THE BIRTH AND DEATH OF WORLDS 423 



cold, life upon the planets will no longer be possible ; our 

 system will be simply a series of revolving icicles. This pro- 

 bable fate seems already that of millions of others. It is a 

 disclosure of recent years that the universe is full of dark suns. 

 Half a century ago we knew of none at all. Now we must 

 believe with Arrhenius that the number of dark suns far exceeds 

 the number of those that blaze. 



It follows from this fact of dissipation that in the course of 

 time all the suns now lighting the heavens will one day go out. 

 So we might picture the universe, originally dispersed in nebulge, 

 gradually gathering itself together into clumpy aggregations, 

 these in turn condensing into suns and glowing planets, eventu- 

 ally to sputter and go out, then whirl on in icy immobility 

 throughout the endless years. The picture is not inviting. To 

 most minds it is dispiriting. We have no need to suppose it 

 is true. 



In any account of creation we must take note of the new 

 stars that blaze out into the heavens and show for a little, then 

 disappear or sink back into obscurity. Originally it was sup- 

 posed that these apparitions were rare ; we have seen that 

 they are probably of frequent occurrence, and that in some 

 instances at least they result from the collision of two suns. 

 Their motions accelerated by their mutual attraction, they 

 would approach each other with frightful velocities. If they 

 struck the crash would be terrific. The amount and the degree 

 of heat generated by the impact of two vast bodies would be 

 such as utterly to dissipate them into vapour. They would be 

 diffused again into the primal fire-mist from which they sprung, 

 slowly to cool through the ages, slowly to grow hot again through 

 their contraction and coalescence. 



It is from the crash of suns, then, that the nebulae may come. 

 This is their origin, and this is the round of cosmic life. So at 

 least, so far as our present knowledge extends, must we conceive 

 it. It is thus that the cosmic process is sketched in the brilliant 

 pages of Arrhenius. 1 



In this view the basis of the elements, the substance of the 

 universe, is eternal, likewise the process which it pursues. A 

 new Moleschott might now write a Kreislauf der Materie, a 

 Circulation of Matter. Devolution follows evolution, regenera- 

 tion follows degeneration, world without end. 



1 Lehrbuch der Kosmischen Physik, Leipzig, 1902. 



