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PROFESSOR A. S. EDDINGTON, F.R.S., ON 



Our journey must be somewhat hurried ; if we moved with 

 the speed of light, the exploration of the universe of stars would 

 take thousands of years. We should take four years to reach 

 the nearest star — other than the sun. But we shall move with 

 the speed of thought and leave the laggard light-waves far 

 behind. 



We are going, then, to consider the stars — the fixed stars 

 they are often called to distinguish them from the planets ; but 

 the name is a particularly unfortunate one, since our subject is 

 the movements of these " fixed stars." It is a numerous 

 company with which w T e have to deal. A photograph of the 

 sky shows it crowded with these tiny points of light, and each 

 point means a body of the same character as our sun — a globe 

 of fire which may be anything from a million times the size of 

 the earth upwards. Many of the stars are even bigger and 

 brighter than the sun, only they are so far off as to be reduced 

 to mere points. We can scarcely doubt that some at least of 

 them have families of planets circulating round them, to which 

 they give light and heat as the sun warms and illuminates the 

 earth, but there is no evidence whatever on this point. 



We ought to begin by getting some idea of the scale of this 

 stellar universe. The stars number some hundreds of millions 

 — a number that is quite inconceivable. I am sure that no 

 astronomer can grasp such numbers, and I doubt whether even 

 the Chancellor of the Exchequer can do so. But, though the 

 number of the stars is vast, it is not a number beyond experi- 

 ence. If we took every star that has been seen or photographed, 

 or indeed every star which could be photographed with the most 

 powerful telescope yet built, and divided them among the 

 inhabitants of the British Empire, it is unlikely that there 

 would be enough stars to go round. 



But when we come to the distances of the stars, the numbers 

 are — to say the least — unusual. The nearest star is distant 

 24,000,000,000,000 miles, and that is only the beginning, 

 because we must consider some of the most distant stars. 

 However, if I were to add three more noughts on to that last 

 number, that would represent a limit beyond which we shall not 

 attempt to penetrate ; in fact, we should be getting near the 

 limits of the stellar system, at least in certain directions. 



The distance which separates the sun from the nearest star is 

 much the same as that which separates any typical star from its 

 nearest neighbour. To form some idea of the sparsity of the 

 stars in space, take a sphere with the sun as centre and radius a 

 hundred billion miles (four times the distance of the nearest 



