Triggering a nuclear chain reaction

Richard Rhodes’ magisterial The Making of the Atomic Bomb (1986) begins very memorably. As he steps off the kerb to cross the road in central London on a dreary autumn morning in 1933, Hungarian physicist Leo Szilard, a refugee from Nazi Germany, has a vision. He realises how it might be possible for radioactive decay of a nucleus to initiate a chain reaction so as to ‘liberate energy on an industrial scale, and construct atomic bombs’. In that moment, Rhodes writes, ‘time cracked open before him and he saw a way to the future, death into the world and all our woe, the shape of things to come.’