6 THE NATURE OF LIFE 



of time and space in which to find con- 

 ditions favorable to the origin of Hfe. It 

 may be that such conditions have never 

 existed on our planet and perhaps have 

 occurred but rarely in the history of the 

 universe. It is not impossible, however, 

 that we may learn of their occurrence, 

 in the past or the present, since the spec- 

 troscope gives us accurate information 

 about the composition of heavenly bod- 

 ies and, in the case of distant stars, tells 

 us what they were like thousands of 

 years ago. If we do not observe on 

 the earth the conditions necessary for 

 the origin of life we may perhaps hope 

 to find them in some of these heavenly 

 bodies which might differ su£Bciently 

 from our planet to provide the necessary 

 combination of factors. 



Arrhenius thinks that spores of bac- 

 teria might be carried to the upper limits 

 of our atmosphere and thence be expelled 

 into interstellar space, poetically called the 

 "ether sea." There the spores might be 

 driven away from the sun by the action 



