Richard C. Tolman | |
|---|---|
 Richard C. Tolman in 1945 | |
| Born | (1881-03-04)March 4, 1881 West Newton, Massachusetts, U.S. |
| Died | September 5, 1948(1948-09-05) (aged 67) Pasadena, California, U.S. |
| Alma mater | Massachusetts Institute of Technology (BS,PhD) |
| Scientific career | |
| Fields | Physical chemistry Statistical Mechanics Cosmology |
| Institutions | California Institute of Technology |
| Thesis | The Electromotive Force Produced in Solutions by Centrifugal Action (1910) |
| Doctoral advisor | Arthur Amos Noyes |
| Doctoral students | Allan C. G. Mitchell Linus Pauling |
Richard Chace Tolman (March 4, 1881 – September 5, 1948) was an Americanmathematical physicist andphysical chemist who made many contributions tostatistical mechanics andtheoretical cosmology.[1] He was a professor at theCalifornia Institute of Technology (Caltech).[2]
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Tolman was born inWest Newton, Massachusetts to a successful businessman and a Quaker mother. Tolman attended the local public schools before matriculating at theMassachusetts Institute of Technology (MIT), where he earned hisbachelor's degree inchemical engineering 1903.[2] He spent the following year studying abroad in Germany before returning to MIT for further studies. He was mentored byArthur Amos Noyes, a pioneer of physical chemistry, and received PhD in 1910 under Noyes' supervision.[3] He subsequently worked briefly at various universities before the outbreak of World War I.[2]
In 1912, he conceived of the concept ofrelativistic mass, writing that "the expression is best suited for the mass of a moving body."[4]
During the First World War, Tolman served in the Chemical Warfare Service, attaining the rank of Major. When the war ended, he continued working for the government for some years, researchingnitrogen fixation.[2]
In a 1916 experiment withThomas Dale Stewart, Tolman demonstrated that electricity consists ofelectrons flowing through a metallicconductor. A by-product of this experiment was a measured value of themass of the electron.[5][2] This early work sparked Tolman's interest inchemical kinetics and statistical mechanics.[2] Tolman and his collaborators at the Fixed Nitrogen Research Laboratory at the University of California thanked the government for enabling them to conduct fundamental research that had little immediate relevance to their assigned project, writing that "such a liberal policy is of great importance in maintaining a proper scientific attitude on the part of the staff of a research laboratory."[2]
Tolman was a member of theTechnical Alliance in 1919, a forerunner of theTechnocracy movement where he helped conduct an energy survey analyzing the possibility of applying science to social and industrial affairs.[6][7][8]
Tolman was elected a Fellow of theAmerican Academy of Arts and Sciences in 1922.[9] The same year, he joined the faculty of the California Institute of Technology, where he became professor of physical chemistry and mathematical physics and later Dean of Graduate Studies.[2] One of Tolman's early students at Caltech was the theoretical chemistLinus Pauling, to whom Tolman taught theold quantum theory. Tolman was elected to theNational Academy of Sciences of the United States in 1923.[10] His years at Caltech were his most productive.[2]
In 1927, Tolman published a text on statistical mechanics whose background was the old quantum theory ofMax Planck,Niels Bohr andArnold Sommerfeld.[11] Tolman was elected to theAmerican Philosophical Society in 1932.[12] In 1938, he published a new detailed work that covered the application of statistical mechanics toclassical andquantum systems.[13][14] In his work on the subject, Tolman built heavily upon the key contributions ofLudwig Boltzmann,J. Willard Gibbs,Paul andTatyana Ehrenfest.[2]
Tolman took an interest ingeneral relativity. He researched the application ofthermodynamics torelativistic systems andcosmology. He established a number of theoretical results important in the study of an expanding universe.[2] In his 1934monograph titledRelativity, Thermodynamics, and Cosmology,[15] Tolman demonstrated howblack body radiation in an expanding universe cools but remainsthermal – a key pointer toward the properties of thecosmic microwave background.[16] Also in this monograph, Tolman was the first person to document and explain how a closed universe could equal zero energy. He explained how all mass energy is positive and all gravitational energy is negative and they cancel each other out, leading to a universe of zero energy.[16] His investigation of theoscillatory universe hypothesis, whichAlexander Friedmann had proposed in 1922, drew attention to difficulties as regardsentropy and resulted in its demise until the late 1960s. Tolman interpreted astronomical observations in terms of the new cosmology in collaboration withEdwin Hubble.[2]
During the 1930s, Tolman obtained solutions to theEinstein field equations describing thestatic spherically symmetric perfect fluid.[17][18]J. Robert Oppenheimer,Robert Serber, andGeorge Volkoff, built upon this work in their investigation the stability ofneutron stars, obtaining theTolman-Oppenheimer-Volkoff limit.[19][20]
DuringWorld War II, Tolman served as scientific advisor to GeneralLeslie Groves on theManhattan Project.[2] At the time of his death inPasadena, he was chief advisor toBernard Baruch, the U.S. representative to theUnited Nations Atomic Energy Commission.
He resumed civilian life in 1947 and published some papers on the thermodynamics of surface phases. He died on September 5, 1948, three weeks after suffering acerebral hemorrhage without warning.[2]
Each year, thesouthern California section of theAmerican Chemical Society honors Tolman by awarding itsTolman Medal "in recognition of outstanding contributions to chemistry."
Tolman's brother was thebehavioral psychologistEdward Chace Tolman. He married psychologistRuth Sherman Tolman in 1924.[2]
