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L. H. Thomas Lectures



Supernovae and the Discovery of the Accelerating Universe


Space Telescope Science Institute
Johns Hopkins University


Monday, October 19, 2015

301 Riddick Hall



In 1929 Edwin Hubble discovered that our Universe is expanding. Eighty years later, the Space Telescope which bears his name is being used to study an even more surprising phenomenon, that the expansion is speeding up. The origin of this effect is not known, but is broadly attributed to a type of "dark energy" first posited to exist by Albert Einstein and now dominating the mass-energy budget of the Universe. I will describe how our team discovered the acceleration of the Universe and why understanding the nature of dark energy presents one of the greatest remaining challenges in astrophysics and cosmology.





The L. H. Thomas lectures are among the most prestigious general audience presentations in the Triangle. Since 1980, over twenty different Nobel prize winners have spoken in the series. The L. H. Thomas lectures are cosponsored by the Department of Physics of North Carolina State University, the College of Sciences Foundation, and the SAS Institute.

A Memoir, compiled by David Jackson, can be downloaded here as a PDF. More biographies and memoirs of National Academy of Science members can be found at the National Academies Press.

 


Llewellyn Hilleth Thomas came to the Department of Physics at North Carolina State University in 1968 as a University Professor where he continued his distinguished career in physics and mathematics. His lectures, participation in seminars, and advice on a wide range of research problems have been invaluable to students and faculty.

Professor Thomas was born in London on October 21, 1903. He was taught at home until age seven and then attended a private school. At the age of 11 he attended the Merchant Taylor's school in London. In 1921 he obtained a scholarship to study pure and applied mathematics at Trinity College, Cambridge. He won a senior scholarship in 1923 and an Isaac Newton Studentship in 1924, receiving a first class honors degree in mathematics with distinction in advanced subjects. In 1925, during his second year of graduate study, he was awarded the Smith prize for an essay on adiabatic invariants which formed the basis of his first publication.

The period 1925-26 was spent at Bohr's institute in Copenhagen where, in addition to continuing work on the passage of electrified particles through matter, he performed calculations on the relativistic motion of an electron with spin angular momentum and on self-consistent fields for atoms. Seven papers on these topics were published as part of his doctoral studies. His second article, entitled "Motion of the Spinning Electron," describes an effect which bears his name--The Thomas Precession of an electron. His third paper describes a statistical model for an atom which was concurrently being developed by Fermi. Today this model of the atom is known as the Thomas-Fermi model. Another paper in this series is acknowledged by contemporary atomic collision scientists as the pioneering theoretical work on the classical model of charge transfer for protons on atomic hydrogen. He received his Ph.D. in 1927 and M.A. in 1928 from Cambridge University.

L. H. Thomas joined the Department of Physics at Ohio State University as an Assistant Professor in 1929. He was promoted to Associate Professor in 1930 and to Professor in 1936. He wrote two papers which were published in 1938 describing the Thomas Cyclotron--a heavy particle, high energy accelerator now in use at several important nuclear physics installations. During World War II he served as a physicist and ballistician at the Ballistic Research Laboratory at the Aberdeen Proving Ground, Maryland where he was an author of numerous technical reports. Following the war in 1946 he accepted a position as a member of the senior staff at the Watson Scientific Computing Laboratory established by IBM at Columbia University. He was appointed an Honorary Professor at Columbia in 1950 and a Fellow of IBM in 1963. While with IBM, he authored over 40 papers on numerical methods and applications in atomic physics, plasma physics, general relativity, and applied mathematics.

In 1963 he received the D.Sc. degree from Cambridge University and the Davisson-Germer prize in 1982 from the American Physical Society "for his early pioneering contributions to the theory of the spin-orbit interaction in atoms and the statistical model of atoms."

Professor Thomas was a fellow of the American Physical Society and a member of the National Academy of Science. He was also a member of Sigma Xi, the American Association for the Advancement of Science, the British Association for the Advancement of Science, the Royal Astronomical Society, and the Cambridge Philosophical Society.

Llewellyn H. Thomas died in Raleigh, NC, on April 20, 1992.