On November 4, 2011, Norman F. Ramsey, one of the titans of 20th century science, passed away in Wayland, Massachusetts. His life and career had spanned almost a century. The technologies that sprung from his work touch the lives of billions living today. Magnetic Resonance Imaging (MRI), a mainstay of medical diagnostics technology, and the Atomic Clock, which makes Global Positioning System (GPS) possible, are among the technologies derived from the experimental techniques Dr. Ramsey developed.
A DISTINGUISHED CAREER IN SCIENCE
Born on August 27, 1915 in Washington, DC, Norman Foster Ramsey Jr. was the son of Norman Foster Ramsey, a West Point educated military officer, and Minna Bauer Ramsey, a mathematics instructor. With his father frequently receiving new assignments, Ramsey, at 15, graduated from high school in Fort Leavenworth, Kansas — a town known as the site, not of a famous academic institution, but an infamous Federal Prison. But in time he would receive and give back even more to the finest academic institutions in the world. He attended Columbia University, graduating at the top of his class, with a bachelor’s degree in mathematics. This led to a scholarship to attend Cambridge University in England, where he earned a second bachelor’s degree, this time in physics. In those heady days at Cambridge, he came into contact with many of the pioneers of modern physics, including J. J. Thomson, discoverer of the electron; Rutherford, discoverer of the atomic nucleus; Chadwick, discoverer of the neutron; Cockcroft, who made one of the earliest particle accelerators; Eddington, astronomer whose observations in 1919 confirmed one of the major predictions of Einstein’s General Relativity; Max Born, who put a statistical/probabilistic interpretation on quantum mechanics, but known outside physics as the grandfather of Australian singer/actress Olivia Newton-John; and the incomparable, inscrutable Dirac, who formulated axiomatic quantum mechanics — all Nobel Laureates. Norman Ramsey used to quip that he had attended one lecture by the famous J. J. Thomson (1858-1940) “… already so old that his dentures would fall out during the most inopportune moments.” Then he would add, “I am now even older, but my teeth are not going to fall out!”
After Cambridge, Dr. Ramsey returned to Columbia, and under “I. I.” (Isidor Isaac) Rabi, wrote the first PhD thesis on Nuclear Magnetic Resonance (NMR). From there he briefly took an academic position teaching at the University of Illinois. But with the War in Europe escalating, he took leave from Illinois in order to head a group developing the 3-cm radar at MIT. This was followed by an even more critical wartime stint on the Manhattan Project in Los Alamos, developing the atom bomb. After the war he briefly returned to Columbia and, with Rabi, revived the experiments on molecular beam methods that had been in dormancy during the war years. On the side, he helped to start the Brookhaven National (Accelerator) Lab, where he headed the first physics division. In 1947 he accepted a position on the faculty of Harvard, and there in 1949, designed the equipment to measure atomic and molecular energies (frequencies) with hitherto unseen precision. Indeed, one of the characteristic frequencies in the vibrations of the Cesium (Cs) atom became the basis for the Atomic Clock, and in time led to a new definition of the unit of time. One second corresponds to 9,192,631,770 vibrations of Cs, a phenomenon possessing far greater stability than the slightly vagrant revolutions of the earth around the sun, the traditional time measure since ‘time immemorial’.
In the 50s he found the time to serve as advisor to NATO, where he spearheaded the creation of the NATO Scholarship to train future scientists. And in the 60s and 70s, with the experience of having established the Brookhaven Lab, he collaborated on the design of the Fermi Lab in Batavia, Illinois. With Daniel Kleppner, one of his scores of PhD students, he developed the H-MASER in 1960. In time, this technology was invoked in experimental confirmation of General Relativity’s prediction that gravity has an effect on the passage of time. (Time runs faster in the penthouse than in the basement of a building.)
He served on the faculty of Harvard University for forty years, retiring officially in 1986. But, he repeatedly failed retirement, always keeping a hand in new work going on in his field. Forty-five years after working on Nuclear Magnetic Resonance (MRI) with Rabi at Columbia, he saw the work extended to medicine. As Magnetic Resonance Imaging (MRI) this technology has revolutionized medicine, enabling radiologists to peer inside the organs comprised of soft tissue with uncanny resolution.
One of the greatest experimental physicists of the 20th century, he was rare among experimentalists for staying abreast of developments in theoretical physics, viewing this as “a hobby.” His entire career had been immersed in a sea of Nobel Prize Winners. His PhD advisor, Rabi, won the Nobel Prize in 1944. It would be the compendium of Norman Ramsey’s discoveries that led to his award of the 1989 Nobel Prize in Physics. Daniel Kleppner, one of the scores of his PhD students at Harvard, now a distinguished professor of physics emeritus at MIT, had been the thesis advisor to William Phillips who received the 1997 Nobel Prize in Physics. Ramsey used to refer to Bill Phillips as his “research grandson.”
A FEW PERSONAL RECOLLECTIONS
I knew and admired Norman Ramsey deeply. Personally he was as modest and gracious as he was brilliant and wise. During the early 70s he had served as the visiting professor at Oxford University, and it was there that I first met him. I was a postdoc in the Department of Theoretical Physics, Oxford, having earned my PhD in the United States funded by a NATO Scholarship, but oblivious at the time to the fact that this remarkable man had been responsible in its creation.
In March of 2006 I gave a lecture at Harvard, and was a guest in the home of Norman and Ellie Ramsey, who had attended the talk. At one point in my talk, I had asked the audience, comprised mostly of non-scientists the question, “How many of you here believe that there exists extra-terrestrial intelligence?” People in the audience watched Professor Ramsey, reluctant to commit until they could see Ramsey’s response. Suddenly, when he raised his hand, all the other hands in the room shot up. When I followed up with the tongue in cheek sequel, “How many of you believe there exists terrestrial intelligence?” Dr. Ramsey laughed with gusto. He knew that in the Washington, DC area where I live there is room for debate. Norman Ramsey, possibly the most brilliant son of the city, represents clear evidence that at least at one time there existed immense intelligence in the city.