The Atom Bomb

The atom bomb is one of the most important discoveries in modern day science. Countless scientists worked relentlessly on the project and their efforts opened the door for present and future exploration of the atom.

Just before the beginning of World War II, Albert Einstein wrote a letter to President Franklin D. Roosevelt. Urged by Hungarian-born physicists Leo Szilard, Eugene Wingner, and Edward Teller, Einstein told Roosevelt about Nazi German efforts to purify Uranium-235 which might be used to build an atomic bomb. Shortly after that the United States Government began work on the Manhattan Project. The Manhattan Project was the code name for the United States effort to develop the atomic bomb before the Germans did. “The first successful experiments in splitting a uranium atom had been carried out in the autumn of 1938 at the Kaiser Wilhelm Institute in Berlin” Just after Einstein wrote his letter. So the race was on. Major General Wilhelm D. Styer called the Manhattan Project “the most important job in the war . . . an all-out effort to build an atomic bomb.” It turned out to be the biggest development in warfare and science’s biggest development this century.

The most complicated issue to be addressed by the scientists working on the Manhattan Project was the production of ample amounts of enriched uranium to sustain a chain reaction. At the time, Uranium-235 was hard to extract. Of the Uranium ore mined, only about 1/500th of it ended up as Uranium metal. The Uranium metal is relatively rare, occurring in Uranium at a ratio of 1 to 139.

Separating the one part Uranium-235 proved to be a challenge. No ordinary chemical extraction could separate the two isotopes. Only mechanical methods could effectively separate U-235 from U-238. Scientists at Columbia University solved this difficult problem.

A massive enrichment plant was built at Oak Ridge, Tennessee. H. C. Urey and his associates and colleagues at Columbia University designed a system that worked on the principle of gaseous diffusion. After this process was completed, Ernest O. Lawrence from the university of California in Berkeley implemented a process i nvolving magnetic separation of the two isotopes. Finally, a gas centrifuge was used to further separate the Uranium-235 from the Uranium-238. The Uranium-238 is forced to the bottom because it had more mass than the Uranium-235. This Uranium was then transported to a laboratory headed by J. Robert Oppenheimer. Oppenheimer was the major force behind the Manhattan Project. He literally ran the show and saw to it that all of the great minds working on this project made their brainstorms work. He oversaw the entire project from its conception to its completion. Once the purified Uranium reached New Mexico, it was made into the components of a gun-type atomic weapon. The scientists were so confident that the gun-type atomic bomb would work that no test was conducted and it was first employed in military action over Hiroshima, Japan, on Aug. 6, 1945.

Once again the University of Chicago, under Enrico Fermi’s direction built the first reactor. This led to the construction of five large reactors at Hanford, Wash., where U-238 was irradiated with neutrons and changed into plutonium. The plutonium was sent to Los Alamos.

There was a debate at Los Alamos about whether to test the new plutonium implosion bomb before it was actually dropped. “Harvard explosives expert George B. Kistiakowsky and Oppenheimer both argued for such a test, but initially Groves was opposed. He was afraid that if the test failed, the precious plutonium would be scattered all across the countryside.”(Szasz 26) Brigadier General Leslie R. Groves, the man the army placed in charge, was eventually persuaded. Hanford’s plutonium production was increasing fast enough so that a test would cause little delay in time. They feared that if they dropped the untested plutonium bomb and it failed to work, “the enemy would find themselves owners of a gift atomic weapon.”(Szasz 26) The final agreement for the test was that the bomb would be placed in “a gigantic, 214-ton, cylinder-shaped tank (called Jumbo ).”(Szasz 26) If the plutonium correctly fissioned, the tank would be vaporized. If it did not work correctly, the conventional explosives would be contained in the tank and the plutonium would stay in the tank. After further development of the implosion design and fears that “Jumbo” would dramatically distort all “their complicated instrumentation-the raison d tre for the test,”(Szasz 36) the world’s largest pressure tank was not used.

On Monday, July 16, 1945, at 5:29:45 A.M., Mountain War Time, a plutonium bomb ignited at the Trinity site, a remote site in the New Mexico desert. “The explosion created’s brilliant flash that was seen in three states. There were many reports from civilians from all over that described the experience. People who saw it said it looked like the sun had risen for a few minutes and then went back down. Others thought they had seen a large plane or meteor crash. A sheep herder who was laying sleeping on a cot fifteen miles away was blown off. The Smithsonian Observatory on Burro Mountain confirmed a shock but noted that the vibrations were unlike any earthquake ever recorded. An eight year-old boy was awakened and ran for his Methodist parents, and they considered if this might be the end of the world. The most powerful statement that has been cited in practically every coverage of the atomic bomb is Georgia Green’s experience. She was being driven to Albuquerque. “What was that?” she asked her brother-in-law, who was driving. This was very unusual because Georgia Green was blind. Brigadier General Farrell wrote a letter for the Secretary of War. ” No man-made phenomenon of such tremendous power had ever occurred before . . . Thirty seconds after the explosion came, first, the air blast pressing hard against people and things, to be followed almost immediately by the 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. Words are inadequate tools for the job of acquainting those not present with the physical, mental and psychological effects.”

Upon witnessing the explosion, reactions among the bomb’s creators were mixed. Their mission had been successfully accomplished, however, they questioned whether “the equilibrium in nature had been upset as if humankind had become a threat to the world it inhabited.” Oppenheimer was ecstatic about the success of the bomb. Many people who were involved in the creation of the atomic bomb signed petitions against dropping the bomb.

The atomic bomb has been used twice in warfare. The Uranium bomb nicknamed “Little Boy,” which weighed over 4.5 tons, was dropped over Hiroshima on August 6, 1945. At 0815 hours the bomb was dropped from the Enola Gay. It missed Ground Zero at 1,980 feet by only 600 feet. At 0816 hours, in the flash of an instant, 66,000 people were killed and 69,000 people were injured by a 10 kiloton atomic explosion.

Nagasaki fell to the same treatment as Hiroshima on August 9, 1945. The plutonium bomb, “Fat Man,” was dropped on the city. It missed its intended target by over one and a half miles. Nagasaki’s population dropped in one split-second from 422,000 to 383,000. 39,000 were killed, over 25,000 were injured. That blast was less than 10 kilotons as well. Physicists who have studied the atomic explosions conclude that the bombs utilized only 0.1% of their respective explosive capabilities.

Controversy still exists about dropping the two atomic bombs on Japan. Arguments defending the Japanese claim “the atomic bomb did not win the war in the Pacific; at best, it hastened Japanese acceptance of a defeat that was viewed as inevitable.” Other arguments state that the United States should have warned the Japanese, or that we should have invited them to a public demonstration. On the other side, advocates claimed that the invasion of the Japanese islands could and would result in over one million military casualties plus the civilian losses based on previous invasions of Japanese occupied islands.

Bibliography

• Batchelder, R.C. The Irreversible Decision. Houghton Mifflin Company Boston, The Riverside Press Cambridge, 1962
• Grolier Electronic Publishing, Inc. Academic American Encyclopedia.
• Groueff, Stephane. Manhattan Project. Boston: Little, Brown and Company, 1967
• Szasz, Ferenc Morton. The Day The Sun Rose Twice. Albuquerque: University of New Mexico Press, 1956
• Taylor, Alan John Percivale. The Second World War. New York: G.P. Putnam’s Sons, 1975
• York, Herbert Frank. The Advisors: Oppenheimer, Teller, and The Superbomb. San Francisco: W.H. Freeman and Company, 1976

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