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Michelson, Albert

( The American physicist, Nobel Prize in Physics, 1907)

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Biography Michelson, Albert
December 19, 1852, Mr.. - May 9, 1931
American physicist Albert Abraham Michelson was born in Strelna (Germany), near the Polish border, the son of merchant Samuel Michelson and the doctor's daughter Rosalie (Pzhlyubska) Michelson. M. was the eldest of three children. When M. was two years old whose parents emigrated to the United States, where his father became a supplier of dry food during the Gold Rush in California and Nevada. M. was sent to relatives in San Francisco, where he became a disciple of male high school. Later he moved to the board to the principal, who awakened his interest in natural sciences and advised to go to the Naval Academy United States in Annapolis (Maryland). Armed with a letter of recommendation from his congressman, M. appealed to President Ulysses C. Grant a request for admission to the academy, though no one vacancy was not. His perseverance has made to officials was so impressed that in 1869. for him was allocated one seat listeners. M. graduated from the Academy in 1873, two years served as a midshipman, and in 1875. was appointed professor of physics and chemistry of the Academy. This post he held for the next four years.
In 1878, Mr.. M. interested in measuring the speed of light. Light and optics have become a matter of his life. Although by that time the speed of light has been measured by the French physicists Hippolyte Fizeau, Leon Foucault and Marie Alfred Cornu, the results of these measurements can not be considered accurate. Using given to him by his stepfather $ 2000, M. significantly improved the method of Foucault and measured the speed of light with previously unattainable accuracy. His work attracted international attention. In 1880, Mr.. M. left Annapolis and two years studying optics in Europe. During his stay in Europe, he designed an interferometer - a device in which the measurement of various optical phenomena is based on the interference of light waves.
Having mastered the art of physical devices, M. invented the interferometer to detect Earth's motion through a stationary ether, which was believed at the time, fills all space. Scottish physicist James Clerk Maxwell, proved theoretically that light is an electromagnetic wave, suggested that the electromagnetic wave must be distributed in a certain environment. Maxwell's electromagnetic theory, it would seem, indirectly confirmed the existence of ether. Maxwell also suggested that the existence of ether can be detected by measuring the speed of light relative motion of the Earth. If the broadcast is indeed a luminous environment and the Earth moves relative to it, the speed of light would be different and depend on whether the light is moving toward Earth, from her or at an angle to it. Experimentally detect the motion of the earth through the ether could not be anyone, but it was assumed that the failure of all attempts due to lack of adequate measuring devices. It is this gap and intended to make M. his interferometer.
In very high-M. beam with poluposerebrennogo mirror is split into two, and then these two beams joined again, M. believed that since the two beams of light are different ways (in the direction of motion of the Earth and perpendicular to it), then they should have and the different speed relative to Earth. Consequently, the waves of the two beams at the connection will have different phases, which should give the interference pattern, similar to that observed when crossing the waves on the surface of the pond. When interference occur alternating light and dark bands that form the so-called interference pattern.
The first attempt to detect the earth's motion through the ether with an interferometer M. taken in 1881, when he worked with Hermann von Helmholtz in Berlin. To his surprise, he found no interference pattern: both the beam spread with equal speed. M. was so confident in the accuracy of their measurements, . that the communication of his experiment, . published in 'American natural science journal' ( "American Journal of Science"), . dared to make a bold statement at the time: 'So, . shown, . that the hypothesis of a stationary ether is wrong ',
. While the importance of the experimental M. been widely recognized, some physicists pointed to possible sources of error in the scheme of the experiment, casting doubt on the correctness of the conclusions.
Before returning to the United States (1882) M. retired from the Naval Academy to become professor of physics at Keyzovskom Institute of Technology (now University of Case-Western Reserve) in Cleveland (Ohio). It was there that he began collaboration with Edward I. Morley. Their famous experiment in 1887, Mr.. was a repetition of Berlin in 1881, but with improved interferometer constructed to exclude noticed earlier sources of errors. Result of the experiment and this time was negative: the interference pattern did not arise. Movement of the Earth did not affect the speed of light.
Although the experiment of Michelson - Morley casting doubt on the existence of a completely stationary ether, scientists do not reject the concept entirely. As noted by M. himself, the negative result of the experiment could be explained if the broadcast attracted Earth and moved almost to its speed. But such a hypothesis is not possible to completely get rid of the problems. This problem attracted the attention of such eminent physicist, as Hendrik Lorentz. Classic presentation of the motion were based on a fixed reference frame (in this case related to the ether), on which he could make the measurement of absolute motion.
. The failures always comprehend all attempts to prove the existence of such a system were one of the most difficult problems encountered in the late XIX century
. classical physics. Works Lorentz led Albert Einstein published in 1905. his special theory of relativity. This theory rejects the existence of stationary frames of reference and the absolute motion. Thus fell away and the need for the existence of ether. From the viewpoint of the special theory of relativity Einstein's movement can be completely described in terms of motion of the observer. According to another postulate, light travels at a constant rate regardless of the motion of the observer or light source. Although the experiment of Michelson - Morley only indirectly contributed to the formation of the special theory of relativity (in 1905. Einstein was not aware of it), in retrospect it was important to her confirmation.
Puzzled results of his experiment, M. was nevertheless satisfied with the accuracy of measurements achieved by an interferometer, and suggested other options for its use. From 1889 to 1893. M. was a professor of physics at Clark University in Uorkestre (Massachusetts). There, he used the interferometer to determine the length of the meter in one of the wavelengths of the spectral lines of cadmium. Such an approach would enable the laboratories to get rid of the physical standards of the type of metal rods, whose length depends on the processing and temperature. This metrology project, completed in 1902, brought M. international recognition. In 1893, Mr.. He became head of the newly established Faculty of Physics, University of Chicago.
Portfolio M. to establish the metric standard was 'byproduct' conducted in 1887 ... 1897. Studies of light emitted by excited atoms (ie. atoms that have absorbed energy, for example by heating). It was known that if the emitted light decomposed into components with different wavelengths (different colors) with the help of a spectrograph, then the resulting line spectrum is characteristic for each chemical element type. Physicists have seen in the spectra of atoms clue to the atomic structure. Exploring the spectral lines with the help of his interferometer, M. found that they consist of several closely spaced 'genuine'. Such fine structure of the scientists could not explain until you see the 20-ies. quantum mechanics. Now interferometer M. applied to the analysis of light every day and remains one of the most powerful tools of modern analysis.
M. was awarded the Nobel Prize in Physics 1907. 'for the creation of high-precision optical instruments and performed with them using spectroscopic and metrological investigations'. Speaking at the award ceremony, K.B. Hasselberg of the Royal Swedish Academy of Sciences noted that the Michelson interferometer made it possible to measure 'with an unusually high degree of accuracy'.
In an effort to create more accurate and sophisticated instruments, M. set out to increase the resolving power of spectrographs, using larger precision diffraction gratings. Such a lattice is decomposed by falling on them in the light beam components with different wavelengths. M. interested in diffraction gratings, made in the form of mirrors, for which suffered a large number of thin lines with narrow spaces between them. The study he was able to create the largest and thin diffraction gratings, surpasses anything that was available to him. Initially M. supposed to give this work a few years, but the problem is so seized him that he did not stop doing it until the end of life.
. After a break caused by the need to work for the needs of the naval forces of the United States during the First World War, M
. returned to his studies. At this time his interests turned to astronomy. M. ultimately offer several ways to use an interferometer to measure the diameter of such small objects, like asteroids, small moons of the planets of the solar system and large bright stars. In 1920, Mr.. M. first succeeded in measuring the diameter of a distant star. He reported that the diameter of the giant star Betelgeuse is 240 million. miles. Through these studies, performed at the telescope of Mount Wilson Observatory near Pasadena, M. increasingly been in California. He worked in the California Institute of Technology. M. made the first hardness of the Earth, defined with the help of an interferometer tidal water level fluctuations in the pipes, buried in the ground. In 1925, Mr.. became the first honorary professor at the University of Chicago, but in 1929. left Chicago and devoted himself entirely to research in California.
Marriage M. Margaret Heminuey (1877), from which a daughter and two sons, ended in divorce in 1897. Two years later, M. married Edna Stanton. From this marriage the M. had three daughters. M. was known watercolor painter and a gifted violinist. He taught music and their children. M. well played tennis, billiards, chess and bridge, and loved sailing.
Known for its dedication, M. always preferred to research administrative work and teaching. He did not like to talk with graduate students and occasionally, from time to time, gave lectures and presentations.
In the last year of life, a few serious blows, M. continued to conduct research literally lying in bed. His latest project, until the completion of which he was not destined to survive, was another attempt to clarify the measurement of the speed of light. M. died from a brain hemorrhage May 9, 1931, Mr.. in Pasadena (California).
Although M. never defended his doctoral dissertation, he was awarded for its achievements honorary degree of Doctor of eleven major universities in Europe and America. In addition to the Nobel Prize among his numerous awards were the Copley Medal of Royal Society of London (1907), . Henry Draper Medal of the National Academy of Sciences USA (1916), . Franklinovskogo Medal of the Franklin Institute (1923), . Gold Medal of the Royal Astronomical Society of London (1923) and a medal Daddella Physical Society of London,
. M. was a member of many scientific societies and academies, including the National Academy of the United States, Royal Society of London, the French Academy of Sciences and the Sciences. He was president of the American Physical Society (1901 ... 4903) and the National Academy of Sciences USA (1916).

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Michelson, Albert, photo, biography
Michelson, Albert, photo, biography Michelson, Albert  The American physicist, Nobel Prize in Physics, 1907, photo, biography
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