362 THE WORLD MACHINE 



of stars are known, we shall be a little better off. Then it will 

 be possible to gain some idea of average star spacing, and we 

 shall be able to fix the position of the sun, probably, with re- 

 ference to the brighter and nearer stars. It is quite possible 

 that we have much nearer neighbours, for example, than alpha 

 Centauri. The analogy of the planets points to such a con- 

 clusion. Uranus was discovered before any of the five hundred 

 asteroids, and even Neptune before the most of them ; and 

 the asteroids are on the average ten or twelve times nearer 

 than the outer planet. 



Following the same analogy, it is likely that these more 

 neighbourly suns or sunlets would be very much smaller than the 

 star of the Centaur that is, smaller than our own sun. For 

 anything we now know, there is no reason to suppose that they 

 may not vary as greatly in size as, let us say, the asteroids 

 from Jupiter. There may be blazing suns no larger than the 

 earth. On the other hand, between our own system and the 

 Centaur there may be dark bodies vastly larger than our sun. 

 They could scarcely be known to us save by their gravitational 

 pull. For aught we now know, some of these dark bodies might 

 be our nearest neighbours. If they had not been extinct too 

 long, it would be very curious to visit them and examine, so 

 far as we might, the ruins of extinct civilisations on their planets. 

 Of course, the present chances of escape from our own system 

 are exceedingly slight. But the advance in our physical know- 

 ledge within the last two or three hundred years is probably 

 but the merest beginning. He would be a blind man who would 

 assert that such an escape is forever an impossibility. 



The conclusion of present-day computation is that the suns 

 are numbered by the thousands of millions ; planets and dark 

 stars probably by hundreds of thousands of millions. The dis- 

 tribution would involve a corresponding vastity of space. 



There is no great interest in mere numbers, however pro- 

 digious they may be ; but from out this computation of a 

 seeming endless welter of blazing suns, at least one curious 

 inference may be drawn that is, the probably colossal number 

 of inhabitable worlds. Our solar system contains at least nine 

 bodies, ranging in size from Jupiter to the moon, which at some 

 stage or other of their evolution might present a theatre for life. 

 It now seems indubitable that the stuff of the universe is all the 



