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5.14 Major Developments in Science and Tech-nology During WWII

THE SCIENCE AND TECHNOLOGY OF WORLD WAR II

Resources from North Carolina Digital History (Learn NC) and the National WWII Museum discussing the advance-ments and innovations in science and technology resulting from World War II:

• The science and technology of World War II - North Carolina . . .• Science and Technology of WWII• How the Science and Technology of World War II Influences ...

WWII DEVELOPMENTS IN AVIATION

FIGURE 5.69Boeing B-17 "Flying Fortress" levels offfor a run over a target. Photo showsthe chin turret with .50 caliber machineguns featured in later models. The B-17 weighed about 60,000 lbs., carried abomb load of 6000 lbs., at a speed ofapproximately 300 miles per hour.

Military aircraft in World War II included bombers, fighters, and reconnaissance airplanes, as well as a limitednumber of cargo transports, gliders, blimps, and even jets. Aircraft of various kinds had played a highly visible,but relatively minor role in World War I, but during World War II they were arguably the most important weaponsdelivery system.

Both the primary aggressors in the war, Germany and Japan, launched their campaigns with heavy air strikes. TheGerman Luftwaffe, or air force, used fighters and dive-bombers to overrun Denmark and Holland early in the war,as a prelude to their capture of France. Fighters such as the Messerschmitt BF-109 and the Focke Wulf 190 provedto be formidable weapons. Then, improved bombers rained bombs on England in an attempt to knock this enemyout of the war. The British responded with advanced fighters such as the famous Spitfire, which was guided bythe new technology of radar. This was the Battle of Britain, a conflict fought entirely in the air and which forceda radical change in Germany’s war plans when they found themselves unable to dominate the British skies. Japanalso inaugurated its war on the U.S with an air attack. The Japanese used aircraft carriers, which had been in service

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since the 1920s in the famous Japanese surprise attack on Pearl Harbor, Hawaii, which destroyed most of the U.SPacific fleet using aircraft almost exclusively.

Technologically, military aircraft rapidly evolved during the war. The wood-and-fabric biplanes of the World War Iwere superseded by sleek aluminum airframes with powerful, often supercharged piston engines. While the Britishhad the Spitfire and the Germans the Messerschmitt, the U.S made innovations as well, developing the successfulP-51 Mustang in collaboration with the British, and introducing important innovations in long-range bombers, suchas the B-17 “Flying Fortress” and the famous B-29.

FIGURE 5.70A Royal Air Force Supermarine Spitfire (Britain) flies over Normandy,France during a reconnaissance mission.

Radically new types of aircraft also emerged. The Germans, English, and Americans began to experiment with jet-powered aircraft, with the Germans and British actually flying some combat missions in them. These new aircraftachieved very high speeds using the jet engine , a new type of engine that had no propellers. The Germans, and, toa lesser extent, the Americans even developed pilotless, guided missiles during the war, such as Germany’s V1 andV2 weapons. However, the bulk of aerial combat was conducted using propeller-driven, human-piloted fighters andbombers.

Over the course of the war, many important battles took place on land and at sea, but it is significant that many ofthe closing events of the war also depended on aircraft. Once the Allies began retaking territory in Europe, heavybombers began to attack within Germany. By destroying much of its ability to produce fuel and munitions, bombersturned the tide on the German war effort.

Finally, the large bombers developed late in the war, such as the B-29 were huge craft capable of delivering atomicbombs nearly anywhere in the world. The U.S used a B-29 called the Enola Gay in its final airborne attack—droppingthe atomic bomb on Japan. By the end of the war in 1945, fighters and bombers had been transformed into highlyeffective weapons systems. Today’s fighters and bombers use jet engines and remain central to military forces aroundthe world.

• A Collection of Articles on Naval Aviation in World War II

WWII WEAPONRY DEVELOPMENTS

Aircraft Carriers

Many of World War II’s greatest battles were fought at sea, making naval technologies crucial to all sides. Manykinds of ships, such as battleships, submarines, and aircraft carriers, had been used in previous wars, but the globalnature of World War II made naval battles especially important. These vessels ranged from heavily armed warshipsto numerous support craft such as fuel ships and troop landing boats. Of all the ships used in the war, aircraft carrierswere the largest.

An aircraft carrier is a ship whose primary purpose is to bring airplanes closer to distant battle areas. Since mostWorld War II aircraft had a range of just a few hundred miles, it was necessary to bring the aircraft to the battlefront,and using a ship to do so made a lot of sense in the Pacific where much of the fighting took place on islands andcoastal areas.

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FIGURE 5.71P-51 Mustangs - United States

FIGURE 5.72Boeing B-29 Superfortress

The first true aircraft carriers were built by the Japanese in the 1920s. Japan remained an innovator in aircraft carrierdesign and construction during the years leading to World War II, operating nine of them by 1941. Their largestcarriers of the war were the Akagi and Kaga, each capable of launching over 90 aircraft. The Allies, however, alsohad extremely effective carriers. British ships, such as the Ark Royal and the Eagle, and American ships, such asYorktown and Enterprise, each carried 100 aircraft or more. The largest aircraft carriers, such as the Enterprise wereover 800 feet (245 meters) long and 100 feet (30 meters) wide, and carried almost 3,000 crew members.

The first aircraft carriers had evolved from ordinary naval ships, which were fitted with landing strips built on theirdecks. By World War II, however, most aircraft carriers were designed for this purpose from the beginning. Small

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FIGURE 5.73B-29s dropping bombs over Japan

aircraft were usually stored below the deck and taken to the landing strip on elevators. Because the strip was short,a catapult (usually a piston-type device driven by steam from the ship’s boilers) helped launch the craft into the air.U.S carriers used a hook on the bottom of the plane to catch a wire, strung across the deck, which helped bring theplane to a halt. A central control tower located to the side of the landing strip housed advanced radio communicationand radar equipment used to keep in touch with aviators and track both friendly and enemy craft. Although theairplanes carried on these ships were not large enough to sink the larger “capital” ships (such as battleships) at thebeginning of the war, rapid improvements in carriers led to their becoming the major offensive naval weapon by1945.

The effectiveness of large aircraft carriers was demonstrated early in the war, when dozens of Japanese fightersand bombers, launched from aircraft carriers, decimated the U.S Pacific fleet at Pearl Harbor, Hawaii in late 1941.In May of 1942, aircraft from Japanese and U.S carriers battled at the Coral Sea, the first naval conflict wherethe opposing ships did not make contact. This battle resulted in the sinking of the Lexington. The JapaneseNavy also took heavy losses, most notably at the Battle of Midway in June 1942. There they lost four carriers

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FIGURE 5.74Aircraft lined up and awaiting deploymenton the USS Yorktown.

FIGURE 5.75The HMS Ark Royal circa early 1939. Courtesy: U.S National Archives.

and hundreds of airplanes—its naval power declined steadily after that. By contrast, ship production in the U.Saccelerated dramatically in 1944 and 1945, when dozens of aircraft carriers (and other ships) were completed. Mostcame too late to make a major difference in the war, and many ships on order were cancelled at the end of the war inmid-1945.

Today, nine countries possess aircraft carriers, although the United States and Great Britain are the only militaryforces that rely heavily on them. The Royal Navy currently has three, and the U.S has 12.

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FIGURE 5.76The sinking of the USS Lexington duringthe Battle of the Coral Sea. Crewmen canbe seen jumping overboard to escape theburning vessel.

The Atomic Bomb

From the online exhibit The Manhattan Project An Interactive History

Provided by the U.S. Department of Energy

In the early morning hours of August 6, 1945, a B-29 bomber named Enola Gay took off from the island of Tinianand headed north by northwest toward Japan. The bomber’s primary target was the city of Hiroshima, located on thedeltas of southwestern Honshu Island facing the Inland Sea. Hiroshima had a civilian population of almost 300,000and was an important military center, containing about 43,000 soldiers.

The bomber, piloted by the commander of the 509th Composite Group, Colonel Paul Tibbets, flew at low altitudeon automatic pilot before climbing to 31,000 feet as it neared the target area. At approximately 8:15 a.m. Hiroshimatime the Enola Gay released “Little Boy,” its 9,700-pound uranium bomb, over the city. Tibbets immediately doveaway to avoid the anticipated shock wave. Forty-three seconds later, a huge explosion lit the morning sky as LittleBoy detonated 1,900 feet above the city, directly over a parade field where soldiers of the Japanese Second Armywere doing calisthenics. Though already eleven and a half miles away, the Enola Gay was rocked by the blast. Atfirst, Tibbets thought he was taking flak. After a second shock wave (reflected from the ground) hit the plane, thecrew looked back at Hiroshima. “The city was hidden by that awful cloud. . . boiling up, mushrooming, terrible andincredibly tall,” Tibbets recalled. The yield of the explosion was later estimated at 15 kilotons (the equivalent of15,000 tons of TNT).

On the ground moments before the blast it was a calm and sunny Monday morning. An air raid alert from earlierthat morning had been called off after only a solitary aircraft was seen (the weather plane), and by 8:15 the city wasalive with activity — soldiers doing their morning calisthenics, commuters on foot or on bicycles, groups of womenand children working outside to clear firebreaks. Those closest to the explosion died instantly, their bodies turned toblack char. Nearby birds burst into flames in mid-air, and dry, combustible materials such as paper instantly ignitedas far away as 6,400 feet from ground zero. The white light acted as a giant flashbulb, burning the dark patterns ofclothing onto skin and the shadows of bodies onto walls. Survivors outdoors close to the blast generally describe aliterally blinding light combined with a sudden and overwhelming wave of heat. (The effects of radiation are usuallynot immediately apparent.) The blast wave followed almost instantly for those close-in, often knocking them fromtheir feet. Those that were indoors were usually spared the flash burns, but flying glass from broken windows filledmost rooms, and all but the very strongest structures collapsed. One boy was blown through the windows of hishouse and across the street as the house collapsed behind him. Within minutes 9 out of 10 people half a mile or lessfrom ground zero were dead.

People farther from the point of detonation experienced first the flash and heat, followed seconds later by a deafeningboom and the blast wave. Nearly every structure within one mile of ground zero was destroyed, and almost every

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FIGURE 5.77Enola Gay bombardier Thomas Ferebeewith the Norden Bombsight on Tinian afterthe dropping of Little Boy.

FIGURE 5.78A photograph of the mushroom cloud resulting from the explosion of theatomic bomb over Nagasaki, Japan, on August 8, 1945.

building within three miles was damaged. Less than 10 percent of the buildings in the city survived without anydamage, and the blast wave shattered glass in suburbs twelve miles away. The most common first reaction of thosethat were indoors even miles from ground zero was that their building had just suffered a direct hit by a bomb.Small ad hoc rescue parties soon began to operate, but roughly half of the city’s population was dead or injured. Inthose areas most seriously affected virtually no one escaped serious injury. The numerous small fires that eruptedsimultaneously all around the city soon merged into one large firestorm, creating extremely strong winds that blew

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towards the center of the fire. The firestorm eventually engulfed 4.4 square miles of the city, killing anyone who hadnot escaped in the first minutes after the attack. One postwar study of the victims of Hiroshima found that less than4.5 percent of survivors suffered leg fractures. Such injuries were not uncommon; it was just that most who couldnot walk were engulfed by the firestorm.

Even after the flames had subsided, relief from the outside was slow in coming. For hours after the attack theJapanese government did not even know for sure what had happened. Radio and telegraph communications withHiroshima had suddenly ended at 8:16 a.m., and vague reports of some sort of large explosion had begun to filter in,but the Japanese high command knew that no large-scale air raid had taken place over the city and that there wereno large stores of explosives there. Eventually a Japanese staff officer was dispatched by plane to survey the cityfrom overhead, and while he was still nearly 100 miles away from the city he began to report on a huge cloud ofsmoke that hung over it. The first confirmation of exactly what had happened came only sixteen hours later withthe announcement of the bombing by the United States. Relief workers from outside he city eventually began toarrive and the situation stabilized somewhat. Power in undamaged areas of the city was even restored on August 7th,with limited rail service resuming the following day. Several days after the blast, however, medical staff began torecognize the first symptoms of radiation sickness among the survivors. Soon the death rate actually began to climbagain as patients who had appeared to be recovering began suffering from this strange new illness. Deaths fromradiation sickness did not peak until three to four weeks after the attacks and did not taper off until seven to eightweeks after the attack. Long-range health dangers associated with radiation exposure, such as an increased dangerof cancer, would linger for the rest of the victims’ lives, as would the psychological effects of the attack.

No one will ever know for certain how many died as a result of the attack on Hiroshima. Some 70,000 peopleprobably died as a result of initial blast, heat, and radiation effects. This included about twenty American airmenbeing held as prisoners in the city. By the end of 1945, because of the lingering effects of radioactive fallout andother after effects, the Hiroshima death toll was probably over 100,000. The five-year death total may have reachedor even exceeded 200,000, as cancer and other long-term effects took hold.

At 11:00 a.m., August 6 (Washington D.C. time), radio stations began playing a prepared statement from PresidentTruman informing the American public that the United States had dropped an entirely new type of bomb onthe Japanese city of Hiroshima — an “atomic bomb.” Truman warned that if Japan still refused to surrenderunconditionally, as demanded by the Potsdam Declaration of July 26, the United States would attack additionaltargets with equally devastating results. Two days later, on August 8, the Soviet Union declared war on Japan andattacked Japanese forces in Manchuria, ending American hopes that the war would end before Russian entry into thePacific theater. By August 9th, American aircraft were showering leaflets all over Japan informing its people that“We are in possession of the most destructive explosive ever devised by man. A single one of our newly developedatomic bombs is actually the equivalent in explosive power to what 2,000 of our giant B-29s can carry on a singlemission. This awful fact is one for you to ponder and we solemnly assure you it is grimly accurate. We have justbegun to to use this weapon against your homeland. If you still have any doubt, make inquiry as to what happened toHiroshima when just one atomic bomb fell on that city.” Meanwhile, Tibbets’s bomber group was simply waiting forthe weather to clear in order to drop its next bomb, the plutonium weapon nicknamed “Fat Man” that was destinedfor the city of Nagasaki.

Nagasaki was an industrial center and major port on the western coast of Kyushu. As had happened at Hiroshima,the “all-clear” from an early morning air raid alert had long been given by the time the B-29 had begun its bombingrun. A small conventional raid on Nagasaki on August 1st had resulted in a partial evacuation of the city, especiallyof school children. There were still almost 200,000 people in the city below the bomb when it exploded. Thehurriedly-targeted weapon ended up detonating almost exactly between two of the principal targets in the city, theMitsubishi Steel and Arms Works to the south, and the Mitsubishi-Urakami Torpedo Works to the north. Had thebomb exploded farther south the residential and commercial heart of the city would have suffered much greaterdamage. In general, though Fat Man exploded with greater force than Little Boy, the damage at Nagasaki was notas great as it had been at Hiroshima. The hills of Nagasaki, its geographic layout, and the bomb’s detonation overan industrial area all helped shield portions of the city from the weapon’s blast, heat, and radiation effects. Theexplosion affected a total area of approximately 43 square miles. About 8.5 of those square miles were water, and

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33 more square miles were only partially settled. Many roads and rail lines escaped major damage. In some areaselectricity was not knocked out, and fire breaks created over the last several months helped to prevent the spread offires to the south.

Although the destruction at Nagasaki has generally received less worldwide attention than that at Hiroshima, it wasextensive nonetheless. Almost everything up to half a mile from ground zero was completely destroyed, includingeven the earthquake-hardened concrete structures that had sometimes survived at comparable distances at Hiroshima.According to a Nagasaki Prefectural report “men and animals died almost instantly” within 1 kilometer (0.62 miles)of the point of detonation. Almost all homes within a mile and a half were destroyed, and dry, combustible materialssuch as paper instantly burst into flames as far away as 10,000 feet from ground zero. Of the 52,000 homesin Nagasaki, 14,000 were destroyed and 5,400 more seriously damaged. Only 12 percent of the homes escapedunscathed. The official Manhattan Engineer District report on the attack termed the damage to the two Mitsubishiplants “spectacular.” Despite the absence of a firestorm, numerous secondary fires erupted throughout the city. Fire-fighting efforts were hampered by water line breaks, and six weeks later the city was still suffering from a shortageof water. A U.S. Navy officer who visited the city in mid-September reported that, even over a month after the attack,“a smell of death and corruption pervades the place.” As at Hiroshima, the psychological effects of the attack wereundoubtedly considerable.

FIGURE 5.79These two images show an aerial view ofthe city of Nagasaki, Japan before andafter the atomic bomb was dropped onAugust 9, 1945. The top image shows citybuildings and the second image showsthe same area but the buildings havebeen obliterated.

As with the estimates of deaths at Hiroshima, it will never be known for certain how many people died as a resultof the atomic attack on Nagasaki. The best estimate is 40,000 people died initially, with 60,000 more injured. ByJanuary 1946, the number of deaths probably approached 70,000, with perhaps ultimately twice that number deadtotal within five years. For those areas of Nagasaki affected by the explosion, the death rate was comparable to thatat Hiroshima.

The day after the attack on Nagasaki, the emperor of Japan overruled the military leaders of Japan and forced them

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to offer to surrender (almost) unconditionally.

• U.S. Aircraft Carriers of WWII• The atomic bomb - Learn NC• The Atomic Bomb and the End of World WarII• World War II.• 29177010-Encyclopedia-of-Weapons-of-World-War-II

WWII DEVELOPMENTS IN COMMUNICATION AND INFORMATION TECHNOLOGY

FIGURE 5.80Radar in operation in the second WorldWar / Signal Corps photo.

• Navigational technical advances• Radar During WWII - PBS• Radar During WWII• War of Secrets: Cryptology in WWII• WWII Communications Equipment

WWII DEVELOPMENTS IN MEDICINE

• History of WWII Medicine• Discovery and Development of Penicillin• Thanks to Penicillin Lesson Plan• Penicillin

WWII AND INDUSTRY

• THE WAR . At Home . War Production |PBS

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FIGURE 5.81Eight-rotor Enigma (Courtesy U.S. Na-tional Cryptologic Museum)

FIGURE 5.82Enigma in field

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FIGURE 5.83Inside the bulge under the bomber’s fuse-lage, a rotating dish bounced a signaloff the ground, creating a picture on thenavigator’s screen

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FIGURE 5.84By 1944, laboratories across the coun-try were stepping up their productionof penicillin, including Schenley in In-diana, whose advertisement stated that"When the thunderous battles of thiswar have subsided to pages of silentprint in a history book, the greatestnews event of World War II may well bethe discovery and development of peni-cillin." - Credit: Research and Devel-opment Division, Schenley Laboratories,Inc., Lawrenceburg, Indiana

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5.15 Tennessee’s Impact on World War II

TENNESSEE’S IMPACT ON WWII

FORT CAMPBELL BASE (CAMP CAMPBELL) - CLARKSVILLE, TN

FIGURE 5.85Company C, 702nd Tank Battalion "RedDevils", Camp Campbell, 1943

FIGURE 5.86A WAC is at work in the Ordnance Sec-tional Camp Campbell, Tennessee

• Fort Campbell - Official Website• Fort Campbell• Fort Campbell• POW Camps in WWII

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FIGURE 5.87This 1945 photograph shows the giant 44acre K-25 plant in Oak Ridge, Tennessee,where the uranium for the first atomicweapon was produced. (AP Photo/U.S.Department of Energy)

FIGURE 5.88Calutron operators at their panels, in theY-12 plant at Oak Ridge, Tennessee, dur-ing World War II. The calutrons were usedto refine uranium ore into fissile material.During the Manhattan Project effort toconstruct an atomic explosive, workerstoiled in secrecy, with no idea to what endtheir labors were directed. Gladys Owens,the woman seated in the foreground, didnot realize what she had been doing untilseeing this photo in a public tour of the fa-cility fifty years later. (Ed Westcott/DOE)

OAK RIDGE NUCLEAR FACILITIES - OAK RIDGE, TN

• The Secret City• Oak Ridge• Secret Atomic City in Tennessee Video - World War II History• Oak Ridge, the secret city• Oak Ridge National Laboratory

TVA (TENNESSEE VALLEY AUTHORITY)

• TVA Goes to War• Home-Front Defenders• Tennessee Valley Authority

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FIGURE 5.89A caultron "racetrack" uranium refinery atthe Y-12 plant in Oak Ridge, Tennessee,during the Manhattan Project. The light-colored bars along the top are solid silver.(Ed Westcott/DOE)

FIGURE 5.90The Tennessee Valley

ALCOA (ALUMINUM COMPANY OF AMERICA) - ALCOA, TN

• Alcoa Inc. Needed Electricity• Alcoa in the USA: The Alcoa Story (see World War II)• Alcoa, Inc.

CAMP FORREST - Tullahoma, TN

• Camp Forrest• Camp Forrest• CAMP FORREST• Camp Forrest: World War II-era memories• POW Camps in WWII

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FIGURE 5.91Norris Dam located near Knoxville, Ten-nessee; first to be completed on the TVAsystem. Located on the Clinch River.Anderson County (Tenn.), 1946.

FIGURE 5.92Aerial view of Soddy before it was floodedby TVA. ca. 1941

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FIGURE 5.93An aerial view of the Aluminum Companyof America (ALCOA), located in Alcoa,Tennessee.

FIGURE 5.94ALCOA (Aluminum Company of America)Aluminum Plant.

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FIGURE 5.95Aerial view of Camp Forrest. 1941

FIGURE 5.96Overview of Camp Forrest showing men, tents and trucks. 1943.

FIGURE 5.97Another aerial view of the new barrackslocated at Camp Forrest, Tullahoma, Ten-nessee. 1941

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FIGURE 5.98Camp Forrest entrance, c. 1942.

FIGURE 5.99Living quarters at Camp Forrest, c. 1942.

FIGURE 5.100Guard tower at Camp Forrest, c. 1942.

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5.16 Manhattan Project

THE MANHATTAN PROJECT

FIGURE 5.101This once classified photograph features the first atomic bomb — aweapon that atomic scientists had nicknamed "Gadget." The nuclear agebegan on July 16, 1945, when it was detonated in the New Mexico desert.

Early in 1939, the world’s scientific community discovered that German physicists had learned the secrets of splittinga uranium atom. Fears soon spread over the possibility of Nazi scientists utilizing that energy to produce a bombcapable of unspeakable destruction.

Scientists ALBERT EINSTEIN, who fled Nazi persecution, and ENRICO FERMI, who escaped Fascist Italy, werenow living in the United States. They agreed that the President must be informed of the dangers of atomic technologyin the hands of the Axis powers. Fermi traveled to Washington in March to express his concerns on governmentofficials. But few shared his uneasiness.

Einstein penned a letter to President Roosevelt urging the development of an atomic research program later that year.Roosevelt saw neither the necessity nor the utility for such a project, but agreed to proceed slowly. In late 1941, theAmerican effort to design and build an ATOMIC BOMB received its code name — the MANHATTAN PROJECT.

At first the research was based at only a few universities — Columbia University, the University of Chicago andthe University of California at Berkeley. A breakthrough occurred in December 1942 when Fermi led a group ofphysicists to produce the first controlled NUCLEAR Chain Reaction under the grandstands of Stagg Field at theUniversity of Chicago.

FIGURE 5.102Leaving nothing to chance, Los Alamos atomic scientists conducted a pre-test test in May 1945 to check the monitoring instruments. A 100-ton bombwas exploded some 800 yards from the Trinity site where Gadget wouldbe detonated a few weeks later.

After this milestone, funds were allocated more freely, and the project advanced at breakneck speed. Nuclearfacilities were built at Oak Ridge, Tennessee and Hanford, Washington. The main assembly plant was built atLos Alamos, New Mexico. Robert Oppenheimer was put in charge of putting the pieces together at Los Alamos.After the final bill was tallied, nearly $2 billion had been spent on research and development of the atomic bomb.The Manhattan Project employed over 120,000 Americans.

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Secrecy was paramount. Neither the Germans nor the Japanese could learn of the project. Roosevelt and Churchillalso agreed that the Stalin would be kept in the dark. Consequently, there was no public awareness or debate. Keeping120,000 people quiet would be impossible; therefore only a small privileged cadre of inner scientists and officialsknew about the atomic bomb’s development. In fact, Vice-President Truman had never heard of the ManhattanProject until he became President Truman.

FIGURE 5.103Enrico Fermi, a physicist who left fascist Italy for America, encouraged theU.S. to begin atomic research. The result was the top-secret "ManhattanProject."

Although the Axis powers remained unaware of the efforts at Los Alamos, American leaders later learned that aSoviet spy named Klaus Fuchs had penetrated the inner circle of scientists.

By the summer of 1945, Oppenheimer was ready to test the first bomb. On July 16, 1945, at Trinity Site nearAlamogordo, New Mexico, scientists of the Manhattan Project readied themselves to watch the detonation of theworld’s first atomic bomb. The device was affixed to a 100-foot tower and discharged just before dawn. No one wasproperly prepared for the result.

FIGURE 5.104This crater in the Nevada desert was created a 104 kiloton nuclear bombburied 635 feet beneath the surface. It is the result of a 1962 testinvestigating whether nuclear weapons could be used to excavate canalsand harbors.

A blinding flash visible for 200 miles lit up the morning sky. A mushroom cloud reached 40,000 feet, blowing outwindows of civilian homes up to 100 miles away. When the cloud returned to earth it created a half-mile wide cratermetamorphosing sand into glass. A bogus cover-up story was quickly released, explaining that a huge ammunitiondump had just exploded in the desert. Soon word reached President Truman in Potsdam, Germany that the projectwas successful. The world had entered the nuclear age.

THE DECISION TO DROP THE BOMB

America had the bomb. Now what? When Harry Truman learned of the success of the Manhattan Project, he knewhe was faced with a decision of unprecedented gravity. The capacity to end the war with Japan was in his hands, butit would involve unleashing the most terrible weapon ever known.

American soldiers and civilians were weary from four years of war, yet the Japanese military was refusing to give

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FIGURE 5.105Winston Churchill, Harry Truman, and Josef Stalin meet at the PotsdamConference. They discussed the post-war order and peace treaty issues.

up their fight. American forces occupied Okinawa and Iwo Jima and were intensely fire bombing Japanese cities.But Japan had an army of 2 million strong stationed in the home islands guarding against invasion.

For Truman, the choice whether or not to use the atomic bomb was the most difficult decision of his life.

FIGURE 5.106A "mushroom" cloud rises over the city of Nagasaki on August 9, 1945,following the detonation of "Fat Man." The second atomic weapon usedagainst Japan, this single bomb resulted in the deaths of 80,000 Japanesecitizens.

First, an Allied demand for an immediate unconditional surrender was made to the leadership in Japan. Although thedemand stated that refusal would result in total destruction, no mention of any new weapons of mass destruction wasmade. The Japanese military command rejected the request for unconditional surrender, but there were indicationsthat a conditional surrender was possible.

Regardless, on August 6, 1945, a plane called the Enola Gay dropped an atomic bomb on the city of Hiroshima.Instantly, 70,000 Japanese citizens were vaporized. In the months and years that followed, an additional 100,000perished from burns and radiation sickness.

FIGURE 5.107This map shows the range of the destruction caused by the atomic bombdropped over Hiroshima. Exploding directly over a city of 320,000, thebomb vaporized over 70,000 people instantly and caused fires over twomiles away.

Two days later, the Soviet Union declared war on Japan. On August 9, a second atomic bomb was dropped on

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Nagasaki, where 80,000 Japanese people perished. On August 14, 1945, the Japanese surrendered.

Critics have charged that Truman’s decision was a barbaric act that brought negative long-term consequences to theUnited States. A new age of nuclear terror led to a dangerous arms race.

Some military analysts insist that Japan was on its knees and the bombings were simply unnecessary. The Americangovernment was accused of racism on the grounds that such a device would never have been used against whitecivilians.

Other critics argued that American diplomats had ulterior motives. The Soviet Union had entered the war againstJapan, and the atomic bomb could be read as a strong message for the Soviets to tread lightly. In this respect,Hiroshima and Nagasaki may have been the first shots of the Cold War as well as the final shots of World War II.Regardless, the United States remains the only nation in the world to have used a nuclear weapon on another nation.

FIGURE 5.108On August 6, the city of Hiroshima, Japanremembers those who lost their liveswhen the atomic bomb fell. Thousands at-tend the Hiroshima Peace Memorial Cer-emony annually.

Truman stated that his decision to drop the bomb was purely military. A Normandy-type amphibious landingwould have cost an estimated million casualties. Truman believed that the bombs saved Japanese lives as well.Prolonging the war was not an option for the President. Over 3,500 Japanese kamikaze raids had already wroughtgreat destruction and loss of American lives.

The President rejected a demonstration of the atomic bomb to the Japanese leadership. He knew there was noguarantee the Japanese would surrender if the test succeeded, and he felt that a failed demonstration would be worsethan none at all. Even the scientific community failed to foresee the awful effects of Radiation Sickness. Trumansaw little difference between atomic bombing Hiroshima and Fire Bombing Dresden or Tokyo.

The ethical debate over the decision to drop the atomic bomb will never be resolved. The bombs did, however, bringan end to the most destructive war in history. The Manhattan Project that produced it demonstrated the possibilityof how a nation’s resources could be mobilized.

Pandora’s box was now open. The question that came flying out was, "How will the world use its nuclear capability?"It is a question still being addressed on a daily basis.

• History of the Atomic Bomb• The Decision to Drop the Atomic Bomb• Nagasaki Archive

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