Here, Rhonda Martens offers the first extended study of Kepler's philosophical views and shows how those views helped him construct and justify the new astronomy.".

Johannes Kepler (1571-1630) is remembered, along with Copernicus and Galileo, as one of the greatest Renaissance astronomers. A gifted analytical thinker, he made major contributions to physics, astronomy, and mathematics. Kepler was trained as a theologian, yet did not hesitate to challenge church doctrine and prevailing scientific beliefs by supporting the theory of a Sun-centered solar system. As Imperial Mathematician to the Holy Roman Emperor, he analyzed the precise observations of the heavens that his predecessor, the great astronomer Tycho Brahe, had recorded. The book follows the ingenious scientist along the difficult pathway from raw data to his monumental discovery--the three Laws of Planetary Motion. Kepler also made fundamental contributions to optical theory, including a correct description of the function of the eye and a new and improved telescope design. His unique Rudolfine Tables, universal calculations of planetary motion, were unprecedented in their accuracy. James Voelkel vividly describes these scientific achievements, providing enough background in astronomy and geometry so even beginners can follow Kepler's thinking and enjoy this book. Equally captivating is his account of Kepler's tumultuous life, plagued by misery, disease, war, and fervent religious persecution.Oxford Portraits in Science is an ongoing series of scientific biographies for young adults. Written by top scholars and writers, each biography examines the personality of its subject as well as the thought process leading to his or her discoveries. These illustrated biographies combine accessible technical information with compelling personal stories to portray the scientists whose work has shaped our understanding of the natural world.

Johannes Kepler contributed importantly to every field he addressed. He changed the face of astronomy by abandoning principles that had been in place for two millennia, made important discoveries in optics and mathematics, and was an uncommonly good philosopher. Generally, however, Kepler's philosophical ideas have been dismissed as irrelevant and even detrimental to his legacy of scientific accomplishment. Here, Rhonda Martens offers the first extended study of Kepler's philosophical views and shows how those views helped him construct and justify the new astronomy. Martens notes that since Kepler became a Copernican before any empirical evidence supported Copernicus over the entrenched Ptolemaic system, his initial reasons for preferring Copernicanism were not telescope observations but rather methodological and metaphysical commitments. Further, she shows that Kepler's metaphysics supported the strikingly modern view of astronomical method that led him to discover the three laws of planetary motion and to wed physics and astronomy--a key development in the scientific revolution. By tracing the evolution of Kepler's thought in his astronomical, metaphysical, and epistemological works, Martens explores the complex interplay between changes in his philosophical views and the status of his astronomical discoveries. She shows how Kepler's philosophy paved the way for the discovery of elliptical orbits and provided a defense of physical astronomy's methodological soundness. In doing so, Martens demonstrates how an empirical discipline was inspired and profoundly shaped by philosophical assumptions.

In Measuring Shadows, Raz Chen-Morris demonstrates that a close study of Kepler’s Optics is essential to understanding his astronomical work and his scientific epistemology. He explores Kepler’s radical break from scientific and epistemological traditions and shows how the seventeenth-century astronomer posited new ways to view scientific truth and knowledge. Chen-Morris reveals how Kepler’s ideas about the formation of images on the retina and the geometrics of the camera obscura, as well as his astronomical observations, advanced the argument that physical reality could only be described through artificially produced shadows, reflections, and refractions. Breaking from medieval and Renaissance traditions that insisted upon direct sensory perception, Kepler advocated for instruments as mediators between the eye and physical reality, and for mathematical language to describe motion. It was only through this kind of knowledge, he argued, that observation could produce certainty about the heavens. Not only was this conception of visibility crucial to advancing the early modern understanding of vision and the retina, but it affected how people during that period approached and understood the world around them.

This is one of the most important studies in decades on Johannes Kepler, among the towering figures in the history of astronomy. Drawing extensively on Kepler's correspondence and manuscripts, James Voelkel reveals that the strikingly unusual style of Kepler's magnum opus, Astronomia nova (1609), has been traditionally misinterpreted. Kepler laid forth the first two of his three laws of planetary motion in this work. Instead of a straightforward presentation of his results, however, he led readers on a wild goose chase, recounting the many errors and false starts he had experienced. This had long been deemed a ''confessional'' mirror of the daunting technical obstacles Kepler faced. As Voelkel amply demonstrates, it is not. Voelkel argues that Kepler's style can be understood only in the context of the circumstances in which the book was written. Starting with Kepler's earliest writings, he traces the development of the astronomer's ideas of how the planets were moved by a force from the sun and how this could be expressed mathematically. And he shows how Kepler's once broader research program was diverted to a detailed examination of the motion of Mars. Above all, Voelkel shows that Kepler was well aware of the harsh reception his work would receive--both from Tycho Brahe's heirs and from contemporary astronomers; and how this led him to an avowedly rhetorical pseudo-historical presentation of his results. In treating Kepler at last as a figure in time and not as independent of it, this work will be welcomed by historians of science, astronomers, and historians.

A contemporary of Galileo and a forerunner of Isaac Newton, Johannes Kepler (1571-1630) was a pioneering German scientist and a pivotal figure in the history of astronomy. This colorful, well-researched biography brings the man and his scientific discoveries to life, showing how his contributions were every bit as important as those of Copernicus, Galileo, and Newton. It was Kepler who first advocated the completely new concept of a physical force emanating from the sun that controls the motion of the planets--today we call this gravity and take it for granted. He also established that the orbits of the planets were elliptical in shape and not circular. And his three laws of planetary motion are still used by contemporary astronomers and space scientists. The author focuses not just on these and other momentous breakthroughs but also on Kepler's arduous life, punctuated by frequent tragedy and hardships. His first wife died young, and eight of the twelve children he fathered succumbed to disease in infancy or childhood. He was frequently caught up in the religious persecutions of the day. His mother narrowly escaped death when she was accused of being a witch. Intermingling historical and personal details of Kepler's life with lucid explanations of his scientific research, this book presents a sympathetic portrait of the man and underscores the critical importance of Kepler's discoveries in the history of astronomy.

The brilliant German mathematician Johannes Kepler (1571-1630), one of the founders of modern astronomy, revolutionized the Copernican heliocentric theory of the universe with his three laws of motion: that the planets move not in circular but elliptical orbits, that their speed is greatest when nearest the sun, and that the sun and planets form an integrated system. This volume contains two of his most important works: The Epitome of Copernican Astronomy (books 4 and 5 of which are translated here) is a textbook of Copernican science, remarkable for the prominence given to physical astronomy and for the extension to the Jovian system of the laws recently discovered to regulate the motions of the Planets. Harmonies of the World (book 5 of which is translated here) expounds an elaborate system of celestial harmonies depending on the varying velocities of the planets.