The Historic Atomic Bombing of Hiroshima and Nagasaki


On August 6, 1945, during World War II (1939-45), an American B-29 bomber dropped the world’s first deployed atomic bomb over the Japanese city of Hiroshima. The explosion wiped out 90 percent of the city and immediately killed 80,000 people; tens of thousands more would later die of radiation exposure. Three days later, a second B-29 dropped another A-bomb on Nagasaki, killing an estimated 40,000 people. Japan's Emperor Hirohito announced his country's unconditional surrender in World War II in a radio address on August 15, citing the devastating power of "a new and most cruel bomb."

Even before the outbreak of war in 1939, a group of American scientists--many of them refugees from fascist regimes in Europe--became concerned with nuclear weapons research being conducted in Nazi, Germany. In 1940, the U.S. government began funding its own atomic weapons development program, which came under the joint responsibility of the Office of Scientific Research and Development and the War Department after the U.S. entry into World War II. The U.S. Army Corps of Engineers was tasked with spearheading the construction of the vast facilities necessary for the top-secret program, codenamed "The Manhattan Project " (for the engineering corps' Manhattan district).

Over the next several years, the program's scientists worked on producing the key materials for nuclear fission--uranium-235 and plutonium (Pu-239). They sent them to Los Alamos, New Mexico, where a team led by J. Robert Oppenheimer worked to turn these materials into a workable atomic bomb. Early on the morning of July 16, 1945, the Manhattan Project held its first successful test of an atomic device--a plutonium bomb--at the Trinity test site at Alamogordo, New Mexico

By the time of the Trinity test, the Allied powers had already defeated Germany in Europe. Japan, however, vowed to fight to the bitter end in the Pacific, despite clear indications (as early as 1944) that they had little chance of winning. In fact, between mid-April 1945 (when President Harry Truman took office) and mid-July, Japanese forces inflicted Allied casualties totaling nearly half those suffered in three full years of war in the Pacific, proving that Japan had become even more deadly when faced with defeat. In late July, Japan's militarist government rejected the Allied demand for surrender put forth in the Potsdam Declaration, which threatened the Japanese with "prompt and utter destruction" if they refused.

General Douglas MacArthur and other top military commanders favored continuing the conventional bombing of Japan already in effect and following up with a massive invasion, codenamed "Operation Downfall." They advised Truman that such an invasion would result in U.S. casualties of up to 1 million. In order to avoid such a high casualty rate, Truman decided--over the moral reservations of Secretary of War Henry Stimson, General Dwight Eisenhower and a number of the Manhattan Project scientists--to use the atomic bomb in the hopes of bringing the war to a quick end. Proponents of the A-bomb--such as James Byrnes, Truman's secretary of state--believed that its devastating power would not only end the war, but also put the U.S. in a dominant position to determine the course of the postwar world.

Hiroshima, a manufacturing center of some 350,000 people located about 500 miles from Tokyo, was selected as the first target. After arriving at the U.S. base on the Pacific island of Tinian, the more than 9,000-pound uranium-235 bomb was loaded aboard a modified B-29 bomber christened Enola Gay (after the mother of its pilot, Colonel Paul Tibbets). The plane dropped the bomb--known as "Little Boy"--by parachute at 8:15 in the morning, and it exploded 2,000 feet above Hiroshima in a blast equal to 12-15,000 tons of TNT, destroying five square miles of the city.

Hiroshima's devastation failed to elicit immediate Japanese surrender, however, and on August 9 Major Charles Sweeney flew another B-29 bomber, Bockscar, from Tinian. Thick clouds over the primary target, the city of Kokura, drove Sweeney to a secondary target, Nagasaki, where the plutonium bomb "Fat Man" was dropped at 11:02 that morning. More powerful than the one used at Hiroshima, the bomb weighed nearly 10,000 pounds and was built to produce a 22-kiloton blast. The topography of Nagasaki, which was nestled in narrow valleys between mountains, reduced the bomb's effect, limiting the destruction to 2.6 square miles.

At noon on August 15, 1945 (Japanese time), Emperor Hirohito announced his country's surrender in a radio broadcast. The news spread quickly, and "Victory in Japan" or "V-J Day" celebrations broke out across the United States and other Allied nations. The formal surrender agreement was signed on September 2, aboard the U.S. aircraft carrier Missouri, anchored in Tokyo Bay.



Detailed Account

 At 2:45 a.m. on Monday, August 6, 1945, a B-29 bomber, the Enola Gay, took off from Tinian, a North Pacific island in the Marianas, 1,500 miles south of Japan. The twelve-man crew  were on board to make sure this secret mission went smoothly. Colonel Paul Tibbets, the pilot, nicknamed the B-29 the "Enola Gay" after his mother. Just before take-off, the plane's nickname was painted on its side.The Enola Gay was a B-29 Superfortress (aircraft 44-86292), part of the 509th Composite Group. In order to carry such a heavy load as an atomic bomb, the Enola Gay was modified: new propellers, stronger engines, and faster opening bomb bay doors. (Only fifteen B-29s underwent this modification.) Even though it had been modified, the plane still had to use the full runway to gain the necessary speed, thus it did not lift off until very near the water's edge.

The Enola Gay was escorted by two other bombers that carried cameras and a variety of measuring devices. Three other planes had left earlier in order to ascertain the weather conditions over the possible targets.On a hook in the ceiling of the plane, hung the ten-foot atomic bomb, "Little Boy." Navy Captain William S. Parsons ("Deak"), chief of the Ordnance Division in the "Manhattan Project," was the Enola Gay's weaponeer. Since Parsons had been instrumental in the development of the bomb, he was now responsible for arming the bomb while in-flight. Approximately fifteen minutes into the flight (3:00 a.m.), Parsons began to arm the atomic bomb; it took him fifteen minutes. Parsons thought while arming "Little Boy": "I knew the Japs were in for it, but I felt no particular emotion about it."2"Little Boy" was created using uranium-235, a radioactive isotope of uranium. This uranium-235 atomic bomb, a product of $2 billion of research, had never been tested. Nor had any atomic bomb yet been dropped from a plane. Some scientists and politicians pushed for not warning Japan of the bombing in order to save face in case the bomb malfunctioned.There had been four cities chosen as possible targets: Hiroshima, Kokura, Nagasaki, and Niigata (Kyoto was the first choice until it was removed from the list by Secretary of War Henry L. Stimson). The cities were chosen because they had been relatively untouched during the war. The Target Committee wanted the first bomb to be "sufficiently spectacular for the importance of the weapon to be internationally recognized when publicity on it was released."

 On August 6, 1945, the first choice target, Hiroshima, was having clear weather. At 8:15 a.m. (local time), the Enola Gay's door sprang open and dropped "Little Boy." The bomb exploded 1,900 feet above the city and only missed the target, the Aioi Bridge, by approximately 800 feet.Staff Sergeant George Caron, the tail gunner, described what he saw: "The mushroom cloud itself was a spectacular sight, a bubbling mass of purple-gray smoke and you could see it had a red core in it and everything was burning inside. . . . It looked like lava or molasses covering a whole city. . . ." The cloud is estimated to have reached a height of 40,000 feet.Captain Robert Lewis, the co-pilot, stated, "Where we had seen a clear city two minutes before, we could no longer see the city. We could see smoke and fires creeping up the sides of the mountains. Two-thirds of Hiroshima was destroyed. Within three miles of the explosion, 60,000 of the 90,000 buildings were demolished. Clay roof tiles had melted together. Shadows had imprinted on buildings and other hard surfaces. Metal and stone had melted.Unlike many other bombing raids, the goal for this raid had not been a military installation but rather an entire city. The atomic bomb that exploded over Hiroshima killed civilian women and children in addition to soldiers. Hiroshima's population has been estimated at 350,000; approximately 70,000 died immediately from the explosion and another 70,000 died from radiation within five years.While the people of Japan tried to comprehend the devastation in Hiroshima, the United States was preparing a second bombing mission.

  The second run was not delayed in order to give Japan time to surrender, but was waiting only for a sufficient amount of plutonium-239 for the atomic bomb. On August 9, 1945 only three days after the bombing of Hiroshima, another B-29, Bock's Car (picture of crew), left Tinian at 3:49 a.m.The first choice target for this bombing run had been Kokura. Since the haze over Kokura prevented the sighting of the bombing target, Bock's Car continued on to its second target. At 11:02 a.m., the atomic bomb, "Fat Man," was dropped over Nagasaki.

 The atomic bomb exploded 1,650 feet above the city.Fujie Urata Matsumoto, a survivor, shares one scene: The pumpkin field in front of the house was blown clean. Nothing was left of the whole thick crop, except that in place of the pumpkins there was a woman's head. I looked at the face to see if I knew her. It was a woman of about forty. She must have been from another part of town -- I had never seen her around here. A gold tooth gleamed in the wide-open mouth. A handful of singed hair hung down from the left temple over her cheek, dangling in her mouth. Her eyelids were drawn up, showing black holes where the eyes had been burned out. . . . She had probably looked square into the flash and gotten her eyeballs burned.7Approximately 40 percent of Nagasaki was destroyed. Luckily for many civilians living in Nagasaki, though this atomic bomb was considered much stronger than the one exploded over Hiroshima, the terrain of Nagasaki prevented the bomb from doing as much damage. Yet the decimation was still great. With a population of 270,000, approximately 70,000 people died by the end of the year.I saw the atom bomb. I was four then. I remember the cicadas chirping. The atom bomb was the last thing that happened in the war and no more bad things have happened since then, but I don't have my Mummy any more.