Six Weeks Apart

This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.

For most of 1945, two American physics groups worked toward the same discovery without knowing about each other. At Harvard, Edward Purcell, fresh off wartime radar research, reasoned that if a sample of solid paraffin were placed in a magnetic field and bathed in radio waves of just the right frequency, its hydrogen nuclei should absorb energy in a way a receiver could detect. On 15 December 1945 his team measured exactly that. Three hundred kilometers away at Stanford, Felix Bloch had been approaching the same physics from the opposite direction, asking not what the nuclei would absorb but what signal they would induce in a nearby coil as their spins realigned, a method he called nuclear induction. His team confirmed it in January 1946. Neither group knew the other was close until word reached them through the physics grapevine that spring, and the two papers, describing what was recognizably the same phenomenon reached by two different routes, appeared in the Physical Review within weeks of each other. Bloch and Purcell shared the 1952 Nobel Prize in Physics for discoveries that, within a generation, gave chemists a routine way to read the structure of a molecule from the inside, and gave medicine, decades later, the imaging technique now known as MRI.