Theodore Lyman (physicist)

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Theodore Lyman, in London in 1934

Theodore Lyman (born November 23, 1874 in Boston , Massachusetts , † October 11, 1954 in Cambridge , Massachusetts) was an American physicist .

career

Lyman studied at Harvard , where he received his PhD in 1900 with a thesis entitled False Spectra from the Rowland Concave Grating . After two years in Cambridge (England), where he worked under JJ Thomson and at the University of Göttingen , he returned to Harvard, before becoming a professor since 1907 ( tenure from 1917 and Hollis Professor of Mathematics and Natural Philosophy from 1921 ). In 1925 he retired 15 years early at his own request, but continued his work in teaching, doctoral supervision and research. The last doctoral thesis under his supervision was finished in 1942.

research

His scientific work took place in the field of spectroscopy , especially in the area of ultraviolet light. In his doctoral thesis, he demonstrated what would later become known as Lyman ghosts , false spectral lines that (as Carl Runge previously suspected) arise from optical light due to defects in the diffraction gratings . By 1906 he had detected over a hundred spectral lines of hydrogen in the region down to a wavelength of 100 nm. In 1917 he published the evidence of the first three members of the now named after him spectral series ( Lyman series ) of the hydrogen atom. Until 1917 he continued to improve his techniques and was able to analyze spectra down to 50 nm. From 1917 to 1919 he was drafted into military service. After that he found it difficult to find his way back into research.

“When I was mustered out of the service in the spring of 1919 I found it impossible to resume my academic work or my research with any enthusiasm. It took some time for me to get back into harness. Meanwhile a number of people had entered the field of vacuum spectroscopy. I had lost the leadership and I never regained it. Moreover, the untimely death of Professor Sabine increased my administrative burdens. "

- Theodore Lyman

Until 1926 he discovered several spectral lines of helium , later he dealt with the absorption coefficients of various gases and instrumental questions, but has not published anything since 1926 because the results did not meet his standards.

Use in the First World War

In the First World War Lyman took part in the rank of captain and was entrusted as assistant to Augustus Trowbridge with the direction of the development of sound and light measuring systems for the location of the opposing artillery ; later he organized a tracking school near Langres and finally commanded a battalion of over 1000 men.

Honors

In recognition of his services, he was elected to the National Academy of Sciences in 1917 . He was a member of the American Philosophical Society , a Fellow American Academy of Arts and Sciences , of which he was also President from 1924 to 1927, and a Fellow American Physical Society , of which he was President from 1921 to 1922. He was also an honorary member of the Optical Society of America and the Royal Institution in 1918 he was awarded the Rumford Medal of the American Academy of Arts and Sciences, in 1930 the Elliott Cresson Medal of the American Philosophical Society and in 1931 the Frederic Ives Medal of the Optical Society of America.

In 1970 the International Astronomical Union named a lunar crater after him in his honor.

Web links

Individual evidence

  1. ↑ a b P. W. Bridgman: Theodore Lyman (1874-1954). Biographical Memoir. (PDF) National Academy of Sciences, 1957 (English).;
  2. ↑ John Geert Hagmann: Mobilizing US physics in World War I . In: Physics Today . tape 70 , no. 8 , 2017, p. 44 , doi : 10.1063 / PT.3.3660 (English).
  3. ↑ James L. Gilbert: World War I and the Origins of US Military Intelligence . Scarecrow Press, 2012, p. 76 (English, limited preview in Google Book Search).
  4. ^ Frederic Ives Medal / Jarus W. Quinn Prize. In: osa.org. Retrieved January 27, 2018 .
  5. ↑ Planetary Names: Crater, craters: Lyman on Moon. In: Gazetteer of Planetary Nomenclature: Lyman. International Astronomical Union (IAU) Working Group for Planetary System Nomenclature (WGPSN), accessed January 27, 2018 .
personal data
SURNAME Lyman, Theodore
BRIEF DESCRIPTION American physicist
DATE OF BIRTH November 23, 1874
PLACE OF BIRTH Boston , Massachusetts
DATE OF DEATH October 11, 1954
Place of death Cambridge , Massachusetts