THE UNIVERSE IN WHICH WE LIVE 3 



Naturally the most interesting, as it is the most conspicuous, 

 of all the heavenly bodies is the sun; it has been worshiped as a 

 diety by many primitive peoples. While astronomy has robbed 

 it of its mysticism, it has increased our wonder at the marvels it 

 displays. In the first place, it is tremendously large as compared 

 to our earth, having a diameter of 866,540 miles, about no times 

 that of the earth. More than 1,300,000 bodies the size of the 

 earth could be packed into the space occupied by the sun. It is 

 because of its enormous mass that the sun is the center of our 

 solar system, holding the planets in their orbits by its gravita- 

 tional pull. 



The sun is the chief source of all of our energy light, heat, and 

 chemical rays emanating from it. We all realize from experience 

 that the sun is the source of light and warmth. We know that its 

 chemical rays produce marvelous changes in the photographic 

 plate when a picture is taken. But few stop to think how very 

 dependent we are on the sun in all our daily activities. It is the 

 stored-up energy of the sun, caught and held by the plant, that 

 is released from the wood we burn to keep us warm. Coal isj 

 compressed vegetation, the imprisoned sunlight of ages long gone 

 by, so the heat that glows in our coal stove is really sunlight. 

 Plants cannot live without sunlight, for its energy is the source 

 of all their vital activities. It is this energy stored up in the 

 plant in the form of sugar, starch, and other plant products that 

 is released when we take these plant foods and burn them in 

 our bodies, so that really we live on condensed sunshine. Even 

 the meat we eat is that, too, for the source of animal energy is 

 that of the plant. The electric light which we turn on in our 

 homes is sunlight, for the electric current comes from a generator 

 run by steam that is made by heat which in turn comes from the 

 coal. Surely the sun is the immediate giver of all good gifts, and 

 it is quite comprehensible that the savage should see in this life- 

 giving orb the personification of divine power. 



In spite of the fact that the sun does so much for the earth, 

 warming its surface, providing energy for all life's processes and 



