Radioactivity and nuclear energy
It was quickly noted after the discovery of radioactivity Radioactive decay is the process in which an unstable atomic nucleus spontaneously loses energy by emitting ionizing particles and radiation. This decay, or loss of energy, results in an atom of one type, called the parent nuclide transforming to an atom of a different type, called the daughter nuclide. For example: a carbon-14 atom emits in 1897, that the total energy due to radioactive processes is about one million times greater than that involved in any known molecular change. However, it raised the question where this energy is coming from. After eliminating the idea of absorption and emission of some sort of Lesagian ether particles Le Sage's theory of gravitation is the most common name for the kinetic theory of gravity originally proposed by Nicolas Fatio de Duillier in 1690 and later by Georges-Louis Le Sage in 1748. The theory proposed a mechanical explanation for Newton's gravitational force in terms of streams of tiny unseen particles impacting on all material objects, the existence of a huge amount of latent energy, stored within matter, was proposed by Ernest Rutherford Ernest Rutherford, 1st Baron Rutherford of Nelson, OM, FRS was a New Zealand born British chemist and Physicist who became known as the father of nuclear physics. He discovered that atoms have a small charged nucleus, and thereby pioneered the Rutherford model (or planetary model, which later evolved into the Bohr model or orbital model) of the and Frederick Soddy Frederick Soddy was an English radiochemist. He received the Nobel Prize for Chemistry in 1921, and has a crater named for him on the far side of the Moon in 1903. Rutherford also suggested that this internal energy is stored within normal matter as well. He went on to speculate in 1904:[60][61]
| “ | If it were ever found possible to control at will the rate of disintegration of the radio-elements, an enormous amount of energy could be obtained from a small quantity of matter. | ” |
Einstein mentions in his 1905 paper that mass-energy equivalence might perhaps be tested with radioactive decay, which releases enough energy (the quantitative amount known roughly even by 1905) to possibly be "weighed," when missing. But the idea that great amounts of usable energy could be liberated from matter, however, proved initially difficult to substantiate in a practical fashion. Because it had been used as the basis of much speculation, Rutherford himself, rejecting his ideas of 1904, was once reported in the 1930s to have said that: "Anyone who expects a source of power from the transformation of the atom is talking moonshine."
The popular connection between Einstein, E=mc2, and the atomic bomb A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission or a combination of fission and fusion. Both reactions release vast quantities of energy from relatively small amounts of matter; a modern thermonuclear weapon weighing little more than a thousand kilograms can produce an explosion was prominently indicated on the cover of Time Time is an American newsmagazine. A European edition (Time Europe, formerly known as Time Atlantic) is published from London. Time Europe covers the Middle East, Africa and, since 2003, Latin America. An Asian edition (Time Asia) is based in Hong Kong. As of 2009, Time no longer publishes a Canadian advertiser edition. The South Pacific edition, magazine in July 1946 by the writing of the equation on the mushroom cloud itself.This changed dramatically after the demonstration of energy released from nuclear fission In nuclear physics and nuclear chemistry, nuclear fission is a nuclear reaction in which the nucleus of an atom splits into smaller parts, often producing free neutrons and lighter nuclei, which may eventually produce photons . Fission of heavy elements is an exothermic reaction which can release large amounts of energy both as electromagnetic after the atomic bombings of Hiroshima and Nagasaki 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 the executive order of U.S. President Harry S. Truman on August 6 and August 9, 1945, respectively. After six months of intense fire-bombing of 67 other Japanese cities, followed by an ultimatum which in 1945. The equation E = mc2 became directly linked in the public eye with the power and peril of nuclear weapons A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission or a combination of fission and fusion. Both reactions release vast quantities of energy from relatively small amounts of matter; a modern thermonuclear weapon weighing little more than a thousand kilograms can produce an explosion. The equation was featured as early as page 2 of the Smyth Report The Smyth Report was the common name given to an administrative history written by physicist Henry DeWolf Smyth about the Allied World War II effort to develop the atomic bomb, the Manhattan Project. The full title of the report was the unwieldy Atomic Energy for Military Purposes; The Official Report on the Development of the Atomic Bomb under, the official 1945 release by the US government on the development of the atomic bomb, and by 1946 the equation was close-enough linked with Einstein's work that the cover of Time Time is an American newsmagazine. A European edition (Time Europe, formerly known as Time Atlantic) is published from London. Time Europe covers the Middle East, Africa and, since 2003, Latin America. An Asian edition (Time Asia) is based in Hong Kong. As of 2009, Time no longer publishes a Canadian advertiser edition. The South Pacific edition, magazine prominently featured a picture of Einstein next to an image of a mushroom cloud emblazoned with the equation.[62] Einstein himself had only a minor role in the Manhattan Project The Manhattan Project was the codename for a project conducted during World War II to develop the first atomic bomb. The project was led by the United States, and included scientists from the United Kingdom and Canada. Formally designated as the Manhattan Engineer District , it refers specifically to the period of the project from 1942–1946: he had cosigned a letter The Einstein–Szilárd letter was a letter sent to United States President Franklin D. Roosevelt on August 2, 1939, that was signed by Albert Einstein but largely written by Leó Szilárd in consultation with fellow Hungarian physicists Edward Teller and Eugene Wigner. The letter advised Roosevelt that Nazi Germany might be researching the use of to the US President in 1939 urging funding for research into atomic energy, warning that an atomic bomb was theoretically possible. The letter persuaded Roosevelt to devote a significant portion of the wartime budget to atomic research. Without a security clearance, Einstein's only scientific contribution was an analysis of an isotope separation Isotope separation is the process of concentrating specific isotopes of a chemical element by removing other isotopes, for example separating natural uranium into enriched uranium and depleted uranium. This is a crucial process in the manufacture of uranium fuel for nuclear power stations, and is also required for the creation of a uranium based method based on the rate of molecular diffusion through pores, a now-obsolete process that was then competitive and contributed a fraction of the enriched uranium Enriched uranium is a kind of uranium in which the percent composition of uranium-235 has been increased through the process of isotope separation. Natural uranium is 99.284% 238U isotope, with 235U only constituting about 0.711% of its weight. 235U is the only isotope existing in nature (in any appreciable amount) that is fissionable by thermal used in the project.[63]
While E = mc2 is useful for understanding the amount of energy released in a fission reaction, it was not strictly necessary to develop the weapon. As the physicist and Manhattan Project participant Robert Serber Robert Serber was an American physicist who participated in the Manhattan Project put it: "Somehow the popular notion took hold long ago that Einstein's theory of relativity, in particular his famous equation E = mc2, plays some essential role in the theory of fission. Albert Einstein had a part in alerting the United States government to the possibility of building an atomic bomb, but his theory of relativity is not required in discussing fission. The theory of fission is what physicists call a non-relativistic theory, meaning that relativistic effects are too small to affect the dynamics of the fission process significantly."[64] However the association between E = mc2 and nuclear energy has since stuck, and because of this association, and its simple expression of the ideas of Albert Einstein himself, it has become "the world's most famous equation".[65]
While Serber's view of the strict lack of need to use mass-energy equivalence in designing the atomic bomb is correct, it does not take into account the pivotal role which this relationship played in making the fundamental leap to the initial hypothesis that large atoms could split into approximately equal halves. In late 1938, while on the winter walk on which they solved the meaning of Hahn's experimental results and introduced the idea that would be called atomic fission, Lise Meitner Lise Meitner was part of the team that discovered nuclear fission, an achievement for which her colleague Otto Hahn was awarded the Nobel Prize. Meitner is often mentioned as one of the most glaring examples of scientific achievement overlooked by the Nobel committee. A 1997 Physics Today study concluded that Meitner's omission was "a rare and Otto Robert Frisch Otto Robert Frisch , Austrian-British physicist. With his collaborator Rudolf Peierls he designed the first theoretical mechanism for the detonation of an atomic bomb in 1940 made direct use of Einstein's equation to help them understand the quantitative energetics of the reaction which overcame the "surface tension-like" forces holding the nucleus together, and allowed the fission fragments to separate to a configuration from which their charges could force them into an energetic "fission." To do this, they made use of "packing fraction," or nuclear binding energy Binding energy is the mechanical energy required to disassemble a whole into separate parts. A bound system has typically a lower potential energy than its constituent parts; this is what keeps the system together. The usual convention is that this corresponds to a positive binding energy values for elements, which Mitner had memorized. These, together with use of E = mc2 allowed them to realize on the spot that the basic fission process was energetically possible:
...We walked up and down in the snow, I on skis and she on foot. ...and gradually the idea took shape... explained by Bohr's idea that the nucleus is like a liquid drop; such a drop might elongate and divide itself... We knew there were strong forces that would resist, ..just as surface tension. But nuclei differed from ordinary drops. At this point we both sat down on a tree trunk and started to calculate on scraps of paper. ...the Uranium nucleus might indeed be an unstable drop, ready to divide itself... But, ...when the two drops separated they would be driven apart by electrical repulsion, about 200 MeV in all. Fortunately Lise Meitner remembered how to compute the masses of nuclei... and worked out that the two nuclei formed... would be lighter by about one-fifth the mass of a proton. Now whenever mass disappears energy is created, according to Einstein's formula E = mc2, and... the mass was just equivalent to 200 MeV; it all fitted! [66]
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