Shadow of the Bomb

A Brief Chronology of the Atomic Bomb During World War II

January 1942 — The Metallurgy Laboratory is established at the University of Chicago to consolidate research on a nuclear chain reaction and on plutonium.

December 2, 1942 — Enrico Fermi leads a team of scientists in creating the first controlled nuclear chain reaction under the stands at the University of Chicago’s Stagg Field.

January 1943 — Land is purchased near Hanford, Wash., for construction of a plutonium-producing nuclear reactor.

February 1943 — Construction on a uranium separation plant begins at Oak Ridge, Tenn.

April 1943 — The Los Alamos, N.M., National Laboratory opens.

July 16, 1945 — The world’s first atomic bomb is detonated in the New Mexico desert. The explosion is equal to 18.6 kilotons of TNT.

August 6, 1945 — An atomic bomb, “Little Boy,” is dropped on Hiroshima, Japan, by an American bomber, the Enola Gay. Approximately 70,000 people are killed instantly. By the end of 1945, the death toll reaches 140,000.

August 9, 1945 — Another atomic bomb, “Fat Man,” is dropped on the Japanese city of Nagasaki, killing 40,000 instantly. By year’s end, another 30,000 are dead. On Aug. 14, the Japanese surrender, ending the combat phase of World War II. The formal surrender takes place on Sept. 2.