FOWLER (Fowler), William( The American physicist, Nobel Prize in Physics, 1983)
Comments for FOWLER (Fowler), William
Biography FOWLER (Fowler), William
born August 9, 1911
American physicist William Alfred Fowler was born in Pittsburgh (Pennsylvania), he was the eldest of three children, Jenny Summers (Watson) Fowler and John McLeod Fowler, accountant. When William was two years old, the family moved to r. Lima (Ohio), a major railway junction, where the boy for life acquired a love for locomotives. The school teacher encouraged his interest in science and technology. Entered the University of Ohio in 1929 to specialize in ceramics, he moved to the second-year student at the newly opened specialization in applied physics and graduated with honors from University. To get an education, F. had to look for jobs during the summer student vacation, and after school, he worked in the electronic laboratory Faculty of Electrical Engineering. He really enjoyed himself to perform physical measurements and make engineering. In the last year he wrote a thesis 'Focusing of Electron Beams' ( "Focusing of Electron Beams").
Entering graduate of California Institute of Technology (Caltech), F. engaged in Kellogovskoy Radiation Laboratory under the leadership of the Danish physicist Charles Lauritsen, from whom he learned, as he himself said that, 'how to do physics and get pleasure from their work'. In 1936, Mr.. He became a doctor, with a thesis entitled 'Radioactive elements with low atomic weight' ( "Radioactive Elements of Low Atomic Number"). Since that time, F. Officer Kellogovskoy laboratory, where in 1970 he. became the first professor of physics at the institute (university scientific knowledge in the institute).
. During the Second World War Kellogovskaya laboratory engaged in military research, and FA, while remaining a civilian man who helped develop the fuses, rocket and torpedo guns and atomic weapons
. For this work he received from the Government of the United States in 1948. Medal of Merit. At the end of the war, F., Lauritsen, and Lauritsen's son Thomas continued nuclear research, focusing primarily on the nuclear reactions in stars.
In 1939, Mr.. physicist, a specialist in nuclear physics, Hans Bethe discovered the energy source of stars, finding that the energy produced by nuclear reactions leading to the conversion of hydrogen nuclei into helium nuclei. There are several varieties, or isotopes, of hydrogen at each having one proton (carrying a positive electric charge) in the nucleus and, consequently, the atomic number is 1. The most common form contains only a proton in the nucleus, so its mass number is also equal to 1. However, in the nucleus of heavy hydrogen, or deuterium, one proton and one neutron, so that its mass number is 2. A nucleus of tritium contains one proton and two neutrons, which makes its mass number is 3.
Each helium nucleus contains two protons (atomic number 2), and in its most common form in the nucleus contains more and two neutrons (mass number 4). However, other isotopes of helium have more or fewer neutrons and, consequently, other mass numbers. In the nuclear reactions can involve the various isotopes, many of which are unstable (radioactive). Isotopes occurring in normal conditions, as a rule, are among the most stable, while others moved over time to more stable types of decays and radiation. Bethe extrapolate the results of laboratory measurements of nuclear reactions and calculated apparent reaction rate in terms of existing presumably in the center of stars, which led him to the discovery of their source of energy.
. Specializes in cosmology George Gamow in his conception of the origin of the Universe, . known as the theory of 'big bang', . speculated, . that atomic nuclei heavier than helium could be formed by adding neutrons, . one unit mass at a time,
. However, Hans Staub and William Stephens found that no stable nucleus does not have a mass 5, and F. colleagues found that no stable nucleus has a mass of 8. These two holes refuted Gamow's scheme in two respects. First, the addition of one neutron to the nucleus of helium mass 4 can not lead to atoms of heavier elements, because the unstable nucleus of mass 5 splits before additional neutrons can with him to interact. Second, . merger of two helium nuclei of mass 4 (like the two hydrogen nuclei) also will not lead to the atoms of heavier elements, . because the unstable nucleus breaks up before a mass of 8, . than nuclear reactions can add additional neutrons (Heavier elements have also a large number of protons, . but neutrons can pass into protons, . to compensate for their lack of, . so that here there is no obstacle).,
. In 1951, Mr.
. in Kellogovskuyu laboratory came physicist E.E. Salpeter, . and he was able to prove, . that three helium nuclei (each with a mass 4) could form the nucleus of carbon (mass 12) with conditions, . which are available in red giant stars (the stars in the intermediate stage of evolution, . with a large volume and relatively low surface temperature), . but not in those, . which accompanied the 'big bang',
. Two years later, British astronomer Fred Hoyle led Ward Veylinga in Kellogovskuyu laboratory, . to posgavit experiment, . which would give a quantitative confirmation that, . that helium can, . burning, . transformed into carbon at the temperature and density, . which are characteristic of red giants.,
. As a result of working with Hoyle, as well as with Margaret and Geoffrey Burbidge during a sabbatical in 1954 ... 1955
. in England, where he was a Fulbright scholar at Cambridge University, S. formulated a comprehensive theory, which summarized the nuclear reactions leading to the synthesis of all naturally occurring elements, and explain the relative values of their prevalence, observed by astronomers. In their article 1957. 'The synthesis of elements in the stars' ( "Sunthesis of the Elements in Star"), . which appeared in the journal "Review of modern physics' (" Reviews of Modern Physics "), . to appear, . that formed during the 'Big Bang' hydrogen and helium could be the basis of nuclear fusion in stars of all elements - from carbon to uranium,
. These elements could then be thrown into space by supernova explosions that appear in the evolution of heavy stars. A physicist. Cameron, regardless of them expressed the same basic ideas at the same time.
Combining the data of nuclear astrophysics and the theory of the structure of stars, F. played a major role in creating the basic model of stellar. In accordance with this model, a cloud of gas (mostly hydrogen and helium) is compressed under its own gravitational forces. When the cloud becomes sufficiently dense and hot, hydrogen is converted into helium and the cloud becomes a star. As the burning of hydrogen in the center of the star, it shrinks even more. If the star is massive enough, the nucleus again becomes sufficiently dense and hot, which allows helium to move into carbon. Then the star greatly expands and becomes a red giant. If a star has enough mass, . its kernel is repeating cycles of depletion of nuclear fuel, . compression core and a new nuclear ignition products of previous nuclear reactions until, . There may be produced as a result of the kernel will not be composed mostly of iron (atomic weight 56),
. If the iron core becomes too massive, it explodes stellar atmosphere, becoming a supernova, and compressed to a density similar to the density of atomic nuclei. If the star is massive enough to form an iron core, it usually loses its atmosphere after it becomes a red giant.
F. and colleagues have suggested that elements heavier than iron are formed by successive capture of neutrons by nuclei of heavy stars, either before or during the formation of a supernova. As a result of these processes are part of the synthesized heavy elements dispersed in the space where they can enter into the future of star systems.
F. received in 1983. Nobel Prize in physics, 'a theoretical and experimental study of nuclear reactions that are essential for the formation of chemical elements of the universe'. He shared the prize with the astrophysicist Chandrasekhar Subrahmanyanom. In his speech, Sven Johansson of the Royal Swedish Academy of Sciences identified the work of F. a 'comprehensive theory of the formation of chemical elements in the Universe' and noted that 'this theory still forms the basis of our knowledge in this area'. In reply, S. said that he 'came to a young graduate student at Caltech 50 years ago, and now known as the oldest graduate student at Caltech'. And he added - 'The great attraction of the process of learning is that by making its small contribution to this process, we thus continue to study and enjoy this study'. In his Nobel lecture F. an overview of experimental and theoretical aspects of an educational theory of the elements. In conclusion, he reminded the audience that their bodies, except for hydrogen and oxygen, consists mainly of heavy elements. 'Thus, we can say that you and your neighbor, and I, each of us and together we are a really and literally a handful of star dust'.
In 1940. F. married Ardiyen Foy Olmsted, they have two daughters. 'The most conspicuous feature of F. is his love for people - once wrote, Hans Bethe. He is full of humor and goodwill, and infects these other '. F. enjoys mountaineering, actively root for Pittsburgh professional baseball and football teams, in addition, he has kept since childhood love for locomotives.
F. - Member of the National Academy of Sciences, Honorary Member of the Royal Society of Arts in London, Corresponding Member of the Royal Astronomical Society. He was president of the American Physical Society, worked in the National Research Council and the Council for Space Sciences. Among his awards is the award in honor of the successful launch of spacecraft 'Apollo' from the organization of NASA (1969), Tom Bonner Prize of the American Physical Society (1970), the National Medal 'For his scientific achievements'. National Science Foundation (1974), Eddington Medal of the Royal Astronomical Society (1978) and a gold medal Brusovsky Pacific Astronomical Society (1979). He has honorary degrees from Chicago and University of Liц¬ge, Ohio State University and Denison University, as well as the Paris Observatory.