Building a Bomb

Heinrich Hertz demonstrates the existence of radio waves.

Wilhelm Conrad Röntgen, a German physicist, discovers X-rays, a high-frequency counterpart to the radio waves discovered by Hertz.

During a series of experiments with X-rays emitted by the element uranium, French physicist Henri Becquerel discovers a new kind of energy emitted by uranium atoms. This energy will come to be known as radiation.

Marie and Pierre Curie isolate two previously unknown elements: radium and polonium. Both are highly radioactive. For their work, the Curies are awarded the 1903 Nobel Prize in Physics, which they share with Becquerel. Further research with these elements will lead to a Nobel Prize in Chemistry in 1911 for Marie. Unfortunately, both Marie and Pierre will suffer radiation poisoning as a result of their work.

Albert Einstein publishes a paper arguing that matter can be converted to energy according to the now-famous formula E=mc2 (the energy emitted by this conversion will be equal to the mass of the original matter multiplied by the speed of light squared).

The chemist Ernest Rutherford identifies the structure of the atom: a cloud of electrons surrounding a very dense nucleus of protons.

Physicist James Chadwick, working in Rutherford’s laboratory, discovers neutrons, uncharged particles that exist alongside protons in the nucleus. This discovery will soon lead to experiments in splitting the nucleus, a crucial first step in the development of atomic fission.

The German physicists Otto Hahn and Fritz Strassmann theorize a process of uranium fission that will allow a chain reaction to occur.

January 1939   
Frédéric Joliot, the son-in-law of Marie and Pierre Curie, provides experimental proof of Hahn and Strassmann’s theory and begins early experiments in building a nuclear reactor.

August 1939     
A group of physicists, including Doctor Atomic’s Edward Teller, writes a letter to president Franklin Delano Roosevelt. In the letter, they argue that, with Hahn and Strassmann’s discoveries, a nuclear bomb is possible and that Germany may well be working to create one. Crucially, the physicists suggest that the United States start working to create an atomic bomb before Germany can.

Summer 1942  
Over the course of just a few summer weeks, J. Robert Oppenheimer and a group of colleagues work out a practical concept for a fission bomb. Oppenheimer, along with General Leslie Groves, will be put in charge of a top-secret lab on a high plateau in the New Mexico desert: Los Alamos. With Oppenheimer and Groves representing scientific and military interests respectively, the scientists of the Manhattan Project begin developing the bomb.

December 1942
The Italian physicist Enrico Fermi conducts the world’s first controlled nuclear reaction­­—on a squash court under the University of Chicago stadium. Fermi will go on to be one of the lead scientists on the Manhattan Project.

May 8, 1945     
Germany surrenders unconditionally to the Allied forces.

June 16, 1945   
In the early morning hours, the United States tests an atomic bomb at the Trinity test site.

August 6, 1945
Although some politicians and scientists have suggested that Japan can be induced to surrender even without a nuclear attack, an atomic bomb is dropped on the city of Hiroshima. 70,000 civilians are killed in the explosion, and as many more are seriously injured.

August 9, 1945
The U.S. drops a second atomic bomb on Japan, this time on the city of Nagasaki.

August 15, 1945              
Japan surrenders.

Critical InquiryWhile many people hoped that the atomic bomb would end World War II, Oppenheimer expressed a hope that the bomb would mark the end of all war. What do you think he meant? Why might the atomic bomb have this effect? Did the atomic bomb end all war? Has an atomic bomb been used in a war since the explosion at Nagasaki?