Sunshine | The long path to discovery A little more than one century ago, in 1919, a nagging question received the beginning of an answer. Almost simultaneously, two eminent scientists, Jean Perrin (1870-1942) in France and Arthur Eddington (1882-1944) in the United Kingdom, speculated that the energy source at the core of the Sun was to be found in sub-atomic reactions. Their intuition was a huge departure from the theories that had prevailed for the previous seven decades. Jean Perrin's intuition that the energy source at the core of the Sun was to be found in sub-atomic reactions was a huge departure from the theories that had prevailed for the previous seven decades.Armed with the science of the mid-19th century, physicists and astronomers had long thought that "solar heat" resulted from the constant fall of meteors and asteroids into the Sun. In 1841, calculations by Julius von Mayer (1814-1878), a German physician and chemist, indicated that asteroids striking the Sun at high velocity would generate "from 4,600 to 9,200 times as much heat as would be generated by the combustion of an equal mass of coal." There was a flaw in the model, however: in order to keep the Sun shining, a huge number of asteroids would be required and no one could explain where they would come from.