Archive for August 6th, 2008

On July 26, 1945, the Allied leaders meeting in the Berlin suburb of Potsdam issued their final ultimatum to Japan:  accept unconditional surrender or suffer the complete destruction of the military and Japanese homeland.  Japan’s response, with its country in ruins, was complete and utter rejection.

And so President Truman faced horrible options.  Option 1…He could order the Army Air Force to drop the atomic bombs and hope for a Japanese surrender.  This was risky because the device to be used first was a U-235 bomb…which had never been fully tested (the Trinity Test used a Plutonium weapon).  Option 2…He could order the invasion of mainland Japan and, after the experience on Iwo Jima and Okinawa, face the prospect of millions of deaths on both sides and another year or more of fighting.  Option 3…He could order the bombs dropped and still be forced to invade (the Japanese leadership was extremely stubborn).

The President chose Option 1, hoping desperately to avoid Option 3.  And so, in the early morning hours of August 6, 1945, 3 B-29’s departed from Tinian with a primary target of Hiroshima and secondary targets of Kokura and Nagasaki.  At 8:15am, the B-29 Enola Gay dropped its single-bomb payload.  One minute later, while still in flight, cordite bags in the top of “Little Boy” exploded.  The explosion pushed a Tungsten-Carbide disk holding 9 U-235 disks (disks delivered by the ill-fated USS Indianapolis) down a short gun bore and into 6 more U-235 rings sitting on Polonium-Beryllium initiators.  An estimated 0.7kg of the total 64kg of U-235 underwent fission, and 0.6g (less than the weight of a small paper-clip) of mass was converted directly into energy.  And that was enough to generate an explosion equivalent to more than 26,000,000 pounds of TNT.

The Atomic Age, conceived in Chicago in 1942 and born on July 16th, took its first victims on August 6th.  The estimates vary, but 70,000+ immediate deaths is no stretch.  And thousands upon thousands more would die in the ensuing months and years from radiation.  Truman held his breath.  The U.S. Army held its breath.  Surely Japan’s military-led government would call for a halt to the fighting.

Recommended Reading: Shockwave: Countdown to Hiroshima – A must-read.

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