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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.

Kepler's essay, On the Six-Cornered Snowflake, provides the first published evidence of the ideas of regular arrangements and close-packing which have proved fundamental to crystallography. In it, Kepler ponders on the problem of why snowflakes are hexagonal, two centuries before the first successful steps were taken towards its solution. The purpose of this volume is to display the historical, literary, scientific, and philosophical treasures of Kepler's essay. The book includes the modernized text of the 1611 Latin edition, with an English translation by Colin Hardie on the opposite pages. The text is accompanied by an introduction giving details of the history of the work, and two essays; Professor B. J. Mason's discussion of the scientific meaning and validity of Kepler's arguments and their relation to the history of crystallography and of space filling, and L. L. Whyte's examination of Kepler's facultas formatrix in relation to the history of philosophical and scientific ideas on the genesis of forms.

New to Penguin Classics, the astonishing story of the Copernican Revolution, told through the words of the ground-breaking scientists who brought it about In the late fifteenth century, it was believed that the earth stood motionless at the centre of a small, ordered cosmos. Just over two centuries later, everything had changed. Not only was the sun the centre of creation, but the entire practice of science had been revolutionised. This is the story of that astonishing transformation, told through the words of the astronomers and mathematicians at its heart. Bringing together excerpts from the works and letters of Copernicus, Galileo, Kepler, Descartes, Newton and others for the first time, The Dawn of Modern Cosmology is the definitive record of one of the great turning points in human history. Edited with Translations, Notes and an Introduction by Aviva Rothman