Outlines of Astronomy |
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Common terms and phrases
altitude amount angle angular appear apsides arise ascertained astronomers axis bright calculation celestial centre circle comet curve described diameter difference direction disc distance disturbed body disturbing force diurnal diurnal motion double stars earth ecliptic effect elements ellipse epoch equal equator equinoctial equinox error exact excentricity fixed globe gravity greater heavens heliocentric horizon inclination increase inequality instance instrument interval Jupiter latitude latter less light longitude lunar magnitude mass mean measure meridian moon moon's motion nearly nebula node normal force nutation object observed orbit parallax parallel perigee perihelion period perpendicular perturbations planet planetary pole portion position precession precisely proper motions proportion recede recess reckoned refraction remarkable respect result revolution right ascension rotation round satellites Saturn seen sidereal sidereal day situation solar sphere spherical stars station sun's suppose syzygies tangential force telescope tion Uranus variation velocity visible whole zenith
Popular passages
Page 209 - ... of those great deposits of dynamical efficiency which are laid up for human use in our coal strata. By them the waters of the sea are made to circulate in vapour through the air, and irrigate the land, producing springs and rivers.
Page 234 - 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 209 - The sun's rays are the ultimate source of almost every motion which takes place on the surface of the earth. By its heat are produced all winds, and those disturbances in the electric equilibrium of the atmosphere which give rise to the phenomena of lightning, and probably also to terrestrial action and the aurora.
Page 257 - ... us, it is no longer mere analogy which strikes us, no longer a general resemblance among them, as individuals independent of each other, and circulating about the sun, each according to its own peculiar nature, and connected with it by its own peculiar tie. The resemblance is now perceived to be a true family likeness ; they are bound up in one chain — interwoven in one web of mutual relation and harmonious agreement, subjected to one pervading influence which extends from the centre to the...
Page 20 - Admission to its sanctuary, and to the privileges and feelings of a- votary, is only to be gained by one means — sound and sufficient knowledge of mathematics, the great instrument of all exact inquiry, without which no man can ever make such advances in this or any other of the higher departments of science as can entitle him to form an independent opinion on any subject of discussion within their range.
Page 202 - The part of the sun's disc not occupied by spots is far from uniformly bright. Its ground is finely mottled with an appearance of minute, dark dots, or pores, which, when attentively watched, are found to be in a constant state of change. There is nothing which represents so faithfully tliis appearance as the slow subsidence of some flocculent chemical precipitates in a transparent fluid, when viewed perpendicularly from above...
Page 164 - This remarkable belt has maintained, from the earliest ages, the same relative situation among the stars ; and, when examined through powerful telescopes, is found (wonderful to relate ! ) to consist entirely of stars scattered by millions, like glittering dust, on. the black ground of the general heavens.
Page 18 - Almost all its conclusions stand in open and striking contradiction with those of superficial and vulgar observation, and with what appears to every one, until he has understood and weighed the proofs to the contrary, the most positive evidence of his senses. Thus, the earth on which he stands, and which has served for ages as the unshaken foundation of the firmest structures, either of art or nature, is divested by the astronomer of its attribute of fixity, and conceived by him as turning swiftly...
Page 485 - This earth? reciprocal, if land be there, Fields and inhabitants: her spots thou seest As clouds, and clouds may rain, and rain produce Fruits in her soften'd soil, for some to eat Allotted there; and other suns perhaps, With their attendant moons, thou wilt descry, Communicating male and female light; Which two great sexes animate the world, Stored in each orb perhaps with some that live...
Page 257 - When we contemplate the constituents of the planetary system from the point of view which this relation affords us, it is no longer mere analogy which strikes us, no longer a general resemblance among them, as individuals independent of each other, and circulating about the sun, each according to its own peculiar nature, and connected with it by its own peculiar tie. The resemblance is now perceived to be a true family likeness ; they are bound up in one chain, interwoven in one web of mutual relation...