The Manhattan Project was one of the most secretive projects in the history of the United States. It took place during World War II and its purpose was to create a bomb by splitting atoms apart. This project was a success and created one of the most devastating bombs ever used by mankind, the atomic bomb. The president at the time, Harry S. Truman, had to face the many factors that were involved in making the decision to drop the bomb. In this paper I will discuss those and the events leading up to The Manhattan Project.
The factors in dropping the bomb can be put into three categories: military, moral and political. I will also go into the scientific means of developing such a weapon. Albert Einstein was living in Germany at the time Hitler came into power. Albert Einstein, Edward Teller, Leo Szilard and the rest of his colleagues wrote a letter in August 1939 to warn the United States that Germany was researching and developing nuclear weapons. They were afraid that once Germany finished building the bomb, they would use it on the United States.
When President Franklin Delano Roosevelt received the letter, he was both amazed and scared. He was amazed that science could make such a devastating weapon, a weapon that could destroy an entire city. President Roosevelt then quickly assembled the Manhattan Project so they could build the bomb before Germany. The Manhattan Project started in 1942 in Oak Ridge, Tennessee. The name “Manhattan Project” was secretly coded as a United States effort in an attempt to build an atom bomb during World War II.
It was named after the Manhattan Engineer District of the US Army Corps of Engineers, because most of the research was done in New York City. In Oak Ridge there were tests for separating a rare Uranium-235 (U-235) an unstable isotope from Uranium-238 (U-238). General Leslie Groves was chosen by President Roosevelt to lead the project. Grove’s major task was to build the huge industrial facilities needed to separate the small amounts of rare uranium-235, uranium-238 and plutonium needed for a bomb. He built the facilities on an isolated mesa at Los Alamos, New Mexico. The project employed nearly 129,000 people.
But out of those couple of thousands of scientists, there were six scientists who contributed to the project the most: Neils Bohr, Joseph Carter, Glen Seaborg, Enrico Fermi, Richard Feynman, and Albert Einstein. (Wyden, 1984, pg. 113) Albert Einstein predicted that mass could be converted into energy early in the century. The idea of energy from atoms comes from Einstein’s equation: E=mc2. Atoms consist of three sub-atomic particles. The particles are protons, neutrons, and electrons. The neutrons and protons are closely clustered to form the nucleus and the electrons orbit around the nucleus.
The actual mass of a nucleus is always less than the sum of the neutrons and protons that make up the nucleus. The difference is the mass equivalent of the energy of formation of the nucleus from its constituents. The conversion of mass to energy follows Einstein’s equation, E=mc2, where E is the energy equivalent to a mass, m, and c is the velocity of light. His theory was confirmed experimentally by John D. Cockcroft and Ernest Walton in 1932. In 1939, Otto Hahn and Fritz Strassmann discovered nuclear fission. (Lanouette, 1992, pg. 82)
Fission is a process where certain nuclei of heavy atoms split up into two nearly equal parts when they are bombarded by neutrons. Neutrons are used to split the atom because they have no electrical charge. If scientist used a particle that has a positive charge, the uranium atom would repel the positive charge particle. (Taffel, 1992, pg. 790) Neils Bohr discovered that U-235 had the capability to create fission. To initiate fission, a nucleus from a heavy element is bombarded with neutrons. The nucleus breaks into two fragments, releasing energy and two or more neutrons.
Each of these neutrons has enough energy to split another heavy nucleus, and the process continues to repeat itself. This is the basis of the chain reaction that makes nuclear weapons possible. It proceeds with such speed that the number of neutrons doubles every 10 billionth of a second, and the entire reaction may be completed in just a few billionths of a second. The result is the production of energy millions of times greater than the initial reaction that started the chain. For example, the energy released in the fission of is equal to that of 3,000 tons of burning coal or 9,000 tons of exploding TNT. But the most complicated issue was the extraction of the scarce isotope, U-235.
An isotope is the same atom but in a different form. The new atom would have the same number of protons but different numbers of neutrons. Joseph Carter was the scientist who worked on the refinement of Uranium. Uranium is used because it has the largest atoms of any other natural element. The larger the atom is, the harder it is to stabilize. The lower the stabilization is, the easier it is for the nucleus to split and release energy. Other natural atoms have stable atoms and can only be split by bombardment by particle accelerators.
These accelerators are circular and causes the particles to spin around until the particles strike each other. The ratio of conversion from Uranium ore to Uranium metal is 500:1. Of that conversion, only 0. 7% of Uranium is U-235, the other is U-238. To make matters worse, U-235 cannot be separated chemically because U-238 and U-235 are chemically similar. There are two ways of detonating an atomic bomb. The first way is the gun barrel. In 1945, Uranium-235 bomb purity was shipped to Los Alamos, New Mexico where it was transformed into a gun-type weapon.
The way that this bomb works is, two pieces of U-235, individually not large enough to sustain a chain reaction, were brought together rapidly in a gun barrel to form a supercritical mass that exploded instantaneously. Confidence was so high that this model would work that no test was conducted, and it was first employed in military action over Hiroshima, Japan, on Aug. 6, 1945. The second way of detonating the atomic bomb is through implosion. Implosion is the detonation of explosives on the outer surface that causes the detonation/shock wave to move inward.
It didn’t use uranium 235. Instead the bomb used plutonium 239. The scientist used plutonium 239 instead of using uranium 235 because uranium 235 was harder to get. To explode the plutonium 239 bomb it must first be imploded by compressing the subcritical spherical fissionable mass with specially designed explosives. That means there is not enough fissionable material to detonate the atomic bomb. The engineers working on the bomb had to carefully design a smooth, symmetrical implosion setup so that the shock waves would reach each part of the core at the same time.
Once the shock wave is transmitted to the fissionable core it compresses the core and raises the density to the point of superciticality, which means there is enough fissionable material. And this leads to a great explosion. So, the fissionable mass is crushed to a great density, and once the mass has reached that supercritical density it explodes outwards. On July 16, 1945 in Alamogordo, New Mexico, the first atomic bomb, coded name, “The Gadget”, was tested.
This atomic bomb used plutonium 239 in detonating the bomb. When the bomb exploded, a huge mushroom cloud of radioactive vapor covered the sky. On the soil, there were fragments of green radioactive glass. The blast was equal to the force of about 40,000 pounds (18,000 kilograms) of dynamite. The bomb was 2,000 times greater than the most powerful bomb in existence at the time. There were many reasons President Truman had to consider in dropping the atomic bomb. First lets look at the military, moral, and political consequences of his decision.
One of the major reasons that contributed to the bombing was the unprovoked and unexpected bombing of the US military base on Pearl Harbor on December 7, 1941. The unexpected bombing caused 19 ships to sink and about 2,400 American soldiers and sailors to be killed. This normally would not have provoked such a harsh response except for the fact that the United States was not at the time involved in the war. This was the first time that a battle was fought on American soil for hundreds of years and the American people weren’t going to sit back and do nothing about the situation.
They wanted to get revenge on Japan or they would not be satisfied. There was also a tremendous amount of propaganda spreading throughout the United States to increase America’s hatred toward Japan. Newspaper and radio always used the slogan “Hirohito must go! ” to further anger the Americans about the Pearl Harbor bombing. Since Americans hated Japan, this pressured Truman to do something about the injustice. (Cayton, Perry, Winkler, 1995, pg. 788) Many believed that Japan was ready to surrender and that there was no good reason to drop such a bomb.
Japan’s military resources were greatly depleted due to non-stop American air raids over Japanese military sites. However, Japan was reluctant to surrender unconditionally to American terms because they had too much pride for their Japanese emperor. The Japanese fought not only for the glory of their emperor, they fought for the glory of their country. Instead of surrendering, the Japanese soldiers would rather commit kamikaze attacks, which are “suicide missions in which pilots would deliberately slam their bomb-filled planes into American ships in the Pacific. ” (Cayton, Perry, Winkler, 1995, pg. 0)
The United States also didn’t want any more Americans soldiers to risk and lose their lives to fight the war. In a June 18, 1945, meeting, General Marshall told President Truman that the first 30 days of the invasion of Kyushu could result in 31,000 casualties. But Admiral Leahy pointed out that the huge invasion force could sustain losses proportional to those on Okinawa, making the operation much more costly. Had the Kyushu invasion failed to force Japan to surrender, the United States planned to invade the main island of Honshu, with the goal of capturing Tokyo.
American deaths would have increased dramatically. Truman knew that Japan had some two million troops defending the home islands. He believed, along with the many Americans who would have had to invade Japan, that such a campaign might have become, in his words from June 18, 1945, “an Okinawa from one end of Japan to the other. ” Added to the American losses would have been several times as many Japanese casualties, military and civilian. For Truman, even the lowest of the causality estimates was unacceptable.
To prevent an invasion and to save as many lives as possible, he chose to use the atomic bomb. There were many of his advisors agreed with dropping the bomb and who pressured him into the bomb dropping. Here is what one of his military advisors had to say: “From a conference at Potsdam, President Truman issued an ultimatum to the Japanese government to ‘proclaim now the unconditional surrender of all Japanese armed forces…, the alternative for Japan is prompt and udder destruction. ‘ They rejected our ultimatum. The fault for what happens is theirs. Presidential Advisers-Document Packet) Others did not agree, as shown below from another military advisor.
“The rejection of the Potsdam Declaration is not a valid reason for using the atomic bomb. We did not specifically tell them what ‘utter destruction’ meant. And we have tied their hands in the matter of unconditional surrender. There is no way they can or will surrender without guarantee that the Emperor will not be executed. Such betrayal of the Emperor would be against a thousand years of Japanese tradition.
Presidential Advisers-Document Packet) Japanese intentions remained unclear towards the near end of the war. Some of Truman’s advisors believed that Japan was ready to surrender and was looking for a diplomatic way to end the war while other believed that Japanese leaders supported the war and wanted to fight to the end. Japan also believed that the Soviet Union might even enter the war in the Pacific on Japans side. With the growing tensions between the Soviet Union and the US, Truman couldn’t afford the Soviets to aid Japan in any way.
It would prolong the war and dramatically increase the already high death toll from the war. While this was true at the end of the war a retired Admiral Kantaro was brought back into office as head of the new government. He wanted to end the war and appointed like-minded officials into key government positions. In fact the only reason that they might not have surrendered was because the United States constantly insisted on an unconditional surrender. This idea of surrender was humiliating to some Japanese while some merely wanted to know what would become of their Emperor Hirohito.
He was believed to be a direct descendant of the sun god and the people feared that “unconditional surrender” meant that their emperor would be tried as a war criminal and possibly executed. If the US just insured the emperor that he would keep his position there might have been no need to use the atomic bomb. There was also many political reasons back home that Truman faced every day. When President Truman took over the office, he didn’t know that the United States was creating an atomic bomb. Truman just found out when he got to the office.
He learned that the Manhattan Project took five years and approximately two billion dollars to develop the atomic bomb. If he didn’t use the atomic bomb, he would not have a chance at all to be re-elected. All the hard work and money would be wasted on nothing. If the Americans had found out that all those resources were wasted, they would be upset at Truman. Truman wasn’t liked nearly as much as Roosevelt and he knew that he must do something quick to gain America’s support. He felt enormous pressure to toughen up. This is taken from a newspaper editorial before the bombing: Public opinion clamors for a speedy end to the war.
The Japanese must be clearly punished for their sneak attack on Pearl harbor that they never try such a despicable act again. We demand unconditional surrender. We will not tolerate that our leaders accept anything else. ” (Presidential Advisers-Document Packet) This is one of the reasons he was reluctant to call for anything else besides “unconditional surrender”. The dropping of the atomic bomb would do just that. America needed to show their power and wanted an immediate and complete end the war. In addition, the Soviet Union could see the wrath of the Americans.
So Truman thought that this would give him the respect from the American citizens and to show that he could take control of the situation. Here is what a historian had to say about the situation. “Whatever is done to Japan has to be seen not only as a means to end the war but also as a warning to the Soviet Union. The Russians have remained neutral throughout this Asian campaign. Now they will enter to gain the spoils. They are already expanding their influence in occupied areas of Europe. We must demonstrate to them the strength, fury, and will of an American whose interests are attacked. “