When Harry Truman became the US president in April 1945, following the death of Franklin Roosevelt, he was taken aside by the War Secretary, Henry Stimson. America, Stimson told him, had been secretly developing “an explosive of almost unbelievable power”. Although he’d been vice- president for more than a year, it was the first Truman had heard of the atom bomb.

Meanwhile, in Hiroshima and Nagasaki, there was puzzlement as to why, with most other Japanese cities being bombed daily, theirs had remained untouched. (One theory in Nagasaki was that the West didn’t want to harm the city’s 12,000 Christians.) In fact, they’d been spared because the Americans wanted the targets for the new weapons to be “mostly intact, to demonstrate the awesome destructive power of an atomic bomb”.

This double perspective—from both the American and Japanese points of view—continues throughout Hiroshima Nagasaki. The research is meticulous, but, like Antony Beevor in Stalingrad and D-Day, Paul Ham (above right) always balances the political, military and scientific background with the human stories. The result is popular history at its most gripping.

Ham is no dispassionate chronicler. Some of the Americans involved did have moral qualms—but they kept them to themselves (and their diaries). “Total war,” notes Ham dryly, “had debased everyone.” More controversially, he doesn’t think the atom bombs were militarily necessary. The traditional defence is that an invasion of Japan might have cost a million American lives. But, according to Ham, an invasion wasn’t necessary either. Japan would have been defeated—perhaps was defeated—anyway.

And here’s one of the book’s many great set pieces. In the early hours of July 16, 1945, with the decision already taken to use the bomb, only one question remained: would it work? A group of military men and scientists from the “Manhattan Project” drove to the New Mexican desert to find out:

The newcomers went through the bomb drill, read aloud by torchlight. At the short siren—‘minus five minutes to Zero’—all observers were to prepare ‘a suitable place to lie down on’; at the long siren—‘minus two minutes to Zero’—all were ‘to lie prone on the ground…the head away from Zero’. Sunburn lotion was passed around. Welders’ goggles and special sunglasses were issued.

The mood wavered between faith and doubt. General Groves [the director of the Manhattan Project] thought of how he would react if the count reached zero and nothing happened. ‘I was spared that embarrassment,’ he later wrote. Nervous scientists prayed their own input would not be responsible for a dud. A hundred of them had placed bets on the force of the blast. Groves found the gambling distasteful; one scientist, in black comic mood, angered him by taking bets on whether the bomb would ignite the atmosphere and destroy New Mexico, or the world. In fact, Groves had warned the state governor that he might have to declare martial law if a disaster were to occur. As the deadline approached, everyone—‘Christian, Jew and Atheist’—prayed ‘harder than they had ever prayed before’.

The first man-made nuclear explosion detonated at 5.29 and 45 seconds. Within a millionth of a second the 32 detonation points on the outer sphere fired, triggering a chain reaction inside the plutonium core. Radiation waves fled the casing at the speed of light. Billions of neutrons liberated billions more in conditions that resembled ‘the universe moments after its first primordial explosion’. The nuclear dawn was visible 400 kilometres away in Santa Fe; a blind woman later claimed to have seen the light.

Every sign of life within a three-kilometre radius ceased to exist. The shock wave knocked down men standing at 16 kilometres. From the centre of the fireball a column of hot gases and radioactive dust shot into the sky and swelled outwards in the shape of the head of a jellyfish, a sight hitherto unseen. The head reached 12 kilometres and lingered.

Mutual congratulations and ‘restrained applause’—a few men indulged in a triumphant jig—greeted the success. Hushed murmurs ‘bordering on reverence’ followed. Understandably, words were inadequate and the moral conundrum too great: the chemist Henry Linschitz was reduced to asking himself, ‘My God, we’re going to drop that on a city?’ The scientists sought refuge in a litany of statistics and data: milliseconds after the blast the core temperature was 10,000 times that of the surface of the sun; the radioactive fallout was a million times stronger than the world’s radium supply; and so on.

‘The war is over,’ a colleague told Groves soon after the test.

‘Yes,’ Groves replied, ‘after we drop two bombs on Japan.’

Press releases were dispatched to quell local media interest: ‘Several inquiries have been received concerning an explosion this morning. A remotely located ammunition magazine exploded. There was no loss of life or injury to anyone.’ Thoroughly deceived, the New Mexican media relegated the incident to a routine news item.

Hiroshima Nagasaki by Paul Ham is published by Doubleday

Images: Creative Commons

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