COULD ONE BOMB DESTROY THE WORLD?

How big a bang are arms manufacturers capable of creating?

- STEPHEN KELLY

There is a scene in Christopher Nolan's film Oppenheimer (a biopic of J Robert Oppenheimer, the man who invented the nuclear bomb) in which Leslie Groves, an army engineer played by Matt Damon, worries about destroying the world. This is just before the Trinity test, the first-ever detonation of an atomic bomb, and Oppenheimer says he's confident that the chances of annihilating all life on Earth are near zero. "Near zero?" splutters Groves. "Zero would be nice!"

In reality, Groves's concerns were those of Manhattan Project physicist Edward Teller. According to Steven Biegalski, Chair of Nuclear and Radiological Engineering at Georgia Institute of Technology, Teller was worried that the heat of the explosion "would cause the hydrogen in the atmosphere to undergo fusion, setting off a catastrophic chain reaction that would continue around the globe and destroy Earth". In other words: there was a fear that it would set the world on fire. "This obviously did not happen," adds Biegalski. "The density of fusible atoms and the energy balance prevent it from happening."