Chien-Shiung Wu

“The sudden liberation of our thinking on the very structure of the physical world was overwhelming.”

Chien-Shiung Wu (1912–97)
Physicist
Faculty 1944–80
Emerita 1980–87
ScD 1982 (hon.)

In 1956 and early 1957, physicist C. S. Wu and her colleagues conducted an ingenious experiment showing that—at least in the case of radioactive decay—nature knows left from right. Wu’s work verified a hypothesis put forth in 1956 by her Columbia colleague Tsung-Dao Lee and Chen-Ning Yang that, unlike all other known physical forces, the "weak" interactions among decaying particles are not always symmetrical in nature. Before Wu’s measurements, the laws of physics had always shown complete symmetry between left and right—the world reflected in a mirror appeared no less possible than the world in front of it. As a result of her measurements, on the afternoon of January 15, 1957 the Department of Physics at Columbia University called a press conference to announce the dramatic overthrow of this basic law of physics, known as conservation of parity. The next day, The New York Times carried a front-page headline, “Basic Concept in Physics Reported Upset in Tests,” and the news quickly spread.

In 1957 Lee and Yang received the Nobel Prize for their theoretical work on the subject. Over her lifetime, Wu contributions to research brought her many awards, including the National Medal of Science in 1975, the first Wolf Prize in Physics in 1978, and Columbia's Pupin Medal in 1991. She was elected to the National Academy of Sciences in 1958, the Royal Society of Edinburgh in 1969 and the American Academy of Arts and Sciences in 1972. In 1973, she was became the first woman to head the American Physical Society, and she was also the first living scientist to have an asteroid named after her.

Wu came to Columbia in 1944, after emigrating from China in 1936, and receiving her doctorate from the University of California Berkeley in 1940, and working on the Manhattan Project, in which she helped develop a process to produce bomb-grade uranium. She became a full professor in 1958 and was appointed the first Michael I. Pupin Professor of Physics in 1973. Her later research included the study of molecular changes in hemoglobin associated with sickle-cell anemia. Her book Beta Decay, published in 1965, remains the standard reference for nuclear physicists.


	C. S. Wu's “Beta-Decay and Parity Nonconservation” in 1972.


	Lee and Yang’s Nobel Prize.


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