Michelson was born inStrelno,Posen,Kingdom of Prussia (modern-day Strzelno, Poland), to Jewish parents,[5] the son of Samuel Michelson[6] and his wife, Rozalia Przyłubska.[7] He moved to the US with his parents in 1855, at the age of two. He grew up in the mining towns ofMurphy's Camp, California, andVirginia City, Nevada, where his father was a merchant. His family was non-religious, and Michelson himself was a lifelongagnostic.[8][9][10] He spent his high school years in San Francisco in the home of his aunt, Henriette Levy (née Michelson), who was the mother of authorHarriet Lane Levy.[11]His sister was the novelistMiriam Michelson.
Michelson was fascinated with the sciences, and the problem of measuring thespeed of light in particular. While atAnnapolis, he conducted his firstexperiments on thespeed of light, as part of a class demonstration in 1877. His Annapolis experiment was refined, and in 1879,[16] he measured the speed of light in air to be299864±51 kilometres per second, and estimated the speed of light in vacuum as299940 km/s, or186380 mi/s.[17][18][19] After two years of studies in Europe, he resigned from theNavy in 1881. In 1883 he accepted a position as professor of physics at theCase School of Applied Science inCleveland, Ohio, and concentrated on developing an improvedinterferometer. In 1887 he andEdward Morley carried out the famousMichelson–Morley experiment which failed to detect evidence of the existence of theluminiferous ether. He later moved on to useastronomical interferometers in the measurement of stellar diameters and in measuring the separations of binary stars.
Michelson died inPasadena, California, at the age of 78.[21] The University of Chicago Residence Halls remembered Michelson and his achievements by dedicating 'Michelson House' in his honor. Case Western Reserve has dedicated a Michelson House to him, and Michelson Hall (an academic building of science classrooms, laboratories and offices) at theUnited States Naval Academy also bears his name. Michelson Laboratory atNaval Air Weapons Station China Lake in Ridgecrest, California, is named for him. There is a display in the publicly accessible area of the Lab which includes facsimiles of Michelson's Nobel Prize medal, the prize document, and examples of his diffraction gratings. In 2017, a newly renovated physics research center at the University of Chicago was renamed in honor of Michelson as well.[22]
Numerous awards, lectures, and honors have been created in Albert A. Michelson's name.[23] Some of the current awards and lectures named for Michelson include the following: the Bomem-Michelson Award and Lecture annually presented until 2017 by the Coblentz Society;[24] theMichelson–Morley Award and Lecture, along with the Michelson Lecture Series,[25] and the Michelson Postdoctoral Prize Lectureship,[26] all of which are given annually byCase Western Reserve University; the A.A. Michelson Award presented every year by theComputer Measurement Group;[27] the Albert A. Michelson Award given by theNavy League of the United States;[28] and the Michelson Memorial Lecture Series[29] presented annually by the Division of Mathematics and Science at theU.S. Naval Academy.
In 1877 Michelson married Margaret Hemingway, daughter of a wealthy New York stockbroker and lawyer and the niece of his commanderWilliam T. Sampson. They had two sons and a daughter.[30][31]
In 1899, he married Edna Stanton. They raised three daughters.[31]
Page one of Michelson'sExperimental Determination of the Velocity of LightConcluding page of Michelson'sExperimental Determination of the Velocity of Light
Michelson was fascinated by light all his life. Once asked why he studied light, he reputedly said, "because it's so much fun".[33]
As early as 1869, while serving as an officer in theUnited States Navy, Michelson started planning a repeat of the rotating-mirror method ofLéon Foucault for measuring the speed of light, using improved optics and a longer baseline. He conducted some preliminary measurements using largely improvised equipment in 1878, about the same time that his work came to the attention ofSimon Newcomb, director of the Nautical Almanac Office who was already advanced in planning his own study.
Michelson's formal experiments took place in June and July 1879. He constructed a frame building along the north sea wall of the Naval Academy to house the machinery.[34] Michelson published his result of 299,910 ± 50 km/s in 1879 before joiningNewcomb in Washington DC to assist with his measurements there. Thus began a long professional collaboration and friendship between the two.
Simon Newcomb, with his more adequately funded project, obtained a value of 299,860 ± 30 km/s, just at the extreme edge of consistency with Michelson's. Michelson continued to "refine" his method and in 1883 published a measurement of 299,853 ± 60 km/s, rather closer to that of his mentor.
Lt. Cmdr. Albert A. Michelson while serving in theU.S. Navy. He rejoined the U.S. Navy in World War I,[35] when this portrait was taken.
In 1906, a novel electrical method was used byE. B. Rosa and theNational Bureau of Standards to obtain a value for thespeed of light of 299,781 ± 10 km/s. Though this result has subsequently been shown to be severely biased by the poor electrical standards in use at the time, it seems to have set a fashion for rather lower measured values.
In 1922, theUnited States Coast and Geodetic Survey began two years of painstaking measurement of the baseline using the recently availableinvar tapes. With the baseline length established in 1924, measurements were carried out over the next two years to obtain the published value of 299,796 ± 4 km/s.[36]
Famous as the measurement is, it was beset by problems, not least of which was the haze created by the smoke from forest fires which blurred the mirror image. It is also probable that the intensively detailed work of thegeodetic survey, with an estimated error of less than one part in 1 million, was compromised by a shift in the baseline arising from theSanta Barbara earthquake of June 29, 1925, which was an estimated magnitude of 6.3 on theRichter scale.
The period after 1927 marked the advent of new measurements of the speed of light using novelelectro-optic devices, all substantially lower than Michelson's 1926 value.
Michelson sought another measurement, but this time in an evacuated tube to avoid difficulties in interpreting the image owing to atmospheric effects. In 1929, he began a collaboration withFrancis G. Pease and Fred Pearson to perform a measurement in a 1.6 km tube 3 feet in diameter at the Irvine Ranch near Santa Ana, California.[37][38] In multiple reflections the light path was increased to 5 miles. For the first time in history the speed of light was measured in an almost perfect vacuum of 0.5 mm of mercury. Michelson died with only 36 of the 233 measurement series completed and the experiment was subsequently beset by geological instability and condensation problems before the result of299774±11 km/s, consistent with the prevailingelectro-optic values, was published posthumously in 1935.[38]
Application of basic statistical principles in Michelson's study of speed of light
During June and early July 1879, Michelson refined experimental arrangements from those developed byHippolyte Fizeau andLéon Foucault. The experimental setup was as follows: Light generated from a source is directed towards a rotating mirror through a slit on a fixed plate; the rotating mirror reflects the incoming light and at a certain angle, towards the direction where another fixed flat mirror is placed whose surface is perpendicular to the incoming ray of light; the rotating mirror should have rotated by an angle α by the time the ray of light travels back and is reflected again towards the fixed plate (the distance between the fixed mirror and the rotating one is recorded as D); a displacement from the slit is detected on the plate which measures d; the distance from the rotating mirror to the fixed plate is designated as the radiusr while the number of revolutions per second of the mirror is recorded asω. In this way,tan(2α) =d/r;Δt = (α/2π)/ω; speed of light can be derived as c = 2D/Δt.
While at plain sight, four measured quantities are involved: distanceD, radiusr, displacementd and rotating mirror revolution per second ω, which seems simple; yet based on the limitation of the measurement technology at that time, great efforts were made by Michelson to reducesystematic errors and apply subsequent corrections. For instance, he adopted a steel measuring tape with a said length of 100 feet and he intended to measure tens of times across the distance; still, he measured its length against a copy of the official standard yard to find out it as 100.006 feet, thus eliminating a systematic error, albeit small.
Aside from the efforts to reduce as much as possible the systematic errors, repeated measurements were performed at multiple levels to obtain more accurate results. As R.J. MacKay and R.W. Oldford remarked in their article,[39] 'It is clear that Michelson appreciated the power of averaging to reduce variability in measurement', it is clear that Michelson had in mind the property that averages vary less which should be formally described as: the standard deviation of the average ofn independent random variables is less than that of a single random variable by a factor of the square root of n. To realize that, he also strived to have each measurement not influencing each other, thus being mutuallyindependent random variables.
Astatistical model for repeated measurements with the assumption of independence or identical distributions is unrealistic. In the case of light speed study, each measurement is approached as the sum of quantity of interest and measurement error. In the absence of systematic error, the measurement error of speed of light can be modeled by a random sample from a distribution with unknown expectation and finite variance; thus, the speed of light is represented by the expectation of the model distribution and the ultimate goal is to estimate the expectation of the model distribution on the acquired dataset. The law of large numbers suggests to estimate the expectation by the sample mean.[40]
In 1887 he collaborated with colleagueEdward Williams Morley of Western Reserve University, now part ofCase Western Reserve University, in theMichelson–Morley experiment. Their experiment for the expected motion of theEarth relative to theaether, the hypothetical medium in which light was supposed to travel, resulted in anull result. Surprised, Michelson repeated the experiment with greater and greater precision over the next years, but continued to find no ability to measure the aether. The Michelson–Morley results were immensely influential in the physics community, leadingHendrik Lorentz to devise his now-famousLorentz contraction equations as a means of explaining the null result.
There has been some historical controversy over whetherAlbert Einstein was aware of the Michelson–Morley results when he developed his theory ofspecial relativity, which pronounced the aether to be "superfluous". In a later interview, Einstein said of the Michelson–Morley experiment, "I was not conscious it had influenced me directly ... I guess I just took it for granted that it was true."[41] Regardless of Einstein's specific knowledge, the experiment is today considered the canonical experiment in regards to showing the lack of a detectable aether.[42][43]
The precision of their equipment allowed Michelson and Morley to be the first to get precise values for thefine structure in the atomic spectral lines[44] for which in 1916Arnold Sommerfeld gave a theoretical explanation, introducing thefine-structure constant.
The horizontal structure mounted at the top of theHooker Telescope implements Michelson's stellar interferometer (1920). Mirrors on that stage (not visible in picture) redirect starlight from two smaller apertures up to 20 feet (6m) apart into the telescope.
In 1920 Michelson andFrancis G. Pease made the first measurement of the diameter of a star other than the Sun. Michelson had inventedastronomical interferometry and built such an instrument at theMount Wilson Observatory which was used to measure the diameter of thered giantBetelgeuse. A periscope arrangement was used to direct light from two subpupils, separated by up to 20 feet (6m), into the main pupil of the 100 inch (2.5m)Hooker Telescope, producing interference fringes observed through the eyepiece. The measurement of stellar diameters and the separations of binary stars took up an increasing amount of Michelson's life after this.
Beginning in the 1970s, astronomical interferometry was revived, with the configurations using two (or more) separate apertures (with diameters small compared to their separation) being often referred to as "Michelson Stellar Interferometry". This was to distinguish it fromspeckle interferometry, but should not be confused with theMichelson interferometer which is one commonlaboratory interferometer configuration of which the interferometer used in the Michelson–Morley experiment was an instance. Michelson's concept of interfering light from two relatively small apertures separated by a substantial distance (but with that distance, orbaseline, now often as long as hundreds of meters) is employed atmodern operational observatories such asVLTI,CHARA and the U.S. Navy'sNPOI.
Gravitational waves are detected using a Michelson interferometer with a laser light source. In 2020 there were three Michelson interferometer gravitational wave detectors operational, and a fourth under construction. These Michelson interferometers have arms 4 kilometers in length, set at 90 degree angles to each other, with the light passing through 1 m diameter vacuum tubes running their entire length. A passing gravitational wave will slightly stretch one arm as it shortens the other. This is precisely the motion to which these Michelson interferometers are most sensitive. As of 2020 fifteengravitational wave events had been observed using these Michelson interferometers.
In the 1890s Michelson built a mechanical device called the harmonic analyzer, for computing coefficients ofFourier series and drawing graphs of their partial sums. He andS. W. Stratton published a paper about this machine in theAmerican Journal of Science in 1898.[45][46]
"Albert Abraham Michelson was born in this city on December 19, 1852. He was a professor at the University of Chicago, a Nobel laureate, who, with his famous experiments on the speed of light, started a new era in the development of physics. This plaque, for the commemoration of the great physicist was founded by Polish Physical Society." A commemorative plaque inStrzelno, Poland, installed by thePolish Physical Society.
In Season 3 Episode 26 of the television seriesBonanza ("Look to the Stars", broadcast March 18, 1962), Ben Cartwright (Lorne Greene) helps the 16-year-old Michelson (portrayed by 25-year-old Douglas Lambert (1936–1986)) obtain an appointment to theU.S. Naval Academy, despite the opposition of the bigoted town schoolteacher (played byWilliam Schallert).Bonanza was set in and aroundVirginia City, Nevada, where Michelson lived with his parents prior to leaving for the Naval Academy. In a voice-over at the end of the episode, Greene mentions Michelson's 1907 Nobel Prize.
The home in which Michelson lived as a child inMurphys Camp, California, was in the store of his father, first on Main Street, across from the Sperry & Perry Hotel, and after the 1859 fire in a store next to the hotel. His aunt Bertha Meyers owned a house on Main Street toward the east end of town and Michelson probably visited her family there frequently.
New Beast Theater Works in collaboration with High Concept Laboratories produced a 'semi-opera' about Michelson, his obsessive working style and its effect on his family life. The production ran from February 11 to February 26, 2011, in Chicago at The Building Stage. Michelson was portrayed byJon Stutzman. The play was directed byDavid Maral with music composed byJoshua Dumas.[citation needed]
Norman Fitzroy Maclean wrote an essay "Billiards Is a Good Game"; published inThe Norman Maclean Reader (ed. O. Alan Weltzien, 2008), it is an appreciation of Michelson from Maclean's vantage point as a graduate student regularly watching him play billiards.[47]
^National Academy of Sciences, Washington, DC, 1938, Vol. XIX) quotes (on p. 128) Michelson's sister, the novelist Miriam Michelson, as having written of her parents in a letter to Millikan that "both Albert Michelson's father and mother were born of Jewish parents ..."
^Bulletin de la Société des sciences et des lettres de Łódź: Série, Recherches sur les déformations, Volumes 39–42. Société des sciences et des lettres de Łódź. 2003. p. 162.Michelson's biographers stress, that our hero was not conspicuous by religiousness. His father was a free-thinker and Michelson grew up in non-religious family and have no opportunity to acknowledge the belief of his forebears. He was agnostic through his whole life and only for the short period he was a member of the 21st lodge in Washington.
^Livingston, Dorothy Michelson.The Master of Light: A Biography of Albert A. Michelson. University of Chicago Press. p. 106.On the religious question, Michelson disagreed with both these men. He had renounced any belief that moral issues were at stake in ...
^In 1879 a letter from James Clerk Maxwell to the astronomerDavid Peck Todd came to the attention of Michelson, possibly giving him considerable motivation. See the bookSchwinger, J. (1986).Einstein's Legacy. Scientific American Library.2012 e-book.
^James, I. (2009). Driven to Innovate: A Century of Jewish Mathematicians and Physicists p. 101.ISBN978-1-906165-22-2. "In 1877, he married Margaret Hemingway, daughter of a wealthy New York stockbroker and lawyer. This marriage lasted twenty years and produced two sons and a daughter."
^Dekking, F. M.; Kraaikamp, C.; Lopuhaä, H. P.; Meester, L. E. (2005).A Modern Introduction to Probability and Statistics: Understanding Why and How. Springer. p. 248.ISBN978-1852338961.
^Swenson, Loyd S. Jr.,The Ethereal Aether: A History of the Michelson–Morley–Miller Aether-Drift Experiments, 1880–1930, University of Texas Press, 1972
^Note that while Einstein's 1905 paperOn the Electrodynamics of Moving Bodies appears to reference the experiment on first glance—"together with the unsuccessful attempts to discover any motion of the earth relatively to the 'light medium', suggest that the phenomena of electrodynamics as well as of mechanics possess no properties corresponding to the idea of absolute rest"—it has been shown that Einstein was referring to a different category of experiments here.
^Holton, Gerald, "Einstein, Michelson, and the 'Crucial' Experiment",Isis, Vol. 60, No. 2 (Summer, 1969), pp. 133–197doi:10.1086/350468
^AA. Michelson and E. W. Morley, Amer. J. Sci.34, 427 (1887); Phil Mag. 24, 463 (1887).
^Maclean, Norman F. (Summer 1975)."Billiards is a good game". The University of Chicago Magazine. Archived fromthe original on August 17, 2018. RetrievedAugust 16, 2018.
