Chien-Shiung Wu

Chien-Shiung Wu was born May 31, 1912, in Liuhe, a small town near Shanghai, where her father ran one of the region's first schools to admit girls. She graduated from China's National Central University in 1934, then sailed for the United States in 1936, intending only a visit before earning a doctorate under Ernest Lawrence, inventor of the cyclotron, at Berkeley. Barred by both her gender and her nationality from an academic post there after her 1940 PhD, she taught at Smith College and then Princeton, becoming the first woman to teach physics there, before Columbia recruited her in 1944 to work on uranium enrichment for the Manhattan Project. She married fellow physicist Luke Chia-Liu Yuan in 1942 and became a United States citizen in 1954.

By the mid-1950s Wu was Columbia's leading experimentalist in beta decay, the process by which unstable nuclei emit electrons, and in 1956 two theoretical physicists, Tsung-Dao Lee and Chen-Ning Yang, asked her to test something physicists had assumed for thirty years without checking: that nature obeys parity, meaning its laws look the same in a mirror. Working through the Christmas holiday at the National Bureau of Standards' low-temperature lab, Wu cooled cobalt-60 nuclei nearly to absolute zero, aligned their spins with a magnetic field, and on December 27, 1956, recorded a result no one expected -- the electrons flew off preferentially in one direction rather than symmetrically. Nature, it turned out, does not obey parity in weak nuclear interactions, a finding that rewired a foundational assumption of physics and reached print the following February.

Lee and Yang won the 1957 Nobel Prize in Physics for the theory, nine months after Wu's data confirmed it experimentally, and the prize went to them alone. Wu received twenty-three Nobel nominations of her own across three decades and was passed over every time, a pattern colleagues and later historians of science have tied directly to the era's near-total exclusion of women from that recognition. She said little publicly about the omission beyond noting once that whether a nucleus has a preference should not depend on whether the observer is male or female. She kept working, became Columbia's first tenured woman physicist in 1952, and did not receive a major solo prize until the inaugural Wolf Prize in Physics in 1978, more than two decades after the experiment that made her famous.

Wu died of a stroke on February 16, 1997, in New York, and was buried, at her request, at the school in Liuhe her father had founded. She is now routinely called the "First Lady of Physics," a title that circulated in her own lifetime, and her cobalt-60 result is taught in every graduate quantum mechanics course as the moment parity conservation fell. An asteroid, 2752 Wu Chien-Shiung, was named for her in 1990, and in 2021 the United States Postal Service put her on a stamp, part of a broader effort to correct, by naming, what the Nobel committee's era had left uncorrected in her lifetime.

Chien-Shiung Wu's life against the full span of the corpus.

• Manhattan Project uranium enrichment research mission
  Improved gaseous diffusion methods at Columbia's SAM Laboratories 1944
• Confirmation of Fermi's beta decay theory discovery
  Precisely verified Enrico Fermi's theory of allowed beta decay 1949
• The Wu experiment discovery
  Cobalt-60 beta decay experiment disproving conservation of parity 1957
• Beta Decay book
  Co-written textbook that became a standard nuclear physics reference 1965

• May 31, 1912 aged 0 Born in Liuhe, China
• 1936 aged ~24 Emigrates to the United States to study at Berkeley
• 1940 aged ~28 Earns her PhD in physics from Berkeley
• 1944 aged ~32 Joins the Manhattan Project at Columbia's SAM Laboratories
• 1952 aged ~40 Becomes Columbia's first tenured woman physics professor
• December 27, 1956 aged 44 Runs the cobalt-60 experiment disproving conservation of parity
• 1957 aged ~45 Lee and Yang win the Nobel Prize for the theory her experiment confirmed
• 1978 aged ~66 Awarded the inaugural Wolf Prize in Physics
• February 16, 1997 aged 84 Dies of a stroke in New York City

• Ernest Lawrence 1901–1958
  Invented the cyclotron and built the Berkeley model of large-scale team physics. doctoral advisor
• Enrico Fermi 1901–1954
  Italian-American physicist who built the first nuclear reactor and won the Nobel Prize in Physics. confirmed the theory of
• J. Robert Oppenheimer 1904–1967
  Theoretical physicist who led the Manhattan Project and became known as the father of the atomic bomb. wartime colleague
• Richard Feynman 1918–1988
  Theoretical physicist known for his work in quantum mechanics and his accessible teaching style. influenced