The future was Oppenheimer’s priority. While the use of the bomb was never his decision, he did seem to believe that, in the long run, it was the lesser of two evils. In 1939, he knew that the achievement of nuclear fission made a bomb inevitable. In 1945, he believed that the bomb made nuclear war inevitable, unless its hideous power could be demonstrated to the world before the current conflict ended. “They won’t fear it until they understand it,” he says in the film, “and they won’t understand it until they’ve used it”. Colleagues including Teller and Niels Bohr (played by Kenneth Branagh) agreed, although for them, this belief that using the bomb could avert future wars did not make it any less terrible.

Nolan’s decision to tell the story of the bomb through Oppenheimer’s eyes – not just his experiences but also his concerns – gives the film its contemporary urgency. What was done to Hiroshima and Nagasaki is history, but the existential threat of nuclear weapons is still with us, as Oppenheimer knew it would be.

This awareness is captured in his most famous quotation. The physicist later claimed that at Trinity he had thought of a line from the Bhagavad Gita – “Now I am become Death, destroyer of worlds” – but nobody heard him say it on the day, so Nolan uses voiceover sleight of hand to acknowledge the ambiguity. Perhaps the line was a retrospective bid for gravitas, or a plea for forgiveness, and Oppenheimer was playing screenwriter with his own life. But it carries that deeper truth. Regardless of the globe-of-fire theory, or what Truman decided to do, Oppenheimer knew in that bright white moment that his work had radically changed the world, and might one day end it.

Everything Must Go: The Stories We Tell About the End of the World by Dorian Lynskey will be published in spring 2024.

Oppenheimer is on general release now

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