__NOTOC__ Felix Arnold Edward Pirani (2 February 1928 – 31 December 2015) was a British theoretical physicist, and professor at King's College London, specialising in

gravitational physics In physics, gravity () is a fundamental interaction which causes mutual attraction between all things with mass or energy. Gravity is, by far, the weakest of the four fundamental interactions, approximately 1038 times weaker than the strong ...

and

general relativity General relativity, also known as the general theory of relativity and Einstein's theory of gravity, is the geometric theory of gravitation published by Albert Einstein in 1915 and is the current description of gravitation in modern physics ...

. Pirani and Hermann Bondi wrote a series of articles (1959 to 1989) that established the existence of plane wave solutions for

gravitational waves Gravitational waves are waves of the intensity of gravity generated by the accelerated masses of an orbital binary system that propagate as waves outward from their source at the speed of light. They were first proposed by Oliver Heaviside in 1 ...

based on general relativity. During the last half of the 20th century Pirani was politically active, studied

disarmament Disarmament is the act of reducing, limiting, or abolishing weapons. Disarmament generally refers to a country's military or specific type of weaponry. Disarmament is often taken to mean total elimination of weapons of mass destruction, such as ...

and advocated the responsible use of science. His most famous scientific results include works on the physical meaning of the curvature tensor,

, and the algebraic classification of the

Weyl tensor In differential geometry, the Weyl curvature tensor, named after Hermann Weyl, is a measure of the curvature of spacetime or, more generally, a pseudo-Riemannian manifold. Like the Riemann curvature tensor, the Weyl tensor expresses the tidal f ...

, which he discovered in 1957 independently of A.Z. Petrov and is sometimes called the Petrov-Pirani classification.

Early life and education

Pirani was born in England, to parents who were both musicians. Pirani's family, who were Jewish, moved to Canada at the start of World War II. He studied at the University of Western Ontario (Bachelor 1948), the University of Toronto (Master's degree in 1949). He obtained his D. Sc. at the

Carnegie Institute of Technology Carnegie Mellon University (CMU) is a private research university in Pittsburgh, Pennsylvania. One of its predecessors was established in 1900 by Andrew Carnegie as the Carnegie Technical Schools; it became the Carnegie Institute of Technology ...

(now Carnegie Mellon University) in 1951 under

Alfred Schild Alfred Schild (September 7, 1921 – May 24, 1977) was a leading Austrian American physicist, well known for his contributions to the Golden age of general relativity (1960–1975). Biography Schild was born in Istanbul on September 7, 1921. His ...

. His D. Sc. dissertation was an early contribution to the quantum theory of general relativity. He also obtained a PhD in physics at

Cambridge University The University of Cambridge is a Public university, public collegiate university, collegiate research university in Cambridge, England. Founded in 1209 and granted a royal charter by Henry III of England, Henry III in 1231, Cambridge is the world' ...

in 1956 under

Hermann Bondi Sir Hermann Bondi (1 November 1919 – 10 September 2005) was an Austrian- British mathematician and cosmologist. He is best known for developing the steady state model of the universe with Fred Hoyle and Thomas Gold as an alternative to the ...

Scientific work

Pirani performed post-doctoral research at the

Institute for Advanced Studies The Institute for Advanced Study (IAS), located in Princeton, New Jersey, in the United States, is an independent center for theoretical research and intellectual inquiry. It has served as the academic home of internationally preeminent scholar ...

in Dublin. In 1958 he started teaching at King's College London (where Bondi was also teaching) and in 1968 became professor of rational mechanics there.

American Institute of Physics The American Institute of Physics (AIP) promotes science and the profession of physics, publishes physics journals, and produces publications for scientific and engineering societies. The AIP is made up of various member societies. Its corpora ...

br>Dean Rickles interview in Institute of Physics history June 2011
/ref> In 1957 Pirani independently discovered what was later called the Petrov classification (also Petrov–Pirani–Penrose classification) and separately discovered by Petrov in 1954. In 1959 Bondi, Pirani and Ivor Robinson published a fundamental paper on gravitational wave solutions in general relativity and showed the existence of plane gravitational wave solutions. Pirani's work with Bondi and Robinson resulted in correspondence between Pirani and

Albert Einstein Albert Einstein ( ; ; 14 March 1879 – 18 April 1955) was a German-born theoretical physicist, widely acknowledged to be one of the greatest and most influential physicists of all time. Einstein is best known for developing the theory ...

, some of whose partially expressed views on the subject had been challenged by the paper. In 1972 Pirani,

Jürgen Ehlers Jürgen Ehlers (; 29 December 1929 – 20 May 2008) was a German physicist who contributed to the understanding of Albert Einstein's theory of general relativity. From graduate and postgraduate work in Pascual Jordan's relativity research group ...

and Alfred Schild showed that the space-time geometry of general relativity can be constructed from simple measuring processes with light beams and free-falling particles.

Popular books

In 1960 Pirani revised the general audience book "The ABC of Relativity", originally written by

Bertrand Russell Bertrand Arthur William Russell, 3rd Earl Russell, (18 May 1872 – 2 February 1970) was a British mathematician, philosopher, logician, and public intellectual. He had a considerable influence on mathematics, logic, set theory, linguistics, ...

in 1925. He continued revisions up to 2002. In the 1990s he began writing books aimed at the general audience, e.g. " Introducing the Universe", translated into French as "L'Astronomie sans aspirine" (astronomy without aspirin).

Political views

Pirani was politically active in the 1970s and 1980s, had a left leaning stance, and opposed the unchecked use of science for military purposes.Gerald Wick, "Activism with feeling"

New Scientist ''New Scientist'' is a magazine covering all aspects of science and technology. Based in London, it publishes weekly English-language editions in the United Kingdom, the United States and Australia. An editorially separate organisation publish ...

and Science Journal 11 February 1971, pp 311–312 Along with DNA pioneer Maurice Wilkins, who was also at King's, Pirani was involved in the

British Society for Social Responsibility in Science The British Society for Social Responsibility in Science (BSSRS) was a radical science movement most active in the 1970s. The main aims of the BSSRS was to raise awareness of the social responsibilities of scientists, the political aspects of sci ...

.Hilary Rose, Ideology of/in the natural sciences 1980 pp xxviii In 1971 Pirani told the

that during an academic visit to the

University of North Carolina The University of North Carolina is the multi-campus public university system for the state of North Carolina. Overseeing the state's 16 public universities and the NC School of Science and Mathematics, it is commonly referred to as the UNC Sy ...

issues about slavery and the

American civil war The American Civil War (April 12, 1861 – May 26, 1865; also known by other names) was a civil war in the United States. It was fought between the Union ("the North") and the Confederacy ("the South"), the latter formed by states ...

"hit him in the face" and upon his return to England he joined the Scientists of the Left and the

Campaign for Nuclear Disarmament The Campaign for Nuclear Disarmament (CND) is an organisation that advocates unilateral nuclear disarmament by the United Kingdom, international nuclear disarmament and tighter international arms regulation through agreements such as the Nuc ...

and became a political activist. Pirani studied disarmament and founded the Science Forum as a group of scientists that met monthly in London to discuss the social problems of science.

20 December 1962, pp 699 Pirani's efforts were based on his view that the public belief that "science will solve the world's problems" is a delusion because funding for research comes from the top levels of the social hierarchy, which controls the direction of scientific progress for its own purposes.

References

External links

* * {{DEFAULTSORT:Pirani, Felix British relativity theorists 1928 births 2015 deaths Alumni of the University of Cambridge