CORRECTION: Stamp honors woman who worked on Manhattan Project

Feb. 14—Correction appended

A new "forever" stamp commemorates a Chinese American scientist who worked on the Manhattan Project during her groundbreaking career as a nuclear physicist who broke gender barriers.

The U.S. Postal Service issued a stamp honoring the late Chien-Shiung Wu on Thursday to coincide with the International Day of Women and Girls in Science.

Some scientists believe Wu, whose son now works at Los Alamos National Laboratory, was snubbed for a Nobel Prize in the 1950s because of sexism and that the stamp helps atone for the snub.

Wu's son, Vincent Yuan, said his mother would like being on a stamp but would be humble about the honor.

"She wasn't one to go around bragging about the honors she had gotten," said Yuan, a nuclear physicist at the Los Alamos lab. "What would mean a lot to her would be all the work accomplishments, and whether they were recognized by her fellow citizens and people in the field."

Born in 1912, Wu moved to the U.S. from China in 1936 and earned a Ph.D. in nuclear physics in 1940 from the University of California, Berkeley.

In 1944, Wu was hired at the Division of War Research at Columbia University, where she worked on uranium enrichment and radiation detectors for the Manhattan Project.

She was part of a team conducting highly classified research to produce the world's first atomic bomb. Their research delved into splitting and harnessing the power of the uranium atom.

After the war, Wu remained a Columbia research professor, focusing on beta decay — a type of radioactive decay that leads to certain particles being changed and emitted.

Wu created a more precise spectrometer to better explain beta decay, a problem that had confounded physicists for decades.

In 1956, physicists Tsung-Dao Lee and Chen-Ning Yang enlisted Wu's help in developing a theory on a type of quantum mechanics known as conservation of parity.

At the time, physicists believed the universe had a built-in symmetry and would continue to function if its stronger and weaker forces were switched around. Essentially, they thought objects and forces that are mirror images of each will behave in the same way.

Wu crafted an experiment that disproved the decades-old theory. It later would be deemed revolutionary.

"In 1956, Wu proved, essentially, that the universe knows its right hand from its left," Science magazine says in a Feb. 5 article.

Her colleagues received a Nobel Prize in physics, but she did not.

To this day, a debate rages in and out of scientific circles about whether Wu suffered discrimination in the male-dominated profession. The American Association of University Women are among those that believe she did.

"Chien-Shiung Wu is widely considered one of the most influential scientists in history, but her achievements were not widely acknowledged due to her gender and race," the group wrote in an online article.

Wu died in 1997 at age 85.

Wu's granddaughter Jada Yuan, a Los Alamos High School graduate and a Washington Post feature writer, promoted the stamp on Twitter.

She called her grandmother a trailblazing physicist who she hopes will inspire science-minded girls and women.

Vincent Yuan said his mother would be happy at the gains women have made in the sciences. She would see many now hold tenured teaching jobs at universities and reaching upper management positions at agencies such as Los Alamos lab, he said.

But being a scientist, she would look at the hard data and discern where more progress could be made, Yuan said. For instance, they still might be underrepresented in tenured faculty, he said.

He said he's not certain whether to blame sexism on his mother not getting the Nobel Prize, but he thinks she deserved it. She won other prestigious awards for that work, he said.

"There certainly were a lot of other people in physics who think she should have gotten it," he said. "But I think it was in her nature that she didn't dwell on it."

Correction: This story has been amended to reflect the following correction. A previous version of this story contained a headline that incorrectly reported that Chien-Shiung Wu worked at Los Alamos National Laboratory.