200 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1954 



peculiar condition, but if we look at the universe as a whole we realize 

 that it is not peculiar at all. Fully half of the material universe is 

 just as highly ionized. We just do not realize what an odd place we 

 live in, or that it is this oddity that makes life possible. The ioniza- 

 tion in prominences greatly changes the character of the forces that 

 can act on them, other than the action of gravity, which is a function 

 only of mass or weight, regardless of ionization. Ionized materials 

 are conductors of electricity, which means that they are subjected to 

 forces in changing electric and magnetic fields. It is this property of 

 conductors that accounts for the power of an electric motor. 



Now we know that the sun is a place of very strong magnetic fields. 

 They have perfectly measurable effects on the spectrum by means of 

 which we can determine their strength. The fields are especially 

 strong and active near the sunspots, and it is precisely here that we 

 find the most active prominences. We can say quite definitely that the 

 solar magnetic fields must have a profound effect on the motion of 

 ionized prominence material. The problem now is to determine 

 whether the fields could account for the observed motions. It turns 

 out to be a very complicated problem about which there is still a great 

 deal of lively controversy among astronomers. The general conclu- 

 sion at present is that solar magnetism almost certainly controls the 

 motion and support of prominences, but the details of how it is done 

 will not be unraveled very soon. 



Reprints of the various articles in this Report may be obtained, as 

 long as the supply lasts, on request addressed to the Editorial and Pub- 

 lications Division, Smithsonian Institution, Washington 25, D. C. 



