The nuclear bombing of Hiroshima and Nagasaki

                   

This article is taken directly from Volume Two of my memories titled “Whistling in the Face of Robbers” beginning at page 224. I was eleven years old when the two bombs were dropped. Please note that the paragraphs in my book are indented. I am placing this article in my blog on Sunday August 9th because that day is the 70th anniversary of the atomic bomb exploding over Nagasaki, Japan. 

The United States exploded the first atomic device at a site near Alamogordo, New Mexico. At 5:30 am, July 16, 1945, scientists from Los Alamos, watching from observation bunkers 10,000 yards (6.2 miles) away that were south of the tower holding the atomic device exploded it with a plutonium core, releasing a blast equivalent to 18,600 tons of TNT. The Trinity Test, as it was called, vaporized the metal tower from which the device was exploded and turned the sand around the base of the tower into glass. A brigadier general who had observed the test from one of the bunkers later wrote, “The whole country was lighted by a searing light with the intensity many times that of the mid-day sun. Thirty seconds after the explosion came, the air blast pressing hard against people and things, to be followed almost immediately by a strong sustained awesome roar which warned of doomsday and made us feel that we puny things were blasphemous to dare tamper with forces heretofore reserved to the Almighty. ”The blast following the explosion sent searing heat across the desert and knocked some of the observers to the ground. It also knocked over a 200-ton steel container half a mile from ground zero.                                        

On the evening of 16^th of July during Truman's second day at Potsdam, he received a cryptic notification that the atomic bomb had been successfully tested early that morning at Alamogordo, New Mexico. On the 21^st he received via special courier a detailed report on the test results from General Leslie Groves, the head of the project.                                                            

On August 1, 1945, five days before the bombing of Hiroshima, the U.S. Army Air Force dropped one million leaflets over Hiroshima, Nagasaki, and 33 other Japanese cities warning that those cities were going to be destroyed within a few days and advising the residents to leave to save their lives. One side of the leaflet had a photo of five U.S. bombers unloading bombs and a list of the targeted cities.                                                       

The people of Japan were well aware of the destructive power of American bombers since they knew how much of Tokyo was heavily destroyed by US bombs raining on that city. The message in the leaflets in Japanese was as follows;                                                                                                                       

“Read this carefully as it may save your life or the life of a relative or friend. In the next few days, some or all of the cities named on the reverse side will be destroyed by American bombs. These cities contain military installations and workshops or factories which produce military goods. We are determined to destroy all of the tools of the military clique which they are using to prolong this useless war. But, unfortunately, bombs have no eyes. So, in accordance with America’s humanitarian policies, the American Air Force, which does not wish to injure innocent people, now gives you warning to evacuate the cities named and save your lives. America is not fighting the Japanese people but is fighting the military clique which has enslaved the Japanese people. The peace which America will bring will free the people from the oppression of the military clique and mean the emergence of a new and better Japan. You can restore peace by demanding new and good leaders who will end the war. We cannot promise that only these cities will be among those attacked but some or all of them will be, so heed this warning and evacuate these cities immediately.”                              

Newspapers and leaflets in the Japanese language were printed on Saipan. From there, Air Force B-29s flying at 20,000 feet dropped 500-pound M-16 fire bomb containers converted into leaflet casings. These opened at 4,000 feet to deploy millions of leaflets, effectively covering a whole Japanese city with information. In just the last three months of formal psychological warfare, the American Office of War Information (OWI) produced and deployed over 63 million leaflets informing the Japanese people of the true status of the war and providing advance warning to 35 cities targeted for destruction.                                            

There is no question that the Allies’ superior military power and determined spirit defeated Japan. But it was the Allies’ communication network that provided war information directly to the Japanese people and an unprecedented response by the Emperor that pushed Japan to accept its defeat.                                                                                                               

From Saipan which was captured by the U.S. in July 1944 OWI bombarded Japan with radio messages through its 50,000-watt standard-wave station on Saipan, Radio KSAI. The station also picked up 100,000-watt shortwave transmissions from the OWI station in Honolulu and relayed them to Japan. Japanese language broadcasts consisted of news on the status of the war, bombing warnings, and messages from Japanese prisoners of war on Saipan urging surrender. KSAI radio transmissions served many purposes: to Japan’s civilian government, they were a vital source of news, received at a time when the fanaticism of the Japanese militarists denied civilian leaders access to information about the status of the war. The broadcasts were also aimed towards hidden Japanese soldiers on occupied Pacific islands by tempting them to surrender by promising them fair treatment as prisoners of war.                                                                       

There is no doubt in my mind whatsoever that the Japanese civilians and probably most of the members of the Japanese armed forces were keen on surrendering since the war had cost them enormous losses of Japanese lives. Even though surrender would be a shameful act, as far as they were concerned, enough was enough.                                                                    

Postwar surveys showed that the Japanese people trusted the accuracy of the leaflets and many residents of the targeted cities prepared immediately to leave their homes. However, the Japanese government regarded the leaflets with such concern that it ordered the arrest of those who kept or even read the leaflets and did not turn them in to their local police stations.                                                                                                                 

Japan had two governments in 1945—a military government determined to fight to the last and the other was a civilian government that had long recognized the need to surrender. The military clearly held the upper hand, rendering the civilian leaders impotent through political intimidation and threats of imprisonment. Civil-military friction, disagreements within political factions, and intergenerational tensions resulted in a bewildering array of conflicting reports on current conditions being disseminated to the Japanese people.                                                        

There is little doubt in anyone’s mind today that Japanese government agencies, military and civilian alike, realized by mid-summer of 1945 that their country could not win the war. Japan’s cities were being destroyed almost at will. Although attempting to avoid the Emperor’s palace, the Allies had devastated Tokyo in only six hours of bombing on 9-10 March 1945, leaving 100,000 dead and over 1,000,000 homeless, an even worse toll than from the later atomic bombing of Hiroshima. 

And yet, the Japanese military maintained a defiant stance, even as they recognized the need to shift from aggression to defense of their homeland. They were well prepared, both psychologically and technically, for this final stand. The Americans never underestimated the desire of Japan’s military leaders to preserve their honor by fighting literally to the last man, woman, and child. It was because of this military stance of the Japanese military leaders that the Americans believed that the use of atomic bombs would bring a quick end of the war with Japan and at the same time, save millions of Japanese lives and the lives hundreds of thousands of American soldiers.                                 

On the 26^th of July, 1945, the heads of state of the United States, Great Britain, and the Soviet Union, meeting in Potsdam, Germany, agreed to give Japan an opportunity to end the war. Their terms called for the disarmament and abolition of the Japanese military; elimination of military influence in political forums; Allied occupation of Japan; liberation of Pacific territories gained by Japan since 1914; swift justice for war criminals; maintenance of non-military industries; establishment of freedom of speech, religion and thought; and introduction of respect for fundamental human rights. The final section demanded that the government of Japan “proclaim now the unconditional surrender of all Japanese armed forces.” The alternative for Japan was “prompt and utter destruction.                                                                                                            

The terms of the surrender were passed on to Japan by official communication sent through diplomatic channels. 

                                                     

Despite the warnings of utter destruction of the major cities of Japan and the terms of surrender being passed onto to the Japanese officials, the Japanese military leaders stubbornly refused to accept the unconditional surrender of their armed forces.  

                                                                         

The Truman administration finally realized that the Japanese were not accepting of the Potsdam Declaration that demanded an unconditional surrender by Japan. The Japanese had asked Russia to act as intermediary for them at the Potsdam Conference. However, unbeknownst to the Japanese, the Soviet Union was about to enter the war against them. Consequently, Stalin did not convey to the Americans all of the questions and concerns the Japanese had. One major question was the preservation of their Emperor as head of Japan if they surrendered. But this was never made clear to Churchill and Truman and the harsh statement coming from the conference is what resulted. However, President Truman was well aware of the importance of the role the Emperor of Japan with the Japanese people so he convinced the other Allied leaders that Emperor Hirohito would remain as the Emperor of Japan.   

                                                     

At 2:45 a.m. on the 6^th of August, the American B-29 superfortress bomber Enola Gay left the island of Tinian near Saipan. Its target was Hiroshima, where the 2nd Japanese Army stood poised to defend Japan against an expected Allied invasion of their homeland. As the Enola Gay came within sight of the Japanese mainland, the pilot, Tibbets began the climb to the drop altitude above 30,000 feet.  

                                                             

The first atomic bomb was then dropped on August 6, 1945 when a B-29 bomber (Enola Gay) released its 9,700-pound uranium bomb, nicknamed Little Boy, over the city of Hiroshima in southern Japan. Hiroshima was an important military and communications center with a population of 300,000. It was also the only primary target city thought not to have American prisoners in that city. The bombardier’s target was the T-shaped Aioi Bridge in the center of the city.  

                                                                

The atomic bomb Little Boy was a gun type of bomb. At one end of a gun’s barrel was a Uranium-235 target shaped like a sphere with a conical wedge removed from it. Another cone-shaped bullet of U-235 was at the other end with its point toward the gap in the target. The bullet was fired by the charge of cordite at a set altitude after dropping. The force of the impact would weld the two pieces of uranium together. The fused mass was sufficient to go critical resulting in a runaway cascade of fishioning uranium atoms. The explosion would follow instantly. 

                                                          

The bomb was detonated 1,900 feet—a third of a mile (580 metres—0.58 kilometres) above the city, killing 80,000 people instantly and injuring another 35,000. Later 60,000 would die from radiation poisoning. The bomb devastated everything within five square miles.   

                                              

The blast from the atomic bomb’s explosion only lasted for one-half of a second, but in this amount of time, a great deal of damage was done. The fireball had a radius of 180 metres (590 feet). It vaporized every living being in that immediate area. The subsequent air blast radius was 340 metres (1,115 feet). As the gasses expanded, a blast wave was produced. As this blast wave moved outward, it created static overpressure. This static overpressure then in turn created dynamic pressure. The static overpressure had the power to crush buildings. The dynamic pressure created winds which had the power to blow down trees and small buildings. The blast pressure and fireball together only lasted for approximately eleven seconds, but because it contained fifty percent of the atomic bomb’s latent energy, a great deal of destruction occurred. The bomb explosion was equivalent to 15 thousand tons of TNT.  

                                                                  

The blast from the atomic bomb in Hiroshima was measured to be about four and a half to six and seven tenths tons of pressure per square metre.                                                                                                                        

Because of this dramatic change in the pressure, most sections of the cities were destroyed. The static overpressure in Hiroshima caused almost ninety-two percent of all the buildings to be destroyed. The static overpressure created a dynamic pressure that had winds up to four hundred miles (643 kilometres) per hour—far more than a class f-5 tornado. 

These winds caused serious cuts, scratches, lacerations and/or compound fractures, which came about when people and glass fragments were projected through the air. By combining the results of the static overpressure and the dynamic pressure, one can begin to see what damage was caused by the atomic bomb’s blast. 

                                                                             

The thermal radiation produced by the atomic bomb explosion accounted for thirty-five percent of the atomic bomb’s damage. Thermal radiation can come in either one of three forms; ultraviolet radiation, visible radiation, or infrared radiation. The ultraviolet radiation is absorbed so rapidly by air particles that it has no substantial effect on people. However, the visible and infrared radiation creates an enormous amount of heat to be produced, approximately ten million degrees Celsius at the centre of the fireball.   

                                                                                           

This kind of heat has two main effects. The first is known as flash burns. These flash burns are produced by the flash of thermal radiation right after the explosion. Flash burns can be either first degree burns (bad sun burns), second degree burns (blisters, infections, and scars), or third degree burns (destroyed skin tissue and flesh). The second type is known as flame burns. These are burns that come from one of two different types of fires, which are created when flammable materials are ignited by the thermal radiation. There are two kinds of raging fires. The first type is called firestorms. A firestorm is violent, has raging winds, and has extremely high temperatures; but fortunately it does not spread very rapidly. The second type is called a conflagration. A conflagration is when the fire spreads everywhere. The thermal radiation produced by the atomic bomb’s explosion accounted for most of the deaths or injuries. In Hiroshima and Nagasaki the thermal radiation accounted for approximately twenty to thirty percent of the deaths or injuries from the atomic bomb’s explosion. 

                                                                           

Those who survived and who were at a distance of four kilometers from the hypocenter received first degree burns. Those that were at a distance of only three and one half kilometers (2.5 miles) from the hypocenter received second degree burns.  Those that were at a distance of only ninety-seven hundredths of a kilometer from the hypocenter received third degree burns and only if they were deep inside an enclosed  building. Ninety-five percent of the burns created from the thermal radiation were by flash burns, and only five percent of the burns were by direct flame burns. The reason for this low number of flame burns is that only two to ten percent of the buildings actually caught on fire.                                                     

By combining the damage from both the flash and flame burns one can begin to see the effects that an atomic bomb’s thermal radiation had. Approximately eighty thousand people were killed in Hiroshima from their injuries.                                                                                                                             

The final effect that an atomic bomb caused was the nuclear radiation produced from the fission process. The nuclear radiation came in the form of either Gamma rays or Beta particles. Gamma rays are electromagnetic radiation originating in the atomic nuclei, physically identical to x-rays. They can enter into living tissue extremely easily and destroy the cells. Beta particles are negatively charged particles, identical to an electron moving at a high velocity. These forms of nuclear radiation are measured in RADs (radiation-absorbed-dose), which is defined as the absorption of five ten millionths joule per gram of material. During the initial nuclear radiation, mostly Gamma rays were emitted from the fireball. This period of initial nuclear radiation lasts for approximately one minute. During the residual nuclear period (fallout) the Beta particles and more of the Gamma rays are emitted. The residual radiation has two stages: early fallout and delayed fallout. In early fallout, the heavy and highly radioactive particles fall back to the earth, usually within the first twenty-four hours. In delayed fallout, the tiny and often invisible particles fall back to the earth, and usually last from a couple of days but can last several years. The nuclear radiation from the atomic bomb’s explosion was not the main cause of death, but it did still have serious results. In Hiroshima, the initial nuclear radiation was spread over a distance of approximately fifty-three hundredths of a kilometer. In Nagasaki, the initial nuclear radiation only spread one and six thousandths of a kilometer. The reason why the nuclear radiation was not the main caused of deaths or injuries was that the atomic bomb was detonated so high in the atmosphere; approximately five hundred and seventy meters (1,900 feet in Hiroshima, and approximately five hundred and ten meters). In Nagasaki, the bomb exploded 1,673 feet—just under a third of a mile (half a kilometre) above the city. Even without causing many immediate deaths, the nuclear radiation probably caused the most serious effects. Those who suffered the effects of nuclear radiation were those who suffered from cataracts, leukemia, cancer of the thyroid, cancer of the breast, cancer of the lungs, cancer of the stomach, and mental retardation on babies in-utero. Others suffered from tumors of the esophagus, tumors of the colon, tumors of the salivary glands, and tumors of the urinary tract organs. Those who suffered the least were those who experienced increased rates of birth mortality, birth defects, infertility, and susceptibility towards illnesses. The total number of people affected by the nuclear radiation was estimated to be thirty-five thousand people in Hiroshima, and twenty-one thousand people in Nagasaki. It was the blast, the thermal radiation, and the nuclear radiation from an atomic bomb explosion that had severe effects on both humans and on the environment in which they lived in.  

                                           

Meanwhile two senior American military figures—General Groves and Admiral Purnell were convinced that two atomic bombs dropped within days of the other would have such an overwhelming impact on the Japanese government that it would surrender. President Truman agreed with them.                                                                                                     

Nagasaki was not America’s primary target. It was Kokura. The three potential targets for a second bomb were Kokura, Kyoto and Niigata. Nagasaki was only added to a list of potential targets when Kyoto was withdrawn because of its religious associations although it had originally been the secondary target for a second bomb. The third potential target was Niigata but this was withdrawn from the list as the distance to it was considered to be too great. Therefore, the Americans were left with just two targets—Kokura and Nagasaki and they chose Nagasaki. 

                         

Nagasaki was a major shipbuilding city and a large military port. But it was not a favoured target as it had been bombed five times in the previous twelve months and any damage caused by an atomic bomb would have been difficult to assess. Also, the way Nagasaki had grown as a port meant that the impact of a powerful bomb might be dissipated as the city had grown across hills and valleys. The city was also broken up with stretches of water.   

                                                                                       

Whereas the Enola Gay  had had a relatively uneventful journey to her target at Hiroshima, the same was not true for the plane picked to drop the next atomic bomb.  It was named Bockscar. Both Bockscar and Enola Gay were B29 Superfortress bombers. The crew of Bockscar gathered for their takeoff at 03.40 hours, August 9th, at Tinian Island. The flight commander, Major Sweeney, found that one of the fuel pumps on the B29 was not working. For this reason, 800 gallons of aviation fuel had to sit in its fuel tank since it could not be used for the engines. The plane had to carry its weight and get nothing in return from the fuel.  

                               

Bockscar carried an atomic bomb that differed from Little Boy. The second bomb was quite fat whereas the first bomb was slim. The second bomb was obviously called Fat Man. 

                                                                  

Fat Man was not a gun-type bomb but instead it used the implosion method by having a circle of 64 detonators that would drive pieces of plutonium together into a supercritical mass.  

                                                   

Fat Man weighed about 10,000 lbs and was 10 feet 8 inches long. It had the explosive capacity of about 20,000 tons of high explosives (TNT). 

           

By the time Bockscar got near to its primary target, Kokura, it became clear that the weather had saved the city. The city was covered by cloud. Pilot Sweeney made three runs over the city but could find no break in the clouds. With lack of fuel being an issue, he decided to move to his only other target which was Nagasaki. Sweeney only had enough fuel for one run over the city and not enough to fly back to Tinian. He would have to land at Okinawa.                                                                                                                    

The bombardier targeted a race track and at 28,900 feet, Fat Man was dropped. As Nagasaki had been targeted in the past, people in the city had become blasé when the air raid siren sounded. The same was true on August 9^th. The irony was that Nagasaki was well served with good bomb shelters and far fewer people would have been killed or injured if the air raid sirens hadn’t been ignored. The surrounding hills had tunnels dug into them which would have been very effective for the people who could have reached them. 

                                                                                                                   

Fat Man was a very effective bomb. Its blast was bigger than Little Boy’s but its impact was reduced by the natural topography of the city. Where the bomb blast hit at its peak, massive damage was done. An area about 2.3 miles by 1.9 miles was destroyed but other parts of the city were saved from the blast. Curiously, the city’s train service was not interrupted and the fire damage that followed Hiroshima did not occur in Nagasaki as many parts of the city were broken up by water. The fires simply could not cross these gaps so they burned out. The fireball radius was 200 meters (656 feet) and its air blast radius was 180 meters (1,115 feet). In Nagasaki, the total number killed was eighty thousand. The total number severely injured was seventy-four thousand nine hundred and nine. The total number slightly injured was one hundred and twenty thousand eight hundred and twenty.                                                                                                           

The foremost characteristic of the physical damages caused by the Nagasaki atomic bombing was the tremendous, instantaneous destruction wreaked by the blast wind and the subsequent fires. These fires broke out simultaneously with the destruction of buildings over a wide area. The complete destruction and burning of wooden buildings extended beyond a distance of two kilometers from the Nagasaki hypocenter. The fierce blast wind, heat rays reaching several thousand degrees, and deadly blast and radiation generated by the explosion crushed, burned and killed everything in sight and reduced a third of the city into a barren field of rubble.  

                      

This kind of horror has put fear in the minds of government officials around the world and that is why that since 1945, no more of those such bombs have been dropped on any city in the world. However what is frightening is that there are as many as eleven countries that currently have nuclear bombs in their arsenals. All told, there are approximately 15,695 nuclear warheads with a destructive capacity of 5,000 megatons (5,000 million tons of TNT) stored around the world. That is enough to kill almost everyone in the world. The stupidity of making that many nuclear bombs is mind boggling especially when you consider that it is conceivable that if one of those bombs falls from the air onto a city, more will follow and just as dominoes fall, one after another will continue to fall until all those bombs have exploded and killed billions in the holocaust, effectively wiping out most of the human beings on Earth and most of the animals on Earth also. 

          

In 1969, Russia detonated a 50 megaton nuclear bomb that is equivalent to 50 million tons of TNT. If such a bomb was dropped on Toronto, it would literally destroy every building in an area from Oshawa to Hamilton. If dropped on Manhattan, it would destroy everything from Jersey City to most of Long Island. Now you know why no-one wants a nuclear war. It would literally annihilate almost everyone in the world.

                             

I hope you have found this article interesting.