Atomic Bomb


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 instantaneously."(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
instantly 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'être
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
instant, 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. 

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