Born in England, the son of a geneticist, Roger Penrose received a Ph.D. in 1957 from Cambridge University. Penrose then became a professor of applied mathematics at Birkbeck College in 1966 and a Rouse Ball Professor of Mathematics at Oxford University in 1973. Penrose, a mathematician and theoretical physicist, has done much to elucidate the fundamental properties of black holes. With Stephen Hawking, Penrose proved a theorem of Albert Einstein's general relativity, asserting that at the center of a black hole there must evolve a "space-time singularity" of zero volume and infinite density, in which the current laws of physics do not apply. He also proposed the hypothesis of "cosmic censorship," which claims that such singularities must possess an event horizon. In 1969 Penrose described a process for the extraction of energy from a black hole, as well as how rotational energy of the black hole is transferred to a particle outside the hole. In addition, Penrose has done much to develop the mathematics needed to unite general relativity, which deals with the gravitational interactions of matter, and quantum mechanics, which describes all other interactions.
Malcolm Longair is Emeritus Jacksonian Professor of Natural Philosophy and Director of Development at the Cavendish Laboratory, University of Cambridge. He has held many highly distinguished positions within physics and astronomy and has served on and chaired many international committees, boards and panels, working with both NASA and the European Space Agency. He has received much recognition for his work, including the Pilkington Prize of the University of Cambridge for Excellence in Teaching and a CBE in the millennium honours list for his services to astronomy and cosmology. His previous well-received books for Cambridge University Press include Theoretical Concepts in Physics (2003), The Cosmic Century: A History of Astrophysics and Cosmology (2005) and High Energy Astrophysics (2011).
