306 



ORIGIN OF THE EARTH 



Fig. 290. Theoretical restoration of the parent nebula of the solar system. 

 The nuclei of the several planets may be identified by their distances from the 

 center. The dimensions of the inner parts are made disproportionately large. 



in the planetesimal hypothesis, but most of these must be passed 

 without mention here. 



The assumed meetings and unions of planetesimals and nuclei at 

 the crossings of their orbits imply a relatively slow evolution of the 

 nebula into the solar system. The planetesimal hypothesis therefore 

 implies a slow growth of the earth. With such a mode of growth, 

 the stages of the earth's early history depart widely from those 

 postulated by the Laplacian and the meteoritic hypotheses. 



