Selections from Kepler's Astronomia NovaJohannes Kepler wrote Astronomia Nova (1609) in a singleminded drive to sweep away the ancient and medieval clutter of spheres and orbs and to establish a new truth in astronomy, based on physical causality. Thus a good part of the book is given over to a nontechnical discussion of how planets can be made to move through space by physical forces. This is the theme of the readings in the present module. The selection includes Kepler's Introduction as well as a selection of chapters that develop the physics of planetary motion. In these ground-breaking chapters, the true Kepler emerges, not as a speculative mystic or a number-crunching drudge, but as a first-rate scientific thinker with a wonderfully engaging narrative style. |
From inside the book
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Page 36
... sun they are traversing their own true and proper positons . But since they cannot be seen when in conjunction with the sun , only the opposition to the sun remains as suitable for this purpose . * But since the sun's mean and apparent ...
... sun they are traversing their own true and proper positons . But since they cannot be seen when in conjunction with the sun , only the opposition to the sun remains as suitable for this purpose . * But since the sun's mean and apparent ...
Page 45
... sun's apparent angular motion in the sky . Therefore , although such theories might be accurate in representing angular positions , they might be wrong about the earth's distances from the sun . But how could those dis- tances be ...
... sun's apparent angular motion in the sky . Therefore , although such theories might be accurate in representing angular positions , they might be wrong about the earth's distances from the sun . But how could those dis- tances be ...
Page 102
... sun's apparent diameter is to be made inversely proportional to the distances . That is , from the diagram above , sin QTR = 2QR / ST , and because angle QTR is small , the angle and its sine are nearly proportional , so that QTR = 1 ...
... sun's apparent diameter is to be made inversely proportional to the distances . That is , from the diagram above , sin QTR = 2QR / ST , and because angle QTR is small , the angle and its sine are nearly proportional , so that QTR = 1 ...
Contents
Introduction to the celestial motions | 29 |
The earth like other planets moves nonuniformly | 45 |
The sun is a magnet and rotates in its space | 63 |
Copyright | |
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Common terms and phrases
aethereal air angle aphelion appear Appendix argument Astronomia Nova astronomical axis carried celestial Chapter 32 circumference Copernican Copernicus demonstrated diagram diameter distances diurnal motion Donahue trans earth's motion earth's orbit eccentric anomaly eccentric circle epicycle equal equated anomaly eyes faculty force geometrical Green Lion heavens heavy bodies human hypothesis immaterial species Kepler Latin latitude law of sines light line of apsides magnetic Mars Mars's mathematical mean anomaly measure Mercury moon motive power mover moving power Mysterium cosmographicum nature observations opposite optical equation path perigee perihelion period planet moves planetary models position present proportional psalmodist Ptolemy ratio reader reciprocation rotation scripture second inequality semidiameters solar body solar theory space speed stars straight lines sun or earth sun's apparent sun's mean superior planets Taurus theory things tions translation traversed triangle tricity Tycho Brahe zodiac