COSMOGONY — JEANS 177 



out of candle ends on an empty stage on which the drama is ah-eady 

 over. There is not time for many more phinets to be born. 



LIFE AND THE UNIVERSE 



The planets are the only places we knovv^ where life can exist. The 

 stars are too hot; even tlieir atoms are broken up by the intense heat. 

 Nebulae are in every way unsuitable; even if cool solid bodies exist in 

 them, they would [)robably be so drenched with highly penetrating 

 radiation as to render life impossible. Life demands a special type 

 of matter, such as does not produce intense light and heat by trans- 

 forming itself into radiation. We find it only in the surfaces of the 

 stars, which ai'e too hot for life, and in the planets which have been 

 pulled out of these surfaces. 



On any scheme of cosmogony, life must be limited to an exceedingly 

 small corner of the universe. To our baby's wonderings whether 

 other cradles and other babies exist, the answer appears to be that 

 there can at best be very few cradles, and there is no conceivable 

 means of knowing whether they are tenanted by babies or not. We 

 look out and see a universe consisting primarily of matter which is 

 transforming itself into radiation, and producing so much heat, 

 light, and highly penetrating radiation as to make life impossible. 

 In rare instances special accidents may produce bodies such as our 

 earth, fojined of a special cool ash which no longer produces radia- 

 tion, and here life may be possible. But it does not at present look as 

 though nature had designed the universe primarily for life; the 

 normal star and the normal nebula have nothing to do with life ex- 

 cept making it impossible. Life is the end of a chain of by-products; 

 it seems to be the accident, and torrential deluges of life-destroying 

 radiation the essentiaj. 



There is a temptation to base wide-reaching inferences on the fact 

 that the universe as a whole is apparently antagonistic to life. Other 

 quite different inferences might be based on the fact of our earth 

 being singularly well adapted to life. We shall, I think, do well to 

 avoid both. Each oak in a forest produces many thousands of 

 acorns, of which only one succeeds in germinating and becoming an 

 oak. The successful acorn, contemplating myriads of acorns lying 

 crushed, rotten, or dead on the ground, might argue that the forest 

 must be inimical to the growth of oaks, or might reason that nothing 

 but the intervention of a special providence could account for its own 

 success in the face of so many failures. We must beware of both 

 tj^pes of hasty inference. 



In any case our S-daj's-old infant can not be very confident of 

 any interpretation it puts on a universe which it onh^ discovered a 



