Maria Goeppert Mayer was born on June 28, 1906. A German-born American theoretical physicist, and Nobel laureate in Physics for proposing the nuclear shell model of the atomic nucleus. She was the second woman to win a Nobel Prize in physics (the first being Marie Curie). In 1986, the Maria Goeppert-Mayer Award for early-career women physicists was established in her honor. A graduate of the University of Göttingen, Goeppert Mayer wrote her doctoral thesis on the theory of possible two-photon absorption by atoms. Today, the unit for the two-photon absorption cross section is named the Goeppert Mayer (GM) unit.