Richard Chace Tolman (March 4, 1881 – September 5, 1948) was an American mathematical physicist and physical chemist who made many contributions to statistical mechanics and theoretical cosmology. He was a professor at the California Institute of Technology (Caltech).
Early life and education
Tolman was born in West Newton, Massachusetts to a successful businessman and a Quaker mother. Tolman attended the local public schools before matriculating at the Massachusetts Institute of Technology (MIT), where he earned his bachelor's degree in chemical engineering 1903. He subsequently worked briefly at various universities before the outbreak of World War I.
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, researching nitrogen fixation.
thumb|Richard C. Tolman and [[Albert Einstein at Caltech, Pasadena, 1932]]
Tolman was elected a Fellow of the American Academy of Arts and Sciences in 1922. 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. His years at Caltech were his most productive. Tolman was elected to the American Philosophical Society in 1932. In 1938, he published a new detailed work that covered the application of statistical mechanics to classical and quantum systems. In his work on the subject, Tolman built heavily upon the key contributions of Ludwig Boltzmann, J. Willard Gibbs, Paul and Tatyana Ehrenfest. Tolman demonstrated how black body thermal radiation in an expanding universe results in coolinga key pointer toward the properties of the cosmic microwave background. Also in this monograph, Tolman was the first person to document and explain how a closed universe could possess net 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. It was Tolman who spurred J. Robert Oppenheimer's interest in relativistic astrophysics by introducing to astronomers working at the Mount Wilson Observatory in Pasadena, California. Oppenheimer, Robert Serber, and George Volkoff, built upon Tolman's work in their investigation of the stability of neutron stars, obtaining the Tolman-Oppenheimer-Volkoff limit.
During World War II, Tolman served as scientific advisor to General Leslie Groves on the Manhattan Project.