Everything about Albert A Michelson totally explained
Albert Abraham Michelson (
December 19,
1852 –
May 9,
1931) was a
Prussian-born
American physicist known for his work on the measurement of the
speed of light and especially for the
Michelson-Morley experiment. In
1907 he received the
Nobel Prize in Physics. He became the first American to receive the
Nobel Prize in sciences.
Biography
Michelson, the son of a
Jewish merchant, was born to a
Jewish family in what is today
Strzelno,
Poland (then
Strelno,
Provinz Posen in the
Kingdom of Prussia). He moved to the
United States with his parents in 1855, when he was two years old. He grew up in the rough mining towns of
Murphy's Camp,
California and
Virginia City, Nevada, where his father was a merchant. He spent his high school years in
San Francisco in the home of his aunt, Henriette Levy (
née Michelson), who was the mother of
author Harriet Lane Levy.
President
Ulysses S. Grant awarded Michelson a special appointment to the
U.S. Naval Academy in 1869. During his four years as a
midshipman at the Academy, Michelson excelled in
optics,
heat and
climatology as well as drawing. After his graduation in 1873 and two years at sea, he returned to the Academy in 1875 to become an instructor in
physics and
chemistry until 1879. From 1880 to 1882, Michelson undertook postgraduate study at
Berlin under
Hermann Helmholtz and at
Paris.
Michelson was fascinated with the sciences and the problem of measuring the
speed of light in particular. While at
Annapolis, he conducted his first experiments of the speed of light, as part of a class demonstration in 1877. After two years of studies in
Europe, he resigned from the
Navy in 1881. In 1883 he accepted a position as professor of physics at the
Case School of Applied Science in
Cleveland, Ohio and concentrated on developing an improved
interferometer. In 1887 he and
Edward Morley carried out the famous
Michelson-Morley experiment which seemed to rule out the existence of the
aether. He later moved on to use
astronomical interferometers in the measurement of stellar diameters and in measuring the separations of binary stars.
In 1889 Michelson became a professor at
Clark University at
Worcester, Massachusetts and in 1892 was appointed professor and the first head of the department of physics at the newly organized
University of Chicago.
In 1899, he married Edna Stanton and they raised one son and three daughters.
In 1907, Michelson had the honor of being the first American to receive a
Nobel Prize in Physics "for his optical precision instruments and the spectroscopic and metrological investigations carried out with their aid". He also won the
Copley Medal in 1907, the
Henry Draper Medal in 1916 and the
Gold Medal of the Royal Astronomical Society in 1923. A
crater on the
Moon is named after him.
Michelson died in
Pasadena, California at the age of 78. The University of Chicago Residence Halls remembered Michelson and his achievements by dedicating
Michelson House
in his honor. Case Western Reserve has also dedicated a Michelson House to him, and an academic building at the
United States Naval Academy also bears his name. Michelson Laboratory at
Naval Air Weapons Station China Lake in
Ridgecrest, California is named after him. There is an interesting display in the publicly accessible area of the Lab of Michelson's Nobel Prize medal, the actual prize document, and examples of his diffraction gratings.
Speed of light
Early measurements
As early as 1877, while still serving as an officer in the
US Navy, Michelson started planning a refinement of the rotating-mirror method of
Léon 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 which time his work came to the attention of
Simon Newcomb, director of the
Nautical Almanac Office who was already advanced in planning his own study. Michelson published his result of 299,910±50 km/s in 1879 before joining
Newcomb 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.
Mount Wilson and Lookout Mountain
In 1906, a novel electrical method was used by
E. B. Rosa and
N. E. Dorsey of the
National Bureau of Standards to obtain a value for the
speed 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.
From 1920, Michelson started planning a
definitive measurement from the
Mount Wilson Observatory, using a baseline to Lookout Mountain, a prominent bump on the south ridge of
Mount San Antonio (
Old Baldy), some 22 miles distant.
In 1922, the
U.S. Coast and Geodetic Survey began two years of painstaking measurement of the baseline using the recently available
invar 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.
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 the
Geodetic Survey, with an estimated error of less than one part in 1 million, was compromised by a shift in the baseline arising from the
Santa Barbara earthquake of
29 June 1925 which was an estimated magnitude of 6.3 on the
Richter scale.
Michelson, Pease & Pearson
The period after 1927 marked the advent of new measurements of the
speed of light using novel
electro-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 1930, he began a collaboration with
Francis G. Pease and
Fred Pearson to perform a measurement in a 1.6
km tube at
Pasadena, California. 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 of 299,774±11 km/s, consistent with the prevailing
electro-optic values, was published posthumously in 1935...
Interferometry
In 1887 he collaborated with colleague
Edward Williams Morley in the
Michelson-Morley experiment. Their experiment for the expected motion of the
Earth relative to the
aether, the hypothetical medium in which
light was supposed to travel, resulted in a
null result. Though it may appear that
Albert Einstein didn't know of the work, it gave a boost the acceptance of the
theory of relativity.
Astronomical interferometry
From 1920 and into 1921 Michelson and
Francis G. Pease became the first individuals to measure the diameter of a star other than the Sun. They used an
astronomical interferometer at the
Mount Wilson Observatory to measure the diameter of the super-giant star
Betelgeuse. A periscope arrangement was used to obtain a densified pupil in the interferometer, a method later investigated in detail by
Antoine Émile Henry Labeyrie for use in with "Hypertelescopes". The measurement of stellar diameters and the separations of binary stars took up an increasing amount of Michelson's life after this.
Michelson in popular culture
In an episode of the
television series
Bonanza (
Look to the Stars, broadcast
March 18,
1962), Ben Cartwright (
Lorne Greene) helps the 16-year-old Albert Abraham Michelson (portrayed by 25-year-old
Douglas Lambert (1936-1986)) obtain an appointment to the
U.S. Naval Academy, despite the opposition of the
anti-semitic town schoolteacher,
William Schallert.
Bonanza was set in and around
Virginia City, Nevada, where Michelson lived with his parents prior to leaving for the Naval Academy. In the
postscript to the episode, Greene mentions Michelson's 1907
Nobel Prize.
The home in which Michelson lived as a child in
Murphys Camp, California is now a
tasting room for
Twisted Oak Winery.
Michelson House in
Shoreland Hall, an undergraduate dorm at
The University of Chicago, is named after him.
Michelson House, an undergraduate residence hall at
Case Western Reserve University in
Cleveland, Ohio, is named after him.
Honours and awards
Further Information
Get more info on 'Albert A Michelson'.
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