Memorable World History/Authors

The Life and Disappearance of Ettore Majorana

Ettore Majorana (/ˌmædʒəˈrænə/, Italian: [ˈɛttore majoˈraːna]; born on 5 August 1906 – probably died after 1959) was an Italian theoretical physicist who worked on neutrino masses. On March 25, 1938, he disappeared under mysterious circumstances while going by ship from Palermo to Naples. The Majorana equation and Majorana fermions are named after him. In 2006, the Majorana Prize was established in his memory.

Life and work

There are several categories of scientists in the world; those of second or third rank do their best but never get very far. Then there is the first rank, those who make important discoveries, fundamental to scientific progress. But then there are the geniuses, like Galilei and Newton. Majorana was one of these.

— (Enrico Fermi about Majorana, Rome 1938,)

Gifted in mathematics

Majorana was born in Catania, Sicily. Mathematically gifted, he was very young when he joined Enrico Fermi's team in Rome as one of the "Via Panisperna boys", who took their name from the street address of their laboratory.

His uncle Quirino Majorana was also a physicist.

He began his university studies in engineering in 1923 but switched to physics in 1928 at the urging of Emilio Segrè. His first papers dealt with problems in atomic spectroscopy.

First published academic papers

His first paper, published in 1928, was written when he was an undergraduate and coauthored by Giovanni Gentile, Jr., a junior professor in the Institute of Physics in Rome. This work was an early quantitative application to atomic spectroscopy of Fermi's statistical model of atomic structure (now known as the Thomas–Fermi model, due to its contemporaneous description by Llewellyn Thomas).

In this paper, Majorana and Gentile performed first-principles calculations within the context of this model that gave a good account of experimentally-observed core electron energies of gadolinium and uranium, and of the fine structure splitting of caesium lines observed in optical spectra. In 1931, Majorana published the first paper on the phenomenon of autoionization in atomic spectra, designated by him as "spontaneous ionization"; an independent paper in the same year, published by Allen Shenstone of Princeton University, designated the phenomenon as "auto-ionization", a name first used by Pierre Auger. This name has since become conventional, without the hyphen.

In 1932, he published a paper in the field of atomic spectroscopy concerning the behaviour of aligned atoms in time-varying magnetic fields. This problem, also studied by I.I. Rabi and others, led to an important sub-branch of atomic physics, that of radio-frequency spectroscopy. In the same year, Majorana published his paper on a relativistic theory of particles with arbitrary intrinsic momentum, in which he developed and applied infinite dimensional representations of the Lorentz group, and gave a theoretical basis for the mass spectrum of elementary particles. Like most of Majorana's papers in Italian, it languished in relative obscurity for several decades.

Experiments in 1932 by Irène Joliot-Curie and Frédéric Joliot showed the existence of an unknown particle that they suggested was a gamma ray. Majorana was the first to interpret correctly the experiment as requiring a new particle that had a neutral charge and a mass about the same as the proton; this particle is the neutron. Fermi told him to write an article, but Majorana didn't bother. James Chadwick proved the existence of the neutron by experiment later that year, and he was awarded the Nobel Prize for this discovery.

Majorana was known for not seeking credit for his discoveries, considering his work to be banal. He wrote only nine papers in his lifetime.

Work with Heisenberg, illness, isolation