THE FINITE UNIVERSE 



worlds appear to have a mass thousands of times 

 that of our sun, which has in turn three hundred 

 thousand times the mass of our earth. The calcu- 

 lated speed of Arcturus, the great star near the 

 Bear, is three hundred and seventy-five miles per 

 second, and its estimated light about eight thou- 

 sand times that of the sun. Yet this, as all other 

 known bodies, seems to obey Newton's law. We 

 may, therefore, infer that we live in a universe all of 

 whose particles or masses, be they atoms or Arc- 

 turian suns, draw to each other, mass for mass, with 

 even force. 



These particles and masses show another curious 

 relationship. If the atomic weight of the elemen- 

 tary substances be multiplied by the specific heat, 

 the result is a constant quantity. It seems not un- 

 likely that the amount of heat that can be taken 

 up is also fixed. Several considerations suggest 

 such an upper limit to temperature. The stars we 

 know are very hot, far hotter, probably, than 

 any temperature producible by terrestrial means. 

 On the other hand, as we climb high mountains, 

 or men go up in balloons, it grows very cold. The 

 inference is that space must be extremely cold. 

 Space is either empty or contains a substance 

 which does not seem to absorb the radiant heat 

 of the stars. One might think, therefore, that 

 the temperature of space is the coldest possible 



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