INFRA-ASTRONOMY 45 



universe. As a matter of fact, our visible universe 

 resembles a rarefied gas rather than a liquid or 

 solid. For the average distance between the mole- 

 cules of atmospheric air is 1000 times their diameter, 

 whereas the distance of the nearest fixed star is 3000 

 times the diameter of the solar system, and the 

 other stars are much further off. Other parts of 

 our universe are, of course, much denser, and approach 

 more closely to what we may call the liquid state. 

 But the starry universe immediately surrounding us 

 corresponds to a gas, with solar systems for mole- 

 cules. 



For a solid like a copper wire we have no analogy 

 on our own world scale. For the atoms of copper 

 are so densely packed as to be in actual contact, 

 or even compressed. If we brought the stars of the 

 Milky Way into actual contact, there would inevitably 

 be a great conflagration, in the course of which their 

 individuality would be hopelessly lost. There is less 

 chance of that in the infra- world, since the hardness 

 of the bodies is much greater, while the velocities 

 remain the same. But there is another circumstance 

 h enables the atoms the solar system of the 

 infra-world to approach each other as far as the 

 orbits of their outermost electrons and yet remain 

 separate systems. It is the electrostatic repul 

 between the electrons thus brought close t<>u r > th< r. 

 Most atoms have a large number of elect 

 volving round them, estimated in some cases at 



