Dennis William Siahou Sciama, (; 18 November 1926 – 18/19 December 1999) was a British physicist who, through his own work and that of his students, played a major role in developing British physics after the Second World War. He was the PhD supervisor to many famous cosmologists, including Stephen Hawking, Martin Rees and David Deutsch; he is considered one of the fathers of modern cosmology. Education and early life Sciama was born in Manchester, England, the son of Nelly Ades and Abraham Sciama. He was of Syrian-Jewish ancestry — his father born in Manchester and his mother born in Egypt, but both traced their roots back to Aleppo, Syria. Sciama earned his PhD in 1953 at the University of Cambridge supervised by Paul Dirac, with a dissertation on Mach's principle and inertia. His work later influenced the formulation of scalar-tensor theories of gravity. Career and research Sciama taught at Cornell University, King's College London, Harvard University and the University of Texas at Austin, but spent most of his career at the University of Cambridge (1950s and 1960s) and the University of Oxford as a Senior Research Fellow in All Souls College, Oxford (1970s and early 1980s). In 1983, he moved from Oxford to Trieste, becoming Professor of Astrophysics at the International School for Advanced Studies (SISSA), and a consultant with the International Centre for Theoretical Physics. He also taught at the Scuola Normale Superiore of Pisa. From 1972 to 1973 he was the Donegall Lecturer in Mathematics at Trinity College Dublin. During the 1990s, he divided his time between Trieste (with a residence in nearby Venice) and his main residence at Oxford, where he was a visiting professor until the end of his life. Sciama made connections among some topics in astronomy and astrophysics. He wrote on radio astronomy, X-ray astronomy, quasars, the anisotropies of the cosmic microwave radiation, the interstellar and intergalactic medium, astroparticle physics and the nature of dark matter. Most significant was his work in general relativity, with and without quantum theory, and black holes. He helped revitalize the classical relativistic extension to general relativity known as Einstein-Cartan gravity. Early in his career, he supported Fred Hoyle's steady state cosmology, and interacted with Hoyle, Hermann Bondi, and Thomas Gold. When evidence against the steady state theory, e.g., the cosmic microwave radiation, mounted in the 1960s, Sciama abandoned it and worked on the Big Bang cosmology; he