Roy Kerr

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Roy P. Kerr

Roy Kerr with his wife.jpg
Roy Kerr with his wife, 2009
Born (1934-05-16) 16 May 1934 (age 86)
Kurow, New Zealand
NationalityNew Zealand
Education St. Andrew's College, Christchurch
Alma mater
Known for Kerr metric
Awards Hector Medal (1982)
Hughes Medal (1984)
Rutherford Medal (1993)
Albert Einstein Medal (2013)
Crafoord Prize (2016)
Scientific career
FieldsMathematics
Institutions University of Canterbury
Syracuse University
Thesis Equations of Motion in General Relativity  (1960)

Roy Patrick Kerr FRS CNZM FRSNZ ( /kɜːr/ ; born 16 May 1934) is a New Zealand mathematician who discovered the Kerr geometry, an exact solution to the Einstein field equation of general relativity. His solution models the gravitational field outside an uncharged rotating massive object, including a rotating black hole. [1] [2] His solution to Einstein's equations predicted spinning black holes before they were discovered. [3] [4]

Contents

Early life and education

Kerr was born in 1934 in Kurow, New Zealand. [5] He was born into a dysfunctional family, and his mother was forced to leave when he was three. When his father went to war, he was sent to a farm. After his father's return from war, they moved to Christchurch. He got into St Andrew's College, a private school, as his father had served under a former headmaster. [6] Kerr's mathematical talent was first recognised while he was still a high school student at St Andrew's College. Although there was no maths teacher there at the time he was able in 1951 to go straight into third year Mathematics at the Canterbury University College of the University of New Zealand, the precursor to the University of Canterbury. Their regulations did not permit him to graduate until 1954 and so it was not until September 1955 that he moved to the University of Cambridge, where he earned his PhD in 1959. [7] His dissertation concerned the equations of motion in general relativity. [5]

Career and research

After a stint as a postdoctoral researcher at Syracuse University, where Einstein's collaborator Peter Bergmann was professor, [8] [9] he spent some time working for the United States Air Force at Wright-Patterson Air Force Base. Kerr speculated that the "main reason why the US Air Force had created a General Relativity section was probably to show the U.S. Navy that they could also do pure research." [10]

Work at Texas and Canterbury

In 1962 Kerr joined Alfred Schild and his Relativity Group at the University of Texas at Austin. As Kerr wrote in 2009:

By the summer of 1963, Maarten Schmidt at Caltech had shown that certain starlike objects (now called quasars) were actually distant objects emitting enormous amounts of energy. Nobody understood how they could be so bright. In an effort to unravel this mystery, several hundred astronomers, astrophysicists, and general relativists gathered for a conference in Dallas, held in early December that year. This would be the First (of what since then has become the biennial) Texas Symposium on Relativistic Astrophysics. [11]

Kerr presented to the Symposium his solution to the Einstein field equations. [12] In 1965, with Alfred Schild, he introduced the concept of Kerr-Schild perturbations and developed the Kerr-Newman metric. [13] [14] [15] During his time in Texas, Kerr supervised four PhD students.

In 1971, Kerr returned to the University of Canterbury in New Zealand. Kerr retired from his position as Professor of Mathematics at the University of Canterbury in 1993 after having been there for twenty-two years, including ten years as the head of the Mathematics department.

Awards and honours

In 2008 Kerr was appointed to the Yevgeny Lifshitz ICRANet Chair in Pescara, Italy.

Fulvio Melia interviewed Kerr about his work on the solution for the book Cracking the Einstein Code: Relativity and the Birth of Black Hole Physics published in 2009. [17] Kerr contributed an "Afterword" of two and a half pages.

In 2012 it was announced that Kerr would be honoured by the Albert Einstein Society in Switzerland with the 2013 Albert Einstein Medal. He is the first New Zealander to receive the prestigious award. [18]

In December 2015, the University of Canterbury awarded Kerr an honorary Doctor of Science. [19]

In May 2016 Kerr was awarded the Crafoord Prize in Astronomy by The Royal Swedish Academy of Sciences.

Personal life

Kerr is married to Margaret. [6] In 2013 they moved from Christchurch to Tauranga. Kerr was a notable bridge player representing New Zealand internationally in the mid 1970s. [20] He was co-author of the Symmetric Relay System, a bidding system in contract bridge. [21]

Related Research Articles

Black hole Compact astrophysical object with gravity so strong nothing can escape

A black hole is a region of spacetime where gravity is so strong that nothing—no particles or even electromagnetic radiation such as light—can escape from it. The theory of general relativity predicts that a sufficiently compact mass can deform spacetime to form a black hole. The boundary of the region from which no escape is possible is called the event horizon. Although the event horizon has an enormous effect on the fate and circumstances of an object crossing it, it has no locally detectable features. In many ways, a black hole acts like an ideal black body, as it reflects no light. Moreover, quantum field theory in curved spacetime predicts that event horizons emit Hawking radiation, with the same spectrum as a black body of a temperature inversely proportional to its mass. This temperature is on the order of billionths of a kelvin for black holes of stellar mass, making it essentially impossible to observe.

General relativity Einsteins theory of gravitation as curved spacetime

General relativity (GR), also known as the general theory of relativity (GTR), is the geometric theory of gravitation published by Albert Einstein in 1915 and the current description of gravitation in modern physics. General relativity generalizes special relativity and refines Newton's law of universal gravitation, providing a unified description of gravity as a geometric property of space and time, or spacetime. In particular, the curvature of spacetime is directly related to the energy and momentum of whatever matter and radiation are present. The relation is specified by the Einstein field equations, a system of partial differential equations.

Timeline of gravitational physics and general relativity

The no-hair theorem states that all black hole solutions of the Einstein–Maxwell equations of gravitation and electromagnetism in general relativity can be completely characterized by only three externally observable classical parameters: mass, electric charge, and angular momentum. All other information about the matter which formed a black hole or is falling into it "disappears" behind the black-hole event horizon and is therefore permanently inaccessible to external observers. Physicist John Archibald Wheeler expressed this idea with the phrase "black holes have no hair" which was the origin of the name. In a later interview, Wheeler said that Jacob Bekenstein coined this phrase.

Kerr metric Rotating solution of Einsteins equations, featuring axisymmetric ergosphere and event horizon around a singularity

The Kerr metric or Kerr geometry describes the geometry of empty spacetime around a rotating uncharged axially-symmetric black hole with a quasispherical event horizon. The Kerr metric is an exact solution of the Einstein field equations of general relativity; these equations are highly non-linear, which makes exact solutions very difficult to find.

Rotating black hole Black hole with angular momentum

A rotating black hole is a black hole that possesses angular momentum. In particular, it rotates about one of its axes of symmetry.

Kerr–Newman metric equations in general relativity

The Kerr–Newman metric is the most general asymptotically flat, stationary solution of the Einstein–Maxwell equations in general relativity that describes the spacetime geometry in the region surrounding an electrically charged, rotating mass. It generalizes the Kerr metric by taking into account the field energy of an electromagnetic field, in addition to describing rotation. It is one of a large number of various different electrovacuum solutions, that is, of solutions to the Einstein–Maxwell equations which account for the field energy of an electromagnetic field. Such solutions do not include any electric charges other than that associated with the gravitational field, and are thus termed vacuum solutions.

Brandon Carter Australian physicist

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 the CNRS.

Numerical relativity is one of the branches of general relativity that uses numerical methods and algorithms to solve and analyze problems. To this end, supercomputers are often employed to study black holes, gravitational waves, neutron stars and many other phenomena governed by Einstein's theory of general relativity. A currently active field of research in numerical relativity is the simulation of relativistic binaries and their associated gravitational waves. Other branches are also active.

History of general relativity Theory of Gravitation

General relativity (GR) is a theory of gravitation that was developed by Albert Einstein between 1907 and 1915, with contributions by many others after 1915. According to general relativity, the observed gravitational attraction between masses results from the warping of space and time by those masses.

Ezra Theodore Newman is an American physicist, known for his many contributions to general relativity theory. He is Professor Emeritus at the University of Pittsburgh. Newman was awarded the 2011 Einstein Prize from the American Physical Society:

For outstanding contributions to theoretical relativity, including the Newman–Penrose formalism, Kerr–Newman solution, Heaven, and null foliation theory. For his intellectual passion, generosity and honesty, which have inspired and represented a model for generations of relativists.

Alfred Schild was a leading Austrian American physicist, well known for his contributions to the Golden age of general relativity (1960–1975).

A ring singularity or ringularity is the gravitational singularity of a rotating black hole, or a Kerr black hole, that is shaped like a ring.

Taub–NUT space asymptotically locally flat (ALF) hyperkähler manifold

The Taub–NUT metric is an exact solution to Einstein's equations. It may be considered a first attempt in finding the metric of a spinning black hole. It is sometimes also used in homogeneous but anisotropic cosmological models formulated in the framework of general relativity.

Jürgen Ehlers German physicist

Jürgen Ehlers 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 at Hamburg University, he held various posts as a lecturer and, later, as a professor before joining the Max Planck Institute for Astrophysics in Munich as a director. In 1995, he became the founding director of the newly created Max Planck Institute for Gravitational Physics in Potsdam, Germany.

Tevian Dray is an American mathematician who has worked in general relativity, mathematical physics, geometry, and both science and mathematics education. He was elected a Fellow of the American Physical Society in 2010.

Achille Papapetrou was a Greek theoretical physicist, who contributed to the general theory of relativity. He is known for the Mathisson–Papapetrou–Dixon equations, the Majumdar–Papapetrou solution, and the Weyl−Lewis−Papapetrou coordinates of gravity theory.

Ivor Robinson was an English mathematical physicist, born and educated in England. He was a principal organizer of the Texas Symposium on Relativistic Astrophysics.

Kerr–Schild perturbations are a special type of perturbation to a spacetime metric which only appear linearly in the Einstein field equations which describe general relativity. They were found by Roy Kerr and Alfred Schild in 1965.

References

  1. Kerr, R. P. (1963). "Gravitational field of a spinning mass as an example of algebraically special metrics". Phys. Rev. Lett. 11 (5): 237–238. Bibcode:1963PhRvL..11..237K. doi:10.1103/PhysRevLett.11.237.
  2. Cracking the Einstein Code by Fulvio Melia, 2009 ISBN   0226519546
  3. Martin Rees, Just Six Numbers – The Deep Forces that Shape the Universe, Phoenix, 1999, ISBN   0 75381 022 0, page 41
  4. Review of Cracking the Einstein Code
  5. 1 2 O'Connor, John J.; Robertson, Edmund F., "Roy Kerr", MacTutor History of Mathematics archive , University of St Andrews .
  6. 1 2 McCrone, John (2 March 2013). "Bright sparks and black holes". The Press . p. C2. Retrieved 2 March 2013.
  7. Roy Kerr at the Mathematics Genealogy Project
  8. APS site: Peter Bergmann receives Einstein prize
  9. Obituary of Peter Bergmann
  10. Kerr (2007). "Discovering the Kerr and Kerr-Schild metrics". arXiv: 0706.1109 [gr-qc].
  11. Roy Kerr (2009) Afterword, page 125 of Cracking the Einstein Code by Fulvio Melia
  12. Kerr, R.P., 1963, Physical Review Letters, 11, 237. Bibcode :  1963PhRvL..11..237K doi : 10.1103/PhysRevLett.11.237
  13. Kerr, R. P. & Schild, A. (1965). "Some algebraically degenerate solutions of Einstein's gravitational field equations". Proc. Symp. Appl. Math. 17: 119.
  14. Debney, G.C.; Kerr, R. P. & Schild, A. (1969). "Solutions of the Einstein and Einstein-Maxwell Equations". J. Math. Phys. 10 (10): 1842. Bibcode:1969JMP....10.1842D. doi:10.1063/1.1664769.
  15. Tomáš Málek (2014). "Extended Kerr-Schild spacetimes: General properties and some explicit examples". Classical and Quantum Gravity. 31 (18): 185013. arXiv: 1401.1060 . Bibcode:2014CQGra..31r5013M. doi:10.1088/0264-9381/31/18/185013.
  16. "New Year honours list 2011". Department of the Prime Minister and Cabinet. 31 December 2010. Retrieved 5 January 2018.
  17. Dan Falk (7 October 2009) Review: Cracking the Einstein Code, New Scientist
  18. Einstein Medal for NZ professor Stuff.co.nz , 20 December 2012
  19. "Two Kiwi greats receive UC Honorary Doctorates" (Press release). University of Canterbury. 10 December 2015. Retrieved 16 December 2015.
  20. "International record for Roy Kerr". World Bridge Federation.
  21. Symmetric Relay System at BridgeGuys.com