A HISTORY OF SCIENCE 



Not only so, but they are moving suns. Instead of 

 being fixed in space, as has been thought, they are whirl- 

 ing in gigantic orbits about some common centre. Is 

 our sun that centre ? Far from it. Our sun is only a 

 star like all the rest, circling on with its attendant 

 satellites our giant sun a star, no different from 

 myriad other stars, not even so large as some; a mere 

 insignificant spark of matter in an infinite shower of 

 sparks. 



Nor is this all. Looking beyond the few thousand 

 stars that are visible to the naked eye, Herschel sees 

 series after series of more distant stars, marshalled in 

 galaxies of millions; but at last he reaches a distance 

 beyond which the galaxies no longer increase. And 

 yet so he thinks he has not reached the limits of his 

 vision. What then ? He has come to the bounds of the 

 sidereal system seen to the confines of the universe. 

 He believes that he can outline this system, this uni- 

 verse, and prove that it has the shape of an irregular 

 globe, oblately flattened to almost disklike proportions, 

 and divided at one edge a bifurcation that is revealed 

 even to the naked eye in the forking of the Milky Way. 



This, then, is our universe as Herschel conceives it 

 a vast galaxy of suns, held to one centre, revolving, 

 poised in space. But even here those marvellous tele- 

 scopes do not pause. Far, far out beyond the confines 

 of our universe, so far that the awful span of our own 

 system might serve as a unit of measure, are revealed 

 other systems, other universes, like our own, each com- 

 posed, as he thinks, of myriads of suns, clustered like 

 our galaxy into an isolated system mere islands of 

 matter in an infinite ocean of space. So distant from 



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