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”(Groueff 9) 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.”(Groueff 5) 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.”(Outlaw 2) At the time,
Uranium-235 was hard to extract. Of the Uranium ore mined, only about
1/500 th of it ended up as Uranium metal. Of the Uranium metal, “the
fissionable isotope of Uranium (Uranium- 235) is relatively rare,
occurring in Uranium at a ratio of 1 to 139.”(Szasz 15) Separating the
one part Uranium-235 from the 139 parts Uranium-238 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.”(2) Scientists at Columbia University solved this
difficult problem. A “massive enrichment laboratory/plant”(Outlaw 2)
was built at Oak Ridge, Tennessee. H. C. Urey, his associates, and
colleagues at Columbia University designed a system that “worked on
the principle of gaseous diffusion.”(2) After this process was
completed, “Ernest O. Lawrence (inventor of the Cyclotron) at the
University of California in Berkeley implemented a process involving
magnetic separation of the two isotopes.”(2) 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. “In this manner uranium-235 was enriched from its normal
0.7% to weapons grade of more than 90%.”(Grolier 5) This Uranium was
then transported to “the Los Alamos, N. Mex., laboratory headed by J.
Robert Oppenheimer.”(Grolier 5) “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.”(Outlaw 3) Once the purified Uranium reached New
Mexico, it was made into the components of a gun-type atomic weapon.
“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 ineztaneously.”(Grolier 5) “It was
originally nicknamed ‘Thin Man'(after Roosevelt, but later renamed
‘Little Boy’ (for nobody) when technical changes shortened the
proposed gun barrel.”(Szasz 25) The scientists were so confident that
the gun-type atomic bomb would work “no test was conducted, and it was
first employed in military action over Hiroshima, Japan, on Aug. 6,
1945.”(Grolier 5) Before the Uranium-235 “Little Boy” bomb had been
developed to the “point of seeming assured of success,”(Grolier 5)
another bomb was proposed. The Uranium-238 that had been earlier ruled
out as an option was being looked at. It could capture a free neutron
without fissioning and become Uranium-239. “But the Uranium-239 thus
produced is unstable (radioactive) and decays first to neptunium-239
and then to plutonium-239.”(Grolier 5) This proved to be useful
because the newly created plutonium-239 is fissionable and it can “be
separated from uranium by chemical techniques,”(6) which would be far
simpler than the physical processes to separate the Uranium-235 from
the Uranium-238. 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 transmuted into plutonium.”(6) The
plutonium was sent to Los Alamos. The problem to overcome in the
development of the plutonium bomb was an isotope of plutonium. The
scientists feared this isotope would cause premature detonation and
most of the plutonium would blow apart before it could all fission.
“To overcome this so-called ‘defect of nature, ‘ the plutonium had to
be brought into a supercritical mass far faster than conventional
ballistics could achieve.”(Grolier 6) Physicist Seth Neddermeyer and
mathematician John von Neumann devised the theory of “implosion.” A
subcritical sphere of plutonium was surrounded by chemical
high-explosives. The 5,300 pounds of explosives were all “carefully
shaped as ‘lenses.’ When these were detonated, they focused the blast
wave so as to compress the plutonium ineztly into a supercritical
mass.”(Szasz 25) This was much more complex, and many people doubted
that it would work. 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’etre 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, the 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.”(Szasz 83)
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.”(Szasz 84) 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.”(Groueff 355) 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.”(Outlaw 3)
Oppenheimer was ecstatic about the success of the bomb, but quoted a
fragment from Bhagavad Gita. “I am become Death, the destroyer of
worlds.” 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 inezt, 66,000 people were killed and 69,000 people were
injured by a 10 kiloton atomic explosion.”(Outlaw 4) [See blast ranges
diagram] 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.”(Outlaw 4) 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.”(Grolier 8) Other arguments state that the United States
should have warned the Japanese, or that we should have invited them
to a public demonstration. “In retrospect that U.S. use of the atomic
bomb may have been the first act of the cold war.”(Grolier 8) 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.
