force the spheres carrying the Moon and planets to move in such a way as to mirror the movements actually observed in the sky.
There were dissenting visions of the cosmos. The most interesting came from the mathematician and astronomer Aristarchus of Samos (c. 310-230 B.C.). Impressed by the work of Eratosthenes of Cyrene (c. 276-194 B.C.), who developed an ingenious geometric procedure for estimating Earth's size, Aristarchus set out to measure the Sun and the Moon and to determine their distance from Earth. Although he underestimated the scale of things by an order of magnitude, Aristarchus got the proportions right, and he found it difficult to believe that a body as large as the Sun would orbit an object as small as Earth. That being the case, he proposed that the movements of the heavenly bodies could best be understood by assuming that the Moon orbited Earth, which, like the other planets, was turning on its axis while circling the Sun. It was one of those rare leaps of the imagination that define genius.
Roman historian Plutarch reported that Aristarchus was threatened with banishment for his radical notions. Perhaps so. Such is often the fate of brilliant men, and of great ideas come seventeen hundred years before their time. In any event, the notion that the earth might not be at the center of all things was too radical for most thinkers. Blessed by the wisdom of the great Aristotle, and placed in something close to its final complex form by the Graeco-Egyptian philosopher Claudius Ptolemy (second century A.D.), the geocentric, spherical universe would continue to dominate cosmological thought in both the Christian and Islamic worlds until the mid-sixteenth century. Then, suddenly, it would be gone.
Why, after a millennium and a half, did the geocentric universe give way in a single generation? A growing dissatisfaction with the accuracy of the predictions offered by the model was certainly a factor. Creaking with age and the weight of a thousand alterations, the ever-turning spheres of the old system remained slightly out of tune with the observational data. Poor translations and incorrect transcriptions could no longer excuse a failure to keep accurate track of something as simple as the precise length of a year. The thing simply did not ring true.
There was an even deeper problem, however. Few could bring themselves to believe that Ptolemy's whirling, whizzing, off-centered contraption of a universe bore the slightest resemblance to the real world. By the sixteenth century a handful of philosophers were prepared to risk charges of heresy in order to demonstrate that God had structured his cosmos in a far simpler and more elegant fashion.
Although Mikolaj Kopernik (1473-1543) did not singlehandedly destroy the Ptolemaic system, he struck the first crucial blow. Known to posterity by his Latinized name, Copernicus, he proposed nothing less than a fundamental reordering of the cosmos along the lines suggested by Aristarchus of Samos.
In the pages of De revolutionibus orbium coelestium (On the revolutions of the celestial spheres), one of the most influential books ever published, this Polish churchman, physician, lawyer, and astronomer removed the earth, and its inhabitants, from the center of the universe. Our planet, he suggested, was but one of six worlds orbiting the Sun. Copernicus was fully aware of the way in which the leaders of his church would react to such a radical notion. As a result, he circulated a short, preliminary presentation of his ideas among scientific colleagues as early as 1512, but refused to publish De Revolutionibus, a full and complete treatment of his system, until shortly before his death in May 1543. In all probability Copernicus himself never saw a printed copy of his masterpiece.
The Copernican revolution did not take Europe by storm. Galileo Galilei feared that he himself would suffer "the fate of our master Copernicus," who "in the eyes of a countless host ... appeared as one to be laughed at and hissed off the stage." Copernicus was rebuked by religious authorities from the pope to John Calvin and Martin Luther, who reminded his followers that Joshua commanded the Sun, not Earth, to stand still.
Nor did astronomers rush to accept the new model. Many, like Tycho Brahe (1546-1601), the greatest observer and celestial record keeper of the age, rejected the notion of a Sun-centered cosmos for the best of all possible reasons: the Copernican model, as originally proposed, was no more accurate or elegant than the Ptolemaic one. In an effort to increase the precision of his scheme, Copernicus had resorted to the assorted astronomical tricks pioneered by his classical predecessors, who espoused a spherical cosmos.
The work of two very different men, Johannes Kepler and Galileo Galilei, was required to complete the Copernican revolution. Galileo (1564-1642), the urbane son of a wealthy patrician family, built his early reputation on studies of motion and gravitation, but he would earn immortality with the telescope. He did not invent the device; that honor probably goes to the Dutch instrument maker Hans Lippershey. Nor was Galileo the first to turn a telescope toward the heavens. Thomas Harriot, the brilliant English mathematician who taught navigation to Sir Walter Raleigh, had already prepared a map of the Moon on the basis of his telescopic observations.
What Galileo did, however, was to recognize the extent to which his observations supported the Copernican theory and to publicize that fact. Peering through his "optik tube," he saw the planets transformed into disks while the stars remained points of light. Venus passed through phases. Four moons could be seen circling Jupiter. Our own Moon was not a silver disk but a real place, complete with mountains, valleys, and what looked like seas. The gossamer band of the Milky Way was resolved into countless stars. There were more stars than could be seen with the naked eye and a sense of incredible depth to the sky. In the pages of a small book, Sidereus Nuncias (Starry messenger), published in March 1610, Galileo announced that be had seen the wonders of the Copernican universe with his own eyes.
Far to the north, Johannes Kepler read, and he wrote to Galileo, asking how he might obtain a telescope of his own. Galileo did not respond. The two men would carry on a sporadic correspondence over the years, but Galileo was never particularly impressed with Kepler's work. Here was a man, after all, so enamored of astrology that he believed the Moon exerted an influence over the tides of the ocean. "It has always hurt me to think that Galileo did not acknowledge the work of Kepler," Albert Einstein once remarked. "That, alas is vanity. You find it in so many scientists."
Galileo, who described the beauty and wonder of space, argued the Copernican case on the basis of experiment and observation. It was Kepler, the theoretical genius, who explained the first principles of the cosmos. Using the finest set of astronomical observations available anywhere, he proposed what have become known as the laws of planetary motion, which explain the motions observed in the heavens in precise mathematical terms.
It had been possible to argue against the Copernican theory, but Kepler's mathematical formulation was unassailable. After twenty-two centuries of speculation the structure of the solar system was finally revealed.
Never before or since has there been such a sudden and stunning shift in the basic intellectual framework within which human beings organize their understanding of the universe. Far from standing stationary at the center of the universe, Earth, and all of its inhabitants, was rushing around the Sun at an incredible speed, spinning on its axis like a top. Even more stunning was the sudden expansion of the universe. The most generous of the Ptolemaic astronomers had assumed that the entire cosmos was smaller than the actual orbit of Earth about the Sun. Even Copernicus had envisioned a finite universe bounded by the final, outer sphere of the stars. Now that was gone, shattered by the vision of the endless starry depths of space as seen through the telescope.
Kepler had no doubt that someday man would voyage into that great unknown. "In the meantime, we shall prepare, for the brave sky-travelers, maps of the celestial bodies," he wrote. "I shall do it for the moon, you Galileo, for Jupiter." He must have relished the thought of such a cosmic voyage. Among his many accomplishments, he can fairly be regarded as the inventor of science fiction. In all the centuries before his time there had been only one other author who had told tales of a journey to the Moon and planets. Lucian of Samosata (c. A.D. 120-180) a Syrian-Greek author, had written two fictional accounts of voyages into the cosmos. But Lucian's fantastic yarns were nothing more than traditional traveler's talessocial and political satires with an unconventional setting. They might as easily have been set in some unknown corner of the earth as in space. Kepler's approach was very different. He used fiction as a means of presenting the best science of the day in the most appealing fashion and of exploring the social implications of new ideas.
In Somnium (Dream), Kepler tells the story of a man who falls asleep while reading an arcane book, only to dream that he is reading yet another book, the tale of Duracotus and his mother, the "wise woman" Floxhilda. Returning home after a period of employment as Tycho Brahe's astronomical assistant. Duracotus is stunned to discover that his mother knows more about the Moon than he does. She has visited the place, carried there by demons. Duracotus persuades his mother to send him to the Moon. The demons give him a "dozing draught," an anaesthetic to protect him from the hazards of the journey, and apply a moist sponge to his nostrils so that he can breath as they ascend through the thin air. Approaching the midpoint of the journey, "conveyance becomes easier" for the demons, suggesting a loss of weight.
Our hero finds the Moon exactly as Galileo had described it, complete with incredibly tall mountains, deep canyons, craters, and plains. The creatures inhabiting the various regions of the Moon have been shaped by their environments. Like pre-Copernican Earthlings, they are convinced that their own world is fixed at the center of the universe with all other planets and moons revolving around it. Suddenly the reader awakes to find that the story within a story is only, after all, a dream.
Somnium seems to have begun as a university thesis on the Copernican system completed as early as 1593. Over the years Kepler transformed the original paper by adding transparently autobiographical elements alluding to his own relationship with Brahe and to the women in his family, who had a reputation for supernatural wisdom. In addition, he altered details to keep the manuscript scientifically up-to-date. He may have begun circulating an early version of the fictionalized manuscript among friends as early as 1609. In 1615 a copy apparently fell into the wrong hands, leading to the arrest of Kepler's mother for witchcraft. Small wonder that the author refused to allow it to be published in his lifetime. The first printed edition appeared in 1634, four years after his death.
Somnium reflects the ironies and contradictions of Kepler's life. Demons carry the hero to the Moon, yet the book is filled with not only the very best contemporary science but also some startlingly good guesses. Readers must have found the book to be an enjoyable and convincing introduction to the Copernican universe. Yet Somnium represents a good deal more than a simple attempt to popularize and communicate good science. Kepler wanted to excite his readers by helping them to imagine what a journey to the Moon might actually be like. Unlike Lucian, who might as well have sent his voyagers to some distant land across the seas, Kepler based his inspired speculations on what little he knew, or thought he knew. He was the first author to describe the hazards that might be encountered spaceairlessness and weightlessness. Rather than telling his readers what the Moon looked like through a telescope, he stood them on its surface, gave them a guided tour of the lunar topography, and showed them Earth suspended in the sky.
Kepler did not invent the notion of life on a plurality of worlds. Lucian had his hippogypii, whereas the followers of the Pythagorean tradition, and even so good a Christian as Bishop Nicholas of Cusa, had argued that God would not have limited his creation to a single race of intelligent beings. But those individuals spoke in terms of what we would now define as parallel universes or different dimensions, not the real world of the stars and planets. Kepler broke the anthropocentric mold, carefully crafting his lunar inhabitants to fit the peculiar niches of their unique environment.
Johannes Kepler had revealed the structure of the solar system and explained the most basic rules governing its operation. Not content with that, he had thrown open the doors of the imagination, suggesting that the Moon and planets were real places, new worlds separated from Earth by the vast chasm of space. Of course few people shared Kepler's confidence that human beings would ever be able to explore those worlds. The notion that one might actually travel into the "fearful void" of space was impious and outrageous unthinkable. And yet ...
Table of Contents
Chapter 1 Prologue: Spaceport! Chapter 2 1. A Plurality of Worlds Chapter 3 2. The Call of the Cosmos Chapter 4 3. Raketenrummel Chapter 5 4. An American Dreamer Chapter 6 5. Vergeltungswaffe! Chapter 7 6. "Our Germans" Chapter 8 7. Selling Space Flight Chapter 9 8. Fellow Travelers Chapter 10 9. This New Ocean Chapter 11 10. Racing to the Moon Chapter 12 11. The Giant Leap: Gemini Chapter 13 12. The Apollog Era Chapter 14 13. Men from Earth Chapter 15 14. Salyut and Skylab: Rooms with a View Chapter 16 15. The Shuttle Era Chapter 17 16. At Home in Orbit Chapter 18 17. Robot Servants and Explorers Chapter 19 18. Outward Bound