Lessons in astronomy including uranography. A brief intoductory course without mathematics (1896)
Young, Charles A. (Charles Augustus), 1834-1908 · Boston, London, Ginn and company · leaf 237
same orbit,with unchanged speed. 304. The Light of Comets.— To some extent their lightmay be mere reflected sunlight; but in the main it is lightemitted by the comet itself under the stimulus of solar action.That the light depends in some way on the sun is shown bythe fact that its brightness… … Fig. 61. —Head of Donatis Comet, Oct. 5, 1858. (Bond.) self-luminous when near the sun is proved by its spectrum,which is not at all like the spectrum of reflected sunlight, butis a spectrum of bright bands, three of which are usually seen, § 304] FORMATION OF TAIL. 227 and have been identified…
Astronomy
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