The Music of the Heavens: Kepler's Harmonic Astronomy

The Music of the Heavens: Kepler's Harmonic Astronomy

Bruce Stephenson
Copyright Date: 1994
Pages: 272
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    The Music of the Heavens: Kepler's Harmonic Astronomy
    Book Description:

    Valued today for its development of the third law of planetary motion,Harmonice mundi(1619) was intended by Kepler to expand on ancient efforts to discern a Creator's plan for the planetary system--an arrangement thought to be based on harmonic relationships. Challenging critics who characterize Kepler's theories of harmonic astronomy as "mystical," Bruce Stephenson offers the first thorough technical analysis of the music the astronomer thought the heavens made, and the logic that led him to find musical patterns in his data. In so doing, Stephenson illuminates crucial aspects of Kepler's intellectual development, particularly his ways of classifying and drawing inferences.

    Beginning with a survey of similar theories associating music with the cyclic motions of planets, from Plato to Boethius, the author highlights Ptolemy'sHarmonics, a source of inspiration for Kepler's later work. Turning to Kepler himself, Stephenson gives an account of his polyhedral theory, which explains the number and sizes of the planetary orbits in terms of the five regular poly-hedral. He then examines in detail an early theory that relates the planets' vel-ocities to a musical chord, and analyzes Kepler's unpublished commentary on Ptolemy'sHarmonics. Devoting most of his attention to Book Five ofHarmonice mundi,in which Kepler elaborated on the musical structure of the planetary system, Stephenson lays important groundwork for any further evaluation of Kepler's scientific thought.

    Originally published in 1994.

    ThePrinceton Legacy Libraryuses the latest print-on-demand technology to again make available previously out-of-print books from the distinguished backlist of Princeton University Press. These paperback editions preserve the original texts of these important books while presenting them in durable paperback editions. The goal of the Princeton Legacy Library is to vastly increase access to the rich scholarly heritage found in the thousands of books published by Princeton University Press since its founding in 1905.

    eISBN: 978-1-4008-6382-2
    Subjects: History of Science & Technology

Table of Contents

  1. Front Matter
    (pp. i-vi)
  2. Table of Contents
    (pp. vii-viii)
  3. Preface and Ackowledgments
    (pp. ix-2)
  4. CHAPTER I Introduction
    (pp. 3-15)

    For as long as people have contemplated the heavens, they have perceived music in the stately cycles of the motions overhead. Attempts to link the organized knowledge of astronomy and of music go back at least as far as Plato—as far as Pythagoras, if we heed the indistinct but nearly unanimous voice of tradition. Certainly Plato’s account of the creation of the world was drenched in the language and symbolism of musical harmony. Music theorists of the Hellenistic world and encyclopedists of the Roman world expounded the subject, and through their writings it passed into the common knowledge of...

  5. CHAPTER II Earlier Theories of Astronomical Harmony
    (pp. 16-46)

    Before turning our attention to Kepler, let us take a look at the tradition that climaxed in hisHarmonice mundi.The tradition probably started with the practical observation that bodies rubbing together make noise. The heavenly spheres, which were enormous and which moved with different speeds, would by this reasoning surely make a tremendous racket. This account was sufficiently old that it was credited to Pythagoras by most writers. Aristotle describes an ancient version of the theory, attributing it only to “the Pythagoreans.”¹

    According to Aristotle these Pythagoreans asserted that the circular rotations of the heavenly spheres produced sounds that...

    (pp. 47-63)

    Among the many talented eccentrics whose pens were loosed by the turmoil of the sixteenth century was the itinerant astrologer Jofrancus Offusius, of whom remarkably little is known today. Offusius would probably be forgotten altogether were it not for a couple of cautiously favorable remarks by Tycho Brahe about his estimate of the distance to the Sun—about which more is to follow—and a couple of unfavorable remarks by Kepler about his astrological theories.¹ His background is unknown; he describes himself as a German lover of knowledge.

    In 1570 Offusius published a small theoretical tract entitledConcerning the Divine...

  7. CHAPTER IV Distances to the Planets
    (pp. 64-74)

    Of all the manifestations of harmony in the physical world, the most sublime were surely those hiding in the proportions of the heavens. It took no great originality to suspect that the heavens had been laid out according to some plan, and no great curiosity to want to discover that plan. The problem was only to discern the proportions themselves.

    Which proportions were of interest depended on the way in which the heavens were laid out. So long as one viewed the heavens geocentrically, planetary distances from Earth were the principal dimensions of the large-scale plan. If one considered the...

  8. CHAPTER V The Polyhedral Theory of the Mysterium cosmographicum
    (pp. 75-89)

    Kepler published his first attempt to explain the dimensions of the solar system in 1596, when he was twenty-five years old, in a book of fewer than a hundred pages entitledIntroduction to the cosmographic treatises, containing the cosmographic mystery concerning the remarkable proportion of the heavenly spheres, and concerning the genuine and proper causes of the number, magnitude, and periodic motions of the spheres, demonstrated by means of the five regular geometric solids.Today it is generally known as theMysterium cosmographicum.¹ Most of the larger problems that concerned Kepler throughout his career as an astronomer were raised in...

  9. CHAPTER VI Kepler’s First Harmonic Planetary Theory
    (pp. 90-97)

    In july of 1599 Kepler wrote to one Edmund Bruce, an Englishman visiting Padua and in contact with Galileo, about a new theory that he hoped might attract the attention of the latter. A few weeks later he described the same theory in a long letter to the Bavarian chancellor J. G. Henvart von Hohenburg, a distinguished and enthusiastic amateur of astronomy and astrology and a frequent correspondent of Kepler’s. Soon afterward he elaborated on it again to his former teacher, Michael Maestlin.¹ To all three of his correspondents he pointed out that the predictions of this new harmonic theory...

  10. CHAPTER VII The Reconstruction of Ptolemy’s Harmonics
    (pp. 98-117)

    Kepler in 1600 was actively seeking employment. His position as a Protestant mathematician, teaching at a Protestant school, in Catholic Styria, was becoming untenable under increasing pressure from the Counter-Reformation authorities. After a very anxious period, he joined Tycho Brahe at the beginning of 1601 in Prague. The two men had quite different expectations from their association. Kepler needed primarily to support his family; from Brahe he also hoped to obtain accurate values for the dimensions of the planetary system, which he could use to perfect his harmonic theory.¹ Tycho wanted to employ Kepler’s skillful pen against his own (deceased)...

  11. CHAPTER VIII The Harmonice mundi
    (pp. 118-127)

    TheHarmonices mundi libri v,to which Kepler had intended to append his translation of Ptolemy’sHarmonics,appeared finally in 1619. The principal theses of its five books were that certain ratios, arising from the eternal geometry of regular polygons, were particularly noble; that the influence of music on the human soul depended upon these ratios, as did the influence of astrological aspects on mundane matters such as the weather and the human soul; and that these same ratios had been systematically embodied in the creation of the solar system. Book 5, with which we shall primarily be concerned, sought...

  12. CHAPTER IX Book 5 of the Harmonice mundi
    (pp. 128-241)

    Book 5 of theHarmonice mundiopens with aprooemium,or preface, in which Kepler exults over his recent discovery of the relationship between the orbital radii of the planets and their periodic times: “At last. . . I brought it into the light, and beyond what I had ever been able to hope, I laid hold of Truth itself: I found among the motions of the heavens the whole nature of Harmony, as large as that is, with all of its parts as explained in book 3. It was not in the same way which I had expected—this...

  13. CHAPTER X Conclusions
    (pp. 242-252)

    Kepler probably hoped that theHarmonice mundiwould endure longer than any of his other books. The science of harmony represented for Kepler, as it had for Ptolemy, a synthesis of all that could be known about order and beauty and about their embodiment in the world. Kepler recognized, however, that few readers would be able to appreciate the intricate harmonies he had detected in the heavens. More than once he admitted as much, as in concluding the preface to book 5: “Let it wait a hundred years for its reader, as God himself has awaited a witness for six...

  14. Bibliography
    (pp. 253-256)
  15. Index
    (pp. 257-260)