244 FROM NEBULA TO NEBULA 



of 6.9 miles a second, would have required a charge of 

 smokeless gunpowder several times heavier than the- 

 satellite's own weight. 



That Darwin was not, however, entirely devoid of 

 the saving salt of common sense, in spite of the indica- 

 tions, is shown by his concluding sentence (The Tides, p. 

 284) : " There is nothing to tell us whether this theory 

 affords the true explanation of the birth of the moon, and 

 I say that it is only a wild speculation incapable of veri- 

 fication. ' ' I leave it to the reader to make his own com- 

 ments. 



THE THIRD-BODY THEORY 



In his very interesting little book, "The Birth of 

 Worlds cmd Systems", published in February, 1911, A* 

 W. Bickerton, Professor of Physics and Chemistry in 

 Canterbury College, of New Zealand, has collected to- 

 gether a series of papers, dating from the year 1878, set- 

 ting forth a unique speculation, to which he has given the 

 title of "Theory of the Third Body." In order that I 

 may not fail to report him correctly, I shall use his own 

 words quite freely. Fortunately his first chapter is it- 

 self an excellent summary of his views : 



A pair of dead suns, that is to say two dark stars, colliding, 

 would possess energy sufficient, if suddenly converted into heat 

 to account for the phenomena of temporary stars. All suns pos- 

 sess proper motion. Hence it was evident that the orbits of two 

 suns, in approaching one another, would be similar to that of an 

 ordinary errant comet. There would be mutual deflection and 

 mutual distortion, and it would be extremely improbable that 

 the suns should meet centre to centre. Much more frequently 

 there would be partial impact or grazing collision; therefore, the 

 problem to consider was, what would happen were a pair of 

 dead suns to graze? * * * The portion of each body actually in 

 the path of the other would be torn from the main portion, and 

 these torn-off portions would coalesce into a new or third body, 

 explosively hot and of surpassing brilliancy. 



The two diminished suns would pass on, each with a fiery 

 scar where it had been cut. Each would be set rotating, and each 

 would be like a policeman's lantern hung by a string and set 

 spinning. Each would present alternatively its bright and dark 

 face to any point on its equatorial plane. * * * 



