Einstein's letter that changed the history of the world

The dramatic tale of the deadly use of atomic energy in the 2023 blockbuster Oppenheimer might have remained science fiction if not for a two-page letter written on August 2, 1939.

"Recent research in the field of nuclear physics has shown the possibility that uranium can be turned into a new and important source of energy," said a printed letter to US President Franklin D. Roosevelt, hand-signed by respected physicist Albert Einstein. This energy, he continues, can be used "to build extremely powerful bombs."

Expressing suspicion of Germany's decision to end uranium sales to occupied Czechoslovakia, the letter became the impetus for a top-secret $2 billion research and development program known as the Manhattan Project, a competition with Germany to develop atomic weapons.

The three-year project, led by physicist Robert Oppenheimer, would push the US into the nuclear age and lead to one of the most significant – and most devastating – inventions in history: the atomic bomb.

On September 10, 2024, Einstein's important and carefully worded letter will be auctioned at Christie's in New York and is expected to fetch more than $4 million. In total, two versions of the letter were written: a shorter version that will be put up for auction, and a more detailed version that was delivered to the White House and is now part of the permanent collection of the Franklin Roosevelt Library in New York.

"In many ways, this letter marks a key turning point in the history of science, technology and humanity," Peter Clarinet, senior specialist in American studies, books and manuscripts at Christie's, told the BBC.

"This is really the first time that the United States government has directly participated in major scientific research," he adds. "This letter set the stage for the United States to take full advantage of the technological changes that were taking place."

Dr Bryn Willcock, Program Director of Swansea University's Department of Politics, Philosophy and International Affairs and lecturer and researcher in American and nuclear history, agrees.

"Most historical accounts of the origin of the bomb begin with a discussion of the letter," he tells the BBC.

"The contents of the letter were key to the initiation of direct action by President Roosevelt," he says, noting that, according to the Atomic Heritage Foundation, the letter played a key role in pushing Roosevelt toward atomic research.

The film Oppenheimer, based on the story of the Manhattan Project, which also mentions the letter, is expected to fuel interest in the auction.

"The letter has been a part of popular culture since 1945 and beyond, so it already has a strong place, but I think the movie Oppenheimer has brought it to a new generation now," says Clarinet.

Clarinet calls Einstein a "mythical character" of popular culture. He certainly demonstrates this in Oppenheimer, lurking on the film's periphery in a cameo we've been waiting for, his identity only revealed when his hat flies off to reveal that famous white head of hair.

Although Einstein's equation E = mc2 explained the energy released in a nuclear reaction and paved the way for its sinister applications, its role in the creation of the atomic bomb is perhaps exaggerated in the film. The heated exchange between Oppenheimer and Einstein in the final scene (Oppenheimer: "When I came to you with these calculations, we thought we could start a chain reaction that would destroy the whole world...") is "nonsense," says Clarinet.

Einstein, whose left-wing views and German background provoked suspicion, "would not have had the appropriate level of access," he says. In fact, as an avowed pacifist, he distanced himself from the project and always insisted that his involvement in the release of atomic energy was "rather indirect."

If anyone was her inspiration, it was Leo Szilard, Einstein's former student. Letter with Szilard's pencil mark “Original not sent!” would remain with Szilard until his death in 1964. Both Einstein, who was born in Germany, and Szilard, who was born in Hungary, were Jews who fled to the United States after the rise of Nazism. And they understood the threat posed by Germany better than anyone.

The letter was Szilard's idea, but he insisted that Einstein write and sign it. Einstein had considerable authority and, after receiving the Nobel Prize in 1921, became "the epitome of modern science," says Clarinet.

"He had such an influence that no one else had. Other people must have been trying to warn Roosevelt about what was going on in the months leading up to it, but suddenly you walk in the door with a letter from Albert Einstein saying you have to do it - it makes an impression."

On July 16, 1945, a prototype bomb known as the "gadget" was successfully detonated in the New Mexico desert. The result was met with both triumph and dismay. On this day, US President Harry Truman wrote in his diary: "We have invented the most terrible bomb in the history of the world."

Germany had surrendered - but not Japan, and it was believed that attacking the Japanese ports of Hiroshima and Nagasaki with terrible and unprecedented force would hasten the end of the war. Although Szilard launched a petition the day after the bomb tests, recommending that Japan be invited to surrender before taking such drastic action, it did not reach power in time.

On August 6, a bomb was dropped on Hiroshima under the code name "Malyuk". "Fat" was blown up in Nagasaki on August 9. An estimated 200,000 people were killed or injured, and many more died over the years from the side effects of the radiation. To date, these are the only cases of direct use of nuclear weapons in war.

It is difficult to say whether the Manhattan Project would have existed without Einstein's letter. Willcock notes that Britain was already "trying hard to push America to support more research" and calls the British-led MAUD report (1941), a study into the possibility of nuclear weapons, "crucial in stimulating American research."

However, Einstein's letter could only accelerate the process. Without it there could have been a delay which, according to Willcock, "would probably have meant that the bomb would not be ready for use until the summer of 1945".

Einstein, for his part, bitterly regretted the violence and chaos his 1939 letter had caused. In 1946, he co-founded the Emergency Committee of Atomic Scientists to talk about the dangers of nuclear war and propose a path to world peace.

In an article for Newsweek magazine in 1947 entitled "Einstein - The Man Who Started It All", he stated: "If I had known that the Germans would not succeed in creating an atomic bomb, I would not have done anything for the bomb." Today, despite the presence of technological know-how, Germany still does not have nuclear weapons.

Einstein devoted the rest of his life to the campaign for nuclear disarmament. In a conversation with chemist and Nobel laureate Linus Pauling in 1954, he called the letter to Roosevelt the "biggest mistake" of his life.

The atomic bomb radically changed the landscape of warfare and sparked an East-West arms race that continues to shape international relations.

"This is still a very relevant issue today. This is the shadow that hangs over humanity, says Clarinet. "This letter is a vivid reminder of how we ended up in the situation we have now."

In July 1955, Einstein's name would posthumously appear in the title of the Russell-Einstein Manifesto, an emotionally worded resolution against nuclear war initiated by philosopher Bertrand Russell and endorsed by Einstein just a week before his death.

"We are addressing people as people," the text says. - Remember your humanity and forget about the rest. If you do, the way to a new paradise opens. If you cannot do this, you will face the risk of universal death."