evidence: That haul was richly deserved. Nolan pulled off an improbable coup, making a three-hour blockbuster about a physicist who supervised other physicists in the writing of equations. "Oppenheimer" has earned nearly $1 billion at the box office so far — and rightly been acclaimed as a great work of cinematic art. The movie’s biggest impact, however, is to make us look at — and think about — history that we’d rather pretend never happened. Its subject, J. Robert Oppenheimer, led the Manhattan Project, which created and tested the world’s first nuclear weapons. As Murphy’s portrayal vividly shows, Oppenheimer was haunted by his world-changing accomplishment. He had ensured that the United States and the Allies would win World War II — but at the cost of giving humanity the means to destroy itself. [...] There are some who argue that nuclear weapons, because of the unthinkable horror of using them, have paradoxically helped keep the peace. But we are at one of those moments when the world is dancing dangerously close to the edge: Russian troops being held at bay by NATO-supplied arms in Ukraine; China threatening a takeover of Taiwan; and Israel conducting an invasion of Gaza that is partly a proxy war against Iran. "Oppenheimer" reminds us how costly one false move could be.