Steven Weinberg

Steven Weinberg


American nuclear physicist (b. 1933) who in 1979 was one of the recipients of the Nobel Prize for Physics for work in formulating the electroweak theory, which explains the unity of electromagnetism with the weak nuclear force.

Weinberg's "scientific interests were always broad, but his most noted work has been in unified field theory. Four forces were believed to drive the laws of physics: gravity, electromagnetism, the strong force (which holds an atom's nucleus together), and the weak force (which breaks an atom apart, as in radioactivity). Around 1967, Weinberg theorized that the electromagnetic and the weak forces are the same at extremely high energy levels. This electroweak theory was confirmed by particle accelerator experiments in 1973. This was one giant step closer to physicists' long-dreamed of goal of finding a single elegant equation to explain all the matter and forces in nature." (From http://www.pbs.org/wgbh/aso/databank/entries/bpwein.html)

Electromagnetism and the weak force were both known to operate by the interchange of subatomic particles. Electromagnetism can operate at potentially infinite distances by means of massless particles called photons, while the weak force operates only at subatomic distances by means of massive particles called bosons. Weinberg was able to show that despite their apparent dissimilarities, photons and bosons are actually members of the same family of particles. His work, along with that of Sheldon Glashow and Abdus Salam, made it possible to predict the outcome of new experiments in which elementary particles are made to impinge on one another. An important series of experiments in 1982-83 found strong evidence for the W and Z particles predicted by these scientists' electroweak theory.

Weinberg conducted research at Columbia University and at the Lawrence Berkeley Laboratory before joining the faculty of the University of California at Berkeley in 1960. During part of his last two years there, 1968-69, he was visiting professor at the Massachusetts Institute of Technology; he joined its faculty in 1969, moving to Harvard University in 1973 and to the University of Texas at Austin in 1983.