246 FROM NEBULA TO NEBULA 



or promise of an end, but a cosmic whole infinite and immortal * *. 



Long ago [p. 21] both Ritter and myself, by different modes 

 of treatment and different modes of statement of results, showed 

 that in a complete collision of similar gaseous suns, the new sun 

 would be only expanded to one- fourth the density ; that is to say, 

 the diameter of the new sun would be the sum of the two dia- 

 meters of the two similar colliding gaseous suns. I also worked 

 out the interesting result that all the colliding energy was exactly 

 turned into potential energy of expansion, in this way leaving the 

 new sun in possession of the same temperature as the old pair. 

 Moreover, the condition was one of gaseous equilibrium and 

 hence stable * * *. 



Then [p. 96] what possibly is the right explanation (of the 

 solar system) occurred to me, a suggestion that improves as more 

 and more study is bestowed upon it. It is a kind of combination 

 theory. The planets were captured by the revolving nebula, but 

 they were independent bodies revolving in any azimuth, about 

 one or both of the original bodies whose impact produced the 

 revolving solar nebula. Perhaps the four inner dense planets 

 belonged to one original body, and the four outer rarer ones be- 

 longed to the other. Further study showed that all might have 

 belonged to only one of the original bodies. We have had much 

 talk over it, and opinions are still divided * * *. 



This, then, is the state of our idea of the origin of the Solar 

 System, as far as we have got at present. We have not appre- 

 ciably altered the idea for thirty years * * *. 



Criticism of the Theory of the Third Body 



Given a universal affinity of cosmic bodies for each 

 other, their collision should seemingly be the rule rather 

 than the exception. Indeed, to account for their remain- 

 ing aloof from each other instead of long ago accumu- 

 lating in a single heap at the center of things has been 

 one of the chief concerns of Newton and Newtonians. 

 One way which, astronomers have adopted to escape this 

 logical difficulty is by the invention of the idea of so-called 

 "proper motions" for stars, on the implied assumption 

 that in the capriciousness, randomness and diversity of 

 such motions lies the desired life-saving principle. In 

 other words, they seek in lawlessness the foil to law. To 

 clinch the matter, they postulate such arbitrary " inher- 

 ent" motions as being likewise irreducible and self -per- 

 petuating. A second way of escape which they have 



