COSMIC EVOLUTION 



consequences may be inferred. The law of the 

 conservation of momentum states that a certain 

 amount of what the mathematicians, in an un- 

 fortunate phrase, call "moment of momentum" 

 is present in our system. Not one particle of that 

 finite quantity can be lost by the solar system as a 

 whole. The alterations now occurring in the dis- 

 tribution of this total have led Professor Darwin 

 to predict that the moon will ultimately return 

 to the earth which gave her sudden birth so many 

 ages before; and from these and other considera- 

 tions, such as the repulsive power of light, which 

 checks the passage of the planets in their orbits, it 

 may further be prophesied that the planets and 

 their satellites must ultimately yield to the gravi- 

 tational influence of our dying sun and must re- 

 turn to the bosom of their parent. We must im- 

 agine the solar system of to-day as then gathered 

 into one central mass, closely aggregated around 

 that point which, from the first, has constituted 

 its centre of gravity. And what will be the state 

 of this shrunken object? It will be a dark star, 

 a dead sun. There are myriads of such in the 

 heavens. Sir Robert Ball has said that to count 

 all the bright stars that we can see and say, " These 

 are all there are," would be like counting the red- 

 hot horseshoes in England and saying, "This is the 

 total number." This dark tomb of ours will, 

 therefore, be just such another as many millions 

 more. There will be no life upon it. We cannot 

 conceive the depths of its cold, for the nebula has 

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