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Thursday, December 10, 2009

Reading List: A Brilliant Darkness

Magueijo, João. A Brilliant Darkness. New York: Basic Books, 2009. ISBN 978-0-465-00903-9.
Ettore Majorana is one of the most enigmatic figures in twentieth century physics. The son of a wealthy Sicilian family and a domineering mother, he was a mathematical prodigy who, while studying for a doctorate in engineering, was recruited to join Enrico Fermi's laboratory: the “Via Panisperna boys”. (Can't read that without seeing “panspermia”? Me neither.) Majorana switched to physics, and received his doctorate at the age of 22.

At Fermi's lab, he almost immediately became known as the person who could quickly solve intractable mathematical problems others struggled with for weeks. He also acquired a reputation for working on whatever interested him, declining to collaborate with others. Further, he would often investigate a topic to his own satisfaction, speak of his conclusions to his colleagues, but never get around to writing a formal article for publication—he seemed almost totally motivated by satisfying his own intellectual curiosity and not at all by receiving credit for his work. This infuriated his fiercely competitive boss Fermi, who saw his institute scooped on multiple occasions by others who independently discovered and published work Majorana had done and left to languish in his desk drawer or discarded as being “too obvious to publish”. Still, Fermi regarded Majorana as one of those wild talents who appear upon rare occasions in the history of science. He said,

There are many categories of scientists, people of second and third rank, who do their best, but do not go very far. There are also people of first class, who make great discoveries, which are of capital importance for the development of science. But then there are the geniuses, like Galileo and Newton. Well, Ettore was one of these.

In 1933, Majorana visited Werner Heisenberg in Leipzig and quickly became a close friend of this physicist who was, in most personal traits, his polar opposite. Afterward, he returned to Rome and flip-flopped from his extroversion in the company of Heisenberg to the life of a recluse, rarely leaving his bedroom in the family mansion for almost four years. Then something happened, and he jumped into the competition for the position of full professor at the University of Naples, bypassing the requirement for an examination due to his “exceptional merit”. He emerged from his reclusion, accepted the position, and launched into his teaching career, albeit giving lectures at a level which his students often found bewildering.

Then, on March 26th, 1938, he boarded a ship in Palermo Sicily bound for Naples and was never seen again. Before his departure he had posted enigmatic letters to his employer and family, sent a telegram, and left a further letter in his hotel room which some interpreted as suicide notes, but which forensic scientists who have read thousands of suicide notes say resemble none they've ever seen (but then, would a note by a Galileo or Newton read like that of the run of the mill suicide?). This event set in motion investigation and speculation which continues to this very day. Majorana was said to have withdrawn a large sum of money from his bank a few days before: is this plausible for one bent on self-annihilation (we'll get back to that infra)? Based on his recent interest in religion and reports of his having approached religious communities to join them, members of his family spent a year following up reports that he'd joined a monastery; despite “sightings”, none of these leads panned out. Years later, multiple credible sources with nothing apparently to gain reported that Majorana had been seen on numerous occasions in Argentina, and, abandoning physics (which he had said “was on the wrong path” before his disappearance), pursued a career as an engineer.

This only scratches the surface of the legends which have grown up around Majorana. His disappearance, occurring after nuclear fission had already been produced in Fermi's laboratory, but none of the “boys” had yet realised what they'd seen, spawns speculation that Majorana, as he often did, figured it out, worked out the implications, spoke of it to someone, and was kidnapped by the Germans (maybe he mentioned it to his friend Heisenberg), the Americans, or the Soviets. There is an Italian comic book in which Majorana is abducted by Americans, spirited off to Los Alamos to work on the Manhattan Project, only to be abducted again (to his great relief) by aliens in a flying saucer. Nobody knows—this is just one of the many mysteries bearing the name Majorana.

Today, Majorana is best known for his work on the neutrino. He responded to Paul Dirac's theory of the neutrino (which he believed unnecessarily complicated and unphysical) with his own, in which, as opposed to there being neutrinos and antineutrinos, the neutrino is its own antiparticle and hence neutrinos of the same flavour can annihilate one another. At the time these theories were proposed the neutrino had not been detected, nor would it be for twenty years. When the existence of the neutrino was confirmed (although few doubted its existence by the time Reines and Cowan detected it in 1956), few believed it would ever be possible to distinguish the Dirac and Majorana theories of the neutrino, because that particle was almost universally believed to be massless. But then the “scientific consensus” isn't always the way to bet.

Starting with solar neutrino experiments in the 1960s, and continuing to the present day, it became clear that neutrinos did have mass, albeit very little compared to the electron. This meant that the distinction between the Dirac and Majorana theories of the neutrino was accessible to experiment, and could, at least in principle, be resolved. “At least in principle”: what a clarion call to the bleeding edge experimentalist! If the neutrino is a Majorana particle, as opposed to a Dirac particle, then neutrinoless double beta decay should occur, and we'll know whether Majorana's model, proposed more than seven decades ago, was correct. I wish there'd been more discussion of the open controversy over experiments which claim a 6σ signal for neutrinoless double beta decay in 76Ge, but then one doesn't want to date one's book with matters actively disputed.

To the book: this may be the first exemplar of a new genre I'll dub “gonzo scientific biography”. Like the “new journalism” of the 1960s and '70s, this is as much about the author as the subject; the author figures as a central character in the narrative, whether transcribing his queries in pidgin Italian to the Majorana family:

“Signora wifed a brother of Ettore, Luciano?”
“What age did signora owned at that time”
“But he was olded fifty years!”
“But in end he husbanded you.”

Besides humourously trampling on the language of Dante, the author employs profanity as a superlative as do so many “new journalists”. I find this unseemly in a scientific biography of an ascetic, deeply-conflicted individual who spent most of his short life in a search for the truth and, if he erred, erred always on the side of propriety, self-denial, and commitment to dignity of all people.

Should you read this? Well, if you've come this far, of course you should!   This is an excellent, albeit flawed, biography of a singular, albeit flawed, genius whose intellectual legacy motivates massive experiments conducted deep underground and in the seas today. Suppose a neutrinoless double beta decay experiment should confirm the Majorana theory? Should he receive the Nobel prize for it? On the merits, absolutely: many physics Nobels have been awarded for far less, and let's not talk about the “soft Nobels”. But under the rules a Nobel prize can't be awarded posthumously. Which then compels one to ask, “Is Ettore dead?” Well, sure, that's the way to bet: he was born in 1906 and while many people have lived longer, most don't. But how you can you be certain? I'd say, should an experiment for neutrinoless double beta decay prove conclusive, award him the prize and see if he shows up to accept it. Then we'll all know for sure.

Heck, if he did, it'd probably make Drudge.

Posted at December 10, 2009 01:47