Ettore Majorana was born on August 5, 1906, in Catania, a medium-sized city just south of Mount Etna on the east coast of Sicily. He was the fourth of five children. A prominent Italian statesman, his grandfather served terms in both chambers of the Italian parliament; it was his father, an engineer, who spotted Majorana’s talent in mathematics when he was five. Majorana excelled under his father’s instruction, and in secondary school, and then at the prestigious Jesuit college Instituto Massimilliano Massimo.1
Majorana set out to become an engineer like his father, but was persuaded to study physics instead by Emilio Segrè and Enrico Fermi. He soon established himself as one of the Via Panisperna boys, Fermi’s team of physicists cloistered on the Via Panisperna in the heart of Rome. It was the Via Panisperna boys who would go on to lay some of the groundwork for nuclear fission.
Majorana made his first major discovery at 25; during his analysis of atomic spectra, he discovered autoionization, which he named spontaneous ionization. Autoionization is the spontaneous emission of an electron from the outermost shell of an excited atom, which converts the atom into a positive ion. Published in only his second paper, it was a substantial discovery.
Over the next seven years, he would write just seven more papers. Fermi would later include Majorana in the company of Galileo Galilei and Isaac Newton, noting that “[t]here are several categories of scientists in the world, … [some of whom] make important discoveries, fundamental to scientific progress.”2 Fermi made his remarks in 1938, but in celebrating Majorana’s genius, he was referring to Majorana’s discovery of the neutron six years before.
In 1931, Frédéric and Irène Joliot-Curie discovered a neutrally-charged particle and concluded that it must be some sort of photon. Together with the proton and the electron, the photon was one of the three subatomic particles then known, and the only one with a neutral charge.
At the time, it was not known how protons could comprise the atomic nucleus. Having positive charges, they should repel one another, making the nucleus completely unstable. According to Fermi, it was Majorana who concluded correctly that neutrons must be tightly packed amidst the protons. What was not known at the time was that these tightly packed neutrons would serve to counteract the repulsive force between protons by means of the strong nuclear force.
Fermi urged Majorana to publish his results. Majorana declined to write the idea up and the discovery of the neutron would instead be credited soon thereafter to James Chadwick—a discovery for which he won the Nobel prize.3
Majorana had by then moved onto his next project, a relativistic wave equation whose two solutions were complex conjugates, thus suggesting the relationship between a given particle and its anti-particle. This time he acquiesced to Fermi’s insistence that he publish; the paper was well received. No subatomic particle then known behaved the way Majorana’s equation predicted. In 2012, experimental physicists at Delft University of Technology announced that they had spotted Majorana fermions that did in fact appear, loosely speaking, to be their own anti-particles. There is now growing speculation that neutrinos may be Majorana particles, and that anti-neutrinos are in fact neutrinos whose spin direction has been reversed.
In 1938, Ettore Majorana dropped off the face of the earth.
Majorana’s influence endures amongst physicists, as it has ever since his disappearance. When the Manhattan project was briefly stuck, Fermi is reported to have said to Eugene Wigner, “If only Ettore were here.”4 Majorana’s absence was brought up regularly enough that one of the army officers running the Manhattan Project asked Wigner where Majorana was, and if he could be induced to emigrate to the United States. All Wigner could tell him was that Majorana was gone, and that nobody knew where.5
After publishing his wave equation in 1932, Majorana left Rome for Leipzig in early 1933, where he worked on atomic nuclei with Werner Heisenberg, a collaboration that lasted for six months, during which the two became good friends.6 Majorana was impressed by Heisenberg’s extraordinary courtesy, despite the fact that he had published a paper correcting some of Heisenberg’s ideas on nuclear structure. During this period in Leipzig, Majorana took to writing letters home expressing sympathy with the Nazis, and the expulsion of Jews from German universities.
“It is inconceivable,” he wrote, “that a country of 65 million [should be] … guided by a minority of 600,000 [Jews], who openly declared they wished to become a separate nation.”7
Many of Majorana’s peers and colleagues were Jewish, including his first mentor, Segrè. Fermi was not Jewish, but his wife was.
From Leipzig, Majorana travelled briefly to Copenhagen to work with Niels Bohr. Upon returning to Leipzig, he developed acute gastritis, which in the autumn of 1933 persuaded him to return to Rome, where he suffered a nervous breakdown and became increasingly reclusive.8 Refusing to see old colleagues, or his family, Majorana grew out his hair and beard, and took to answering letters with notes explaining that he was dead.
Instead of working on physics, he began writing erratically on economics, mathematics, geology, philosophy, even shipbuilding. His reputation remained strong enough that in 1937, after four years of reclusion, he was offered, and accepted, a full professorship in theoretical physics at the University of Naples.
In March 1938, Majorana emptied his bank account and travelled to Palermo hoping to visit Segrè. Italy had begun adopting German-style race laws, and seeing the writing on the wall, Segré had only days before accepted a position at the Berkeley radiation lab in California.
Later that month, Majorana sent a letter to his superior at the university, Antonio Carrelli:
Dear Carrelli,
I have made a decision that was by now inevitable. It doesn’t contain a single speck of selfishness; but I do realise the inconvenience that my unanticipated disappearance may cause to the students and yourself. For this, too, I beg you to forgive me; but above all for having betrayed the trust, the sincere friendship and the sympathy you have so kindly offered me over the past few months. I beg you also to remember me to all those I’ve come to know and appreciate at your Institute, in particular Sciuti, of all I shall preserve the dearest memories at least until eleven o’clock this evening, and possibly beyond.9
This appeared to be a suicide note. On the same day, he sent a note to his family, asking them to mourn him for “no more than three days.”10 Shortly after mailing the letter to Carrelli, Majorana sent him a telegram that said simply, “Do not be alarmed,” and told him to wait for a subsequent letter.11
Mailed the next day, that letter read:
Dear Carrelli,
I hope that my letter and telegram have reached you together. The sea has rejected me and tomorrow I’ll return to the Hotel Bologna [where Majorana was staying in Palermo], perhaps traveling together with this same letter. I have, however, decided to give up teaching. Don’t take me for an Ibsen heroine, because the case is quite different. I’m at your disposal for further details.12
That was the last anyone ever heard from Ettore Majorana.
After mailing the letter, he apparently purchased a ticket from Palermo to Naples and vanished.13 Majorana may have changed his mind about the sea rejecting him and drowned himself. No body was ever recovered. Few of Majorana’s colleagues believed that the thirty-one-year-old physicist had committed suicide.
Vittori Strazzeri, a professor at the University of Palermo, claimed to have seen Majorana on board the ferry to Naples on March 27. One of the sailors said the same thing. Strazzeri also said that he had seen Majorana disembark safely. Neither Strazzeri nor the sailor had ever met Majorana and were going only by descriptions of him that were published once stories of his disappearance reached the press. A few weeks later, a friend claimed to have caught sight of Majorana walking down a Neapolitan street.14
Fermi told his wife that if Majorana “has decided to disappear, no one will be able to find him.”15 He wrote a personal letter to Benito Mussolini asking him to support an investigation into Majorana’s disappearance. A 30,000 Lire reward was offered for information.16
Majorana’s confessor, Monsignor Riccieri, was certain that the very religious Majorana had not committed suicide; he believed that he had joined a monastery. This is also what Majorana’s family believed, but no concrete evidence has ever been found.17 Theories started to circulate that Majorana had been kidnapped and forced to work on an atomic weapon project. Or that he’d been killed to prevent him working on an atomic weapon project. Most far-fetched were rumors of a brilliant nomad wandering the hills of Sicily, helping children with their mathematics homework.18 Less far-fetched were rumors of a peculiar man living in Venezuela, a Sicilian of about Majorana’s age, who drove a yellow Studebaker crammed with mathematical papers. Calling himself Mr. Bini, this character was extremely shy and hated to be photographed. Around 1955, someone managed to snap a photograph of him. Rumors of this photo reached legal authorities in Rome 60 years later.
Although the man in the picture looked like Majorana, Majorana looked like everyone else coming from southern Italy. With nothing but gossip to tie the photograph to Bini and Bini to Majorana, who knows how seriously it can be taken? In February 2015, the Corriere della Sera reported that the Ministero della Giustizia had announced that it was satisfied that the photograph of Bini, in fact, depicted Majorana.19 The case of Majorana’s disappearance was then closed with the conclusion that he had been “alive during the period from 1955 to 1959, and voluntarily living in the Venezuelan city of Valencia.”20
Nothing else is known about Majorana’s disappearance, or his life after 1938.
