Norman F. Ramsey, a Nobel Prize winner in physics and a former Harvard professor, died last Friday at age 96.

Ramsey, who taught at Harvard for forty years, is famous for his development of the “Ramsey Method” and a hydrogen maser used in atomic clocks.

“It is not overstating to say Norman was one of the greatest scientists of the twentieth century,” said physics professor Gerald Gabrielse, who replaced Ramsey in the physics department when he retired in 1987.

Ramsey began teaching at Harvard in 1947 and worked with over 85 graduate students during his tenure.

Ramsey prioritized his work with students and was very involved in guiding their research, said MIT professor Daniel Kleppner, one of his former students. “Harvard was his life from 1947 to the end,” Kleppner said.

Physics professor and Leverett House Master Howard M. Georgi ’68 recalls that Ramsey often attended events in Leverett House when he was in town.

“Each year, after the Nobel Prize in physics was announced, he would gather with [students in] the Senior Common Room and explain what the prize was about,” Georgi wrote in an email. “In 1989, he had to cancel—because he had received the Nobel Prize himself.”

Ramsey’s wife Ellie said that her husband’s research “was broad and deep and would literally take two days to fully describe.”

Ramsey shared the Nobel Prize for developing the separated oscillatory field method that allowed for frequency in an atomic system to be measured more accurately. As a result, scientists are able to measure time and unstable nuclei precisely.

According to Gabrielse, this technique—now referred as the “Ramsey Method”—is frequently used in the field and discussed at physics conferences.

Ramsey was also recognized for developing a hydrogen maser with Kleppner, which allows for precise time measurement now used in GPS devices.

Kleppner said that when he and Ramsey were working on their research, no one in the physics community foresaw the potential applications of the hydrogen maser.

In addition, Ramsey was one of the first to study electric dipole moments in particles and to examine asymmetry within a neutron. According to Gabrielse, Ramsey pioneered this field, but researchers at Harvard continue to study these properties in Ramsey’s absence.

Ramsey received a number of awards for his work, including the National Medal of Science Award, and later served on the presidential committee that selects recipients of the award. According to Ellie, Ramsey was especially pleased when he received an honorary degree from Harvard in 2006.