Elementary astronomy; a beginner's text-book (1899)
Holden, Edward Singleton, 1846-1914 · New York, H. Holt and company · leaf 409
he distances of the stars are frequently expressed by thetime required for light to pass from them to our system.The velocity of light is, it will be remembered, about 384 ASTRONOMY. 300,000 kilometres per second, or such as to pass from theSun to the Earth in 8 minutes 18 seconds. The cut shows… … Fig 201. whose radii are 5, 10, 15, 20, 25, 30 light-years; that is,for spheres whose radii are of such lengths that light,which moves 186,000 miles in a second requires 5, 10, etc.,years to traverse these radii. The time required for light to reach the Earth from a MOTIONS AND DISTANCES OF THE…
Astronomy
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![An illustration from Cosmographia in qvatvor libros distribvta summo ordine, miraqve facilitate, ac breuitate ad magnam Ptolemæi mathematicam constructionem, ad vniuersamque astrologiam institutens. Francisco Barocio ... avtore. Cum præfatione eiusdem autoris, in qua perfecta quidem astrologiæ diuisio, & enarratio autorum illustrium, & voluminum ab eis conscriptorum in singulis astrologiæ partibus habetur: Joannis de Sacrobosco verò 84 errores, et alij permulti suorum expositorum, & sectatorum ostenduntur. rationibusq[uam] redarguuntur. Præcesserunt etiam quædam communia mathematica, necnon arithmetica, & geometrica principia, nonnullæq[uam] propositiones, de quibus in toto opere sæpe fit mentio: ac demum locupletissimus index eorum, quæ ipsa Cosmographia continentur .. (1585)](https://img.insideoutlibrary.com/img/200/ia-cosmographiainqv00baro-381-100.webp)
