LIFE OISJ- WORLDS — BERGET. 647 



say to the altitude of approximately a hundred kilometers. When 

 it has reached that point it is subjected to another category of forces 

 susceptible of acting on it; these are forces of an electrical Idnd. 



It is, indeed, at about that altitude that radiations produce polar 

 auroras. These auroras are caused by the arrival into the atmos- 

 phere of the earth of cosmic dust coming from the sun and driven 

 from it by the pressure of radiation. This dust is charged negatively, 

 and its discharge makes Imiiinous the region of the atmosphere in 

 which it is. Under these conditions, if a spore coming from the 

 earth's surface is also negatively charged by contact vdih the elec- 

 trically charged dust, it may be repelled by the latter, which will 

 drive it toward intersideral space as a result of the electrostatic repul- 

 sion of two charges of the same sign. Calculation shows that an 

 electrical field of 200 volts a meter is enough to produce on a spherule 

 the 0.16 of a micron in diameter a repulsion greater than gravitation; 

 now, the field usually observed in the atmospheric air is greater. 

 Electrostatic repulsion of germs that have reached the higher atmos- 

 phere is, then, not only qualitatively, but even quantitatively possible. 



We have our germ, then, started on its intersideral journey. Let 

 us put aside for a tmie the conditions of existence and destruction 

 that it may encounter among the stars, circumstances that we shall 

 study in a moment. We are going to find out first of all the condi- 

 tions of time of such a journey, effected under the influence of the 

 pressure of radiation which acts on the germ as soon as it is at a suffi- 

 cient distance from the earth. On its way it will be caught, in the 

 neighborhood of a celestial body, by some larger particle of the order 

 of size of a micron, which forms a portion of that dust scattered 

 profusely around the solar systems. Once carried away by this 

 particle, which, because of its greater size, is more subject to the 

 action of attraction than to that of the repelling force, it can then 

 penetrate into the atmosphere of the planets that it will happen to 

 encounter. 



If we assume that this traveling germ has a density equal to that 

 of water, which is obviously accurate for living germs, we find that 

 it ^\-i^l need nearly 20 days for it to reach the planet Mars, 80 to reach 

 Jupiter, 15 months to get to the distant planet of Neptune. These 

 are only planets forming part of our own solar system. If we try 

 to find the time necessaiy for this germ to reach the solar system 

 nearest to ours, that is, the system whose central sun is the star a of 

 the constellation of the Centaur, we will find the duration of the 

 journey to be approximately 9,000 years. 



How will our germ, living at the time of its departure, act in the 

 course of this long journey ? 



Interstellar space has a very low temperature; it is near the 

 absolute zero of the physicists, which is 273° C. below the temperature 



