English mathematician who formulated some of the fundamental theorems that describe black holes, including the singularity theorems, developed jointly with English physicist Stephen Hawking, which state that once the gravitational collapse of a star has proceeded to a certain degree, singularities (which form the centre of black holes) are inevitable. Penrose has also proposed a new model of the universe.
Penrose was born in Colchester, Essex, and studied at University College, London. While he worked for his doctorate at Cambridge in 1957, Penrose and his father were devising geometrical figures, the construction of which is three-dimensionally impossible. (They became well known when incorporated by Dutch artist M C Escher into a couple of his disturbing lithographs.) Penrose was professor at Birkbeck College, London, 1966-73, and then moved to Oxford University.
The existence of a trapped surface within an 'event horizon' (the interface between a black hole and space-time), from which little or no radiation or information can escape, implies that some events remain hidden to observers outside the black hole. Penrose has put forward the hypothesis of 'cosmic censorship' - that all singularities are so hidden - which is now widely accepted.
Calculations in the world of ordinary objects (including Einstein's general theory of relativity) use real numbers, whereas the world of quantum theory often requires a system using complex numbers, containing imaginary components that are multiples of the square root of 1. Penrose holds that all calculations about both the macroscopic and microscopic worlds should use complex numbers, requiring reformulation of the major laws of physics and of space-time. He has proposed a model of the universe whose basic building blocks are what he calls 'twistors'.
His works include The Emperor's New Mind: Concerning Computers, Minds, and the Laws of Physics 1989 and Shadows of the Mind: A Search for the Missing Science of Consciousness 1994.