Analysis: The Atomic Bombings of Hiroshima and Nagasaki: The Nature of An Atomic Explosion
The atomic bombings of Hiroshima and Nagasaki in August 1945 marked a pivotal moment in world history, representing the first use of nuclear weapons in warfare. This event was the culmination of extensive scientific advancements in nuclear physics, particularly the understanding of nuclear fission, which became a reality through the Manhattan Project. The bombings unleashed unprecedented destructive power, generating intense heat, force, and radiation far exceeding that of conventional explosives like TNT. The immediate aftermath was catastrophic, with rapid incineration and severe radiation effects leading to significant civilian casualties and long-term health consequences for survivors.
The nature of an atomic explosion is characterized by its immense energy output; for instance, the energy from one pound of uranium could heat an extraordinary amount of water compared to traditional explosives. The unique radiation effects, including gamma, beta, and alpha rays, posed immediate threats to life and the environment, significantly contributing to injuries and fatalities beyond the physical blast. The bombings not only forced Japan to surrender, hastening the end of World War II, but also ushered in a new era of military strategy and global politics, raising ethical questions about the use of such devastating technology. This historical context continues to resonate in discussions about nuclear weapons and their implications for humanity.
Analysis: The Atomic Bombings of Hiroshima and Nagasaki: The Nature of An Atomic Explosion
Date: June 19, 1946
Author: US Army
Genre: report
Summary Overview
Shortly after the US Army detonated the first atomic weapons over the Japanese cities of Hiroshima and Nagasaki in August 1945, the Army assembled a special Manhattan Project Bomb Investigating Group to assess the sites of the atomic bomb detonations. This military report summarizes the strategy, execution, and aftermath of the bombings. In this section, the report explains the scientific nature of an atomic explosion and its impact by describing the force, heat, and radiation generated in comparison to the more traditional explosive TNT. It emphasizes the great deal of energy generated and released as heat at the moment of detonation, capable of raising temperatures to high levels so rapidly as to cause instant incineration. The report also discusses the radioactive forces unleashed by nuclear weapons, including gamma and beta rays. Along with the physical forces of heat and pressure, radiation is acknowledged as one of the most damaging effects of the atomic bomb and the most unique compared to traditional explosives.
Defining Moment
During the early twentieth century, new theories by innovative physicists such as Albert Einstein greatly advanced human understanding of energy. As early as 1939, research was already underway in Europe to harness the energy released by the division of atoms. Mastering this force would enable the development of weaponry with immense physical power.
In the spring of 1945, Harry S. Truman became president upon the death of Franklin D. Roosevelt. Truman had been vice president only a short time before Roosevelt's death and had little knowledge of the secret military strategies of World War II. It was with great surprise, therefore, that he learned after taking office of an ongoing military program to develop a powerful new kind of weapon based on the principles of nuclear physics. Even more surprising was that such a weapon was nearly ready to be used. That July, scientists in New Mexico successfully detonated the first atomic bomb. Soon thereafter, Truman and other Allied countries fighting Japan issued the Potsdam Declaration, which demanded that the Japanese agree to an unconditional surrender or face “prompt and utter destruction.”
No immediate surrender was forthcoming. Truman faced a choice between either mounting a traditional military invasion of the Japanese islands or authorizing the use of an atomic weapon on a combined civilian and military Japanese target. An invasion involving ground, sea, and air attacks was likely to require many more months of fighting and tens of thousands of American lives as well as hundreds of thousands of Japanese civilian casualties. An atomic attack, by contrast, was expected to kill many thousands of Japanese without any US human costs. It also had the benefit of making a very public demonstration of the incredible new destructive power controlled, at that time, solely by the United States. Some advisers, including a group of scientists who had worked on the bomb and fully grasped its potential for devastation, opposed a nuclear attack, however.
Truman decided to proceed with the nuclear bombing in the hopes that it would force a Japanese surrender and avoid the need for a large-scale invasion. On August 6, 1945, a US bomber dropped the first atomic bomb on the city of Hiroshima. The devastation was immense, but the Japanese government did not immediately agree to a surrender. Three days later, the Soviet Union declared war on Japan and the United States used a second nuclear weapon against the city of Nagasaki. Facing certain defeat, the Japanese surrendered. The atomic age, however, was just beginning, as US scientists and military experts embarked on a period of continued nuclear research and consideration of further applications of their newly proven destructive force.
Author Biography
The US Army Corps of Engineers officially oversaw the development and implementation of the atomic bomb through its management of a top-secret research program known as the Manhattan Project, taken from the name of the administering Manhattan Engineer District. Under the leadership of Major General Leslie Groves, Manhattan Project teams across the country worked to solve the numerous technological challenges required to create the uncontrollable nuclear reaction needed for a successful weapon. In conjunction with high-ranking political officials, they also considered how, where, and whether the weapons they constructed should be used.
After the attacks on Hiroshima and Nagasaki, some of these same military and scientific experts contributed to the US Army's summative report on the matter. These experts included Hans Bethe—a nuclear physicist whose ideas are specifically referenced in this section of the report—along with other physicists active in the Manhattan Project.
Document Analysis
This portion of the US Army's report on the bombings of Hiroshima and Nagasaki focuses on the scientific and technical details of the bomb's detonations and effects. To do this, the report explores three key areas: the overall force and unique features of the atomic bomb as compared to that of existing explosive substances, the immediate effects of the bomb's blast, and the short-term impacts of the radioactive energy released as a by-product of the detonations.
Prior to the development of the atomic bomb, bombs typically employed TNT, or trinitrotoluene, as the main explosive force. TNT's relative stability and predictability had long made it the favored explosive for military use and for civilian applications, such as clearing large rocky areas for mining or construction, and its force has become a standard for comparison. The report therefore compares the nuclear explosions to those of TNT in order to give readers a sense of the immense scale of the atomic bomb's power. For example, the report notes that the detonation of one pound of TNT would generate enough energy to heat thirty-six pounds of water “from freezing temperature… to boiling temperature,” whereas the detonation of one pound of uranium, a radioactive element used in atomic weapons, would generate enough energy to cause an equal rise in temperature of two hundred million pounds of water. The scale of energy released by an atomic explosion was therefore almost unimaginably greater than those of the past.
The contrast between the effects of a traditional explosion and a nuclear one was even starker. In a certain understatement, the report notes that “the atomic bomb gives off greater amounts of radiation” than an explosion of TNT. The radiation released by atomic weapons has immediate effects on living creatures, physical structures, and the environment. The report then describes the creation of flash burns from the intense heat and radiation of the detonation and notes that the various forms of radiation emitted from the explosion were “the major cause of deaths and injuries apart from mechanical injuries” caused by the explosions' pressure waves. The report then delves into the impact of the different types of energy waves formed by a nuclear explosion. Gamma rays, the shortest and most powerful of all energy waves in the electromagnetic spectrum, are unique to atomic explosions and can disrupt the structure of atoms, making these waves especially devastating. The report explains that an atomic explosion also emits a large amount of beta and alpha rays, although their effect is less significant due to their limited range. Along with gamma, beta, and alpha rays, the report also notes that an atomic explosion emits high levels of visible and ultraviolet rays, which produce an intense fireball that “remains at the order of a few times the brightness of the sun for a period of 10 to 15 seconds for an observer at six miles distance.” The report concludes by summarizing the various bursts of radiation released by an atomic explosion and their effects.
Glossary
incandescent: glowing or white with heat
nuclear fission: in physics, the splitting of the nucleus of an atom into nuclei of lighter atoms, accompanied by the release of energy
Bibliography and Additional Reading
Hersey, John. Hiroshima. New York: Knopf, 1946. Print.
“‘Hibakusha’: Those Who Survived and How They Survived.” Children of the Atomic Bomb. University of California at Los Angeles, 10 Oct. 2007. Web. 5 Dec. 2014.
Hogan, Michael J., ed. Hiroshima in History and Memory. New York: Cambridge UP, 1996. Print.
Kort, Michael. Columbia Guide to Hiroshima and the Bomb. New York: Columbia UP, 2007. Print.