Energy and Ether. 1017 



That the solar system has been evolved from a state of incandescent 

 gas in some such manner as this, is rendeied probable by numerous 

 facts. All the planets revolve around the sun in the same direction. 

 Their satellites also revolve around the primaries in the same direction, 

 with one explainable exception, and the sun and planets also revolve on 

 their axes in the same direction. They also revolve in nearly the same 

 plane, and their orbits are all nearly circular, thus differing from those 

 of comets which are extremely eccentric, and which have a separate 

 history of their own. There are, in the distant regions of space, vast 

 numbers of nebulous bodies in various stages of condensation which 

 are proved to consist of hot gases, and no doubt exhibit the preliminary 

 conditions of future solar sj'stems, and' are examples of the former 

 state of our own. This " nebular theory" of the evolution of the solar 

 S} T .stem, which can be merely mentioned in this place, is so extremely 

 probable, and so well accounts for the facts, that it is the commonly ac- 

 cepted theory of astronomers general^. 



The energy generated by the collision which produced the disintegra- 

 tion of the materials that have formed our system is, in considerable 

 part, being lost by radiation into distant space. We may suppose it 

 keeps on going till intercepted by other bodies, which it is certain to be 

 sooner or later. It cannot possibly get beyond the limits of the ether, 

 because it is the motion of the ether, and if it could not be delivered to 

 other bodies capable of absorbing it and turning it into other forms of 

 motion, we should have to conceive of the ether as forever remaining in 

 a state of vibration; that is, there would be perpetual light and heat 

 after all solid bodies had become too cold for further radiation. It is 

 possible to conceive of a state of equilibrium like this, but since the in- 

 finity of past duration has not been sufficient to establish it, it must be 

 concluded to be an impossible condition. 



The energy not radiated away from the solar system takes all the dif- 

 ferent forms that are known to the physicist, the chemist, the biologist, 

 and the psychologist, some of which we have been considering in the 

 foregoing chapters. 



We are informed by the astronomers that the comets, some of which 

 come from regions far beyond the known limits of the solar system, are 

 subjected to enormous extremes of heat and cold. Some of them 

 approach the sun so closely that if they were composed of the most re- 

 fractory materials we know of, they would be reduced to an incandescent 

 vapor. The heat they encounter is vastly greater than that of our hottest 

 furnaces. As they recede from the sun they gradually lose their heat, 

 and in the distant parts of their orbits encounter the intense cold of 

 space. 



Our solar system, the sun with his whole family of planets, is proved 



