See — Temperature of the Sun and Ages of Stars and Nebulae. 5 



Hence we conclude that in condensing from infinity to its 

 present dimensions the total heat developed by a homogene- 

 ous sun would raise the temperature of an equal mass of 

 water about 27 million degrees centigrade. As the mean 

 distance of Neptune is equal to about 6570 of the present 

 radii of the sun, we see by formula (10) that in condensing 

 from infinity to the orbit of the outermost planet, only g-sVirth 

 part as much heat was produced as has been developed since. 



According to the best available authorities the masses of 

 the planets are as indicated in the following table : — 



If we add all these masses together we shall find the total 

 to be y4^;^^th that of the sun. The masses of the comets and 

 asteroids are so small that we mio^ht neojlect them altosjether. 

 For according to a determination recently made by Mr. 

 Rossel of the Johns Hopkins University the combined masses 

 of three hundred or more of the larger asteroids is less than 

 one-eighth that of our moon. Taking therefore the nearest 

 whole number we may assign the sun 746 times the mass of 

 all the other bodies of the planetary system. Thus if we 

 desire to find out the temperature to which a mass equal to 

 the whole solar system would be raised we must multiply the 

 value of /? in (11) by fff, which will produce only a slight 

 change. 



If instead of supposing the particles of the sun to condense 

 from infinite expansion we take a large primitive exterior 

 radius 7?^, the formula for the elevation of temperature 

 becomes 



