As Eddington, Bethe and others were watching the stars (a major discovery is rarely the work of a single individual), others were exploring the intimate structure of the atom to reveal its secrets. In 1911, three years after winning the Nobel Prize in Chemistry for his work on the disintegration of the elements and the chemistry of radioactive substances, New Zealand-born physicist Ernest Rutherford (1871-1937) had elaborated the model of the atom that bears his name. Rutherford understood what tremendous forces could be unleashed from the atom nucleus.
The ''proton-proton chain'' that Hans Bethe identified in 1939 is the complex and lengthy process that enables Sun-like stars to generate energy. In a fusion reactor, the deuterium-tritium reaction is much simpler but produces the same result: light atoms (hydrogen or its two heavy isotopes) fuse into heavier ones (helium), producing large amounts of energy in the process.