Steven Weinberg, an American theoretical physicist, Nobel laureate (1979), and member of the faculty at the University of Texas at Austin (UT Austin) died on July 23, 2021, at the age of eighty-eight. Weinberg was a highly regarded scientist with principal contributions to astrophysics and high energy physics throughout his career. He was honored through numerous other prizes and had been elected to the National Academy of Sciences and Britain’s Royal Society. Besides his pivotal work in physics, Weinberg was also focused on education and public engagements. Weinberg was elected a fellow of the Committee for Skeptical Inquiry (then CSICOP) in 1995.

Weinberg’s fundamental contribution to science was bridging the gap between astrophysics and high energy physics, historically two separate fields of physics. He was able to do so both at the level of public outreach—making his work accessible to lay people and experts alike—and cutting-edge science. Regarding the former, one of his contributions was the popular science book The First Three Minutes: A Modern View of the Origin of the Universe, published in 1977. The book was well received by the general public and was also readily used as an introductory text for university students. A more recent piece, published in 2015, is the science history book To Explain the World: The Discovery of Modern Science, which attracted both interest and controversy.

At the professional level, Weinberg’s work developing the intersection between astrophysics and high energy physics has been of critical importance for the advancement of science, including numerous NASA space missions such as the Cosmic Background Explorer (COBE) and the Wilkinson Microwave Anisotropy Probe (WMAP). These missions carefully examined the cosmic microwave background and probed the geometry of space on large scales. Another mission, Planck, led by the European Space Agency (with notable contributions by NASA) operated between 2009 and 2013. Planck allowed making the most accurate maps of the microwave background at the time; its instruments were sensitive to temperature variations of a few millionths of a degree. Associated theoretical research has the potential to help unravel the physics of the Big Bang as well as cater to fervent topics such as, for example, whether there had been any physics prior to the Big Bang or whether asking this question is fundamentally meaningless.

Steven Weinberg was also a true intellectual giant in the world of high energy particle physics. His paper “A Model of Leptons,” in 1967, laid out the basis for the unification of electromagnetic and weak nuclear interactions. Subsequently, this theory became a fundamental element of the Standard Model of particle physics for which Weinberg was awarded the 1979 Nobel Prize in Physics together with Sheldon Glashow and Abdus Salam. The discoveries of the W-boson, the Z-boson, and more recently the Higgs boson provide strong vindication of the correctness of this theory.

The Standard Model, with the addition of the strong nuclear interaction to electromagnetic and weak forces, has become incredibly successful in correctly predicting a huge range of phenomena in particle physics. Weinberg’s contribution to this success will always be regarded as one of the most important of the modern scientific era. However, Weinberg also realized that the Standard Model was incomplete through, for example, its inability to explain the nature of dark matter. To extend the current theory, Weinberg was well known for his studies of areas such as string theory and supersymmetry.

Weinberg was outspoken and did not mind voicing his opinion on subjects such as religion, Israel, guns in the classroom, and football. He was highly critical of organized religion and a vehement supporter of Israel, a position that entailed some discomfort in segments of the general public supportive of the Palestinian cause. In 2016, he did not shy away from being opposed to a new law that allowed the carrying of concealed guns in the classrooms of UT Austin.

There is also a popular anecdote about football: according to multiple sources, upon his arrival at UT Austin he wanted his salary contractually linked to that of the head football coach. It’s not clear whether this demand was granted (but we assume almost certainly it was not). Obviously, Weinberg’s request may be interpreted in two ways. First, he wanted to secure a significant salary in support of his seminal work. Second, he wanted to draw attention to the exaggerated importance of sports (especially football) on U.S. campuses, a notable anomaly compared to standard university practices around the globe.

Weinberg’s achievements will stand as a major inspiration for future generations of physicists seeking a more complete understanding of the natural universe. He will also be missed for his profound contributions to the public arena, encompassing science philosophy, education, and the intersection between science and politics, including the thriving debate on climate change.