What Happened

In Washington last week, a U.S. mission, sent to Japan to study the action and effects of The Bomb, was still mulling over the evidence. Many facts remained secret, but those released gave the U.S. people a heart-stopping preview of atomic war.

For the first time, the U.S. people had some exact, scientific facts on what happened when The Bomb dropped on Hiroshima and Nagasaki. At about 1,800 feet above ground (Japanese figure), it turned into a blue-white ball of energy as bright as a thousand suns. Its initial temperature, if known, has not been told. (The figure, reading in millions or hundreds of millions of degrees, would be meaningless except to physicists.)

Out of that searing ball came a trip-hammer sequence of blows. First to reach he ground was the radiant heat, which moved with the speed of light (186,000 miles a second). Half a mile away, the heat set clothing and other light, inflammable substances instantly aflame. Dark objects absorbed more radiant heat than light ones. Many a Japanese was branded in stripes from the pattern on his shirt. The gay, flowered designs on the dresses of Japanese women were stenciled in charred exactitude upon their bodies. A mile and a half from the bomb, the flash of heat was strong enough to blister the ace or set a forest afire.

Shock & Blast. Next came the shock wave, essentially a sound wave and moving with the speed of sound. Close on its heels came a shattering blast of air displaced by The Bomb's expanding gases. The shock wave claimed its victims by squeezing their bodies, compressing their internal organs, puncturing their lungs. When the vacuum which followed it reached them, the gas in their stomachs and intestines expanded explosively, rupturing the tissues. Then came the blast, at 500 to 1,000 miles per hour, sweeping them over the ground, along with the churned-up rubble and blazing wood. At first, the blast was as hot as a flame. Even at 4,200 feet from the bomb-point, its pressure was 24 times greater than that of the 1926 Miami hurricane.

Light buildings were houses of cards for the heat and blast; they were burned up or swept away. Most factories collapsed completely. At Nagasaki, the heavy-brick Roman Catholic Church fell into rubble.

Gamma Rays. In both Hiroshima and Nagasaki a few modern buildings of heavy reinforced concrete stood up through the clean-swept desolation. Some military conservatives have pointed to them as proof that only flimsily built Japanese cities need fear atomic bombs.

Such optimism, said members of the mission, was not justified. On the inside, the surviving buildings were empty shells. Even when the fire had not burned them out, the blast had punched through the doors and windows, churning the interiors into hopeless ruin. Example: from a distance, the Nagasaki Medical School looked almost untouched; inside, it was a wreck.

In both stricken cities a few Japanese under shelter survived the heat and blast, only to die later from the invisible gamma rays. Striking through thick concrete, the rays disintegrated their blood cells, allowing raging infections to spread through their bodies (TIME. Feb. 4).

Now members of the mission, with growing uneasiness, were privately applying their knowledge to U.S. cities, to see how they would withstand an atomic bomb. The prospect was not pleasing. Experts, including leaders of the Manhattan Project, believed that buildings of timber or brick would be smashed or burned. Manhattan's stockiest skyscrapers might stand up, but many of their light "curtain walls" would be swept away, leaving only skeleton steel. In downtown New York, a single up-to-date bomb might kill a million people. Some might live for a while, eventually die by inches. Few U.S. buildings could give protection from the stealthy gamma rays.

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