In 1942, The first atomic pile, a sustained controllable nuclear chain reaction, came online in Chicago. Scientist and inventor Enrico Fermi remarked, “This will be remembered as the darkest day in history,“ referring to both the atomic pile and that day’s announcement of Nazi death camps operating in occupied Europe. Actually, most people have no knowledge of that day; they remember the ultimate achievement that began on that date - the atomic bomb.
The Manhattan Project - named because the first team started working in Manhattan - was started before the war began at the urging of Einstein and other scientists. The warning was terrifyingly simple - the best theoretical physics was being done in Germany. A weapon of unimaginable power is possible. If the Nazis get it first, it won’t matter what the size is of the Allied Armed Forces, they could be annihilated in nuclear fire.
But raids on the German uranium and heavy water production facilities showed they were far behind the American efforts. A comprehensive facility, secretly built in Los Alamos, was administrated by US Army General Leslie Groves and managed by civilian scientist Robert Oppenheimer. By 1944, they were developing an atomic weapon that would deliver a knockout blow to Nazi Germany.
But as the spring of 1945 ended, and the bomb moved from theory to reality, the scientists began to question whether it was necessary to develop a weapon. When the bomb was ready for testing in July 1945, a group of scientists, led by Leo Silzard, questioned if dropping the bomb was needed at all.
But the decision was already being made in favor of dropping the weapon on Japan. It was prepared for the B-29, a plane only operating in the Pacific Theatre of Operations. In Utah, The 504th composite group began practicing on dropping one bomb from a high altitude and turning around quickly. The pilots were sworn to secrecy without even knowing what the secret was.
On July 14, 1945, the bomb was detonated in a test in New Mexico. The scientists had no idea of how much explosive power the bomb would have; ideas ran from a dud to setting the atmosphere on fire. Edward Teller, after the war the father of American nuclear doctrine, had the highest guess: 1,000,000 tons of TNT. The bomb had the power of 20,000 tons of TNT. A cover story was that a munitions depot exploded. A blind woman claimed to see the atomic light from miles away; unfortunately, that was the last time anyone connected with nuclear weapons saw the light through blind eyes.
Within two weeks, the 504th Composite Group was ready to fly from Tinian to Japan and deliver its multimillion-dollar payload. From the list of targets that had been preserved for the test, the primary target of Hiroshima was selected. The B-29, “Enola Gay,“ piloted by the squadron commander, Col. Paul Tibbets, flew to Japan and dropped the bomb on August 6, 1945. The bomb was nicknamed “Little Boy” and used U-238 as its nuclear core.
At 8:15 AM, the line from Hiroshima to Tokyo went dead. Reports started coming in that Hiroshima had been obliterated by air attack. Reports of the dead ranged from 75,000 to 180,000 dead; due to radiation, people would be dying for decades from cancer and birth defects.
Controversy reigns about the use of the Hiroshima bomb. Some have argued that the naval blockade would have starved Japan into submission; others have argued that without the bomb, the millions of casualties expected with the invasion of the home islands would have become a reality. The source for that estimate has never been found.
What is certain is that Japan was preparing the bloodiest reception ever for the Allies if they had invaded Honshu, the southernmost island in Japan. Truman would never have been able to hold office if he had a working weapon and choose not to use it. Also, the Alliance between the Western powers and the Soviets was growing tenuous after the fall of Germany; Truman, an unknown quantity to the Soviets, had to show he was unafraid to use a weapon of mass destruction, especially one that only the United States possessed at that time.
What is not certain is the extent that the Japanese could have responded to the Allied unconditional surrender calls of August 6 and 7, 1945. The damage by conventional bombing to the transportation and communication network prevented the Japanese government from fully understanding what had happened in Hiroshima.
So the government did nothing, and on August 9, 1945, the B-29 “Bock’s Car” dropped the ”Fat Man” Plutonium bomb on Nagasaki, the tertiary target. This time the bomb was dropped slightly off target, which minimized the effects, the blast stopped by hills near Nagasaki. 70,000 people were killed, but again the aftereffects caused by radiation continued to kill for decades.
In the 1950’s the United States flew several Japanese women to have plastic surgery for their scars caused during the bombing. Ignored in this public relations tour was that thousands of Japanese carried radioactive scars that would be passed on to their children and would trouble them to this day.