MIRACLES OF SCIENCE 



are to be translated into unthinkable trillions and 

 quadrillions of miles. Professor Campbell's studies 

 show, however, that stars of different types are vari- 

 ously grouped in the universe as regards their average 

 distances from the earth. He found, for example, that 

 the very young stars on his list show an average dis- 

 tance of 534 light-years; whereas stars of the types 

 most like our sun (F and G stars of his catalogue) are 

 on the average only 92 and 145 light years distant re- 

 spectively. It would appear, then, that our sun is one 

 of a great cluster of similar stars located relatively 

 near together. 



CLUSTERS, GROUPS, AND STREAMS OF STARS 



If we view the galaxy of stars from yet another 

 standpoint,' asking what has been revealed as to the 

 ultimate structure of the cosmic mechanism, we learn 

 that a combination of methods, in the hands of many 

 observers, has given some extraordinary glimpses 

 into the arrangement of at least those portions of the 

 universe that lie somewhat within our neighborhood. 



Considering first our immediate environment in 

 space, it appears that our sun, with its inconsequen- 

 tial planetary attendants, is one of a company of sev- 

 enteen stars making up a rather compact cluster about 

 ninety-five billion miles in diameter, roughly one 

 million times the earth's distance from the sun. Seven 

 of these stars are doubles. Five of them are larger 

 than the sun; yet all are comparatively small, the 

 brightest being only forty-eight times brighter than 

 the sun; whereas there are more distant stars in the 

 sky that are ten thousand times more brilliant. 



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