History of Astronomy |
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Page vi
... earth , of the directions of a moving object , Mars - to deduce the exact shape of the path of each of these planets , and their actual positions on these paths at any time . Kepler's masterpiece is one of the most interesting books ...
... earth , of the directions of a moving object , Mars - to deduce the exact shape of the path of each of these planets , and their actual positions on these paths at any time . Kepler's masterpiece is one of the most interesting books ...
Page 6
... earth's equator to the plane of her orbit ( the obliquity of the ecliptic ) has been diminishing slowly since pre- historic times ; and this fact has been confirmed by Egyptian and Chinese observations on the length of the shadow of a ...
... earth's equator to the plane of her orbit ( the obliquity of the ecliptic ) has been diminishing slowly since pre- historic times ; and this fact has been confirmed by Egyptian and Chinese observations on the length of the shadow of a ...
Page 7
... earth to be spherical , and to ascribe the diurnal motions to its rotation . Probably the greatest step ever made in astronomical theory was the placing of the sun , moon , and planets at differ- ent distances from the earth instead of ...
... earth to be spherical , and to ascribe the diurnal motions to its rotation . Probably the greatest step ever made in astronomical theory was the placing of the sun , moon , and planets at differ- ent distances from the earth instead of ...
Page 17
... earth cuts off the sun's light from her . He supposed the earth to be flat , and to float upon water . He determined the ratio of the sun's diameter to its orbit , and apparently made out the diameter correctly as half a decree . He ...
... earth cuts off the sun's light from her . He supposed the earth to be flat , and to float upon water . He determined the ratio of the sun's diameter to its orbit , and apparently made out the diameter correctly as half a decree . He ...
Page 18
... earth in the night . He held that in a solar eclipse the moon hides the sun , and in a lunar eclipse the moon enters the earth's shadow both excellent opinions . But he entertained absurd ideas of the vertical motion of the heavens ...
... earth in the night . He held that in a solar eclipse the moon hides the sun , and in a lunar eclipse the moon enters the earth's shadow both excellent opinions . But he entertained absurd ideas of the vertical motion of the heavens ...
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accurate Airy ancient astron Astronomer Royal astronomical units bright calculations Cape catalogue centre century Chaldæans Chinese comet Copernicus diameter discovered discovery earth Egyptian epicycles equatorial error excentric explain fact fixed stars Galileo Greenwich Halley heavenly bodies heavens heliometer Hipparchus History of Astronomy instruments JOHANNES KEPLER John Herschel Jupiter Jupiter's Kepler Laplace Lick Observatory light line of apses line of sight lunar Mars mathematical mean distance mean motion measured ment Mercury meteor miles a second moon moon's nebulæ Newton observations Observatory orbit parallax period photographic physical planet planetary pole position predicted proper motion proved Ptolemy R. S. Phil records refractor retrograde retrograde motion revolving round ring rotation satellites Saturn seems showing Sir William Herschel Sirius solar eclipse solar system spectra spectroscope spectrum sphere spots stellar sun-spot supposed tables telescope theory tion Trans Tycho Brahe universal gravitation Uranus velocity Venus Verrier
Popular passages
Page 67 - that every particle of matter in the universe attracts every other particle, with a force whose direction is that of the line joining the two, and whose magnitude is directly as the product of their masses, and inversely as the square of their distances from each other.
Page 26 - So he sate and cunningly guided the craft with the helm, nor did sleep fall upon his eyelids, as he viewed the Pleiads and Bootes, that setteth late, and the Bear, which they likewise call the Wain, which turneth ever in one place, and keepeth watch upon Orion, and alone hath no part, in the baths of Ocean. This star, Calypso, the fair goddess, bade him to keep ever on the left as he traversed the deep.
Page 53 - The third, viz. that the squares of the periodic times are proportional to the cubes of the mean distances...
Page 79 - Wherefore if according to what we have already said it should return again about the year 1758, candid posterity will not refuse to acknowledge that this was first discovered by an Englishman.
Page 122 - ... They have not been regarded as so successful as his geometrical analysis of the observed phenomena. It is only just to add that he himself did not attach equal weight to them ; for in answer to objections urged by Lalande to his theory that the spots are depressions, Wilson wrote thus in 1783 : — ' Whether their first production and subsequent numberless changes depend upon the eructation of elastic vapours from below, or upon eddies or whirlpools commencing at the surface, or upon the dissolving...
Page 51 - He then said boldly that it was impossible that so good an observer as Tycho could be wrong by eight minutes* and added, " out of these eight minutes we will construct a new theory that will explain the motions of all the planets.