December 10, 1920] 



SCIENCE 



551 



growing larger very slowly, from tbese ac- 

 cretions, and this may have been the process 

 by which the earth grew from a small nuclear 

 beginning up to its present size. 



Astronomers have determined that our solar 

 system is very completely isolated in space. 

 We are widely separated from our neighbors. 

 I shall not try your patience by quoting the 

 tremendous distances in miles, for they are 

 incomprehensible to all of us. Rays of light 

 sent out by the sun require a little more than 

 eight minutes to reach the earth. The outer- 

 most known planet in our system, iKTeptune, 

 would be reached in four hours and a half. 

 Rays of light leaving the sun at the same time 

 and travelling at the same rate, 186,000 miles 

 I)er second, must travel continuously during 

 four years and a half to reach our nearest 

 known neighbor in space, the bright double 

 star Alpha Centauri. If the distance from the 

 sun to the earth is 1, the distance to our outer 

 planet is SO, and the distance to Alpha Cen- 

 tauri is 275,000. There appears to be an abun- 

 dance of room in the great stellar system to 

 meet the requirements of all. The spectro- 

 graph attached to the Lick telescope has deter- 

 mined that our sun and its family of planets is 

 traveling through the great stellar system with 

 a speed of twelve and a half miles per second, 

 equivalent to four hundred million miles per 

 year. The earth is certainly hundreds of 

 millions 'of years in age, the sun is no doubt 

 at least as old, and the early youth of the 

 earth was lived, not where we now are, but far 

 elsewhere in the stellar system; and its future 

 journeyings will lead to quite other points of 

 observation. 



The question of greatest interest to present- 

 day astronomers is that of stellar systems other 

 than our own. The chances seem strong that 

 the hundreds of thousands of spiral nebulae 

 known to exist in very distant space are other 

 and independent systems of stars, many of 

 them perhaps containing as many stars as our 

 Stellar systems. In other words, our stellar 

 system may be but one of hundreds of thou- 

 sands of isolated stellar systems distributed 

 • through endless space. This is not an estab- 



lished fact, but the evidence seems to run in 

 its favor. 



I have referred to some of the problems and 

 results of astronomical science. The list of 

 interesting items is a long one, but available 

 time has its limits. In brief, it is the astron- 

 omer's duty to discover the truth about his 

 surroundings in space, and make it a part of 

 the knowledge of his day and generation. The 

 ultimate and real value of his work lies in its 

 influence upon the lives of the people of the 

 world, in the changes for the better which it 

 induces in their modes of thought, and in the 

 impulse which it gives to an advancing civili- 

 zation. 



Would that the attractions of the sky to the 

 average man were more potent. It is a curious 

 comment upon the attributes of city life that 

 hundreds of thousands of people, especially 

 children, in London and Paris, in the darkness 

 which gave them semi-concealment from the 

 enemy's destructive air ships, should have ob- 

 tained their first real vision of the starry 

 heavens. What must have been their sensa- 

 tions ? On the other hand, those who can view 

 its beauties and wonders are prone to neglect 

 it; to look down instead of up. Emerson has 

 said somewhere in his immortal essays that if 

 our sky should be clear of clouds but one night 

 in a century, the people of this globe would 

 look forward to the rare event, and not only 

 prepare to behold its beauties themselves, but 

 make sure that their friends far and wide were 

 likewise minded. How the beauties of the 

 night sky would surpass the expectations of 

 the most lively imagination! The wondrous 

 vision would be the prevailing subject of con- 

 versation for years and years, and the repeti- 

 tion of the vision, one hundred years later, 

 would need no advertising. 



Our knowledge of the heavens is in its in- 

 fancy. We have but made a start upon the 

 discovery of the truth about the stars, and the 

 results of astronomical research are not so 

 widely known amongst the people as they 

 should b& This splendid institution. The 

 Warner & Swasey Observatory, presented by 

 men who are masters in telescope and observ- 

 atory design and construction, by men who 



