4 2 4 THE WORLD MACHINE 



The process has obviously three stages the nebular period, 

 the star period, the dark sun period. The duration of these is 

 not coequal. In the estimation of Arrhenius, the nebulous stage 

 is vastly the longest. Next after that would come the dark 

 sun stage ; conceivably this might last for a time which, so 

 far as our human imagination could compass it, would seem 

 infinite. A rushing star might pursue its path through the 

 heavens for ages without meeting with another, in the union 

 with which it might be again scattered to fertilise the ways of 

 space. Yet it is evident that with anything like an average 

 distribution of stars through space, there would be an average 

 chance of impact. Therefore there would be a general average 

 for the period of darkness, as there would be a like average term 

 for the period of nebulous diffusion. 



The period of solar activity, of what we might term solar 

 life, is comparatively easy of computation. In a rough way we 

 already know this period for our own sun. It is easy to see 

 that this period is but an incident, a few seconds, or at most 

 minutes, perhaps, in the arc of this unceasing circle. Just as 

 life appears an inconsequent moment in the evolution of the 

 stellar system, so the term of solar brilliancy, which alone makes 

 this moment of human being possible, is itself but a slender 

 fraction of the larger life of the stars. 



It seems as if we may at last make answer to the inquiry 

 of Epicurus : " And whence came chaos ? " Apparently chaos 

 comes from the cosmos, as the cosmos in its turn comes again 

 from chaos. In this view there was no chaos, no beginning, 

 and there may never be an end. It is conceivable that the 

 universe that is to say, the universe of suns and worlds to 

 which we belong has a finite limit in space, though to space 

 itself the mind may set no bounds. But limits in time for 

 the vast swarm of systems which the telescope brings in view are 

 difficult to perceive. It seems to be a ceaseless turning of a 

 wheel. 



But there remains always the unceasing dissipation of energy. 

 It may be as Arrhenius pictures it, that when a sun has cooled 

 sufficiently to form a crust, it will conserve practically the whole 

 of its heat through a vast period ; it would dissipate less in 

 hundreds of thousands of years then than in a single year now. 

 It may be, too, that the energy radiated away into space from 



