Most people think of the atom as a nucleus surrounded by electron shells, but few realize that the nucleus itself is comprised of shells. Even fewer people know that Maria Goeppert-Mayer was the theoretical physicist that proposed the nuclear shell model of the atomic nucleus. She was the second female Nobel laureate in physics, after Marie Curie.
Maria Goeppert-Mayer was born in the city known today as Katowice, Poland, to Friedrich and Maria née Wolff on June 28, 1906. Even with an impressive pedigree in academics (her father was a sixth-generation university professor), Maria had problems with schools allowing a woman to enter a PhD program, so she went from school to school attending lectures whenever she could. She defended her thesis at the University of Hanover, in front of professors she’d never met. Even after receiving her doctorate, Maria could not obtain a university position.
She entered the world of science by going to work and conferences with her husband, American chemistry professor, Joseph Mayer. Most schools didn’t mind Maria being around discussing science. Some even gave her assignments but they all refused to pay her. During WWII, Maria was invited to work on the Manhattan Project, and participated, but was assigned a side project. Still, she loved science enough to keep working. After the war, she did get hired as a professor of physics at the University of Chicago, but again, it was unpaid. While there, she started her work on the core of the atom, the nucleus.
She published a paper in 1950 explaining why certain numbers of nucleons in the nucleus have more stable configurations than others. Enrico Fermi asked her: “Is there any indication of spin orbit coupling?” She realized that this was, indeed, the case, and assumed that the nucleus is a series of closed shells and pairs of neutrons and protons tend to couple together.
She described it as follows: “Think of a room full of waltzers. Suppose they go round the room in circles, each circle enclosed within another. Then imagine that in each circle, you can fit twice as many dancers by having one pair go clockwise and another pair go counterclockwise. Then add one more variation; all the dancers are spinning twirling round and round like tops as they circle the room, each pair both twirling and circling. But only some of those that go counterclockwise are twirling counterclockwise. The others are twirling clockwise while circling counterclockwise. The same is true of those that are dancing around clockwise: some twirl clockwise, others twirl counterclockwise”.
In 1959, she got hired by the University of California, San Diego; finally, a real paying job! She won the Nobel Prize in 1963, and the San Diego newspaper’s condescending headline said, “S.D. Mother Wins Nobel Prize”.
After her death, The American Physical Society created the Maria Goeppert-Mayer Award to support young female physicists at the beginning of their careers. It is open to all female physicists who hold PhDs.
Other honors include:
-A 35km crater on Venus named after her.
-The unit for the two-photon absorption cross-section is called the Goeppert-Mayer (GM) unit.