Identifier: astronomyforamat00flam (find matches)
Title: Astronomy for amateurs
Year: 1904 (1900s)
Authors: Flammarion, Camille, 1842-1925 Welby, Frances A. (Frances Alice) tr
Subjects: Astronomy
Publisher: New York, D. Appleton and company
Contributing Library: The Library of Congress
Digitizing Sponsor: The Library of Congress

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dars would never serve to enumerate all the dates in this vast world. This splendid globe courses in space at a distanceof 775,000,000 kilometers (480,500,000 miles) from theSun. Hence it is five times (5.2) as remote from the orbof day as our Earth, and its orbit is five times vaster thanour own. At that distance the Sun subtends a diameterfive times smaller than that which we see, and its surfaceis twenty-seven times less extensive; accordingly thisplanetary abode receives on an average twenty-seventimes less light and heat than we obtain. In the telescope Jupiter presents an aspect analogousto that likely to be exhibited by a world covered withclouds, and enveloped in dense vapors (Fig. 45). 149 ASTRONOMY FOR AMATEURS It is, in fact, the seat of formidable perturbations,of strange revolutions by which it is perpetually con-vulsed, for although of more ancient formation thanthe Earth, this celestial giant has not yet arrived at thestable condition of our dwelling-place. Owing to its
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Fig. 45.—Telescopic aspect of Jupiter. considerable volume, this globe has probably preservedits original heat, revolving in space as an obscure Sun,but perhaps still burning. In it we see what our ownplanet must have been in its primordial epoch, in thepristine times of terrestrial genesis. 150 THE PLANETS Since its orbital revolution occupies nearly twelveyears, Jupiter comes back into opposition with the Sunevery 399 days, i. e.^ i year, 34 days, that is with onemonth and four days delay each year. At these periodsit is located at the extremity of a straight line which,passing by the Earth, is prolonged to the Sun. Theseare the epochs to be selected for observation. It shinesthen, all night, like some dazzling star of the first magni-tude, of excessive whiteness: nor can it be confoundedeither w4th Venus, more luminous still ffor she is nevervisible at midnight, in the full South, but is South-w^estin the evening, or South-east in the morning), nor withMars, whose fires are ruddy

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