Dunham, Theodore Jr.
BornNew York, New York, USA, 17 December 1897
DiedChocorua, New Hampshire, USA, 3 April 1984
American physicist, astronomer, and physician Theodore Dunham, Jr., developed coudé spectrographs at Mount Wilson Observatory and at Mount Stromlo Observatory in Australia; introduced the Schmidt camera in spectroscopy; studied stellar atmospheres, interstellar material, and planetary atmospheres; identified CO2in the atmosphere of Venus; developed photoelectric detectors for spectroscopy; and applied physical methods to research in medicine and surgery.
Dunham’s interest in astronomy began early. The son of Theodore Dunham, a surgeon, and Josephine Balestier Dunham, he prepared at Saint Bernard’s School and the Browning School, New York City. As a teenager, Dunham submitted data to the American Association of Variable Star Observers, and by the age of 17, he had built an observatory on the grounds of his family’s cottage in Northeast Harbor, Maine, where his father practiced medicine in the summers.
Theodore W. Richards, Nobel Laureate in Chemistry, was Dunham’s advisor through his 4 years at Harvard College. In his senior year, Dunham worked full time in Richards’s laboratory studying the potential of the zinc electrode. He and Richards were coauthors of Dunham’s first paper. Dunham received an A.B. summa cum laudein 1921.
Dunham next turned to medicine, attending Harvard Medical School, transferring to Cornell University, and living at home in New York City. At Cornell University, he studied under James Ewing, receiving an M.D. in 1925.
His passion for astronomy took Dunham to Princeton University, where he studied under Henry N. Russell. Russell brought back from Mount Wilson Observatory a film copy of a spectrum of α Persei, pulled it out of his left pocket, gave it to Dunham, and said, “Here’s your thesis.”
As a graduate student, on 21 June 1926, Dunham married Miriam Phillips Thompson, daughter of Mr. and Mrs. William G. Thompson of Boston. He received an A.M. and Ph.D. in physics in 1926 and 1927 from Princeton University.
With Russell’s recommendation, in 1927 Dunham went to Mount Wilson Observatory with a National Research Council Fellowship. He was a staff member of Mount Wilson Observatory from 1928 to 1947. On his arrival, Dunham was struck with how he came with the approach of a physicist, while most of the remaining staff were top-notch observers. Russell’s annual visits stimulated the research. Dunham was fired by the spirit of George Hale , the driving force behind Mount Wilson.
In the summer of 1929, Dunham attended a symposium on astronomy and quantum physics at the University of Michigan, where he met Arthur Milne of Oxford and Harry Plaskett , both of whom became lifelong friends. The Milne daughters stayed with the Dunhams from 1940 to 1945.
In 1932, Dunham discovered that the atmosphere of Venus is principally composed of CO2. At that time, astronomers tended to believe that the Earth and Venus had similar atmospheres, but Dunham (with Walter Adams ) found some unusual features in the spectrum of Venus. Dunham demonstrated that if light were sent through a long pipe containing compressed CO2, the same spectrum could be reproduced on the Earth, indicating that CO2, under higher pressure than the Earth’s atmosphere, had been observed in the atmosphere of Venus. Arthur Adel subsequently published a theoretical interpretation of the CO2spectrum that validated these experimental results. Dunham’s conclusion was dramatically confirmed 35 years later in measurements transmitted from United States and Soviet spacecraft. Another of Dunham’s planetary contributions was the confirmation of the presence of methane and ammonia in Jupiter.
While Dunham was at Mount Wilson Observatory, Russell tried to bring him back to Princeton University to groom him as a successor. Adams was also interested in Dunham as his own successor at Mount Wilson Observatory. In April 1934, Russell proposed to Adams that Dunham be shared in a joint appointment between Mount Wilson Observatory and Princeton University. By 1935, out of loyalty to Russell, Dunham accepted a 3-year appointment as a part-time associate professor at Princeton University, where he lectured in 1935 and 1936, but Dunham ultimately decided to remain at Mount Wilson.
His wife’s brother, Charles G. Thompson, and sister-in-law, Alice Bemis Thompson, heard from Dunham about the shortage of funding at Mount Wilson Observatory for equipment to use with its good telescope. In 1936, Mr. and Mrs. Thompson founded the Fund for Astrophysical Research, Inc. [FAR], with a small gift that allowed it to support the purchase of such equipment. Dunham was the FAR’s scientific director from its founding until his death. The FAR’s first project was the figuring of a 36-in. spherical mirror for the Mount Wilson coudé spectrograph.
Before the United States entered World War II, Dunham traveled to England to advise on optical instruments as a member, from 1940 to 1942, of the Section on Instruments of the Office of Scientific Research and Development [OSRD]. From 1942 to 1946, he was chief of the Optical Instrument Section (16.1) of the OSRD, under George Harrison and Vannevar Bush.
After the war, Dunham’s interest in medicine continued. He wanted to work on some ideas on the spectroscopy of cells in his spare time, using a laboratory that his friend Linus Pauling could assist in making available at CalTech. The Carnegie Institution, which operated Mount Wilson, appeared to be taking a dim view of outside scientific activities, and in 1946, as he was leaving the OSRD payroll, Dunham resigned from his Mount Wilson position. Dunham then spent several years applying physical methods to medical research, first from 1946 to 1948 as a Warren Fellow in Surgery at Harvard Medical School and then from 1948 to 1957 at the School of Medicine and Dentistry and the Institute of Optics at the University of Rochester, where he developed instrumentation for spectrophotometric analysis of small regions of biological cells.
At the 1952 International Astronomical Union meeting in Rome, Richard van der Riet Woolley , Jr., asked Dunham to come down to Canberra to build a spectrograph for Mount Stromlo Observatory. Five years later, Dunham joined the faculty of the Australian National University, where he designed and installed a spectrograph at the Mount Stromlo Observatory for use with its 74-in. telescope in studying the composition of the stars of the Southern Hemisphere. From 1965 to 1970, Dunham was a senior research fellow at the University of Tasmania, Australia.
After returning to the United States in 1970, Dunham resumed his earlier association with the Harvard College Observatory. Until his death, he continued to encourage the development of a spectrographic observatory at the University of Tasmania.
Dunham was survived by his wife and children, Theodore Dunham, III, and Mary Huntington Dunham. At the time of his death, he had just completed designing and supervising the construction of a 0.3-m computer-guided telescope of a new alt-azimuth design. It was installed and dedicated in his memory at the new Science Center of the University of Chicago in 1985. The FAR then augmented its small endowment by selling its scientific equipment and began a program of making annual small grants known as the Theodore Dunham, Jr. Grants in Astronomy and Astrophysics.
Dunham was the author of more than 50 scientific articles and a member of many scientific organizations, including the American Physical Society, the Royal Astronomical Society, the American Astronomical Society, the American Association of Variable Star Observers, the Astronomical Society of the Pacific, the American Optical Society, the New York Academy of Sciences, and the International Astronomical Union (in which he was a member of commissions on instruments, stellar spectra, and interstellar material).
- De Vorkin, David M. (2000). Henry Norris Russell:Dean of American Astronomers. Princeton, New Jersey: Princeton University Press.Google Scholar
- Dunham, Theodore, Jr. (1929). “The Spectrum of Alpha Persei.” Contributions from the Princeton University Observatory, no. 9.Google Scholar
- — Oral History Interviews with David M. DeVorkin, 30 April 1977 and 19 April 1978. Niels Bohr Library, American Institute of Physics, College Park, Maryland.Google Scholar
- — Microfilm of Scientific Papers. Niels Bohr Library, American Institute of Physics, College Park, Maryland.Google Scholar
- Dunham, Jr., Theodore, and T. W. Richards (1921). “The Effect of Changing Hydrogen-ion Concentration on the Potential of the Zinc Electrode.” Journal of the American Chemical Society43.Google Scholar