190 ANNUAL EEPOET SMITHSONIAN INSTITUTION, 192 8 



miles at most, but from the heat and light pouring forth it is possible 

 to judge the conditions within. When we plunge below the surface, 

 it will be necessary for us to change our proportions greatl}^ if we 

 are to get any idea of what is going on about us. In those regions 

 we should no longer see the large surface disturbances, such as spots 

 and prominences, wdiich are measured in thousands and millions of 

 miles, but all would appear calm and quiet as the depths of the sea. 

 We would be aware only of increasing temperature and pressure as 

 we approach the center. If, however, we might be diminished by 

 some magic draft to one millionth of a millionth of our size or could 

 see with a microscope that would magnify correspondingly, we 

 should see a wealth of activity, and we should discover that within 

 the stars atoms are moving about with speeds of 100 miles per second 

 and knocking each other about in a most terrific fashion. We should 

 be bewildered by multitudes of free electrons darting this way and 

 that with vastly greater velocities. Electrons would be captured 

 b}'' atoms only to be shoved off again by powerful ether waves or 

 X rays coming from below with the speed of light. The X rays 

 would continue on their zigzag upward course, being absorbed and 

 reemitted as they come in contact with atoms in their path. The 

 atoms would be entirely stripped of their outer shells of electrons. 

 After thousands of years, according to Eddington's computations, 

 these rays finally reach the surface, and their energy is taken up by 

 the cooler atoms and sent out to the corners of the universe as light. 

 Traveling in straight lines for many years they may fall upon our 

 tiny earth and tell to eager scientists the story of their origin and 

 escape. 



In spite of this indescribable confusion, there would be equilibrium 

 in the mean at any point within the star. The knocking about of 

 the atoms and electrons and the outward pressure of radiation, 

 mostly in the form of X rays, would be just sufficient to support 

 the outer layers against the force of gravitation, and thus keep the 

 star from complete collapse. These laboratories of the sky are the 

 scenes of action beyond anything which we know in the coldness of 

 our earthly surroundings. They seem strange and mysterious only 

 because we do not fully understand the processes involved and be- 

 cause we have been accustomed to an entirely different scale of 

 dimensions and temperature. 



We have passed rapidly from the movements of the stars, which 

 are the greatest aggregations of matter in our universe, to the mecha- 

 nism of the atom, which is the smallest complete unit of matter. Our 

 measurements have changed from thousands of light-years for the 

 distances between the stars to a billionth of a billionth of a second, 

 which is the time it takes light to cross the orbit of an electron. The 



