History of Astronomy |
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Page 46
... Mars , for it was by an examination of these results that Kepler was led to the discovery of his immortal laws . After the death of King Frederick the observa- tories of Tycho Brahe were not supported . The gigantic power and industry ...
... Mars , for it was by an examination of these results that Kepler was led to the discovery of his immortal laws . After the death of King Frederick the observa- tories of Tycho Brahe were not supported . The gigantic power and industry ...
Page 52
... propositions until he arrives at his great laws , and he con- cludes his book by comparing observations of Mars , of all dates , with his theory . His first law states that the planets de- scribe ellipses 52 History of Astronomy.
... propositions until he arrives at his great laws , and he con- cludes his book by comparing observations of Mars , of all dates , with his theory . His first law states that the planets de- scribe ellipses 52 History of Astronomy.
Page 54
... Mars to deal with . This enabled him to use a new method , to find the earth's orbit . Observe the date at any time when Mars is in opposition . The earth's position E at that date gives the longitude of Mars M. His period is 687 days ...
... Mars to deal with . This enabled him to use a new method , to find the earth's orbit . Observe the date at any time when Mars is in opposition . The earth's position E at that date gives the longitude of Mars M. His period is 687 days ...
Page 55
... Mars observations were chosen at intervals of a year , when the earth was always in the same place . But Kepler saw much farther than the geo- metrical facts . He realised that the orbits are EA followed owing to a force directed to the ...
... Mars observations were chosen at intervals of a year , when the earth was always in the same place . But Kepler saw much farther than the geo- metrical facts . He realised that the orbits are EA followed owing to a force directed to the ...
Page 65
... Mars . He then saw that the pull of the earth on the moon would be less than for a nearer object . It is said that while thus meditating he saw an apple fall from a tree to the ground , and that this fact suggested the questions : Is ...
... Mars . He then saw that the pull of the earth on the moon would be less than for a nearer object . It is said that while thus meditating he saw an apple fall from a tree to the ground , and that this fact suggested the questions : Is ...
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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.