PAPERS PRESENTED AT GENERAL SESSIONS 69 



fundamental postulate. If we admit that the energy 

 which disappears as radiation reappears as subatomic 

 energy several difficulties are disposed of at once. Xot 

 only do we answer the question ''what becomes of the 

 energies which the stars are pouring so lavishly into 

 space?" but also its antithesis ''what is the origin of the 

 amazing quantities of energy that are locked up within 

 the atoms?" As long as the atoms were regarded as 

 permanent and indestructible units of matter we had no 

 concern as to their origin. They had always existed. 

 But once we have attained the knowledge that atoms are 

 organized structures, questions as to their evolution and 

 dissolution at once present themselves. Their activities 

 during their lively careers furnish materials for study 

 to the physicist, chemist, geologist, and biologist, but at 

 their birth and death the astronomers alone are present. 

 Even to the physicist an atom is a tiny thing. It is much 

 more tiny to the astronomer. Their numbers however 

 are vast beyond conception. In a cubic centimeter of 

 water there are 3 x 10-- atoms and in the entire solar 

 system there are 6 x 10^^ atoms. But so vast is the scale 

 upon which the stellar systems are built that if all the 

 matter in the solar system was distributed uniformly 

 throughout the sun's share of space there would be 10 

 cubic centimeters of space for each atom, and relatively 

 to their size the atoms would be as far apart as are the 

 stars themselves. The density under these conditions 

 would be 3 X 10~-* and it is doubtful, though perhaps 

 not certain, whether a nebulosity so attenuated as this 

 could be detected by any means with which we are ac- 

 quainted. 



The hypothesis that atoms are evolved by radiant 

 energy implies that all space is more or less nebulous. 

 While we do not have direct evidence that this is true, 

 nevertheless it is known that the volumes filled with per- 

 ceptible nebulosity are extremely great, ranging from 

 the naked eye nebula of Orion to the most delicate 

 nebulae registered on long exposed photographic plates. 

 Undoubtedly much more would be discovered if our de- 

 tective agents could be made more highly sensitive, but 



