Dennis W. Sciama

Dennis William Siahou Sciama (November 18 1926 - December 18 1999) was a British physicist who, through his own work and that of his students, played a major role in the rise of British excellence in astrophysics and cosmology after the Second World War.

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Dennis William Sciama (1926-1999)

Life

Sciama earned his Ph.D. in 1953 at Cambridge University under the supervision of Paul Dirac, with a dissertion on Mach's principle and inertia. His work later influenced the formulation of scalar-tensor theories of gravity.

He taught at Harvard, Cornell, King's College London, and the University of Texas at Austin, but spent much of his career at Cambridge (1950s and 60s) and the University of Oxford (1970s and early 80s). In 1983, he moved from Oxford to Trieste, becoming Professor of Astrophysics at the International School of Advanced Studies (SISSA), and a consultant with the International Centre for Theoretical Physics. During the nineties he divided his time between Trieste (and a residence in nearby Venice) and Oxford, where he was a visiting professor until the end of his life. His main home was a large house in Park Town, possibly the most affluent part of Oxford.

Sciama drew on his broad knowledge of physics to make fruitful connections among many 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 alternative 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.

During his retirement, Sciama pursued a theory of dark matter that consists almost entirely of a heavy neutrino, now largely discredited.

A number of the leading astrophysicists and cosmologists of our time completed their doctorates under Sciama's supervision, notably:

• George Ellis (1964)
• Stephen Hawking (1966)
• Brandon Carter (1967)
• Martin Rees (1967)
• Malcom MacCallum (1971)
• John D. Barrow (1977)
• James Binney
• Philip Candelas
• David Deutsch

Sciama also strongly influenced Roger Penrose, who dedicated his The Road to Reality to Sciama's memory. The 1960s group he led in Cambridge (which included Ellis, Hawking, Rees, and Carter), has proved of lasting influence.

Books by Sciama

• 1959. The Unity of the Universe. London: Faber & Faber.
• 1969. The Physical Foundations of General Relativity. New York: Doubleday.
• 1971. Modern Cosmology. Cambridge University Press.
• 1993. Modern Cosmology and the Dark Matter Problem. Cambridge University Press.

External links

• Short bio, the source for much of this entry.
• "Dennis Sciama". Mathematics Geneology Project. American Mathematical Society. Retrieved August 15. {{cite web}}: Check date values in: |accessdate= (help); Unknown parameter |accessyear= ignored (|access-date= suggested) (help)