This Day in History: 1942-06-17

Manhattan Project begins under US Army command on this day in 1942. It is one of the most complex and expensive scientific programs in history and marks the start of what is called “Big Science.” The project ends up producing nuclear weapons from uranium and plutonium, and both kinds were dropped on Japan in August, 1945. At the end of the program, US Army General Leslie Groves tells scientists who are being de-mobilized:

“Five years ago, the idea of Atomic Power was only a dream. You have made that dream a reality. You have seized upon the most nebulous of ideas and translated them into actualities. You have built cities where none were known before. You have constructed industrial plants of a magnitude and to a precision heretofore deemed impossible. You built the weapon which ended the War and thereby saved countless American lives. With regard to peacetime applications, you have raised the curtain on vistas of a new world.” The legacy of the Manhattan project would be to put American science in the global lead until the early 21st century.