A History of AstronomyMethuen & Company, 1907 - 355 pagine |
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accuracy actual Algol appearance astronomy atmosphere Bessel binary body bright brighter catalogue cause celestial centre century CHAPTER comet computed corona deduced determination direction discovered discovery distance double stars earth eclipse effect epoch equator equatorial error evidence Flamsteed gaseous Greenwich Halley heliometer Herschel Hipparchus Huggins hydrogen hydrogen lines hypothesis increasing inferred instance instruments investigation Jupiter Jupiter's known large number latitude Lick Lick Observatory light limb lines longitude lunar magnitude Mars measured Mercury meridian meteors method miles minor planets moon moon's nearly nebula Newton observations obtained orbit parallax Paris Observatory period photograph planetary probably Professor proper motion Ptolemy recognised refractor regarded result revolving rotation Royal Observatory satellites Saturn seen similar Sirius solar system spectra spectroscopic spectroscopic binary spectrum spots stellar Struve successive suggested sun-spots sun's telescope theory tion transit Tycho Uranus variable variable stars variation velocity Venus visible Yerkes Yerkes Observatory zone
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Pagina 49 - 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.
Pagina 339 - So, naturalists observe, a flea Hath smaller fleas that on him prey ; And these have smaller still to bite 'em, And so proceed ad infinitum.
Pagina 52 - Notwithstanding these unavoidable defects, the number and generality of his discoveries relative to this system, and many of the most interesting points of the Physico-mathematical sciences, the multitude of original and profound views, which have been the germ of the most brilliant theories of the geometers of the last century, all of which were presented with much elegance, will assure to the Principia a preeminence above all the other productions of the human intellect.
Pagina 44 - ... solitary example of mental prowess. If Keppler discovered the general laws of the universe, the basis of the discovery was laid by Tycho ; and the marvellous Napier contributed essentially to the issue obtained, by the invention of the logarithms, an admirable artifice, as it has been justly called, which, by reducing to a few days the labour of many months, doubles the life of the astronomer, and saves him the errors and disgust connected with long calculations. If Newton developed the cause...
Pagina 52 - The imperfection of the infinitesimal calculus when first discovered, did not allow him completely to resolve the difficult problems which the theory of the universe offers ; and he was oftentimes forced to give mere hints, which were ^always uncertain till confirmed by rigorous analysis. Notwithstanding these unavoidable defects, the importance and the generality of his discoveries...
Pagina 40 - that the square of the periodic time of any planet is proportional to the cube of its mean distance from the sun...
Pagina 53 - The number and generality of his discoveries relative to the system of the world ... the multitude of original and profound views which have been the germ of the most brilliant theories of geometers . . . will assure the Principia a preeminence above all the other productions of the human intellect.
Pagina 70 - ... subsequently engaged in the same experimental investigation, with apparatus constructed upon an original principle. It is easily seen that if we have the true velocity of light, we have indirectly and at once the solar parallax. For the aberration of the fixed stars gives us a determinate relation between the velocity of light and that of the earth in its orbit. And the velocity of the earth with its periodical time, furnishes directly its mean distance from the sun.
Pagina 203 - ... will exhibit a very resplendent appearance. When the edge of the exterior ring is opposite to the satellite, and enlightened by the sun, it will present a large arch of light in the heavens on each side of the planet, above which will appear half the hemisphere of Saturn. If the satellite turn round its axis in the same time in which it revolves round the planet, as is probable, Saturn and its rings will appear stationary in the heavens, and the planet will present to the inhabitants of the satellite...
Pagina 133 - Kuiper has been the director of the Yerkes Observatory of the University of Chicago (at Williams Bay, Wisconsin) and the McDonald Observatory (at Fort Davis. Texas), operated jointly by the universities of Chicago and Texas. In February 1948 the planet Mars was 63,000,000 miles from earth and in a favorable position for study. Using an infrared spectrograph which he helped to develop and a photoconductive lead-sulphite...