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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 and general relativity. Pirani and Hermann Bondi wrote a series of articles (1959 to 1989) that established the existence of plane wave solutions for gravitational waves based on general relativity.

During the last half of the 20th century Pirani was politically active, studied disarmament and advocated the responsible use of science.

His most famous scientific results include works on the physical meaning of the curvature tensor, gravitational waves, and the algebraic classification of the Weyl tensor, 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 (now Carnegie Mellon University) in 1951 under Alfred Schild. 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 in 1956 under Hermann Bondi.

Scientific work

Pirani performed post-doctoral research at the Institute for Advanced Studies 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.

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

In 1972 Pirani, Jürgen Ehlers 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 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. Along with DNA pioneer Maurice Wilkins, who was also at King's, Pirani was involved in the British Society for Social Responsibility in Science.

In 1971 Pirani told the New Scientist that during an academic visit to the University of North Carolina issues about slavery and the American Civil War "hit him in the face" and upon his return to England he joined the Scientists of the Left and the Campaign for Nuclear Disarmament 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. 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

1. ^ "Felix Pirani obituary". The Guardian. 4 February 2016.
2. ^ "Obituary of Felix Pirani". The Daily Telegraph. 10 February 2016.
3. Memorial to Felix Pirani – The Muchloved Community
4. ^ American Institute of Physics Dean Rickles interview in Institute of Physics history June 2011
5. Pirani, Felix (1956), "On the physical significance of the Riemann tensor", Acta Physica Polonica, 15: 389–405, Bibcode:1956AcPP...15..389P
6. Pirani, Felix A. E (9 April 2009), "Republication of: On the physical significance of the Riemann tensor", General Relativity and Gravitation, 41 (5): 1215–1232, Bibcode:2009GReGr..41.1215P, doi:10.1007/s10714-009-0787-9, S2CID 121457672
7. Pirani, F. A (1 February 1957), "Invariant formulation of gravitational radiation Theory", Phys. Rev., 105 (3): 1089–1099, Bibcode:1957PhRv..105.1089P, doi:10.1103/PhysRev.105.1089
8. ^ H. Bondi, F. A. E. Pirani, I. Robinson (1959). "Gravitational waves in General Relativity III: Exact plane waves" (PDF). Proc. R. Soc. A. 251 (1267): 519–533. Bibcode:1959RSPSA.251..519B. doi:10.1098/rspa.1959.0124. S2CID 122766998.{{cite journal}}: CS1 maint: multiple names: authors list (link)
9. Hermann Bondi; F. A. E. Pirani (8 February 1989). "Gravitational Waves in General Relativity. XIII. Caustic Property of Plane Waves". Proc. R. Soc. A. 251 (1227): 395. Bibcode:1989RSPSA.421..395B. doi:10.1098/rspa.1989.0016. S2CID 121994014.
10. ^ Gerald Wick, "Activism with feeling" New Scientist and Science Journal 11 February 1971, pp 311–312
11. ^ New Scientist 20 December 1962, pp 699
12. David Robinson, Gravitation and general relativity at King's College London, European Physical Journal H 44, pp 181–270 (2019)
13. Peter Galison "The Roots of Special Relativity" 2001 Routledge ISBN 978-0415937153 pp 29
14. "A Century Ago, Einstein's Theory of Relativity Changed Everything". The New York Times. 24 November 2015.
15. Princeton University Albert Einstein Archives Pirani Correspondence with Einstein
16. Ehlers, Pirani, Schild The geometry of free fall and light propagation, in O'Raifeartaigh (Herausgeber) General Relativity. Papers in Honor of J. L. Synge, Oxford University Press 1972, S. 63–84
17. Preface to "The ABC of Relativity" Routledge 2009 ISBN 978-0451609939
18. Felix Pirani Introducing the Universe Totem Books 1990 ISBN 978-1874166061
19. Felix Pirani and Christine Roche L'Astronomie sans aspirine Flammarion 2002 ISBN 978-2080680334
20. Richard Fifield, New Scientist 27 August 1981, pp 533
21. Hilary Rose, Ideology of/in the natural sciences 1980 ISBN 978-0816190027 pp xxviii

External links

• Felix Pirani at the Mathematics Genealogy Project
• Christina Sormani; C. Denson Hill; Paweł Nurowski; Lydia Bieri; David Garfinkle; Nicolás Yunes (August 2017). "A two-part feature: The Mathematics of Gravitational waves". Notices of the American Mathematical Society. 64 (7): 684–707. doi:10.1090/noti1551. ISSN 1088-9477.

• British relativity theorists
• 1928 births
• 2015 deaths
• Alumni of the University of Cambridge
• Jewish British physicists