52 ETERNITY OF LIFE 



of measurements of the right ascensions of stars the parallax 

 of which had been determined with special accuracy. He 

 demonstrated very small but definite oscillations with periods 

 ranging from one and a half to three years. These oscillations 

 can only be explained as disturbances caused by satellites of 

 comparatively small mass. It would certainly be impossible 

 to observe these satellites directly by means of present-day 

 telescopes, but there is now no doubt that there are many 

 stars which, like our Sun, are surrounded by circulating 

 planets. ^^ Twenty-five per cent of the 240 stars observed by 

 Holmberg give indications of the presence of small, invisible 

 planets. Dark satellites having masses comparable with those 

 of our own planets have already been discovered for many 

 stars, e.g. 70 Ophiuchi and 61 Cygni}^ 



It seems, therefore, that our solar system is not unique. 

 There can be no doubt that planets revolve round other 

 stars too, and very many of these are comparable with our 

 Earth. There is therefore nothing to hinder us from suppos- 

 ing that life exists on some of them, maybe even on many 

 of them. 



In his book Lije on other worlds H. Spencer Jones^* 

 analyses a great deal of factual material relating to our prob- 

 lem and arrives at the conclusion that life is distributed 

 throughout the universe and that the number of worlds 

 where life is possible seems to be very considerable (see also 

 the recent book of A. Oparin and V. Fesenkov, Zhizn' vo 

 vselennoi* Moscow (Izd. AN SSSR), 1956). Thus the first 

 condition mentioned above for the acceptance of the theory 

 under discussion, that is to say the wide dispersal of life in 

 the universe, is not ruled out by the findings of contemporary 

 science. The case is, however, different as regards the passage 

 of the germs of life through space. 



The hypotheses concerning this problem may be divided 

 into two groups, (1) the transport of the germs by meteorites 

 (' cosmozoe ' or ' lithopanspermia ') and (2) transport of the 

 germs with cosmic dust under the pressure of light (' radio- 

 panspermia '). 



* Life in the Universe. — Translator. 



