A. A. Michelson

Copyright Michael D. Robbins 2005

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Albert Abraham Michelson—Physicist:

December 19, 1852, Stremlo, Germany. No time of birth is given in the sources considered. A Noon-Chart is offered  below. Died, May 9, 1931, Pasadena, California.          


(Ascendant, unknown; Sun and Mercury both in Sagittarius with Mercury retrograde; Moon in Leo; Venus in Capricorn; Mars conjunct Uranus, both in Scorpio; Jupiter in Taurus; Saturn in Libra; Neptune and Pluto conjunct in Gemini)

He was best known for the Miclelson-Morley experiments concerning the speed of light and demonstrating, so it seemed, the non-existence of the “ether”.

(In 1903) The most important fundamental laws and facts of physical science have all been discovered, and these are now so firmly established that the possibility of their ever being supplemented in consequence of new discoveries is exceedingly remote.

Albert Abraham Michelson
Born December 29, 1852 Strzelno, Poland
Died May 9, 1931 Pasadena, California
Nationality Jewish-Polish
Field Physicist

Notable prizes Nobel Prize for Physics (1907)
Albert Abraham Michelson (surname pronunciation anglicised as "Michael-son") (December 19, 1852 – May 9, 1931) was a Polish-born German-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, the first American to receive the Nobel in the sciences.

Life
Michelson, the son of a Jewish merchant, was born in, what is today Strzelno, Poland (then Strelno, Provinz Posen in the Prussian-occupied region of partitioned Poland). 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.

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.

Conclusion page for the paper pictured above.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 China Lake Naval Weapons Center 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.

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.

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 1932
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 did not know of the work (according to his 1905 paper), it greatly assisted the acceptance of the theory of relativity...

Astronomical interferometry
In 1920-21 Michelson and Francis G. Pease famously became the first people to measure the diameter of a star other than our 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 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.

Biography
Albert Abraham Michelson was born in Strelno, Prussia, on December 19, 1852. Two years later his family emigrated to the United States to settle at Virginia City, Nevada, but they eventually moved to San Francisco where Michelson received his early education in public schools, matriculating from the High School in 1869. He was appointed by President Grant to the U.S. Naval Academy and, after graduation as Ensign in 1873 and a two-years' cruise in the West Indies, he became an instructor in physics and chemistry at the Academy under Admiral Sampson. In 1879, he was posted to the Nautical Almanac Office, Washington, to work with Simon Newcomb, but in the following year, he obtained leave of absence to continue his studies in Europe. He visited the Universities of Berlin and Heidelberg, and the College de France and École Polytechnique in Paris. He resigned from the Navy and in 1883 returned to America to take an appointment as Professor of Physics in the Case School of Applied Science, Cleveland, Ohio. In 1890 he accepted a similar position at Clark University, Worcester, Massachusetts, and in 1892 he became Professor of Physics and the first Head of Department at the new University of Chicago. He rejoined the Navy during World War I, and in 1918 returned to Chicago where in 1925 he was appointed to the first of the Distinguished Service Professorships. Michelson resigned in 1929 to work at the Mount Wilson Observatory, Pasadena.

During his career, Michelson touched on many departments of physics but, perhaps due to a special instinct which he appeared to possess, he excelled in optics. He performed early measurements of the velocity of light with amazing delicacy and in 1881 he invented his interferometer for the purpose of discovering the effect of the Earth's motion on the observed velocity. In cooperation with Professor E.W. Morley, and using the interferometer, it was shown that light travels at a constant speed in all inertial systems of reference. The instrument also enabled distances to be measured with greater accuracy by means of the length of light-waves. At the request of the International Committee of Weights and Measures, Michelson measured the standard metre in terms of wavelength of cadmium light. He invented the echelon spectroscope and during his wartime service in the Navy he performed research work on devices for naval use - he developed a rangefinder which was adapted as part of U.S. Navy equipment. On his return to civilian life, Michelson became more interested in astronomy and in 1920, using light interference and a highly developed version of his earlier instrument, he measured the diameter of the star Betelgeuse: this was the first determination of the size of a star that could be regarded as accurate.

Michelson has contributed numerous papers to many scientific periodicals and among his more substantial works are the classics, Velocity of Light (1902) Light Waves and their Uses (1899-1903); and Studies in Optics (1927).

Michelson was honoured by memberships of many learned societies throughout America and ten European countries, and he received honorary science and law degrees from ten American and foreign universities. He was President of the American Physical Society (1900), the American Association for the Advancement of Science (1910-1911), and the National Academy of Sciences (1923-1927). He was also a Fellow of the Royal Astronomical Society, the Royal Society of London and the Optical Society, an Associate of l'Académie Française and among the many awards he has received are the Matteucci Medal (Societá Italiana), 1904; Copley Medal (Royal Society), 1907; Elliot Cresson Medal (Franklin Institute), 1912; Draper Medal (National Academy of Sciences), 1916; Franklin Medal (Franklin Institute) and the Medal of the Royal Astronomical Society, 1923; and the Duddell Medal (Physical Society), 1929.

Michelson married Edna Stanton of Lake Forest, Illinois in 1899. They had one son and three daughters. He died in 1931.

Albert A. Michelson died on May 9, 1931.