ABSTRACT
The possibility that nuclear fusion reactions may be the dominant source of the energy of stars was first suggested by Arthur Eddington in 1920. However, at that time, a detailed mechanism was unknown. Later, in 1928, George Gamow showed that nuclear reactions proceed through the quantum mechanical tunneling process. A comprehensive treatment of the two main reaction chains, the PP chain and the CNO cycle, which contribute to the main sequence stars, was provided by Hans Bethe in 1939. This work firmly established the validity of the fusion hypothesis.
