| Robert S. Shankland | |
|---|---|
| Born | January 11, 1908 USA |
| Died | March 1, 1982 (aged 74) Cleveland, Ohio, USA |
| Nationality | United States |
| Fields | Physicist |
| Alma mater | Case School for Applied Sciences University of Chicago |
| Doctoral advisor | Arthur Compton |
| Known for | Compton scattering History of modern physics |
Robert Sherwood Shankland (January 11, 1908 - March 1, 1982) was an American physicist and historian.
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Robert S. Shankland was an undergraduate at the Case School for Applied Sciences from 1925–1929 and received his master's degree in 1933. He completed his Ph.D. degree in 1935 for work on photon scattering with Arthur Compton at the University of Chicago. His other research included work on the ionosphere and standard frequency regulations from 1929-1930 with the US National Bureau of Standards, and worked in England on sonar for submarine warfare early in World War II.
Shankland's report on the Albert Michelson's Irvine Ranch experiments was published in 1933. In the British journal Nature, Shankland gave the historical background of how Einstein formulates the first two principles, in 1905, of the special theory of relativity from the Michelson-Morley experiment. Shankland believed that the accepted direct explanation for the Michelson-Morley experiment is provided by the special theory of relativity given by Einstein in 1905. Shankland recorded that Michelson's Santa Ana trip was to look at the science of the aether. Physicists consider the results of Dayton C. Miller's tests on Mount Wilson more accurate than Michelson's.
After completing graduate studies he joined the faculty at Case School for Applied Sciences. In 1941 he succeeded Dayton C. Miller as the Ambrose Swasey Professor of Physics at Case, a position he held until his retirement in 1976. Shankland worked on neutrino experiments with Argonne National Laboratory from 1953–1969, and had other interests including the history of relativity and architectural acoustics. He collaborated with George Szell, the director of the Cleveland Orchestra, to improve the acoustics of Severance Hall, making it easier for musicians to hear each other on the stage.
Shankland's father, Frank North Shankland, was the author of "Modern Romances" and several books on birds and animals. In 1929 Shankland married Hilda Catherine Kinneson. They had five children: Ruth Ellen, Dorothy Margaret, Lois Virginia, Ava Gertrude, and Sherwood Jean, and 14 grandchildren. Hilda died in 1970 and he married Eleanor Newlin. Shankland was a passionate outdoorsman and a knowledgeable collector of iron animal traps and Native American artifacts.
Shankland performed a debated analysis on how Dayton Miller's interferometric results could be caused by thermal fluctuations and therefore be consistent with special relativity; Shankland's explanation is now accepted by most mainstream scientists.
In 1925-1926, Dayton Miller performed interferometric observations at Mount Wilson, similar to the Michelson-Morley experiment, that appeared to reflect a measurable drift of the Earth through the luminiferous aether, in apparent contradiction with other experiments of that type and with relativity's prediction that no aether should be observable.
In 1955, Shankland published a paper analyzing Miller's data, arguing that "the small periodic fringe displacements found by Miller are due in part to statistical fluctuations in the readings of the fringe positions in a very difficult experiment" and "the remaining systematic effects are ascribed to local temperature conditions." Moreover, he argues that the thermal gradients responsible for the effects "were much more troublesome at Mount Wilson than those encountered by experimenters elsewhere, including Miller himself in his work done at Case in Cleveland." In a 1973 review paper on the experimental development of relativity, Shankland included an August 31, 1954 letter to him by Einstein agreeing with his analysis. (Shankland had sent Einstein a manuscript prior to its publication.) Einstein wrote:
In Shankland's re-analysis, no statistically significant signal for the existence of aether was found. The analysis is accepted by mainstream physicists, the abandonment of the concept of the aether is nearly universal, and Miller's observed signal is believed the result of experimenter's bias; the "signal" that Miller observed in 1933 is actually composed of points that are an average of several hundred measurements each, and the magnitude of the signal is more than 10 times smaller than the resolution with which the measurements were recorded.
Though Maurice Allais and James DeMeo do not accept Shankland's refutation and hold to the belief that Miller's experiment invalidates the theory of relativity, Einstein's theory is today regarded by most physicists as proven.