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Roger Penrose
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Sir Roger Penrose
(born
8 August 1931)

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. He is renowned for his work in mathematical physics, in particular his contributions to general relativity and cosmology. He is also a recreational mathematician and philosopher. Roger Penrose is the son of scientist Lionel S. Penrose and Margaret Leathes, and the brother of mathematician Oliver Penrose and correspondence chess grandmaster Jonathan Penrose. He was born in Colchester, Essex, England.

Penrose graduated with a first class degree in mathematics from University College London. In 1955, while still a student, Penrose reinvented the generalized matrix inverse (also known as Moore-Penrose inverse, see Penrose, R. "A Generalized Inverse for Matrices." Proc. Cambridge Phil. Soc. 51, 406-413, 1955.) Penrose earned his Ph.D. at Cambridge (St John's College) in 1958, writing a thesis on tensor methods in algebraic geometry under the well known algebraist and geometer John A. Todd. In 1965 at Cambridge, Penrose proved that singularities (such as black holes) could be formed from the gravitational collapse of dying immense stars. (Ferguson, 1991: 66).

In 1967, Penrose invented the twistor theory which maps geometric objects in Minkowski space into the 4-dimensional complex space with the metric signature (2,2). In 1969 he conjectured the cosmic censorship hypothesis. This proposes (rather informally) that the universe protects us from the inherent unpredictability of singularities (such as the one in the centre of a black hole) by hiding them from our view behind an event horizon. This form is now known as the weak censorship hypothesis; in 1979, Penrose formulated a stronger version called the strong censorship hypothesis. Together with the BKL conjecture and issues of nonlinear stability, settling the censorship conjectures is one of the most important outstanding problems in general relativity. Also from 1979 dates Penrose's influential Weyl curvature hypothesis on the initial conditions of the observable part of the Universe and the origin of the second law of thermodynamics.

Roger Penrose is well known for his 1974 discovery of Penrose tilings, which are formed from two tiles that can only tile the plane nonperiodically, and are the first tilings to exhibit fivefold rotational symmetry. In 1984, such patterns were observed in the arrangement of atoms in quasicrystals. Another noteworthy contribution is his 1971 invention of spin networks, which later came to form the geometry of spacetime in loop quantum gravity. He was influential in popularizing what are commonly known as Penrose diagrams (causal diagrams). In 2004 Penrose released The Road to Reality: A Complete Guide to the Laws of the Universe, a 1,099-page book aimed at giving a comprehensive guide to the laws of physics. In the June 2005 issue of Discover magazine , Penrose outlined his interpretation of quantum mechanics. Penrose is currently the Francis and Helen Pentz Distinguished (visiting) Professor of Physics and Mathematics at Penn State University