48 EVOLUTION OF THE EARTH 



tens of miles per second, their impact with and engulfment by 

 the earth engendered much additional heat. In fact, they 

 liquefied themselves and their earth surroundings as a result 

 of their great impacts. Furthermore, the high internal heat 

 of the earth was accentuated by the condensation accompany- 

 ing the increase of mass from an original earth diameter of 

 5,500 miles to one initially larger than 8,100 miles. At no time, 

 however, does it appear that the earth was necessarily in an 

 astral condition, shining like a star. 



The present diameter of the earth is 7,918 miles, but at the 

 close of the growing period it must have been 200 and possibly 

 even 400 miles greater, for it is well known to geologists that 

 throughout geologic time it has been losing volume, due in 

 part to the loss of heat into space, but probably in greater 

 degree to internal molecular rearrangements. It is now known 

 that the earth does not shrink all the time because of these 

 changes, but does so only periodically, and at these times the 

 surface of the planet becomes wrinkled, giving rise to more or 

 less high ranges of mountains. Even though the earth has 

 been dissipating its inherited and derived energy for at least 

 some hundreds of millions of years, and in so doing repeatedly 

 giving birth to new series of mountains, our mundane sphere 

 is still far from having attained the internal stability that will, 

 when achieved, result in a featureless earth, an atmosphere 

 devoid of the carbon dioxide that is the basis of life, and a 

 universal lifeless ocean — the facial expression which the earth 

 will have in its old age. 



Volcanism during the Formative era. While the earth was 

 internally very hot and viscous, the body-mass was in slow 

 movement, with the heat ever rising toward the surface. 

 These movements simulated a slow boiling process, and the 

 upwellings of the molten matter repeatedly broke through the 

 outer cold shell and engulfed it. As the cold crustal masses 

 descended, they liquefied, and in expanding brought about 



