Dennis William Sciama

Dennis William Sciama

Overview
Dennis William Siahou Sciama FRS (18 November 1926 – 18 December 1999) was a British
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

 physicist
Physicist
A physicist is a scientist who studies or practices physics. Physicists study a wide range of physical phenomena in many branches of physics spanning all length scales: from sub-atomic particles of which all ordinary matter is made to the behavior of the material Universe as a whole...

 who, through his own work and that of his students, played a major role in developing British physics after the Second World War. He is considered as one of the fathers of modern cosmology
Cosmology
Cosmology is the discipline that deals with the nature of the Universe as a whole. Cosmologists seek to understand the origin, evolution, structure, and ultimate fate of the Universe at large, as well as the natural laws that keep it in order...

.

Sciama was born in Manchester
Manchester
Manchester is a city and metropolitan borough in Greater Manchester, England. According to the Office for National Statistics, the 2010 mid-year population estimate for Manchester was 498,800. Manchester lies within one of the UK's largest metropolitan areas, the metropolitan county of Greater...

, England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...

. He was of Syrian Jewish
Syrian Jews
Syrian Jews are Jews who inhabit the region of the modern state of Syria, and their descendants born outside Syria. Syrian Jews derive their origin from two groups: from the Jews who inhabited the region of today's Syria from ancient times Syrian Jews are Jews who inhabit the region of the modern...

 ancestry, his father born in Manchester and his mother in Egypt, both tracing their roots back to Aleppo.

Sciama earned his PhD in 1953 at Cambridge University
University of Cambridge
The University of Cambridge is a public research university located in Cambridge, United Kingdom. It is the second-oldest university in both the United Kingdom and the English-speaking world , and the seventh-oldest globally...

 under the supervision of Paul Dirac
Paul Dirac
Paul Adrien Maurice Dirac, OM, FRS was an English theoretical physicist who made fundamental contributions to the early development of both quantum mechanics and quantum electrodynamics...

, with a dissertation on Mach's principle
Mach's principle
In theoretical physics, particularly in discussions of gravitation theories, Mach's principle is the name given by Einstein to an imprecise hypothesis often credited to the physicist and philosopher Ernst Mach....

 and inertia
Inertia
Inertia is the resistance of any physical object to a change in its state of motion or rest, or the tendency of an object to resist any change in its motion. It is proportional to an object's mass. The principle of inertia is one of the fundamental principles of classical physics which are used to...

.
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Encyclopedia
Dennis William Siahou Sciama FRS (18 November 1926 – 18 December 1999) was a British
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

 physicist
Physicist
A physicist is a scientist who studies or practices physics. Physicists study a wide range of physical phenomena in many branches of physics spanning all length scales: from sub-atomic particles of which all ordinary matter is made to the behavior of the material Universe as a whole...

 who, through his own work and that of his students, played a major role in developing British physics after the Second World War. He is considered as one of the fathers of modern cosmology
Cosmology
Cosmology is the discipline that deals with the nature of the Universe as a whole. Cosmologists seek to understand the origin, evolution, structure, and ultimate fate of the Universe at large, as well as the natural laws that keep it in order...

.

Life


Sciama was born in Manchester
Manchester
Manchester is a city and metropolitan borough in Greater Manchester, England. According to the Office for National Statistics, the 2010 mid-year population estimate for Manchester was 498,800. Manchester lies within one of the UK's largest metropolitan areas, the metropolitan county of Greater...

, England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...

. He was of Syrian Jewish
Syrian Jews
Syrian Jews are Jews who inhabit the region of the modern state of Syria, and their descendants born outside Syria. Syrian Jews derive their origin from two groups: from the Jews who inhabited the region of today's Syria from ancient times Syrian Jews are Jews who inhabit the region of the modern...

 ancestry, his father born in Manchester and his mother in Egypt, both tracing their roots back to Aleppo.

Sciama earned his PhD in 1953 at Cambridge University
University of Cambridge
The University of Cambridge is a public research university located in Cambridge, United Kingdom. It is the second-oldest university in both the United Kingdom and the English-speaking world , and the seventh-oldest globally...

 under the supervision of Paul Dirac
Paul Dirac
Paul Adrien Maurice Dirac, OM, FRS was an English theoretical physicist who made fundamental contributions to the early development of both quantum mechanics and quantum electrodynamics...

, with a dissertation on Mach's principle
Mach's principle
In theoretical physics, particularly in discussions of gravitation theories, Mach's principle is the name given by Einstein to an imprecise hypothesis often credited to the physicist and philosopher Ernst Mach....

 and inertia
Inertia
Inertia is the resistance of any physical object to a change in its state of motion or rest, or the tendency of an object to resist any change in its motion. It is proportional to an object's mass. The principle of inertia is one of the fundamental principles of classical physics which are used to...

. His work later influenced the formulation of scalar-tensor theories of gravity.

He taught at Cornell
Cornell University
Cornell University is an Ivy League university located in Ithaca, New York, United States. It is a private land-grant university, receiving annual funding from the State of New York for certain educational missions...

, King's College London
King's College London
King's College London is a public research university located in London, United Kingdom and a constituent college of the federal University of London. King's has a claim to being the third oldest university in England, having been founded by King George IV and the Duke of Wellington in 1829, and...

, Harvard and the University of Texas at Austin
University of Texas at Austin
The University of Texas at Austin is a state research university located in Austin, Texas, USA, and is the flagship institution of the The University of Texas System. Founded in 1883, its campus is located approximately from the Texas State Capitol in Austin...

, but spent most of his career at Cambridge (1950s and 1960s) and the University of Oxford
University of Oxford
The University of Oxford is a university located in Oxford, United Kingdom. It is the second-oldest surviving university in the world and the oldest in the English-speaking world. Although its exact date of foundation is unclear, there is evidence of teaching as far back as 1096...

 (1970s and early 1980s). In 1983, he moved from Oxford to Trieste
Trieste
Trieste is a city and seaport in northeastern Italy. It is situated towards the end of a narrow strip of land lying between the Adriatic Sea and Italy's border with Slovenia, which lies almost immediately south and east of the city...

, becoming Professor of Astrophysics at the International School of Advanced Studies (SISSA
Sissa
Sissa is a comune in the Province of Parma in the Italian region Emilia-Romagna, located about 100 km northwest of Bologna and about 20 km northwest of Parma....

), and a consultant with the International Centre for Theoretical Physics
International Centre for Theoretical Physics
The Abdus Salam International Centre for Theoretical Physics was founded in 1964 by Pakistani scientist and Nobel Laureate Abdus Salam after consulting with Munir Ahmad Khan. It operates under a tripartite agreement among the Italian Government, UNESCO, and International Atomic Energy Agency...

.

During the 1990s, he divided his time between Trieste (and a residence in nearby Venice
Venice
Venice is a city in northern Italy which is renowned for the beauty of its setting, its architecture and its artworks. It is the capital of the Veneto region...

) and Oxford
Oxford
The city of Oxford is the county town of Oxfordshire, England. The city, made prominent by its medieval university, has a population of just under 165,000, with 153,900 living within the district boundary. It lies about 50 miles north-west of London. The rivers Cherwell and Thames run through...

, where he was a visiting professor until the end of his life. His main home remained in his house in Park Town, Oxford
Park Town, Oxford
Park Town is a small residential area in central North Oxford, a suburb of Oxford, England. It was one of the earliest planned suburban developments in the area.-History and overview:...

.

Sciama drew on his broad knowledge of physics to make fruitful connections among many topics in astronomy
Astronomy
Astronomy is a natural science that deals with the study of celestial objects and phenomena that originate outside the atmosphere of Earth...

 and astrophysics
Astrophysics
Astrophysics is the branch of astronomy that deals with the physics of the universe, including the physical properties of celestial objects, as well as their interactions and behavior...

. He wrote on radio astronomy
Radio astronomy
Radio astronomy is a subfield of astronomy that studies celestial objects at radio frequencies. The initial detection of radio waves from an astronomical object was made in the 1930s, when Karl Jansky observed radiation coming from the Milky Way. Subsequent observations have identified a number of...

, X-ray astronomy
X-ray astronomy
X-ray astronomy is an observational branch of astronomy which deals with the study of X-ray observation and detection from astronomical objects. X-radiation is absorbed by the Earth's atmosphere, so instruments to detect X-rays must be taken to high altitude by balloons, sounding rockets, and...

, quasars, the anisotropies of the cosmic microwave radiation, the interstellar and intergalactic medium, astroparticle physics and the nature of dark matter
Dark matter
In astronomy and cosmology, dark matter is matter that neither emits nor scatters light or other electromagnetic radiation, and so cannot be directly detected via optical or radio astronomy...

. Most significant was his work in general relativity
General relativity
General relativity or the general theory of relativity is the geometric theory of gravitation published by Albert Einstein in 1916. It is the current description of gravitation in modern physics...

, with and without quantum theory
Quantum gravity
Quantum gravity is the field of theoretical physics which attempts to develop scientific models that unify quantum mechanics with general relativity...

, 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
Fred Hoyle
Sir Fred Hoyle FRS was an English astronomer and mathematician noted primarily for his contribution to the theory of stellar nucleosynthesis and his often controversial stance on other cosmological and scientific matters—in particular his rejection of the "Big Bang" theory, a term originally...

's steady state cosmology
Steady State theory
In cosmology, the Steady State theory is a model developed in 1948 by Fred Hoyle, Thomas Gold, Hermann Bondi and others as an alternative to the Big Bang theory...

, and interacted with Hoyle, Hermann Bondi
Hermann Bondi
Sir Hermann Bondi, KCB, FRS was an Anglo-Austrian mathematician and cosmologist. He is best known for developing the steady-state theory of the universe with Fred Hoyle and Thomas Gold as an alternative to the Big Bang theory, but his most lasting legacy will probably be his important...

, and Thomas Gold
Thomas Gold
Thomas Gold was an Austrian-born astrophysicist, a professor of astronomy at Cornell University, a member of the U.S. National Academy of Sciences, and a Fellow of the Royal Society . Gold was one of three young Cambridge scientists who in the 1950s proposed the now mostly abandoned 'steady...

. 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 disfavored.

A number of the leading astrophysicists
Astrophysics
Astrophysics is the branch of astronomy that deals with the physics of the universe, including the physical properties of celestial objects, as well as their interactions and behavior...

 and cosmologists
Physical cosmology
Physical cosmology, as a branch of astronomy, is the study of the largest-scale structures and dynamics of the universe and is concerned with fundamental questions about its formation and evolution. For most of human history, it was a branch of metaphysics and religion...

 of our time completed their doctorates under Sciama's supervision, notably:
  • George Ellis (1964)
  • Stephen Hawking
    Stephen Hawking
    Stephen William Hawking, CH, CBE, FRS, FRSA is an English theoretical physicist and cosmologist, whose scientific books and public appearances have made him an academic celebrity...

     (1966)
  • Brandon Carter
    Brandon Carter
    Brandon Carter, FRS is an Australian theoretical physicist, best known for his work on the properties of black holes and for being the first to name and employ the anthropic principle in its contemporary form. He is a researcher at the Meudon campus of the Laboratoire Univers et Théories, part of...

     (1967)
  • Martin Rees (1967)
  • Gary Gibbons
    Gary Gibbons
    Gary William Gibbons , FRS, is a British theoretical physicist. Gibbons studied in Cambridge,where in 1969 he became a research student under the supervision of Dennis Sciama. When Sciama moved to Oxford, he became a student of Stephen Hawking, obtaining his PhD from Cambridge in 1973...

     (1973)
  • James Binney
    James Binney
    James Jeffrey Binney, FRS, FInstP is a British astrophysicist. He is currently a Professor of Physics at the University of Oxford, where he is head of the Sub-Department of Theoretical Physics as well as a Professorial Fellow at Merton College...

     (1975)
  • John D. Barrow
    John D. Barrow
    -External links:****** The Forum-Publications available on the Internet:************...

     (1977)
  • David Deutsch
    David Deutsch
    David Elieser Deutsch, FRS is an Israeli-British physicist at the University of Oxford. He is a non-stipendiary Visiting Professor in the Department of Atomic and Laser Physics at the Centre for Quantum Computation in the Clarendon Laboratory of the University of Oxford...

  • Adrian Melott
    Adrian Melott
    Adrian Lewis Melott is an American physicist. He is one of the pioneers of using large-scale computing to investigate the formation of large-scale structure in a Universe dominated by dark matter...

     (1981)
  • Antony Valentini
    Antony Valentini
    Antony Valentini is a theoretical physicist and a professor at Clemson University. He is known for his work on the foundations of quantum physics.- Education and career :...

     (1992)


Sciama also strongly influenced Roger Penrose
Roger Penrose
Sir Roger Penrose OM FRS is an English mathematical physicist and Emeritus Rouse Ball Professor of Mathematics at the Mathematical Institute, University of Oxford and Emeritus Fellow of Wadham College...

, 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.

Sciama was elected a Fellow of the Royal Society
Royal Society
The Royal Society of London for Improving Natural Knowledge, known simply as the Royal Society, is a learned society for science, and is possibly the oldest such society in existence. Founded in November 1660, it was granted a Royal Charter by King Charles II as the "Royal Society of London"...

 in 1982. He was also an honorary member of the American Academy of Arts and Sciences
American Academy of Arts and Sciences
The American Academy of Arts and Sciences is an independent policy research center that conducts multidisciplinary studies of complex and emerging problems. The Academy’s elected members are leaders in the academic disciplines, the arts, business, and public affairs.James Bowdoin, John Adams, and...

, the American Philosophical Society
American Philosophical Society
The American Philosophical Society, founded in 1743, and located in Philadelphia, Pa., is an eminent scholarly organization of international reputation, that promotes useful knowledge in the sciences and humanities through excellence in scholarly research, professional meetings, publications,...

 and the Academia Lincei of Rome. He served as president of the International Society of General Relativity and Gravitation, 1980–84.

In 1959, Sciama married Lidia Dina, a social anthropologist, who survived him, along with their two daughters.

His work at SISSA and the University of Oxford led to the creation of a lecture series in his honour, the Dennis Sciama Memorial Lectures. In 2009, the Institute of Cosmology at the University of Portsmouth
University of Portsmouth
The University of Portsmouth is a university in Portsmouth, Hampshire, England. The University was ranked 60th out of 122 in The Sunday Times University Guide...

 elected to name their new building, and their supercomputer in 2011, in his honour.

Books by Sciama

  • 1959. The Unity of the Universe. Garden City, N.Y., Doubleday.
  • 1969. The Physical Foundations of General Relativity. New York: Doubleday. Science Study Series. Short (104 pages) and clearly written non-mathematical book on the physical and conceptual foundations of General Relativity. Could be read with profit by physics students before immersing themselves in more technical studies of General Relativity.
  • 1971. Modern Cosmology. Cambridge University Press
    Cambridge University Press
    Cambridge University Press is the publishing business of the University of Cambridge. Granted letters patent by Henry VIII in 1534, it is the world's oldest publishing house, and the second largest university press in the world...

    .
  • 1993. Modern Cosmology and the Dark Matter Problem. Cambridge University Press.

External links

  • The Renaissance of General Relativity and Cosmology, eds. G. F. R. Ellis et al., Cambridge Univ. Press, 1993. (Contains a Sciama Festschrift with Sciama's complete scientific genealogy).