From Eudoxus to Einstein: A History of Mathematical Astronomy
C. M. Linton
Language: English
Pages: 532
ISBN: 0521045711
Format: PDF / Kindle (mobi) / ePub
Since humans first looked towards the heavens, they have attempted to predict and explain the motions of the sun, moon, and planets. This book describes the theories of planetary motion that have been developed through the ages, from the homocentric spheres of Eudoxus to Einstein's general theory of relativity. It emphasizes the interaction between progress in astronomy and in mathematics, demonstrating how the two have been inextricably linked since Babylonian times.
Planets, Stars and Stellar Systems, Volume 2: Astronomical Techniques, Software, and Data
Magnificent Desolation: The Long Journey Home from the Moon
note is the fact that, for Mercury and Venus, the line joining the Earth to the centre of their epicycles is the same as that joining the Earth to the Sun, whereas for the outer planets, which may appear anywhere with respect to the Sun, the radius connecting the planet to the centre of its epicycle is parallel to the Earth–Sun line. Thus, it is evident that the Sun does not simply orbit the Earth like the other planets, but has a much more significant role. The motion of the Sun also plays a
source of information until superseded by Kepler’s Rudolphine Tables in 1627. This improvement was due, not to his geometrical models being intrinsically 8 more accurate than Ptolemy’s (they are not) but simply because he recomputed many of the parameters that must be entered into the models in order to construct the tables and, since many of these had changed since the time of Ptolemy, the final results were more accurate. The Commentariolus Copernicus developed his heliocentric theory while in
The heliocentric universe A A E C O S Fig. 5.4. Copernicus’ theory for the orbit of the Earth. The Earth E orbits uniformly about O, completing 1 revolution in 1 sidereal year, which Copernicus computes to be 365 days 6 h 9 min 40 s. The centre of the orbit of the Earth is no longer fixed but rotates around C with |C O| = r2 say, completing 1 revolution in 3434 years, and C rotates around the Sun S with |SC| = r1 , completing 1 revolution in just over 53 000 years. The motion around the
contribution came in 1577 following his first sighting of a comet. He saw the comet first on 13 November and began immediately making careful observations, something he continued to do until the comet faded from view in January 1578. In November, its tail stretched 22◦ across the sky and the comet matched Venus for brilliance. By the end of December, Tycho concluded that the comet showed essentially no diurnal parallax and was convinced that it was further away than the Moon, at least 230 Earth
agreement with the physical law. The latter he assumed to be true throughout the orbit. What was the ‘force’ that made the planets move in this way? Kepler believed that it was similar to magnetism, which had been the subject of a very influential 68 book, On the Magnet, by the respected Englishman (and royal physician) William Gilbert in 1600. Gilbert concluded that the Earth was a giant magnet and Kepler reasoned that the ‘motive virtue’ present in the Sun which drove the planets on their
