If you’ve seen the movie “Oppenheimer,” which you should — trust me, it’s gripping even though it’s three hours long and you know how the story ends — you probably noticed several appearances by the physicist Isidor Isaac Rabi, who is portrayed in some ways as Oppenheimer’s voice of conscience. I was a bit puzzled when I watched, because I happened to know that Rabi wasn’t a resident at Los Alamos during the Manhattan Project. But the film was historically accurate: Rabi did visit Los Alamos on occasion, and was present for the Trinity bomb test.
Why wasn’t Rabi at Los Alamos? The film highlights his ethical qualms. But the truth is that he was involved in another secret project applying cutting-edge science to the war effort, MIT’s Radiation Laboratory, which basically worked on advanced radar. The Rad Lab arguably had an even bigger impact on the course of the war than the Manhattan Project, because it turned microwave technology, originally developed in Britain, into a radar system that German submarines couldn’t detect. This was a major factor in the Allies’ 1943 victory in the Battle of the Atlantic, which secured the sea lanes to Britain; this in turn set the stage first for the decisive defeat of the Luftwaffe in early 1944, and then for D-Day.