FROM NEBULA TO NEBULA 



To explain translatory motions by averring that 

 they are "inexplicable" can scarcely be properly digni- 

 fied as scientific or as a "paean of triumph ". Granting, 

 however, the possibility of such motions being inherent 

 or self -existent, are we to understand that this is true of 

 all bodies, or only of such as were primordial? If true 

 of all bodies, it seems strange that Aristotle had not 

 noticed it. On the other hand, if true only of primordial 

 bodies, then must we not only class the sun and the 

 planets as such, but asteroids and comets as well which 

 surely is absurd. Again, if celestial translatory motions 

 are truly natural in the sense of being uncaused, then 

 they might just as well have possessed velocities up to 

 tens of thousands of miles a second and their directions 

 have been equally diverse and erratic. To stipulate, by 

 choice, the self -existence of such haphazard motions as 

 these is only to begin with a chaos worse confounded and 

 to render the task of Nature in the establishment of order 

 all the more protracted and difficult. 



And what of those marvelous adjustments subsisting 

 throughout the universe between the centripetal forces 

 on the one hand and the centrifugal on the other? How 

 does it come that the earth, for example, is endowed with 

 precisely the amount of velocity and physical momentum, 

 and the exact and undeviating tangential motion, requi- 

 site to counterbalance the attraction of the sun? As to 

 these adjustments our modern astronomers, less com- 

 mittal than Newton, maintain complete silence, leaving it 

 to be inferred that the mere assumption of rectilinear 

 motions carries with it, ipso facto, all the attributes with 

 which we may find it expedient to endow them. They 

 offer us nothing to take the place of Newton's "Cause 

 not blind and fortuitous, but very well skilled in me- 

 chanics and geometry." 



According to Newton's third law of motion, to every 

 action there is always an equal and contrary reaction. 

 It therefore follows that, inasmuch as the moon pre- 

 serves her mean distance from the earth virtually unal- 

 tered from age to age, she is reacting against the latter 's 



