The radio signals shouldn’t have been there, but they were. Having performed thousands of nuclear magnetic resonance (NMR) experiments, Princeton University physical chemist Warren S. Warren knew better than most scientists how to tune in radio echoes from atomic nuclei zapped by magnetic force. Those echoes provide the basis for one of the most powerful analytic tools in chemistry—NMR spectroscopy—and also for the magnetic resonance imaging (MRI) machines used widely in hospitals.
