72 ILLINOIS STATE ACADEMY OF SCIENCE 



Saturn would acquire such large masses that they would 

 approach stellar conditions. Their distances from the 

 sun would diminish and the perturbations of the terres- 

 trial planets would doubtless' precipitate them into the 

 sun. Our knowledge of the three body problem is not 

 sufficiently great to say with assurance what would hap- 

 pen to Saturn, but if it too was thrown into the sun Jupi- 

 ter and the sun would remain to form a binary star. 

 Thus it seems reasonable to suppose that one final stage 

 of a planetary system is a binary star, or possibly a 

 multiple one. It is true that over one-third of the stars 

 are binary or multiple, which is an unexpectedly large 

 proportion on any other hypothesis; and the only other 

 reasonable hypothesis as to the origin of binary stars, 

 namely by the process of fission, has encountered appar- 

 ently insurmountable difficulties. 



If we grant that the sun and Jupiter have become a 

 binary star by the above process, and assume futhermore 

 that they enter into a richly nebulous region so that they 

 become five times as massive as their combined present 

 masses, then the period of Jupiter would be reduced 

 from twelve years to thirty-three hours. Its orbit would 

 be circular and we should have a typical short period 

 spectroscopic binary, and the spectral type of the sun 

 would be pushed up well towards type B. On the other 

 hand, if the masses declined, the orbit of Jupiter would 

 expand and become more eccentric and the sun would 

 approach the later type of stars. These conclusions are 

 in striking harmony with the known facts that spectros- 

 copic binaries of type B are short period and circular, 

 while the visual binaries belong to later spectral types 

 and are highly eccentric. 



Assuming that the mass of the galaxy is a billion times 

 the mass of the sun and that it has a radius of 2,000 par- 

 sees, a star at rest upon its borders would acquire a 

 velocity of 46 kilometers in falling to the center. And 

 conversely, a star near the center which has a velocity 

 of 46 kilometers will arrive at the borders of the galaxy 

 in about seventy millions of years, with its speed ex- 

 hausted. On the other hand, a star near the center of 

 the galaxy which has a speed of 80 kilometers per second 



