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Little Boy

A post-war "Little Boy" model.
Type Nuclear weapon
Place of origin United States
Specifications
Weight 4,000 kg
Length 3. A nuclear weapon is an explosive device that derives its destructive force from Nuclear reactions either fission or a combination of fission and fusion. The United States of America —commonly referred to as the 0 m
Diameter 0. 7 m
Blast yield 13 to 16 kilotons

Little Boy was the codename of the atomic bomb which was dropped on Hiroshima, on August 6, 1945 by the 12-man crew of the B-29 Superfortress Enola Gay, piloted by Colonel Paul Tibbets in the 393d Bombardment Squadron, Heavy of the United States Army Air Forces. A code name or cryptonym is a word or name used clandestinely to refer to another name or word A nuclear weapon is an explosive device that derives its destructive force from Nuclear reactions either fission or a combination of fission and fusion. The Japanese city of ( is the capital of Hiroshima Prefecture, and the largest city in the Chūgoku region of western Honshū, the largest of Japan 's Events 1538 - Bogotá, Colombia, is founded by Gonzalo Jiménez de Quesada. Year 1945 ( MCMXLV) was a Common year starting on Monday (link will display the full calendar WikipediaWikiProject Aircraft. Please see WikipediaWikiProject Aircraft/page content for recommended layout See also Colonel In the United States Army, the United States Marine Corps and the United States Air Force, colonel Paul Warfield Tibbets Jr ( February 23, 1915 &ndash November 1, 2007) was a Brigadier general in the United States Air Force The 393d Bomb Squadron ( 393 BS) is part of the 509th Bomb Wing at Whiteman Air Force Base, Missouri. The United States Army Air Forces ( USAAF) was the military aviation arm of the United States of America during and immediately after World War II. [1] It was the first atomic bomb ever used as a weapon and was dropped three days before the "Fat Man" bomb was used against Nagasaki. "Fat Man" is the codename for the Atomic bomb that was detonated over Nagasaki, Japan, by the United States on August 9 ( is the Capital and the largest city of Nagasaki Prefecture in Japan. [2]

The weapon was developed by the Manhattan Project during World War II. The World War II Manhattan Project developed the first Nuclear weapon (atomic bomb World War II, or the Second World War, (often abbreviated WWII) was a global military conflict which involved a majority of the world's nations, including It derived its explosive power from the nuclear fission of uranium 235. Nuclear fission is the splitting of the nucleus of an atom into parts (lighter nuclei) often producing Free neutrons and other smaller nuclei which may Uranium-235 is an isotope of uranium that differs from the element's other common isotope Uranium-238, by its ability to cause a rapidly expanding fission The Hiroshima bombing was the second man-made nuclear explosion in history (the first was the "Trinity" test), and it was the first uranium-based detonation ever. The atomic bombings of Hiroshima and Nagasaki were nuclear attacks near the end of World War II against the Empire of Japan by the United States at A nuclear explosion occurs as a result of the rapid release of energy from an intentionally high-speed Nuclear reaction. Trinity was the first test of technology for a Nuclear weapon. Uranium (jʊˈreɪniəm is a silvery-gray Metallic Chemical element in the Approximately 600 milligrams of mass were converted into energy. It exploded with a destructive power equivalent to between 13 and 16 kilotons of TNT (estimates vary) and killed approximately 140,000 people including associated effects. Units of mass There are three similar units of Mass called the ton: Long ton (simply ton in countries such as the United Trinitrotoluene ( TNT) is a Chemical compound with the formula C6H2(NO23CH3 Little boy was named after Robert Oppenheimer, the scientific head of the project.

Contents

Basic weapon design

Main articles: Gun-type fission weapon and Nuclear weapon design
The "gun" assembly method. When the hollow uranium projectile was driven onto the target spike, a nuclear explosion resulted.
The "gun" assembly method. Gun-type fission weapons are fission -based Nuclear weapons whose design assembles their fissile material into a supercritical mass by the Nuclear weapon designs are physical chemical and engineering arrangements that cause the physics package of a nuclear weapon to detonate When the hollow uranium projectile was driven onto the target spike, a nuclear explosion resulted.

The Mk I "Little Boy" was 10 feet (3. 048 m) in length, 28 inches (71. 12 cm) in diameter and weighed 8,900 lb (4 036. 97 kg). The design used the gun method to explosively force a hollow sub-critical mass of uranium-235 and a solid target spike together into a super-critical mass, initiating a nuclear chain reaction. Gun-type fission weapons are fission -based Nuclear weapons whose design assembles their fissile material into a supercritical mass by the A critical mass is the smallest amount of Fissile material needed for a sustained Nuclear chain reaction. Uranium (jʊˈreɪniəm is a silvery-gray Metallic Chemical element in the A nuclear chain reaction occurs when one Nuclear reaction causes an average of one or more nuclear reactions thus leading to a self-propagating number of these reactions This was accomplished by shooting one piece of the uranium onto the other by means of chemical explosives. It contained 64 kg of uranium, of which 0. 7 kg underwent nuclear fission, and of this mass only 0. Nuclear fission is the splitting of the nucleus of an atom into parts (lighter nuclei) often producing Free neutrons and other smaller nuclei which may 6 g was transformed into energy.

No full test of a gun-type nuclear weapon had occurred before the "Little Boy" device was dropped over Hiroshima. The Japanese city of ( is the capital of Hiroshima Prefecture, and the largest city in the Chūgoku region of western Honshū, the largest of Japan 's The only test explosion of a nuclear weapon had been of an implosion-type weapon using plutonium as its fissionable material, on July 16, 1945 at the Trinity test. Nuclear weapons tests are experiments carried out to determine the effectiveness yield and explosive capability of Nuclear weapons Throughout the twentieth century most nations Events 622 - The beginning of the Islamic calendar. 1054 - Three Roman legates fractured relations between the Western and Year 1945 ( MCMXLV) was a Common year starting on Monday (link will display the full calendar Trinity was the first test of technology for a Nuclear weapon. There were several reasons for not testing the "Little Boy" device. Primarily, scarcity of uranium-235 compared with the relatively large amount of plutonium which, it was expected, could be produced monthly from the Hanford reactors. The Hanford Site is a decommissioned nuclear production complex on the Columbia River in south-central Washington operated by the United States government Additionally, the weapon design was conceptually simple enough that it was only deemed necessary to do laboratory tests with the gun-type assembly (known during the war as "tickling the dragon's tail"). Louis Alexander Slotin (December 1 1910 – May 30 1946 was a Canadian Physicist and Chemist who took part in the Manhattan Project. Unlike the implosion design, which required very sophisticated coordination of shaped explosive charges, the gun-type design was considered almost certain to work without full testing.

Although occasionally used in later experimental devices, the design was only used once as a weapon because of the extreme danger of accidental detonation. Little Boy's design was highly unsafe when compared to modern nuclear weapons, which incorporate many safety features, designed to anticipate various accident scenarios. The main design objectives of Little Boy were to create a nuclear weapon that was absolutely guaranteed to work. As a result, Little Boy incorporated only the most basic safety mechanisms, so an accidental detonation could easily occur during one or more of the following scenarios:

None of the other five Mark I bombs built on the model of Little Boy were used by the U. S. Army.

Assembly details

The exact specifications of the "Little Boy" bomb remain classified because they could still be used to create a viable nuclear weapon. Even so, many sources have speculated as to the design, relying on limited photographic evidence, interviews with former Manhattan Project personnel, and piecing together information from declassified sources to reconstruct its internal dimensions.

According to the website Nuclear Weapon Archive,[3][4] inside the weapon, the uranium-235 material was divided into two parts, following the gun principle: the "projectile" and the "target". The projectile was a hollow cylinder with 60% of the total mass (38. 5 kg). It consisted of a stack of 9 uranium rings, each 6. 25 inches (159 mm) in diameter with a 4-inch-diameter hole in the middle, pressed together into a thin-walled canister 7 inches (180 mm) long. At detonation, it would be pushed down a short section of smooth-bore gun barrel by a tungsten carbide and steel plug. The target was a 4-inch-diameter solid spike, 7 inches long, with 40% of the total mass (25. 6 kg). Made of a stack of 6 washer-like uranium rings somewhat thicker than the projectile rings, it was held in place by a 1-inch-diameter steel bolt that ran through the rings and out the front end of the bomb casing.

When the projectile and plug reached the target, the assembled super-critical mass of uranium would be completely surrounded by a tamper and neutron reflector of tungsten carbide and steel. Neutron generators at the base of the spike would be activated by the impact.

The projectile rings were delivered to Tinian Island on July 26, 1945, by the cruiser USS Indianapolis. Events 657 - Battle of Siffin. 811 - Battle of Pliska; Byzantine Emperor Nicephorus Year 1945 ( MCMXLV) was a Common year starting on Monday (link will display the full calendar Service before World War II Indianapolis was laid down on March 31 1930 by the New York Shipbuilding Corp The target rings arrived two days later by air.

Counter-intuitive design

For the first fifty years after 1945, every published description and drawing of the Little Boy mechanism assumed that a small, solid projectile was fired into the center of a larger target. [4]

Critical mass considerations dictated that in Little Boy the larger, hollow piece would be the projectile. For the assembled fissile core to have more than two critical masses of U-235, one of the two pieces would need to have more than one critical mass, and to avoid criticality by means of shape, namely a hole in the middle. A critical mass is the smallest amount of Fissile material needed for a sustained Nuclear chain reaction. The larger (outer) surface area allows more fission neutrons to escape and hence not cause a new fission.

It was also important for the larger piece to have minimal contact with the tamper of neutron-reflecting tungsten carbide until the moment of detonation. As the projectile, it would have only its back end in contact with tungsten carbide (see drawing above). The rest of the tungsten carbide could be installed around the target spike, called the "insert" by designers, where an air space would keep it away from the sides of the insert. This is the only way to pack the maximum amount of fissile material into a gun-assembly design. [5]

Physical effects of the bomb

Hiroshima was spared conventional bombing in order to serve as a pristine target, one where the effects of a nuclear bomb on a previously undamaged city could be observed. [6] While damage could be studied later, the energy yield of the untested Little Boy design could be determined only at the moment of detonation, using instruments dropped by parachute from a plane flying in formation with the one that dropped the bomb. Radio-transmitted data from these falling instruments indicated a yield of about a dozen kilotons.

Comparing this yield to the observed damage produced a rule of thumb called the 5 psi (1pounds per square inch = 6. 894 kilopascal = 0. 069 bar) lethal area rule. The number of prompt fatalities will approximately equal the number of people inside the lethal area.

The damage came from three main effects: blast, fire, and radiation. [7]

Blast

The blast from a nuclear bomb is the result of x-ray-heated air (the fireball) sending a shock/pressure wave in all directions at the speed of sound, analogous to thunder generated by a bolt of lightning. Studies of Little Boy at Hiroshima have given us most of what we know about urban blast destruction from nuclear weapons. Nagasaki was less useful in that respect because hilly terrain deflected the blast and generated a more complicated pattern of destruction.

Frame house in 1953 nuclear test, 5 psi overpressure.
Frame house in 1953 nuclear test, 5 psi overpressure.

At Hiroshima, severe structural damage to buildings extended about one mile (1. 6 km) in every direction from ground zero, making a circle of destruction two miles (3 km) in diameter. There was little or no structural damage outside a two-mile (3 km) radius. At one mile (1. 6 km), the force of the blast wave was 5 psi, with enough duration to implode houses and reduce them to kindling as it passed. 5 psi is 720 pounds (324 kilogrammes) per square foot (1 sq foot = 0. 09 square meters).

Later test explosions of nuclear weapons, with houses and other test structures placed nearby, confirmed that 5 psi is an important threshold figure. Ordinary urban buildings close enough to experience it will be crushed, toppled, or gutted by the force of air pressure. The picture at right shows the effects of a nuclear-bomb-generated 5 psi pressure wave on a test structure in Nevada in 1953.

The most important effect of this kind of structural damage was that it created fuel for a firestorm. For this reason, the 5 psi contour defines the lethal area for blast and fire.

Fire

The first effect of a nuclear explosion is blinding light, accompanied by radiant heat from the fireball. (The Hiroshima fireball was 1,200 feet (370 m) in diameter. ) Near ground zero, everything flammable burst into flame, and any humans were instantly vaporized. One famous, anonymous Hiroshima victim left only a shadow, permanently etched into stone steps near a bank building. [8]

Hiroshima blast and fire damage, U.S. Strategic Bombing Survey map.
Hiroshima blast and fire damage, U. S. Strategic Bombing Survey map.

Some of the fires started by the fireball's heat were probably blown out by the following blast wave. The blast wave would have started additional fires through overturned stoves, wrecked vehicles, electrical shorts, etc. These numerous small fires quickly merged into a single firestorm which consumed everything inside the 5 psi lethal area.

The Hiroshima firestorm was thus two miles (3 km) in diameter, corresponding closely to the severe blast damage zone. (See the USSBS[9] map, right. ) Blast-damaged buildings provided ideal fuel for the fire. Structural lumber and furniture were splintered and scattered about. Debris-choked roads prevented entry by fire fighters. Broken gas pipes fueled the fire, and broken water pipes rendered hydrants useless.

As the map shows, the firestorm easily jumped the natural firebreaks (river channels) as well as prepared firebreaks. The spread of fire stopped only when it reached the edge of the blast-damaged area and ran out of easily available fuel.

Accurate casualty figures are impossible because so many victims were cremated by the firestorm. For the same reason, the portion of firestorm victims who survived the blast and died of fire can never be known. Casualty figures are based on estimates of how many people were inside the lethal area when the bomb went off.

Radiation

Because Little Boy was detonated 1,900 feet (580 m) above the ground, as an air burst, there was no bomb crater and no local radioactive fallout. [10] Local Fallout is dust and ash from a bomb crater, contaminated with radioactive fission products. It falls back to the ground downwind of the crater and can easily produce, with radiation alone, a lethal area much larger than that from blast and fire. With an air burst, the fission products remain in aerosol form until they rise into the stratosphere, where they dissipate and become part of the global, rather than the local environment.

However, an intense flux of neutron and gamma radiation came directly from the fireball. Most people close enough to receive lethal doses of that direct radiation died in the firestorm before their radiation injuries could become apparent. But survivors on the edge of the lethal area and beyond suffered injuries from radiation as well as from blast and fire.

Some temporary survivors died soon afterward due to the effects of acute radiation sickness, but most of the radiation effects show up statistically, as increases in cancer rates, birth defects, etc. , over the lifetimes of the survivors and their descendants.

Development of the bomb

Uranium for "Little Boy" was enriched in calutrons and by gaseous diffusion at Oak Ridge, Tennessee.
Uranium for "Little Boy" was enriched in calutrons and by gaseous diffusion at Oak Ridge, Tennessee. A Calutron was a Mass spectrometer used for separating the isotopes of Uranium developed by Ernest O Oak Ridge is an incorporated City in Anderson and Roane Counties in East Tennessee, USA, about 25 miles northwest of
Main article: Manhattan Project

The "Little Boy" bomb was constructed through the Manhattan Project during World War II. The World War II Manhattan Project developed the first Nuclear weapon (atomic bomb The World War II Manhattan Project developed the first Nuclear weapon (atomic bomb World War II, or the Second World War, (often abbreviated WWII) was a global military conflict which involved a majority of the world's nations, including Because enriched uranium was known to be fissionable, it was the first approach to bomb development pursued. The vast majority of the work in constructing "Little Boy" came in the form of the isotope enrichment of the uranium necessary for the weapon. Isotope separation is the process of concentrating specific Isotopes of a Chemical element by removing other isotopes for example separating Natural uranium Enrichment at Oak Ridge, Tennessee began in February 1943, after many years of research. Oak Ridge is an incorporated City in Anderson and Roane Counties in East Tennessee, USA, about 25 miles northwest of

The development of the first prototypes and the experimental work started in early 1943, at the time when the Los Alamos Design Laboratory became operational in the framework of the Manhattan Project. Los Alamos National Laboratory (LANL (previously known at various times as Site Y, Los Alamos Laboratory, and Los Alamos Scientific Laboratory) is a Originally gun-type designs were pursued for both a uranium and plutonium weapon (the "Thin Man" design), but in April 1944 it was discovered that the spontaneous fission rate for plutonium from the Hanford enrichment plant was too high to use in a gun-type weapon. The "Thin Man" (formally Mark 2) nuclear bomb was a proposed Plutonium gun-type nuclear bomb which the United States was In July 1944, almost all research at Los Alamos re-oriented around the development of the implosion plutonium weapon. In contrast, the uranium bomb was almost trivial to design.

As part of Project Alberta, Commander A. Francis Birch (left) numbers the bomb while physicist Norman Ramsey watches. This is one of the rare photos where the inside of the bomb can be seen.
As part of Project Alberta, Commander A. Project Alberta was a section of the Manhattan Project which developed the means of delivering the first atomic bombs, used by the United States Army Francis Birch (left) numbers the bomb while physicist Norman Ramsey watches. Norman Foster Ramsey Jr (born August 27, 1915, in Washington DC) is an American Physicist. This is one of the rare photos where the inside of the bomb can be seen.

With plutonium found unsuitable for the gun-type design, the team working on the gun weapon (led by A. Francis Birch), faced another problem: the bomb was simple, but they lacked the quantity of uranium-235 necessary for its production. Enough fissile material was not going to be available before mid-1945. Despite this, Birch managed to convince others that this concept was worth pursuing, and that in case of a failure of the plutonium bomb, it would still be possible to use the gun principle. His team had heavy responsibilities and even though the technology was less complex than for the other project, a lot of rigorous work was still needed. In February 1945, the specifications were completed (model 1850). The bomb, except for the uranium payload, was ready at the beginning of May 1945.

Most of the uranium necessary for the production of the bomb came from the Shinkolobwe mine and was made available thanks to the foresight of the CEO of the High Katanga Mining Union, Edgar Sengier, who had 1000 tons of uranium ore transported to a New York warehouse in 1939. Shinkolobwe is the name of a town and a mine in the Katanga province of the Democratic Republic of the Congo (DRC located near the larger town of The Union Minière du Haut Katanga (UMHK is a Belgian mining company once operating in Katanga, in what is now the Democratic Republic of the Congo (formerly Edgar Sengier ( Kortrijk 1879&ndash Cannes, 26 July 1963) was the director of the Belgian Union Minière du Haut Katanga during A small amount may have come from a captured German submarine, U-234, after the German surrender in May 1945. The majority of the uranium for Little Boy was enriched in Oak Ridge, Tennessee, primarily by means of electromagnetic separation in calutrons and through gaseous diffusion plants, with a small amount contributed by the cyclotrons at Ernest O. Lawrence's Radiation Laboratory. A Calutron was a Mass spectrometer used for separating the isotopes of Uranium developed by Ernest O A cyclotron is a type of Particle accelerator. Cyclotrons accelerate Charged particles using a high- Frequency, alternating Voltage (potential Ernest Orlando Lawrence ( August 8, 1901 – August 27, 1958) was an American physicist and Nobel Laureate best known for his The Ernest Orlando Lawrence Berkeley National Laboratory ( LBNL) is a U The core of Little Boy contained 64 kg of uranium, of which 50 kg were enriched to 89%, and the remaining 14 kg at 50%. With enrichment averaging 80%, it could reach about 2. 5 critical masses. A critical mass is the smallest amount of Fissile material needed for a sustained Nuclear chain reaction. "Fat Man" and the Trinity "gadget", by way of comparison, had five critical masses. " The gadget " was the code-name given to the first nuclear explosive developed under the Manhattan Project during World War II, which was

Construction and delivery

Little Boy in the bomb pit on Tinian, before being loaded into Enola Gay's bomb bay. A section of the bomb bay door is visible on the top right
Little Boy in the bomb pit on Tinian, before being loaded into Enola Gay's bomb bay. A section of the bomb bay door is visible on the top right

On July 14, 1945 a train left Los Alamos carrying several "bomb units" (the major non-nuclear parts of a gun-type bomb) together with a single completed uranium projectile; the uranium target was still incomplete. Events 1223 - Louis VIII becomes King of France upon the death of his father Philip II of France. Year 1945 ( MCMXLV) was a Common year starting on Monday (link will display the full calendar The consignment was delivered to the San Francisco Naval Shipyard at Hunters Point in San Francisco, California[3]. San Francisco Naval Shipyard was a United States Navy Shipyard in San Francisco California, located on 638 acres (2 The City and County of San Francisco is the fourth most populous city There, two hours before the successful test of Little Boy's plutonium-implosion brother at the Trinity test in New Mexico, the bomb units and the projectile were loaded aboard the heavy cruiser USS Indianapolis. Trinity was the first test of technology for a Nuclear weapon. Service before World War II Indianapolis was laid down on March 31 1930 by the New York Shipbuilding Corp Indianapolis steamed, at a record pace, to the airbase at Tinian island in the Mariana Islands, delivering them ten days later on the 26th. Tinian (ˈtɪniən /ˌtiːniˈɑːn/ is one of the three principal islands of the Commonwealth of the Northern Marianas Islands (14°59’51”N 145°37’39”E The Mariana Islands (also the Marianas; up to the early 20th century sometimes called Ladrones Islands, from Spanish Islas de los Ladrones meaning While returning from this mission Indianapolis was sunk by a Japanese submarine, with great loss of life due to a delayed rescue. Also on the 26th the three sections of the uranium target assembly were shipped from Kirtland Air Force Base[3] near Albuquerque, New Mexico in three C-54 Skymaster aircraft operated by the 509th Composite Group's Green Hornet squadron[11] [12]. For the civil airport use of this facility see Albuquerque International Sunport Kirtland Air Force Base is a major United States Air The 509th Composite Group was an air combat unit of the United States Army Air Forces during the Second World War and as the 509th Operations Group, is With all the necessary components delivered to Tinian, bomb unit L11 was chosen, and the final Little Boy weapon was assembled and ready by August 1[3]. Events 30 BC - Octavian (later known as Augustus enters Alexandria, Egypt, bringing it under the control of the Roman

Handling the completed Little Boy was particularly dangerous. Once cordite was loaded in the breech, any firing of the explosive would at worst cause a nuclear chain reaction and at best a contamination of the explosion zone. A nuclear chain reaction occurs when one Nuclear reaction causes an average of one or more nuclear reactions thus leading to a self-propagating number of these reactions The mere contact of the two uranium masses could have caused an explosion with dire consequences, from a simple "fizzle" explosion to an explosion large enough to destroy Tinian (including the 500 B-29s based there, and their supporting infrastructure and personnel). Water was also a risk, since it could serve as a moderator between the fissile materials and cause a violent dispersal of the nuclear material. The uranium projectile could only be inserted with an apparatus that produced a force of 300,000 newtons (67,000 lbf, over 30 tons). For safety reasons, the weaponeer, Captain William Sterling Parsons, decided to load the bags of cordite only after take-off. Rear Admiral William Sterling "Deak" Parsons ( November 26, 1901 - December 5, 1953) was an American Military

Fuse system

The bomb employed a fuse system that was designed to detonate at the most destructive altitude. Calculations showed that for the largest destructive effect, the bomb should explode at an altitude of 580 meters (1,900 feet). The resultant fuse design was a three-stage interlock system:

The bombing of Hiroshima

The mushroom cloud over Hiroshima after the dropping of "Little Boy".
The mushroom cloud over Hiroshima after the dropping of "Little Boy". A mushroom cloud is a distinctive Mushroom -shaped Cloud of condensed Water vapor or Debris resulting from a very large Explosion. The Japanese city of ( is the capital of Hiroshima Prefecture, and the largest city in the Chūgoku region of western Honshū, the largest of Japan 's
Main articles: Enola Gay and atomic bombings of Hiroshima and Nagasaki

The bomb was armed in flight 31,000ft (9600m) above the city, then dropped at approximately 8:15 a. WikipediaWikiProject Aircraft. Please see WikipediaWikiProject Aircraft/page content for recommended layout The atomic bombings of Hiroshima and Nagasaki were nuclear attacks near the end of World War II against the Empire of Japan by the United States at m. (JST). The detonation happened at an altitude of 1980ft (580m). With a power of 13 to 16 kilotons, it was less powerful than "Fat Man," which was dropped on Nagasaki (21–23 kt). Units of mass There are three similar units of Mass called the ton: Long ton (simply ton in countries such as the United "Fat Man" is the codename for the Atomic bomb that was detonated over Nagasaki, Japan, by the United States on August 9 The official yield estimate of "Little Boy" was about 15 kilotons of TNT equivalent in explosive force, i. The explosive yield of a nuclear weapon is the amount of Energy, called the Yield, discharged when a Nuclear weapon is detonated expressed usually Units of mass There are three similar units of Mass called the ton: Long ton (simply ton in countries such as the United Trinitrotoluene ( TNT) is a Chemical compound with the formula C6H2(NO23CH3 e. 6. 3 × 1013 joules = 63 TJ (terajoules)[14]. The joule (written in lower case ˈdʒuːl or /ˈdʒaʊl/ (symbol J) is the SI unit of Energy measuring heat, Electricity TERA is a shielded Twisted pair connector for use with Category 7 twisted-pair data cables developed by The Siemon Company and standardized in 2003 by However, the damage and the number of victims at Hiroshima were much higher, as Hiroshima was on flat terrain, while the hypocenter of Nagasaki lay in a small valley. The hypocenter or hypocentre (literally 'below the center' from the Greek υπόκεντρον) refers to the site of an earthquake or to that of a nuclear

According to published US Army figures 66,000 people were killed as a direct result of the Hiroshima blast, and 69,000 were injured to varying degrees. [15] Most sources refer to a great number more later dying as a result of radiation sickness and cancer or unborn babies that died before birth or were born with deformities [16] but this appears to be just commonly accepted urban myth and unsupported by the actual events and studies. Radiation poisoning, also called " radiation sickness " or a " creeping dose " is a form of damage to organ tissue due to excessive exposure to Cancer (medical term Malignant Neoplasm) is a class of Diseases in which a group of cells display uncontrolled

The survivors of both the Hiroshima and Nagasaki nuclear explosions have subsequently been some of the closest monitored survivors of the Second World War. Both Japanese and American medical institutes launched a massive and thorough epidemiological study after the war. The study included ALL residents of both Hiroshima and Nagasaki who had survived the atomic explosion within a 10 kilometre (6. 2 mile) radius. As previously noted the bombs were exploded as airbursts and there was no residual radioactive fallout, so anyone outside of a 10 kilometre would have received no radioactive contamination.

Investigators questioned the residents to identify their precise locations when the bombs exploded, and used this information to calculate a personal radiation dose for each resident. Data was collected for all 86,572 survivors of the two bursts.

Sixty three years later the results from the extensive study are clear. The post event deaths from nuclear effects are not the alarmist tens of thousands up to 105,000 claimed in several sources. The subsequent deaths are actually less than 1,000 from the combined cities. In fact, in the years since 1945 just 777 eventually died as a result of radiation received from the atomic attacks:

87 have died from leukemia
440 died of radiation induced tumors;
and 250 died of radiation induced heart attacks.

In addition it should be noted that from the pregnant women irradiated by the Hiroshima and Nagasaki bursts only 30 fetuses subsequently developed mental disabilities after they were born and no physical deformities were noted. There have also been no significant birth problems in the years following the explosions as there was no residual radiation at either site, the initial radiations dissipating and decaying in the days and weeks following the bursts. [17]

The success of the bombing was reported with great enthusiasm in the United States in the days following the attacks. The United States of America —commonly referred to as the See Atomic bombings of Hiroshima and Nagasaki for discussion of contemporary opposition to the bombings, on both moral and military grounds. The atomic bombings of Hiroshima and Nagasaki were nuclear attacks near the end of World War II against the Empire of Japan by the United States at

See also

References

  1. ^ The name Little Boy is alleged on a BBC web site to be a reference to former President Roosevelt. White Light/Black Rain The Destruction of Hiroshima and Nagasaki is a 2007 Documentary film written directed and produced by director WikipediaWikiProject Aircraft. Please see WikipediaWikiProject Aircraft/page content for recommended layout "Fat Man" is the codename for the Atomic bomb that was detonated over Nagasaki, Japan, by the United States on August 9 The "Thin Man" (formally Mark 2) nuclear bomb was a proposed Plutonium gun-type nuclear bomb which the United States was The World War II Manhattan Project developed the first Nuclear weapon (atomic bomb Trinity was the first test of technology for a Nuclear weapon. " The gadget " was the code-name given to the first nuclear explosive developed under the Manhattan Project during World War II, which was The atomic bombings of Hiroshima and Nagasaki were nuclear attacks near the end of World War II against the Empire of Japan by the United States at This is a list of Nuclear weapons ordered by state and then type within the states Upshot-Knothole Grable was a nuclear weapons test conducted by the United States as part of Operation Upshot-Knothole.
  2. ^ Hakim, Joy (1995). A History of Us: War, Peace and all that Jazz. New York: Oxford University Press. ISBN 0-19-509514-6.  
  3. ^ a b c d Much of this account is taken from the description of the "Little Boy" by Carey Sublette in Section 8 of his "Nuclear Weapons Frequently Asked Questions", available online at http://nuclearweaponarchive.org/Nwfaq/Nfaq8.html.
  4. ^ a b The most recent updates come from John Coster-Mullen's Atom Bombs: The Top Secret Inside Story of Little Boy and Fat Man, 2003 (first printed in 1996), a self-published account based largely on oral histories but which contains, in its extensive appendix, a declassified U. S. government document detailing the exact mass and configuration of the U-235 rings.
  5. ^ This information appeared in 2002 in Racing for the Bomb, by Robert S. Norris, Steerforce Press, p. 409, with the 2001 printing of John Coster-Mullen's Atom Bombs, p. 24, cited as its source.
  6. ^ Leslie Groves, Now it Can be Told: The Story of the Manhattan Project, 1962. Lieutenant General Leslie Richard Groves ( August 17, 1896 &ndash July 13, 1970) was a United States Army Engineer In April 1945, General Groves was instructed to pick targets for the nuclear bombs. He set the criteria. Page 267, "To enable us to assess accurately the effects of the bomb, the targets should not have been previously damaged by air raids. " Four cities were chosen, including Hiroshima and Kyoto. War Secretary Stimson vetoed Kyoto, and Nagasaki was substituted. Page 275, "When our target cities were first selected, an order was sent to the Army Air Force in Guam not to bomb them without special authority from the War Department. "
  7. ^ Samuel Glasstone and Philip Dolan, The Effects of Nuclear Weapons, Third Edition, 1977, U. S. Dept of Defense and U. S. Dept of Energy.
  8. ^ Photograph in the Hiroshima Peace Memorial Museum. Hiroshima Peace Memorial Museum is located in Hiroshima Peace Memorial Park, in central Hiroshima, Japan. "Photo"
  9. ^ http://www.anesi.com/ussbs01.htm United States Strategic Bombing Survey (Pacific War), 1 July 1946, pp. "July 1st" redirects here For the Ayumi Hamasaki song see H (song. Year 1946 ( MCMXLVI) was a Common year starting on Tuesday (link will display full 1946 calendar of the Gregorian calendar. 22-25.
  10. ^ Glasstone and Dolan, The Effects of Nuclear Weapons, p. 409. "An air burst, by definition, is one taking place at such a height above the earth that no appreciable quantities of surface material are taken up into the fireball. . . the deposition of early fallout from an air burst will generally not be significant. An air burst, however, may produce some induced radioactive contamination in the general vicinity of ground zero as a result of neutron capture by elements in the soil. "
  11. ^ "Victory", Los Alamos National Laboratory's history of the atomic bomb project
  12. ^ "The Story of the Atomic Bomb", USAF Historical Studies Office
  13. ^ Nuclear Bomb Fusing "Little Boy and Fat Man"[1]
  14. ^ Los Alamos National Laboratory report LA-8819, The yields of the Hiroshima and Nagasaki nuclear explosions by John Malik, September 1985. Available online at http://www.mbe.doe.gov/me70/manhattan/publications/LANLHiroshimaNagasakiYields.pdf
  15. ^ The Manhattan Engineer District, United States Army (1946-06-29). Chapter 10 - Total Casualties. The Atomic Bombings of Hiroshima and Nagasaki. The Avalon Project at Yale Law School. Retrieved on 2007-03-19. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 1279 - A Mongolian victory in the Battle of Yamen ends the Song Dynasty in China. This is a 1946 U. S. Army report of unclassified information, republished by the Avalon project of the Yale Law School, USA.
  16. ^ Centers for Disease Control and Prevention (2005-03-23). The Centers for Disease Control and Prevention (or CDC) is an agency of the United States Department of Health and Human Services based in unincorporated Year 2005 ( MMV) was a Common year starting on Saturday (link displays full calendar of the Gregorian calendar. Events 1174 - Jocelin, Abbot of Melrose, is elected Bishop of Glasgow. Prenatal Radiation Exposure: A Fact Sheet for Physicians. CDC Emergency Preparedness & Response web site. Retrieved on 2007-03-19. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 1279 - A Mongolian victory in the Battle of Yamen ends the Song Dynasty in China. This document gives information about likely injury from prenatal radiation exposure. It does not include any information about injuries at Hiroshima directly. It does cite two reports on Hiroshima injuries.
  17. ^ "Is Atomic Radiation as Dangerous as We Thought?. " Der Spiegel. Der Spiegel (pronounced /deːɐ ˈʃpiːɡəl/ German for "The Mirror" is a German weekly Magazine, published in Hamburg

External links

Coordinates: 34°23′07″N 132°27′19″E / 34.38528, 132.45528

Hiroshima Peace Memorial Museum is located in Hiroshima Peace Memorial Park, in central Hiroshima, Japan. A geographic coordinate system enables every location on the Earth to be specified in three coordinates using mainly a spherical coordinate system.

Dictionary

Little Boy

-proper noun

  1. The nickname of the nuclear bomb dropped over Hiroshima, Japan on August 6, 1945.
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