LIFE, CARBON S OUTSTANDING PROPERTY 87 



12. LIFE ON OTHER PLANETS 



Great interest has also centered about the question 

 whether plants, animals, and particularly men, can and do 

 exist on other planets in the universe. Astronomy, after 

 extensive studies, has calculated that forty billion suns are 

 contained in the Milky Way. Some of them may have 

 planets as our sun has. Planets may be, of course, in any 

 condition, either very hot or very cold, or consisting mostly 

 of vapors; and they may be of almost any size. It is pos- 

 sible that some may closely resemble the earth. Men would 

 be able to live on such planets, if it were possible to transfer 

 them there. 



Does this mean that men are actually living there? It 

 is idle to guess. But from what knowledge we have gained 

 thus far, it is reasonable to conclude that the forces of 

 nature are not tied down to any definite scheme. On the 

 earth, on a limited space, under definite conditions, life 

 has branched out very widely; it has reached numerous 

 diversified peaks so that we are impressed with the truly 

 boundless wealth of forms of which nature is capable. 

 Under the conditions on this earth, the warm-blooded ver- 

 tebrates won the race. Man became dominant; his hands 

 became free to use tools; his brain developed to enable him 

 to invent and to use tools. 



But the make-up of plants and animals is determined not 

 only by their present achievements and accomplishments, 

 but also by the history of their kind. If past conditions 

 had been different, if, for instance, a different type of plant 

 had existed, our teeth would be different. If, in the devel- 

 opment of the earth, the ocean had broken over certain 

 ridges, our ancestors would have been forced to adapt them- 

 selves to different conditions. This would have changed 

 the trend of evolution. Countless causes, interconnected 

 in an obscure manner, have contributed to the evolution of 

 man in his present form. 



