The life of the neutrino as we know it began amid personal chaos. Its existence was first postulated by Wolfgang Pauli, a brilliant but troubled Austrian physicist who at 20 wrote a definitive, 200-page book on Albert Einstein’s theory of relativity that Einstein himself admired, and at 25 proposed his “exclusion principle,” a fundamental statement on the behaviour of matter at the subatomic level that later earned him a Nobel Prize. Colleagues called him “God’s whip” and the “conscience of physics” for his ferocious skepticism and probing, often devastating questions. Yet he was also a prodigious drinker and carouser who, while lecturing at the University of Hamburg, was on intimate terms with the Reeperbahn, that city’s notorious red light district, and who suffered strange, haunting dreams.
The neutrino was perhaps Pauli’s least favourite of his contributions to modern physics. In the late 1920s, physicists examining the decay of radioactive materials such as uranium puzzled over a mysterious gap in the amount of energy they shed: they knew uranium emitted energy in the form of electrons, but when they added these electrons up they discovered that some energy was missing. Faced with this mathematical quandary, Pauli found himself forced in 1930 to accept the presence of an invisible and hitherto unknown neutral particle that could account for the loss—a ghostly spectre of the subatomic world. This was the neutrino. “It was the first time anyone ever postulated a missing particle,” says University of Toronto physicist Bob Orr. “Most people thought this was a really stupid idea.” Even Pauli himself called it a “terrible thing,” and he lamented that in proposing it he had “invented a particle that cannot be detected.” Indeed, he placed a standing bet—a case of champagne—on the notion that it never would be, outlining his ideas on the particle in a letter to colleagues that began: “Dear radioactive ladies and gentlemen.”
The improbable and bizarre dogged Pauli for the rest of his life, and have now caught up with his neutrino. Within months of penning that letter, Pauli’s marriage to Käthe Deppner, a Berlin cabaret dancer, collapsed. This, in combination with his mother’s suicide, sent him into a depressive tailspin, and he sought the treatment of Swiss psychiatrist Carl Jung. The two men became friends and embarked upon a joint obsession with the numeral “137,” both believing it a sort of code that would unlock the secrets of the universe. It is perfectly by accident that when Pauli died in a hospital of pancreatic cancer in 1958, he did so in room 137.
ll are elderly but only one has died, and so the Nobel race could turn into an endurance contest.