PROGRESS OF MODERN ASTRONOMY 



our universe are these new universes of Herschel's dis- 

 covery that their light reaches us only as a dim, nebu- 

 lous glow, in most cases invisible to the unaided eye. 

 About a hundred of these nebulae were known when 

 Herschel began his studies. Before the close of the 

 century he had discovered about two thousand more of 

 them, and many of these had been resolved by his 

 largest telescopes into clusters of stars. He believed 

 that the farthest of these nebulae that he could see 

 was at least three hundred thousand times as distant 

 from us as the nearest fixed star. Yet that nearest 

 star so more recent studies prove is so remote that 

 its light, travelling one hundred and eighty thousand 

 miles a second, requires three and one-half years to 

 reach our planet. 



As if to give the finishing touches to this novel 

 scheme of cosmology, Herschel, though in the main 

 very little given to unsustained theorizing, allows him- 

 self the privilege of one belief that he cannot call upon 

 his telescope to substantiate. He thinks that all the 

 myriad suns of his numberless systems are instinct with 

 life in the human sense. Giordano Bruno and a long 

 line of his followers had held that some of our sister 

 planets may be inhabited, but Herschel extends the 

 ,^ht to include the moon, the sun, the stars all the 

 only 1 >r .flics. He believes that he can demonstrate 

 the habitability of our own sun, and, reasoning from 

 analogy, he is firmly convinced that all the suns of all 

 ystems arc "well supplied with inhabitants." In 

 as in some other inferences, Herschel is misled by 

 faulty physics of his time. Future generations, 

 working with perfected instruments, may not sustain 



tot. m. i 33 



