230 COSMOGONIC HYPOTHESES. 



of a system becomes fairly quiescent, such as the Sun now is. In 

 this quiescent stage, the Sun is a globe of liquid with an enor- 

 mous radiation of heat and light waves, and emitting electrons; 

 its heat being mainly clue to atomic disintegration, which will 

 continue as long as any of it remains, or, in other words, as long 

 as it contains atoms of more than gaseous atomic weight. Its 

 end will be approached by its passing into the gaseous or stellar 

 state, which will later devolve into a nebula. There are no dark 

 suns or stars. Continuity requires that the P:^arth and other 

 planets should be going through a like process, but on a much 

 slower scale, owing to their smaller masses, and perhaps also to 

 the different proportions of the elements of which their chemical 

 constitutions are built up. One can imagine that whilst, say 

 Jupiter, is still growing by planetesimal accretion, the Sun's: 

 attractive mass may become so small through the emission of 

 electrons that the centre of our system will be transferred; in the 

 course of ages, to the planet Ju])iter. 



The explosion hypothesis suggests an explanation for the 

 phenomena exhibited by the so-called Novas or new stars. These 

 are small stars which almost instantly increase enormously in 

 luminosity and slowly and somewhat irregularly fade away, often 

 to small nebulae. These may be assumed to be gaseous stars, in 

 which the ratio of the specific heats exceeds one and one-third; 

 they are then essentially unstable, and a time comes when a 

 radical change of state occurs — a sudden blaze up, followed in 

 most cases by a rapid disintegration into the final state of nebu- 

 losity, in which entropy has become a maximum and atomic 

 energ}' a minimum. 



The implication of this hypothesis in the glacial epochs of 

 the Earth is simple. A glacial period will come on slowly as the 

 heat of the Sun falls through the rhythmic close of a period of 

 chemical disintegration ; the hot period will follow suddenly with 

 a prodigious melting of the polar-ice caps and vaporization of a 

 great part of the oceans — a time of cloudy skies and the enor- 

 mous rainfall of a carboniferous era, a time of maximum tem- 

 perature following the epoch of greatest cold comparatively 

 closely. If temperature and time were plotted the curve would 

 resemble that of the light of a variable star, as it should, because 

 the cause at work is the same. 



If we seem to live in an age of uniformity in temperature 

 conditions, it is perhaps because the race can only flourish under 

 such circumstances, the theory gives no promise of continued 

 uniformit^^ An explosive disintegration of atomic energy on the 

 Sun may occur at any time. We can only surmise from past 

 conditions on the Earth that at present the Sun is getting colder 

 in preparation, or as an antecedent to a further outburst. Here, 

 again, the behaviour of variable stars is an indication ; although 

 some of these stars are remarkably regular in their changes, 

 others are not; and generally, the fainter the minimum, the more 

 rapid and brighter the follo^^Mng maximum. 



