290 FROM NEBULA TO NEBULA 



With the escape of the buoyant gases from within 

 him, the sun would naturally collapse upon himself, and 

 there would follow a long period of rejuvenation during 

 which his radiation, color and brilliancy would all be 

 those of a star of lesser mass; and during this same 

 period, which must be regarded as an abnormal and fit- 

 ful stage, he would, furthermore, exhibit fluctuations in 

 all the three attributes mentioned, making of him, for the 

 time being, a typical variable star. 



Although solar and stellar explosions are auto- 

 matically produced by the causes just outlined, it does 

 not follow that these are the sole agents. There must 

 always lie in the back-ground the possibility of collision, 

 not so much with another star, which is a very remote 

 possibility indeed, but with a great comet. The comet 

 of 1840-1841 may have been such a one, and had it been 

 fired by its parent star a shade more accurately, it might 

 have struck the sun amidship, punctured his inflated 

 integument, and precipitated upon us a dire calamity. 



THE GENESIS OF THE SOLAR SYSTEM 



In such catastrophic explosions of the sun, then, be 

 their causes what they may, we have the secret of the 

 genesis of the nuclei of the planets and the method by 

 which these nuclei have been gradually built up into the 

 great bodies we now see. The planets were not created 

 full-grown and full-panoplied, but they have added layer 

 on layer, development to development. Indeed, every 

 biological and geological fact proclaims the truth of this 

 dictum, as every well-informed scientist will freely con- 

 cede. The objections to the hypothesis of self -explosion 

 on the part of the sun in the past and its heretofore total 

 exclusion from consideration, have not been on account 

 of any intrinsic defect, but because it left out of the 

 reckoning the origination of the rotatory motions of the 

 systems and, besides, contravened the dogma of the con- 

 servation of energy. The first of these objections is met 

 by the newly-discovered principle of the Prime Eesult- 

 ant ; the second will be considered in a following chapter. 



