148 FROM NEBULA TO NEBULA 



For all that, the practical astronomers, fired by the 

 passion for physical accuracy for its own sake, are every 

 day planning on an ever more and more ambitions scale 

 to go over the same ground again and again, without any 

 definite object in mind, it seems, save to see how near they 

 may come to the previous marks. There is no way to 

 test their accuracy, so far as they are aware, by final ar- 

 bitrament of Nature, but only by indecisive comparison 

 of their own results with those previously announced. 

 In any case, all their labor goes for naught as long as 

 their architects, the theorists, neglect and refuse to re- 

 form their ground plans so as to give structural place to 

 the plethora of facts (never anticipated by the original 

 architect, Newton) now promiscuously encumbering the 

 ground. Whatever incentives one may have to remain- 

 ing unpersuaded, it must be patent to all that a radical 

 reformation of astronomical theory has become impera- 

 tive. What more likely way, I ask, than by giving to the 

 phrase "UNIVERSAL gravitation" its plenary significance 

 and genuinely universal applications ? 



The principle of the gyroscope is too well recognized 

 to require extended discussion in this place. Eotation in 

 one direction around an axis, under the law of action and 

 reaction, must, and as a matter of everyday mechanics 

 does, generate a reverse movement of the rotating mass 

 in a larger circle around an extraneous point or axis. We 

 are not merely angling at random, then, when we posit 

 that the solar system, because of its integral rotation 

 around an axis within the sun's mass, has a secondary 

 motion of precession around just such an extraneous 

 axis. The existence of such a reaction is a physical neces- 

 sity, not a figment or invention, and any cosmological 

 system that omits it is ipso facto valueless. The sun 

 moves must move in an orbit. It needs no demon- 

 stration; for the law of action and reaction and the prin- 

 ciple of the gyroscope leave no other possibility open. 



It is by no means a novel suggestion that the sun 

 may be pursuing a curved path. Ever since the time of 

 the elder Herschel, and probably long before him, the 



