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- Herausgeber: Balungi Francis
- Kategorie: Wissenschaft und neue Technologien
- Sprache: Englisch
Johannes Kepler was a German astronomer, mathematician, and astrologer. He is a key figure in the seventh century scientific revolution, best known for his laws of planetary motion, and his books Astronomia nova, Harmonices Mundi, and Epitome Astronomiae Copernicanae. These works also provided one of the foundations for Newton's theory of universal gravitation.
Kepler was a mathematics teacher at a seminary school in Graz, where he became an associate of Prince Hans Ulrich von Eggenberg. Later he became an assistant to the astronomer Tycho Brahe in Prague, and eventually the imperial mathematician to Emperor Rudolf II and his two successors Matthias and Ferdinand II. He also taught mathematics in Linz, and was an adviser to General Wallenstein.
Additionally, he did fundamental work in the field of optics, invented an improved version of the refracting (or Keplerian) telescope, and was mentioned in the telescopic discoveries of his contemporary Galileo Galilei.
He was a corresponding member of the Accademia dei Lincei in Rome.Kepler lived in an era when there was no clear distinction between astronomy and astrology, but there was a strong division between astronomy (a branch of mathematics within the liberal arts) and physics (a branch of natural philosophy). Kepler also incorporated religious arguments and reasoning into his work, motivated by the religious conviction and belief that God had created the world according to an intelligible plan that is accessible through the natural light of reason. Kepler described his new astronomy as "celestial physics", as "an excursion into Aristotle's Metaphysics", and as "a supplement to Aristotle's On the Heavens",transforming the ancient tradition of physical cosmology by treating astronomy as part of a universal mathematical physics.
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Veröffentlichungsjahr: 2021
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Table of Contents
kepler
KEPLER
CONTENTS.
CHAPTER I. | ASTRONOMY BEFORE KEPLER.
CHAPTER II. | EARLY LIFE OF KEPLER.
CHAPTER III. | TYCHO BRAHE.
CHAPTER IV. | KEPLER JOINS TYCHO.
CHAPTER V. | KEPLER'S LAWS.
FIGURES EXPLANATORY OF KEPLER'S | THEORY OF THE MOTION OF MARS. | Fig. 1.Fig. 2.
MC | NC
AC | CM
CHAPTER VI. | CLOSING YEARS.
APPENDIX I. | LIST OF DATES.
APPENDIX II. | BIBLIOGRAPHY.
GLOSSARY.
ABERDEEN: THE UNIVERSITY PRESS
KEPLER
PIONEERS OF PROGRESS
MEN OF SCIENCE
Edited by S. CHAPMAN, M.A., D.Sc., F.R.S.
KEPLER
BY
WALTER W. BRYANT
OF THE ROYAL OBSERVATORY, GREENWICH
LONDON:
SOCIETY FOR PROMOTING
CHRISTIAN KNOWLEDGE
NEW YORK: THE MACMILLAN COMPANY
1920
CONTENTS.
CHAPTER I.
ASTRONOMY BEFORE KEPLER.
CHAPTER II.
EARLY LIFE OF KEPLER.
CHAPTER III.
TYCHO BRAHE.
CHAPTER IV.
KEPLER JOINS TYCHO.
CHAPTER V.
KEPLER'S LAWS.
CHAPTER VI.
CLOSING YEARS.
APPENDIX I.
LIST OF DATES.
APPENDIX II.
BIBLIOGRAPHY.
GLOSSARY.
CHAPTER I.
ASTRONOMY BEFORE KEPLER.
In order to emphasise the importance of the reforms introduced into astronomy by Kepler, it will be well to sketch briefly the history of the theories which he had to overthrow. In very early times it must have been realised that the sun and moon were continually changing their places among the stars. The day, the month, and the year were obvious divisions of time, and longer periods were suggested by the tabulation of eclipses. We can imagine the respect accorded to the Chaldaean sages who first discovered that eclipses could be predicted, and how the philosophers of Mesopotamia must have sought eagerly for evidence of fresh periodic laws. Certain of the stars, which appeared to wander, and were hence called planets, provided an extended field for these speculations. Among the Chaldaeans and Babylonians the knowledge gradually acquired was probably confined to the priests and utilised mainly for astrological prediction or the fixing of religious observances. Such speculations as were current among them, and also among the Egyptians and others who came to share their knowledge, were almost entirely devoted to mythology, assigning fanciful terrestrial origins to constellations, with occasional controversies as to how the earth is supported in space. The Greeks, too, had an elaborate mythology largely adapted from their neighbours, but they were not satisfied with this, and made persistent attempts to reduce the apparent motions of celestial objects to geometrical laws. Some of the Pythagoreans, if not Pythagoras himself, held that the earth is a sphere, and that the apparent daily revolution of the sun and stars is really due to a motion of the earth, though at first this motion of the earth was not supposed to be one of rotation about an axis. These notions, and also that the planets on the whole move round from west to east with reference to the stars, were made known to a larger circle through the writings of Plato. To Plato moreover is attributed the challenge to astronomers to represent all the motions of the heavenly bodies by uniformly described circles, a challenge generally held responsible for a vast amount of wasted effort, and the postponement, for many centuries, of real progress. Eudoxus of Cnidus, endeavouring to account for the fact that the planets, during every apparent revolution round the earth, come to rest twice, and in the shorter interval between these "stationary points," move in the opposite direction, found that he could represent the phenomena fairly well by a system of concentric spheres, each rotating with its own velocity, and carrying its own particular planet round its own equator, the outermost sphere carrying the fixed stars. It was necessary to assume that the axes about which the various spheres revolved should have circular motions also, and gradually an increased number of spheres was evolved, the total number required by Aristotle reaching fifty-five. It may be regarded as counting in Aristotle's favour that he did consider the earth to be a sphere and not a flat disc, but he seems to have thought that the mathematical spheres of Eudoxus had a real solid existence, and that not only meteors, shooting stars and aurora, but also comets and the milky way belong to the atmosphere. His really great service to science in collating and criticising all that was known of natural science would have been greater if so much of the discussion had not been on the exact meaning of words used to describe phenomena, instead of on the facts and causes of the phenomena themselves.
