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HISTORY OF TECHNOLOGY, TECHNOLOGY, OBJECTS AROUND US
Atomic bomb. History of invention and production
Directory / The history of technology, technology, objects around us Nuclear weapons (or atomic weapons) - a set of nuclear weapons, their means of delivery to the target and controls. Refers to weapons of mass destruction along with biological and chemical weapons. Nuclear ammunition is an explosive weapon based on the use of nuclear energy released as a result of an avalanche-like nuclear chain reaction of fission of heavy nuclei and / or a thermonuclear fusion reaction of light nuclei. The world of the atom is so fantastic that its understanding requires a radical break in the usual concepts of space and time. Atoms are so small that if a drop of water could be enlarged to the size of the Earth, each atom in that drop would be smaller than an orange. In fact, one drop of water is made up of 6000 billion billion (6000000000000000000000) hydrogen and oxygen atoms. And yet, despite its microscopic size, the atom has a structure to some extent similar to the structure of our solar system. In its incomprehensibly small center, with a radius of less than one trillionth of a centimeter, is a relatively huge "sun" - the nucleus of an atom. Around this atomic "sun" tiny "planets" - electrons - revolve. The nucleus consists of two main building blocks of the Universe - protons and neutrons (they have a unifying name - nucleons). An electron and a proton are charged particles, and the amount of charge in each of them is exactly the same, but the charges differ in sign: the proton is always positively charged, and the electron is always negative. The neutron does not carry an electric charge and therefore has a very high permeability. In the atomic measurement scale, the mass of the proton and neutron is taken as unity. The atomic weight of any chemical element therefore depends on the number of protons and neutrons contained in its nucleus. For example, a hydrogen atom, whose nucleus consists of only one proton, has an atomic mass of 1. A helium atom, with a nucleus of two protons and two neutrons, has an atomic mass of 4. The nuclei of atoms of the same element always contain the same number of protons, but the number of neutrons may be different. Atoms that have nuclei with the same number of protons, but differ in the number of neutrons and related to varieties of the same element, are called isotopes. To distinguish them from each other, a number equal to the sum of all particles in the nucleus of a given isotope is assigned to the element symbol. The question may arise: why does the nucleus of an atom not fall apart? After all, the protons included in it are electrically charged particles with the same charge, which must repel each other with great force. This is explained by the fact that inside the nucleus there are also so-called intranuclear forces that attract the particles of the nucleus to each other. These forces compensate for the repulsive forces of protons and do not allow the nucleus to fly apart spontaneously. The intranuclear forces are very strong, but they act only at a very close distance. Therefore, nuclei of heavy elements, consisting of hundreds of nucleons, turn out to be unstable. The particles of the nucleus are in constant motion here (within the volume of the nucleus), and if you add some additional amount of energy to them, they can overcome internal forces - the nucleus will be divided into parts. The amount of this excess energy is called the excitation energy. Among the isotopes of heavy elements, there are those that seem to be on the very verge of self-decay. Only a small "push" is enough, for example, a simple hit in the nucleus of a neutron (and it does not even have to be accelerated to a high speed) for the nuclear fission reaction to start. Some of these "fissile" isotopes were later made artificially. In nature, there is only one such isotope - it is uranium-235.
Uranus was discovered in 1783 by Klaproth, who isolated it from uranium pitch and named it after the recently discovered planet Uranus. As it turned out later, it was, in fact, not uranium itself, but its oxide. Pure uranium - a silver-white metal - was obtained only in 1842 by Peligo. The new element did not have any remarkable properties and did not attract attention until 1896, when Becquerel discovered the phenomenon of radioactivity of uranium salts. After that, uranium became the object of scientific research and experiments, but still had no practical application. When, in the first third of the 1934th century, the structure of the atomic nucleus more or less became clear to physicists, they first of all tried to fulfill the old dream of alchemists - they tried to turn one chemical element into another. In XNUMX, the French researchers, the spouses Frederic and Irene Joliot-Curie, reported to the French Academy of Sciences about the following experiment: when aluminum plates were bombarded with alpha particles (helium atom nuclei), aluminum atoms turned into phosphorus atoms, but not ordinary, but radioactive, which in turn converted to a stable isotope of silicon. Thus, an aluminum atom, having added one proton and two neutrons, turned into a heavier silicon atom. This experience led to the idea that if neutrons are "fired" at the nuclei of the heaviest element existing in nature - uranium, then one can obtain an element that does not exist in natural conditions. In 1938, the German chemists Otto Hahn and Fritz Strassmann repeated in general terms the experience of the Joliot-Curie spouses, taking uranium instead of aluminum. The results of the experiment were not at all what they expected - instead of a new superheavy element with a mass number greater than that of uranium, Hahn and Strassmann received light elements from the middle part of the periodic system: barium, krypton, bromine and some others. The experimenters themselves could not explain the observed phenomenon. It was not until the following year that the physicist Lisa Meitner, to whom Hahn reported her difficulties, found a correct explanation for the observed phenomenon, suggesting that when uranium was bombarded with neutrons, its nucleus split (fissioned). In this case, nuclei of lighter elements should have been formed (this is where barium, krypton and other substances were taken from), as well as 2-3 free neutrons should have been released. Further research allowed to clarify in detail the picture of what is happening. Natural uranium consists of a mixture of three isotopes with masses of 238, 234 and 235. The main amount of uranium falls on the 238 isotope, the nucleus of which includes 92 protons and 146 neutrons. Uranium-235 is only 1/140 of natural uranium (0%) (it has 7 protons and 92 neutrons in its nucleus), and uranium-143 (234 protons, 92 neutrons) is only 142/1 of the total mass of uranium ( 17500%). The least stable of these isotopes is uranium-0. From time to time, the nuclei of its atoms spontaneously divide into parts, as a result of which lighter elements of the periodic system are formed. The process is accompanied by the release of two or three free neutrons, which rush at a tremendous speed - about 006 thousand km / s (they are called fast neutrons). These neutrons can hit other uranium nuclei, causing nuclear reactions. Each isotope behaves differently in this case. Uranium-238 nuclei in most cases simply capture these neutrons without any further transformations. But in about one case out of five, when a fast neutron collides with the nucleus of the isotope-238, a curious nuclear reaction occurs: one of the neutrons of uranium-238 emits an electron, turning into a proton, that is, the uranium isotope turns into a heavier element - neptunium-239 (93 protons + 146 neutrons). But neptunium is unstable - after a few minutes one of its neutrons emits an electron, turning into a proton, after which the neptunium isotope turns into the next element of the periodic system - plutonium-239 (94 protons + 145 neutrons). If a neutron enters the nucleus of unstable uranium-235, then fission immediately occurs - the atoms decay with the emission of two or three neutrons. It is clear that in natural uranium, most of whose atoms belong to the 238 isotope, this reaction has no visible consequences - all free neutrons will eventually be absorbed by this isotope. But what if we imagine a fairly massive piece of uranium, consisting entirely of the 235 isotope? Here the process will go differently: the neutrons released during the fission of several nuclei, in turn, falling into neighboring nuclei, cause their fission. As a result, a new portion of neutrons is released, which splits the following nuclei. Under favorable conditions, this reaction proceeds like an avalanche and is called a chain reaction. A few bombarding particles may suffice to start it. Indeed, let only 235 neutrons bombard uranium-100. They will split 100 uranium nuclei. In this case, 250 new neutrons of the second generation will be released (an average of 2 per fission). The neutrons of the second generation will already produce 5 fissions, at which 250 neutrons will be released. In the next generation it will be 625, then 1562, then 3906, and so on. The number of divisions will increase without limit if the process is not stopped. However, in reality, only an insignificant part of neutrons gets into the nuclei of atoms. The rest, swiftly rushing between them, are carried away into the surrounding space. A self-sustaining chain reaction can only occur in a sufficiently large array of uranium-235, which is said to have a critical mass. (This mass under normal conditions is 50 kg.) It is important to note that the fission of each nucleus is accompanied by the release of a huge amount of energy, which turns out to be about 300 million times more than the energy spent on fission! (It has been calculated that the total fission of 1 kg of uranium-235 releases as much heat as the combustion of 3 tons of coal.) This colossal surge of energy, released in a matter of moments, manifests itself as an explosion of monstrous force and underlies the operation of nuclear weapons. . But in order for this weapon to become a reality, it is necessary that the charge does not consist of natural uranium, but of a rare isotope - 235 (such uranium is called enriched). Later it was found that pure plutonium is also a fissile material and can be used in an atomic charge instead of uranium-235. All these important discoveries were made on the eve of World War II. Soon secret work began in Germany and other countries on the creation of an atomic bomb. In the United States, this problem was taken up in 1941. The whole complex of works was given the name "Manhattan Project". The administrative leadership of the project was carried out by General Groves, and the scientific direction was carried out by Professor Robert Oppenheimer of the University of California. Both were well aware of the enormous complexity of the task before them. Therefore, Oppenheimer's first concern was the acquisition of a highly intelligent scientific team. In the United States at that time there were many physicists who had emigrated from fascist Germany. It was not easy to involve them in the creation of weapons directed against their former homeland. Oppenheimer spoke to everyone personally, using the full force of his charm. Soon he managed to gather a small group of theorists, whom he jokingly called "luminaries". And in fact, it included the largest experts of that time in the field of physics and chemistry. (Among them are 13 Nobel Prize winners, including Bohr, Fermi, Frank, Chadwick, Lawrence.) In addition to them, there were many other specialists of various profiles. The US government did not skimp on spending, and from the very beginning the work assumed a grandiose scope. In 1942, the world's largest research laboratory was founded at Los Alamos. The population of this scientific city soon reached 9 thousand people. In terms of the composition of scientists, the scope of scientific experiments, the number of specialists and workers involved in the work, the Los Alamos Laboratory had no equal in world history. The "Manhattan Project" had its own police, counterintelligence, communications system, warehouses, settlements, factories, laboratories, and its own colossal budget. The main goal of the project was to obtain enough fissile material from which to create several atomic bombs. In addition to uranium-235, as already mentioned, the artificial element plutonium-239 could serve as a charge for the bomb, that is, the bomb could be either uranium or plutonium. Groves and Oppenheimer agreed that work should be carried out simultaneously in two directions, since it is impossible to decide in advance which of them will be more promising. Both methods were fundamentally different from each other: the accumulation of uranium-235 had to be carried out by separating it from the bulk of natural uranium, and plutonium could only be obtained as a result of a controlled nuclear reaction by irradiating uranium-238 with neutrons. Both paths seemed unusually difficult and did not promise easy solutions. Indeed, how can two isotopes be separated from each other, which differ only slightly in their weight and chemically behave in exactly the same way? Neither science nor technology has ever faced such a problem. Plutonium production also seemed very problematic at first. Prior to this, the entire experience of nuclear transformations was reduced to several laboratory experiments. Now it was necessary to master the production of kilograms of plutonium on an industrial scale, develop and create a special installation for this - a nuclear reactor, and learn how to control the course of a nuclear reaction. And here and there a whole complex of complex problems had to be solved. Therefore, the "Manhattan Project" consisted of several subprojects, headed by prominent scientists. Oppenheimer himself was the head of the Los Alamos Science Laboratory. Lawrence was in charge of the Radiation Laboratory at the University of California. Fermi led research at the University of Chicago on the creation of a nuclear reactor. Initially, the most important problem was obtaining uranium. Before the war, this metal actually had no use. Now that it was needed immediately in huge quantities, it turned out that there was no industrial way to produce it. The Westinghouse company undertook its development and quickly achieved success. After purification of uranium resin (in this form uranium occurs in nature) and obtaining uranium oxide, it was converted into tetrafluoride (UF4), from which metallic uranium was isolated by electrolysis. If at the end of 1941 American scientists had only a few grams of metallic uranium at their disposal, then in November 1942 its industrial production at the Westinghouse plants reached 6000 pounds per month. At the same time, work was underway on the creation of a nuclear reactor. The plutonium production process actually boiled down to the irradiation of uranium rods with neutrons, as a result of which part of the uranium-238 had to turn into plutonium. Sources of neutrons in this case could be fissile uranium-235 atoms scattered in sufficient quantities among uranium-238 atoms. But in order to maintain a constant reproduction of neutrons, a chain reaction of fission of uranium-235 atoms had to begin. Meanwhile, as already mentioned, for every atom of uranium-235 there were 140 atoms of uranium-238. It is clear that the neutrons flying in all directions were much more likely to meet exactly them on their way. That is, a huge number of released neutrons turned out to be absorbed by the main isotope to no avail. Obviously, under such conditions, the chain reaction could not go. How to be? At first it seemed that without the separation of two isotopes, the operation of the reactor was generally impossible, but one important circumstance was soon established: it turned out that uranium-235 and uranium-238 were susceptible to neutrons of different energies. It is possible to split the nucleus of an atom of uranium-235 with a neutron of relatively low energy, having a speed of about 22 m/s. Such slow neutrons are not captured by uranium-238 nuclei - for this they must have a speed of the order of hundreds of thousands of meters per second. In other words, uranium-238 is powerless to prevent the start and progress of a chain reaction in uranium-235 caused by neutrons slowed down to extremely low speeds - no more than 22 m/s. This phenomenon was discovered by the Italian physicist Fermi, who lived in the United States since 1938 and supervised the work on the creation of the first reactor here. Fermi decided to use graphite as a neutron moderator. According to his calculations, the neutrons emitted from uranium-235, having passed through a layer of graphite of 40 cm, should have reduced their speed to 22 m/s and started a self-sustaining chain reaction in uranium-235. The so-called "heavy" water could serve as another moderator. Since the hydrogen atoms that make up it are very close in size and mass to neutrons, they could best slow them down. (About the same thing happens with fast neutrons as with balls: if a small ball hits a large one, it rolls back, almost without losing speed, but when it meets a small ball, it transfers a significant part of its energy to it - just like a neutron in an elastic collision bounces off a heavy nucleus only slightly slowing down, and on collision with the nuclei of hydrogen atoms loses all its energy very quickly.) However, ordinary water is not suitable for slowing down, since its hydrogen tends to absorb neutrons. That is why deuterium, which is part of "heavy" water, should be used for this purpose. In early 1942, under the leadership of Fermi, construction began on the first ever nuclear reactor in the tennis court under the west stands of the Chicago Stadium. All work was carried out by the scientists themselves. The reaction can be controlled in the only way - by adjusting the number of neutrons involved in the chain reaction. Fermi envisioned doing this with rods made from materials such as boron and cadmium, which absorb neutrons strongly. Graphite bricks served as a moderator, from which physicists erected columns 3 m high and 1 m wide. Rectangular blocks with uranium oxide were installed between them. About 2 tons of uranium oxide and 46 tons of graphite went into the entire structure. To slow down the reaction, cadmium and boron rods introduced into the reactor served. If this weren't enough, then for insurance, on a platform located above the reactor, there were two scientists with buckets filled with a solution of cadmium salts - they were supposed to pour them over the reactor if the reaction got out of control. Fortunately, this was not required. On December 2, 1942, Fermi ordered all the control rods to be extended, and the experiment began. Four minutes later, the neutron counters began to click louder and louder. With every minute, the intensity of the neutron flux became greater. This indicated that a chain reaction was taking place in the reactor. It went on for 28 minutes. Then Fermi signaled, and the lowered rods stopped the process. Thus, for the first time, man released the energy of the atomic nucleus and proved that he could control it at will. Now there was no longer any doubt that nuclear weapons were a reality. In 1943, the Fermi reactor was dismantled and transported to the Aragonese National Laboratory (50 km from Chicago). Another nuclear reactor was soon built here, in which heavy water was used as a moderator. It consisted of a cylindrical aluminum tank containing 6 tons of heavy water, into which 5 rods of uranium metal were vertically loaded, enclosed in an aluminum shell. The seven control rods were made from cadmium. Around the tank was a graphite reflector, then a screen made of lead and cadmium alloys. The entire structure was enclosed in a concrete shell with a wall thickness of about 120 m. Experiments on these experimental reactors confirmed the possibility of industrial production of plutonium. The main center of the "Manhattan Project" soon became the town of Oak Ridge in the Tennessee River Valley, whose population in a few months grew to 79 thousand people. The first enriched uranium production plant in history was built here in a short time. Immediately in 1943, an industrial reactor was launched that produced plutonium. In February 1944, about 300 kg of uranium was extracted from it daily, from the surface of which plutonium was obtained by chemical separation. (To do this, the plutonium was first dissolved and then precipitated.) The purified uranium was then returned to the reactor again. In the same year, in the barren, desolate desert on the south bank of the Columbia River, construction began on the huge Hanford Plant. Three powerful nuclear reactors were located here, giving several hundred grams of plutonium daily. In parallel, research was in full swing to develop an industrial process for uranium enrichment. After considering different options, Groves and Oppenheimer decided to focus on two methods: gas diffusion and electromagnetic. The gas diffusion method was based on a principle known as Graham's law (it was first formulated in 1829 by the Scottish chemist Thomas Graham and developed in 1896 by the English physicist Reilly). In accordance with this law, if two gases, one of which is lighter than the other, are passed through a filter with negligible holes, then a little more light gas will pass through it than heavy gas. In November 1942, Urey and Dunning at Columbia University created a gaseous diffusion method for separating uranium isotopes based on the Reilly method. Since natural uranium is a solid, it was first converted to uranium fluoride (UF6). This gas was then passed through microscopic - on the order of thousandths of a millimeter - holes in the filter septum. Since the difference in the molar weights of the gases was very small, behind the baffle the content of uranium-235 increased only by a factor of 1,0002. In order to increase the amount of uranium-235 even more, the resulting mixture is again passed through a partition, and the amount of uranium is again increased by 1 times. Thus, in order to increase the content of uranium-0002 to 235%, it was necessary to pass the gas through 99 filters. This took place in a huge gaseous diffusion plant at Oak Ridge. In 1940, under the leadership of Ernst Lawrence at the University of California, research began on the separation of uranium isotopes by the electromagnetic method. It was necessary to find such physical processes that would allow isotopes to be separated using the difference in their masses. Lawrence made an attempt to separate isotopes using the principle of a mass spectrograph - an instrument that determines the masses of atoms. The principle of its operation was as follows: pre-ionized atoms were accelerated by an electric field, and then passed through a magnetic field in which they described circles located in a plane perpendicular to the direction of the field. Since the radii of these trajectories were proportional to the mass, the light ions ended up on circles of a smaller radius than the heavy ones. If traps were placed in the path of the atoms, then it was possible in this way to separately collect different isotopes.
That was the method. Under laboratory conditions, he gave good results. But the construction of a plant in which isotope separation could be carried out on an industrial scale proved to be extremely difficult. However, Lawrence eventually managed to overcome all difficulties. The result of his efforts was the appearance of the calutron, which was installed in a giant plant in Oak Ridge.
This electromagnetic plant was built in 1943 and turned out to be perhaps the most expensive brainchild of the Manhattan Project. Lawrence's method required a large number of complex, as yet undeveloped devices involving high voltage, high vacuum, and strong magnetic fields. The costs were enormous. Calutron had a giant electromagnet, the length of which reached 75 m and weighed about 4000 tons. Several thousand tons of silver wire went into the windings for this electromagnet. The entire work (excluding the cost of $300 million worth of silver, which the State Treasury provided only temporarily) cost $400 million. Only for the electricity spent by the calutron, the Ministry of Defense paid 10 million. Much of the equipment at the Oak Ridge factory was superior in scale and precision to anything ever developed in the field. But all these expenses were not in vain. Having spent a total of about 2 billion dollars, US scientists by 1944 created a unique technology for uranium enrichment and plutonium production. Meanwhile, at the Los Alamos Laboratory, they were working on the design of the bomb itself. The principle of its operation was in general terms clear for a long time: the fissile substance (plutonium or uranium-235) should have been transferred to a critical state at the time of the explosion (for a chain reaction to occur, the mass of the charge must be even noticeably larger than the critical one) and irradiated with a neutron beam, which entailed is the start of a chain reaction. According to calculations, the critical mass of the charge exceeded 50 kilograms, but it could be significantly reduced. In general, the magnitude of the critical mass is strongly influenced by several factors. The larger the surface area of the charge, the more neutrons are emitted uselessly into the surrounding space. A sphere has the smallest surface area. Consequently, spherical charges, other things being equal, have the smallest critical mass. In addition, the value of the critical mass depends on the purity and type of fissile materials. It is inversely proportional to the square of the density of this material, which allows, for example, by doubling the density, to reduce the critical mass by a factor of four. The required degree of subcriticality can be obtained, for example, by compacting the fissile material due to the explosion of a conventional explosive charge made in the form of a spherical shell surrounding the nuclear charge. The critical mass can also be reduced by surrounding the charge with a screen that reflects neutrons well. Lead, beryllium, tungsten, natural uranium, iron, and many others can be used as such a screen.
One of the possible designs of the atomic bomb consists of two pieces of uranium, which, when combined, form a mass greater than the critical one. In order to cause a bomb explosion, you need to bring them together as quickly as possible. The second method is based on the use of an inward-converging explosion. In this case, the flow of gases from a conventional explosive was directed at the fissile material located inside and compressing it until it reached a critical mass. The connection of the charge and its intensive irradiation with neutrons, as already mentioned, causes a chain reaction, as a result of which, in the first second, the temperature rises to 1 million degrees. During this time, only about 5% of the critical mass managed to separate. The rest of the charge in the bombs of the early design evaporated to no avail. The first atomic bomb in history (named Trinity) was assembled in the summer of 1945. And on June 16, 1945, the first atomic explosion on Earth was carried out at the nuclear test site in the Alamogordo desert (New Mexico). The bomb was placed in the center of the test site on top of a 30-meter steel tower. Recording equipment was placed around it at a great distance. At 9 km there was an observation post, and at 16 km - a command post. The atomic explosion made a tremendous impression on all the witnesses of this event.
According to the description of eyewitnesses, there was a feeling that many suns merged into one and lit up the polygon at once. Then a huge ball of fire appeared above the plain, and a round cloud of dust and light began to slowly and ominously rise towards it. After taking off from the ground, this fireball flew up to a height of more than three kilometers in a few seconds. With every moment it grew in size, soon its diameter reached 1 km, and it slowly rose into the stratosphere. The fireball then gave way to a column of swirling smoke, which stretched out to a height of 5 km, taking the form of a giant mushroom. All this was accompanied by a terrible roar, from which the earth trembled. The power of the exploded bomb exceeded all expectations. As soon as the radiation situation allowed, several Sherman tanks, lined with lead plates from the inside, rushed into the explosion area. On one of them was Fermi, who was eager to see the results of his work. Dead scorched earth appeared before his eyes, on which all life was destroyed within a radius of 1 km. The sand sintered into a glassy greenish crust that covered the ground. In a huge crater lay the mutilated remains of a steel support tower. The force of the explosion was estimated at 5 tons of TNT. The next step was to be the combat use of the bomb against Japan, which, after the surrender of fascist Germany, alone continued the war with the United States and its allies. There were no launch vehicles then, so the bombing had to be carried out from an aircraft. The components of the two bombs were transported with great care by the USS Indianapolis to Tinian Island, where the US Air Force 509th Composite Group was based. By type of charge and design, these bombs were somewhat different from each other. The first bomb - "Kid" - was a large-sized aerial bomb with an atomic charge of highly enriched uranium-235. Its length was about 3 m, diameter - 62 cm, weight - 4 tons. The second bomb - "Fat Man" - with a charge of plutonium-1 had an egg-shaped shape with a large-sized stabilizer. Its length was 239 m, diameter 3 m, weight - 2 tons. On August 6, Colonel Tibbets' Enola Gay B-29 bomber dropped the "Kid" on the large Japanese city of Hiroshima. The bomb was dropped by parachute and exploded, as it was planned, at an altitude of 600 m from the ground. The consequences of the explosion were terrible. Even on the pilots themselves, the sight of the peaceful city destroyed by them in an instant made a depressing impression. Later, one of them admitted that they saw at that moment the worst thing that a person can see. For those who were on earth, what was happening looked like a real hell. First of all, a heat wave passed over Hiroshima. Its action lasted only a few moments, but it was so powerful that it melted even tiles and quartz crystals in granite slabs, turned telephone poles into coal at a distance of 4 km and, finally, so incinerated human bodies that only shadows remained of them on the pavement asphalt. or on the walls of houses. Then a monstrous gust of wind escaped from under the fireball and rushed over the city at a speed of 800 km / h, sweeping away everything in its path. The houses that could not withstand his furious onslaught collapsed as if they had been cut down. In a giant circle with a diameter of 4 km, not a single building remained intact. A few minutes after the explosion, a black radioactive rain fell over the city - this moisture turned into steam condensed in the high layers of the atmosphere and fell to the ground in the form of large drops mixed with radioactive dust. After the rain, a new gust of wind hit the city, this time blowing in the direction of the epicenter. He was weaker than the first, but still strong enough to uproot trees. The wind fanned a gigantic fire in which everything that could burn was burning. Of the 76 buildings, 55 were completely destroyed and burned down. Witnesses of this terrible catastrophe recalled people-torches from which burnt clothes fell to the ground along with tatters of skin, and crowds of distraught people, covered with terrible burns, who rushed screaming through the streets. There was a suffocating stench of burnt human flesh in the air. People lay everywhere, dead and dying. There were many who were blind and deaf and, poking in all directions, could not make out anything in the chaos that reigned around. The unfortunate, who were from the epicenter at a distance of up to 800 m, burned out in a split second in the literal sense of the word - their insides evaporated, and their bodies turned into lumps of smoking coals. Located at a distance of 1 km from the epicenter, they were struck by radiation sickness in an extremely severe form. Within a few hours, they began to vomit severely, the temperature jumped to 39-40 degrees, shortness of breath and bleeding appeared. Then, non-healing ulcers appeared on the skin, the composition of the blood changed dramatically, and the hair fell out. After terrible suffering, usually on the second or third day, death occurred. In total, about 240 thousand people died from the explosion and radiation sickness. About 160 thousand received radiation sickness in a milder form - their painful death was delayed for several months or years. When the news of the catastrophe spread throughout the country, all of Japan was paralyzed with fear. It increased further after Major Sweeney's Box Car aircraft dropped a second bomb on Nagasaki on 9 August. Several hundred thousand inhabitants were also killed and wounded here. Unable to resist the new weapons, the Japanese government capitulated - the atomic bomb put an end to World War II. War is over. It lasted only six years, but managed to change the world and people almost beyond recognition. Human civilization before 1939 and human civilization after 1945 are strikingly different from each other. There are many reasons for this, but one of the most important is the emergence of nuclear weapons. It can be said without exaggeration that the shadow of Hiroshima lies over the entire second half of the 6th century. It became a deep moral burn for many millions of people, both those who were contemporaries of this catastrophe and those born decades after it. Modern man can no longer think about the world the way it was thought before August 1945, XNUMX - he understands too clearly that this world can turn into nothing in a few moments. A modern person cannot look at the war, as his grandfathers and great-grandfathers watched - he knows for sure that this war will be the last, and there will be neither winners nor losers in it. Nuclear weapons have left their mark on all spheres of public life, and modern civilization cannot live by the same laws as sixty or eighty years ago. No one understood this better than the creators of the atomic bomb themselves. “The people of our planet,” wrote Robert Oppenheimer, “should unite. The horror and destruction sown by the last war dictate this idea to us. The explosions of atomic bombs proved it with all cruelty. Other people at other times have said similar words - only about other weapons and of other wars. They have not succeeded. But whoever today says that these words are useless is deluded by the vicissitudes of history. We cannot be convinced of this. The results of our work leave mankind no choice but to create a united world. A world based on law and humanism." Author: Ryzhov K.V.
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