The Chicago Project

The local connections to Oppenheimer

By DEANNA ISAACS

What’s the Chicago connection to the events depicted in Christopher Nolan’s explosive, confusing, and acclaimed Oppenheimer film? Here’s what I learned from University of Chicago professor emeritus and astrophysicist Don Lamb. We spoke last week, before the film opened.

J. Robert Oppenheimer led the World War II e ort known as the Manhattan Project, but the experiment showing it was possible to make and deliver an atomic bomb was conducted right here, under the west stands of Stagg Field at the University of Chicago.

Scientists had already discovered that atomic nuclei, made up of neutrons and protons, release a tremendous amount of energy if they are broken apart. The open question was whether someone could create a hugely powerful bomb by setting up a sustained chain reaction—one in which neutrons from broken nuclei would continue to hit and split other nuclei in an expanding cascade.

“There was a lot of worry among physicists that it could be done,” Lamb told me. “A famous German physicist was known to be interested, and the German army had control over two necessary resources: large amounts of graphite and, once they invaded Norway, heavy water.” Both of those are “moderators”—they slow down the blasting neutrons, which makes a sustained reaction more likely.

“This was extremely frightening,” Lamb said. Physicists in the U.S. sent a letter signed by Albert Einstein to President Franklin Roosevelt, urging the government to facilitate an experiment as soon as possible that would show whether such a bomb could be made or not. Roosevelt agreed.

“And,” Lamb said, “that brings us to the Chicago connection. A committee was set up to figure out how to proceed and where. The chair of that committee was Arthur Holly Compton, professor of physics at the University of Chicago. He more or less single-handedly decided the experiment should be done near Chicago.”

Enrico Fermi and others, who’d been splitting atoms at Columbia University (ergo “Manhattan Project”), quickly moved to the University of Chicago, which had been converted to the war e ort.

Their plan was to build a pile of graphite, put uranium spheres inside, and see if they could get a sustained chain reaction going. Because it was considered somewhat risky, they were going to do it in a forested area southwest of Chicago; a contractor had been hired to assemble the pile there.

Then, Lamb said, “The contractor’s employees went on strike.

“There was such a sense of urgency, Fermi and the team decided to assemble the graphite blocks on campus, under Stagg Field. That space was available because in the 1930s, President Robert Maynard Hutchins had decided that large-scale football was not commensurate with the values and objectives of the university, and had ended it,” Lamb noted.

They recruited laborers from the south side, including high school students, and began

But by the time the bomb was nearing completion, it was the spring of 1945. Nazi Germany’s army was collapsing, and it was clear that Germany would be defeated soon. “There were discussions in Washington about using the bomb on Japan. The physicists were very uncomfortable with this, and many of them were adamantly opposed to it,” Lamb said. “A lot of work had continued in Chicago, and it was physicists here who first spoke out about their concerns.”

They wrote a report explaining their opposition; it’s called the Franck Report, but Eugene Rabinowitch, who would cofound the Bulletin of the Atomic Scientists, wrote it, Lamb said. The report made three main points: how to make the bomb could not be kept secret— other countries would figure it out; once they did, there would be a horrific nuclear arms race; and the only way it could be slowed or stopped was by international treaties on nuclear weapons.

“Most strategic thinkers about nuclear weapons will say that 500 nuclear weapons used on Russia or, vice versa, on the U.S., would destroy the country,” said Lamb. “By the early 1980s, more than 60,000 nuclear weapons were available. The Bulletin of the Atomic Scientists was created here at the University of Chicago to take on the military complex and to try to stop a nuclear catastrophe from happening. That was 1945, and it’s still here, housed in the Harris School of Public Policy.”

Rabinowitch became the Bulletin’s longtime editor; its first board chair was J. Robert Oppenheimer. v

@DeannaIsaacs