﻿NATURE OF THE TEMPORARY STAR OF 1572. 317 



We have no occasion to follow the nebular hypothesis further. We propose 

 that the star of 1572 was in the condition just described, viz. : its matter so much 

 condensed as to have a brilliant disk. Its body surrounded by a ring of opaque 

 nebulous matter, the ring having one opening, and revolving round the star in about 

 three hundred years, in a plane which passes through the solar system. The star and 

 the ring revolving about a distant focus in some unknown period of time. 



We have now to determine what phenomena should characterize a celestial body 

 thus constituted, and by comparing the result with the appearances presented 

 by the star of 1572, to decide upon the competency of the nebular hypothesis to 

 explain its mysteries. 



That an opaque ring revolving round a luminous body should conceal the same from 

 the inhabitants of a world lying in the plane of the ring, is a truth so plain as to 

 require no demonstration. 



Equally palpable is it, that an opening in the ring should reveal the star to observers, 

 when the opening coincided with a line from the observers to the star. 



If we choose to believe that the nebulous matter composing the ring is possessed 

 of the power to refract light, the passage of a ray through the margin of the opening 

 should give a succession of colors to the star, before the interposition of the denser 

 portion of the ring caused its entire disappearance. 



Such a phenomenon did characterize the star of 1572 ; its rays being tinged with 

 the three primary colors, occurring (as reported) in nearly the reverse order of their 

 repangibility, viz. : yellow, red,* and finally faintly blue.f 



The nebular hypothesis does not enlighten us as to any reason for a ring perform- 

 ing its revolutions in unequal periods of time ; while it is a noted fact that between 

 the three apparitions of the supposed identical star, the intervals differed eleven 

 vears. 



We must, therefore, look elsewhere for the cause of this inequality. We find it 

 in that part of the conditions of the star which we derived from astronomical neces- 

 sity, viz. : its revolution about a distant focus. 



With this condition for a basis, and the measurable velocity of light as a modifying 

 influence, a mathematician could, by the use of the symbols for unknown quantities, 

 and an easy calculation, show the necessity for the apparitions of such a body occur- 

 ring after unequal intervals. 



But for our purposes it will be more convenient, and will make a stronger impres- 

 sion upon the understanding, if we endow the various measures of time and space, 

 with coefficients which are significant of real quantities. 



*Astronomie Populaire, vol. i., p. 4-25 

 fPlanetary and Stellar Worlds, p. 293 



