68 FROM NEBULA TO NEBULA 



gravitational, motions. They are the unruly immigrants 

 that I spoke of in the last chapter, and require to be 

 assimilated and chastened into docile, orbit-abiding mem- 

 bers. It is possible that the force behind a given frag- 

 ment might serve to shoot it hyper bolically through one 

 system into another beyond. However, this would likely 

 be a rare occurrence. Here we see that projectile mo- 

 tions are menaces to a system's stability, that they re 

 quire to be subdued and overcome, and how they are 

 overcome. Surely Newton built his universe upon sand 

 when he chose projectile motion for its corner stone ! 



As I suggested before, all matter has doubtless run 

 the celestial cycle many times, so that the chances are 

 a myriad to one that a* given planet has not grown by 

 simple accumulations of cosmic dust, but owes its nu- 

 cleus to a fragment from a deceased star. Or rather, 

 should. I say, to fragments, for I am inclined to believe 

 that stars are almost wholly gaseous, or at least molten, 

 so that the future planet gains separate existence in the 

 form of a jet of coarse spray divided into many globules, 

 which separately congeal and afterward cling together 

 as a unity when their mutual attraction triumphs over 

 the unequal dispersive effect of the explosion that begat 

 them. That all planets are spherical follows from the 

 law of gravitation, provided their parts are sufficiently 

 small or mobile. Were the fragment but one irregular 

 and very rigid block its future shape would depend 

 upon its size alone ; one very large would melt with the 

 fervor of its self -generated heat, whereas a small one, 

 such as an asteroid or a meteor, might be and stay any 

 odd shape. 



If the earth was formed out of star spray in the 

 manner I have described, it must have been many eons 

 ago, not because it is now superficially cold, but be- 

 cause of the circularity of its orbit, which is the evidence 



