What makes the sun shine? How does the sun produce the vast amount of energy necessary to support life on earth? These questions challenged scientists for a hundred and fifty years, beginning in the middle of the nineteenth century. Theoretical physicists battled geologists and evolutionary biologists in a heated controversy over who had the correct answer.
The article traces in non-technical language the historical development of our understanding of nuclear fusion reactions as the source of stellar energy, beginning with the controversy over the age of the sun and earth between Darwin and Kelvin, and including the discovery of radioactivity, the experimental demonstration that four hydrogen nuclei are heavier than a helium nucleus, and the theoretical insights provided by Einstein, Gamow, and Bethe. The concluding sections concern solar neutrino experiments that were designed to test the theory of stellar evolution and which, in the process, apparently revealed new aspects of microscopic physics.
Also see the latest program by Nova entitled, "the Ghost Particle."