On the electric charge of the sun

Abstract

The chief forces which determine the motions of celestial bodies are due to the gravitation of their masses, according to the law of Newton. But besides these forces, which tend to concentrate matter, there exist others of a repulsive nature, as Kepler already observed regarding the comets' tails. As no other repelling forces were known than those between similarly electrified bodies, it was supposed that these forces were of electric origin, and especially Zöllner worked out this theory for explaining the form of the tails of the comets.These electric forces were nevertheless of a highly hypothetical nature, because no reason could be found why the Sun and the particles of the comets' tails should be charged electrically. Therefore the astrophysicists were gratified when a new repelling force, namely, that of the pressure of radiation, which is a consequence of the theories of Maxwell and Bartoli, was introduced for the explanation of the observed repulsions between celestial bodies. According to these theories, the radiation from the Sun would be sufficient to exert a pressure against a totally reflecting spherical drop of 1.5 μ diameter, which would balance its gravity if the drop had a specific weight like that of water. Drops of this magnitude ought, therefore, to swim in the atmosphere of the Sun, just as if they had no weight at all. Bigger drops ought to fall down to the Sun, whereas smaller ones ought to be repelled from it.