A chemistry set in New York
Steven Weinberg was born in New York City on May 3, 1933, to Frederick Weinberg, a court stenographer, and Eva Weinberg, née Israel, a Jewish immigrant from Germany. His father encouraged his early interest in science, which was kindled when a cousin handed down an old chemistry set. By the time he was fifteen or sixteen, Weinberg later wrote, his interests had narrowed to theoretical physics.
He attended the Bronx High School of Science, the selective public school that was a ladder for so many children of immigrant families, and graduated in 1950 in the same class as Sheldon Glashow, the future physicist with whom he would one day share a Nobel Prize. He was the first in his family to go to college.
Cornell, Copenhagen, Princeton
Weinberg studied physics, with a minor in philosophy, at Cornell University, graduating in 1954. At Cornell he met Louise Goldwasser, a fellow undergraduate; they married in 1954, and she went on to become a distinguished legal scholar. He spent the following year at the Institute for Theoretical Physics in Copenhagen, now the Niels Bohr Institute, where, with help from David Frisch and Gunnar Källén, he began doing research. He then completed his doctorate at Princeton in 1957 under Sam Treiman, with a thesis on how the strong nuclear force affects weak-interaction decays.
There followed a decade of restless, wide-ranging work. He was at Columbia from 1957 and at the University of California, Berkeley, from 1959 to 1966, where his daughter, Elizabeth, was born in 1963. He wrote papers on topics as varied as the high-energy behaviour of Feynman diagrams, broken symmetries, scattering theory and muon physics, often, he admitted, chosen because he was trying to teach himself a new area. From 1961–62 he grew seriously interested in astrophysics and began a textbook, Gravitation and Cosmology, published in 1972.
The model of leptons
In the mid-1960s Weinberg was working on spontaneous symmetry breaking, the idea that the underlying laws of nature can have a symmetry that the world we observe does not. On leave from Berkeley, he was a lecturer at Harvard and then a visiting professor at the Massachusetts Institute of Technology. There, in the autumn of 1967, by his own later account while driving to his MIT office, he realised that he had been applying the right idea to the wrong problem. The mathematics he had been trying to use for the strong nuclear force fitted the weak force, responsible for radioactive decay, and the troublesome massless particle it predicted was simply the photon, the particle of light.
The result was a three-page paper, “A Model of Leptons” published in Physical Review Letters in 1967. Building on Glashow’s earlier proposal and on the symmetry-breaking mechanism developed by Peter Higgs and others, it described electromagnetism and the weak force as two faces of a single electroweak force. The symmetry between them is hidden at everyday energies by a field that fills space and gives mass to the heavy W and Z particles that carry the weak force, while leaving the photon massless. Abdus Salam arrived independently at a similar theory in 1968.
At first the paper attracted little attention. That changed in 1971, when Gerard ’t Hooft showed that theories of this kind were mathematically consistent. Then the evidence arrived: weak neutral currents, a new kind of interaction the theory required, were discovered at CERN in 1973; the W and Z particles themselves were found at CERN in 1983, with the predicted masses; and in 2012 the Higgs boson, the last missing piece, was detected at the Large Hadron Collider. Weinberg’s paper became one of the most cited in the history of particle physics, and the electroweak theory became a cornerstone of the Standard Model, the framework that describes all known particles and every force except gravity.
Nobel Prize and a broader physics
In 1979 Weinberg shared the Nobel Prize in Physics with Glashow, his old high-school classmate, and Salam, for their contributions to the theory of the unified weak and electromagnetic interaction. By then he had become an MIT professor in 1969 and, in 1973, succeeded Julian Schwinger as Higgins Professor of Physics at Harvard, with an appointment at the Smithsonian Astrophysical Observatory.
His influence extended well beyond the electroweak theory. In 1974, with Howard Georgi and Helen Quinn, he showed how the strengths of the fundamental forces could converge at very high energies, an important step toward grand unification. In 1978, independently of Frank Wilczek, he noticed that a proposed symmetry implied a new particle, the axion, now a leading candidate for the dark matter that makes up most of the matter in the universe. In 1979 he set out the view that all quantum field theories should be understood as effective theories valid at a particular scale of energy, a way of thinking that now runs through much of modern physics. In 1987 he used anthropic reasoning to estimate an upper limit on the energy of empty space, the cosmological constant, a decade before astronomers discovered that the expansion of the universe is accelerating.
In 1982 he moved to the University of Texas at Austin, where he held the Jack S. Josey–Welch Foundation Chair in Science and led the university’s Theory Group. He taught there for nearly four decades and continued to teach classes into his late eighties. His three-volume The Quantum Theory of Fields (1995–2000) became a standard reference, and he kept turning his lecture notes into textbooks, on cosmology, quantum mechanics and, in his last year, the Foundations of Modern Physics (2021).
The First Three Minutes
Weinberg was also one of the finest science writers of his generation. The First Three Minutes (1977) told, with clarity and restraint, how physics could reconstruct the universe’s earliest moments from the cosmic microwave background and the abundance of light elements. Translated into more than twenty languages, it introduced a wide public to the hot Big Bang and to the radical idea that the history of the cosmos could be calculated.
Its epilogue contained two of the most quoted sentences in popular science: that the more the universe seems comprehensible, the more it also seems pointless, and that the effort to understand it is one of the few things that lifts human life above farce. Dreams of a Final Theory (1992) defended the search for a single set of fundamental laws and made the case for the Superconducting Super Collider, a giant accelerator under construction in Texas; Weinberg testified for it before Congress, but it was cancelled in 1993. To Explain the World (2015), a history of science judged by the standards of modern science, provoked lively argument with historians. His essays for The New York Review of Books, on physics, religion, nuclear weapons and public policy, were collected in Facing Up, Lake Views and Third Thoughts.
Jewish roots, Israel and conscience
Weinberg was the son of Jewish parents, his mother an immigrant from Germany, and he was a lifelong atheist who wrote frankly against religion, most fully in his 2008 essay “Without God.” He argued that religion offers no help in understanding nature and, in a much-quoted 1999 remark, that while good and bad people behave as they will with or without it, it takes religion to make good people do evil.
Yet he was a committed supporter of Israel. In 1983 he founded the Jerusalem Winter School in Theoretical Physics and served as its first director for ten years. In his 1997 essay “Zionism and Its Adversaries” he defended Israel as a liberal democracy under threat. When British academic unions moved to boycott Israeli universities, he cancelled planned visits to Britain, in 2006 to a conference at Durham and in 2007 to a London university, citing what he called a widespread anti-Israel and antisemitic current in British opinion, and describing the boycott as a moral blindness hard to explain except as antisemitism.
He took the moral responsibilities of physicists seriously. He was a member of the JASON group of scientists who advise the U.S. government on defence, a consultant to the Arms Control and Disarmament Agency, and a persistent critic of national missile defence and of nuclear proliferation, themes of his 2004 book Glory and Terror. From 2009 until his death he served on the Board of Sponsors of the Bulletin of the Atomic Scientists.
The man
Colleagues described Weinberg as reserved and private, yet fair, kind, funny and phenomenally hard-working. He ran weekly brown-bag lunch meetings for students and pressed them to explain physics rather than merely describe it; one younger colleague recalled him offering to take over a course on effective field theory when the colleague had to leave for family reasons. He could be blunt in print but rarely unkind, and he relished argument as a form of respect.
He was married to Louise Weinberg, a professor of law at the University of Texas, for sixty-seven years. In 2016, when a Texas law permitted concealed handguns on public university campuses, he announced that he would nonetheless ban guns from his own classes. Among his many honours were the National Medal of Science (1991) and, in 2020, a Special Breakthrough Prize in Fundamental Physics; he was also named Humanist of the Year in 2002.
Last years and legacy
Weinberg died on July 23, 2021, at a hospital in Austin, aged eighty-eight, after several weeks of treatment, and was buried in the Texas State Cemetery. He was survived by Louise and their daughter, Elizabeth. He had been working on a new textbook shortly before his death.
The electroweak theory he set out at thirty-four, in a paper of three pages, sits at the centre of the Standard Model, which has passed every test thrown at it for half a century, from the discovery of neutral currents to the Higgs boson. His textbooks trained generations of physicists, and his popular books taught millions that the universe has a history that can be read. A child of Jewish New York who never claimed that the cosmos cared about humanity, he nonetheless insisted that trying to understand it was among the noblest things humans could do.
Sources & further reading
Steven Weinberg, Biographical, NobelPrize.org · Steven Weinberg, Wikipedia · Steven Weinberg (1933–2021), Physics Today · Steven Weinberg, Nobel laureate in physics and Bulletin board member, dies at 88, Bulletin of the Atomic Scientists · Nobel Prize-winning physicist Steven Weinberg dies at 88, The Times of Israel · Researched from the sources above and checked against them. Spotted an error? Tell us.
A life of tikkun olam. This is part of tikkun olam, the Jewish idea of repairing the world, and every one of us can add to it.