32 FROM NEBULA TO NEBULA 



direst need? Let us, then, consider her cosmic processes 

 under these two heads : 



1. The Principle of Concentration, or Attraction. 



2. The Principle of Dispersion, or Explosion. 



THE PRINCIPLE OF CONCENTRATION OR 

 ATTRACTION 



When Newton conjured with that magical phrase, 

 universal gravitation, he little realized how much more 

 it meant than he construed it to mean. For he seems 

 never to have thought of extending the principle to the 

 stars, but inconsistently restricted it to the solar system, 

 which we all know is little more than a molecule in the 

 greater cosmos. Accordingly, he assumed the sun to be 

 stationary in space and the orbits of the moon and 

 planets to be, literally, closed curves ; quite as though 

 they kept threading the same tunnels in the stagnant 

 ether forever and ever. In short, he conceived our sys- 

 tem to be a universe unto itself wholly independent of 

 and uncorrelated with the stars in general. It is now 

 known with absolute certainty that the sun is flying 

 through space with a velocity of some ten miles a second, 

 and that the orbits of the planets are far from being the 

 re-entering curves that Newton thought them. Here it 

 lay upon the surface that a discovery so amazing might 

 well be fraught with far-reaching potentialities for ex- 

 tending our inquiry beyond the confines of our system 

 into that of the stellar universe beyond. Unfortunately, 

 however, with their customary genius for missing the ob- 

 vious, instead of asking themselves here whether the 

 cumulative gravitation of the stars might not be the 

 cause for this new phenomenon, our Newtonian friends 

 contented themselves with merely rehashing the old 

 banality by saying that such motion is " natural' ' with 

 the sun, as with all other cosmic bodies, and "demands 

 explanation only as mere existence does". As for the 

 planets sharing this same motion of translation, they 



