Tuesday, July 08, 2014

“Oppenheimer and the Atomic Bomb,” by Rebecca Larson

According to the Amazon.com description, “Oppenheimer and the Atomic Bomb” by Rebecca Larson is aimed at high school students -- no bad thing if, like me, you are primarily looking for information about the man and the history, and are fine with less emphasis on details of the physics.

J. Robert Oppenheimer was born to a wealthy New York family on April 22, 1904.  After graduating from Harvard University, he went to Cambridge England, for further study with Ernest Rutherford. While at Cambridge, Oppenheimer was judged to lack aptitude for laboratory physics. 

Max Born, then director of theoretical physics at the University of Gottingen in Germany, invited Oppenheimer to come to Germany and work with him. At the time, Gottingen, Cambridge, and Copenhagen were the three main centers of atomic research in Europe.

Oppenheimer completed his Ph.D. dissertation in May of 1927, on the applications of quantum theory. After that, he pretty much had his pick of American Universities -- all keen to have someone with training in the latest European physics.  He chose the University of California at Berkeley, where he was allowed to found his own program. The University also allowed him to spend each spring term teaching at Cal Tech in Pasadena.
When he first arrived in California, it was 1929, and Oppenheimer was 25 years old. The year before Oppenheimer moved to Berkeley, Edward Orlando Lawrence had been hired as an associate professor.  Lawrence had begun building a cyclotron, or atom smasher. His first effort was an 11 inch cyclotron, which required a two ton magnet to make it work.  Gradually, the cyclotrons evolved up to 60 inches. By the end of the 1930s, Oppenheimer and Lawrence turned Berkeley into an international center for physics.

At first Oppenheimer was considered to be a poor teacher, but he did improve over time and attract students to his orbit. He liked to take groups of students out to dinner at “Jack’s” – a fine restaurant in San Francisco.  Other entertainments included Mexican dinners in Oakland, or trips to the movies. He didn’t make much money as a professor, but family money allowed him to live well.  

Even as a young man, Oppenheimer had a reputation for brilliance in physics, and was known for his sharp wit.  His physical appearance was described as "lanky and slouching, with penetrating blue eyes and wild dark hair." He was also described as impeccable in his clothing and manners, and as able to converse knowledgeable about literature as well as physics. He studied Sanskrit so he could read the Bhagavad Gita, and claimed to know several other languages as well.

Among his vices were chain smoking and arrogance: he didn't hesitate to interrupt or contradict anyone – even Nobel Prize winners. 
The 1936 presidential election was the first time Oppenheimer ever voted.  He became more politically active due to his relationship with Jean Tatlock, a doctoral student in psychology, who was involved in leftist politics and had joined the communist party. His brother Frank and sister-in-law joined the communist party in 1936. Oppenheimer never joined the party, though he was concerned about the Spanish Civil War, and increasingly about the plight of Jews in Germany. 

After the death of his father in 1937, Oppenheimer made a will leaving his inheritance to U.C. for graduate fellowships. He helped found a teachers' union for faculty, teaching assistants, and local school-teachers. In the process, he became friends with Haakon Chevalier, a modern languages professor who served as president of the union.

His relationship with Jean Tatlock lasted three stormy years, ending finally in 1939.  It was two more years (1941) before he broke all ties with leftist groups. He met and married his wife Kitty, and their first child was born in 1941.  

Even against the background of Hitler’s Germany, nuclear physics was advancing.  German-Jewish scientists fled Germany, many to the US. With advances in Rutherford's Cambridge lab and the discovery of artificial radioactivity, the idea of using atomic power as a weapon began to take shape. By 1939, most physicists recognized the potential for explosive weapons. It wasn't until
1942 that the project was made official as the “Manhattan Engineer District” -- and Oppenheimer and Lawrence were both brought in.

During the summer of 1942, discussions went on under secure conditions on the UCB campus. In October 1942, General Leslie R. Groves, chief of the Manhattan project, arrived in Berkeley to visit Lawrence's new “calutron” in the hills above Berkeley. Groves also met with Oppenheimer, and the two of them discussed options for bringing atomic research together in one facility – rather than scattered around numerous centers acting secretly and on their own.  Los Alamos was selected later that year.



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