150 AKNUAL REPORT SMITHSONIAN INSTITUTION, 1942 



tion, each star must have begun its life as a vast mass of nebulous 

 gas, in which state it would present a far more vulnerable target than 

 now for disruptive attacks by other stars. Detailed calculation shows 

 that the chance of a star's producing planets in this early stage, 

 although not large, would be quite considerable, and suggests, with a 

 large margin to spare, that although planetary systems may be rare in 

 space, their total number is far from insignificant. Out of the thou- 

 sands or millions of millions of planets that there must surely be in 

 space, a very great number must have physical conditions very similar 

 to those prevailing on earth. 



We cannot even guess whether these are inhabited by life like our 

 own or by life of any kind whatever. The same chemical atoms exist 

 there as exist here and must have the same properties, so that it is 

 likely that the same inorganic compounds have formed there as have 

 formed here. If so, we would like to know how far the chain of life 

 has progressed, but present-day science can give no help. We can only 

 wonder whether any life there may be elsewhere in the universe has 

 succeeded in managing its affairs better than we have done in recent 

 years. 



