Roger Penrose, now 93, never shied away from wild ideas and the ensuring debates

The contentious genius who made black holes real The first full-length biography reveals more about the mathematician and the man

Roger Penrose, now 93, never shied away from wild ideas and the ensuring debates

The Impossible Man: Roger Penrose and the Cost of Genius Patchen Barss Basic (2024)

In the early days of a book project that would span six years, writer Patchen Barss had the best stroke of luck a biographer can hope for. His subject, the Nobel prizewinning mathematical physicist Roger Penrose, brought him a bundle of hundreds of letters that he had written decades earlier to a friend and confidante, a mathematician called Judith Daniels. After Daniels died of cancer in 2005, her sister found and returned the letters. Expecting them to contain insights into the development of his ideas in the 1970s, Penrose had decided to share them in full.

As Barss relates in The Impossible Man, Penrose had not even looked at the letters again before opening the package in front of his biographer. He started reading, and tears began to roll down his face, as the letters revealed much more than his inner processes of working. The episode goes a long way towards explaining the extraordinary access Barss got into Penrose’s private life — and into details that Penrose had perhaps buried deep in his memory.

The Impossible Man is the first book-length biography of Penrose, a demi-god of mathematical physics and one of the few survivors among the pioneers who established the theory of black holes. Although Barss is more at home detailing the personal aspects of Penrose’s life than describing his science, he offers more than a glimpse of Penrose’s intellect.

The book portrays the mathematician as in equal parts hugely influential and endlessly contentious, and as a man whose visual imagination and artistry helped him to discover patterns of eternal beauty¹. The book is also a meditation on the human costs of being a person of genius and how others often bear those costs.

Penrose was born in 1931 in Colchester, UK, into a family of intellectual overachievers. The book describes how his father, geneticist Lionel Penrose, was emotionally distant and bonded with his four children only over intellectual pursuits such as chess, games of logic or calculus. Lionel exerted suffocating control over his wife, Margaret, a trained physician whom he prevented from practising, and who retreated into isolation. Barss describes how the emotional neglect Penrose experienced from both parents was later mirrored in his relationships with his own children, and might have doomed his first marriage, to the US-born Joan Wedge, from the beginning.

Original thinker

The young Penrose displayed an early, prodigious affinity for geometric patterns. Against the wishes of his father, who wanted Roger to study medicine and saw professional mathematicians as “peculiar, unworldly people”, he decided to study mathematics. Initially, he concentrated on pure, unadulterated theoretical topics. However, during his degree studies at University College London and the University of Cambridge, UK, in the early 1950s, he also developed an interest in Albert Einstein’s general theory of relativity and in quantum physics, after attending classes by another Nobel prizewinner, Paul Dirac.

Penrose’s superpower throughout his career has been an ability to leverage his geometric intuition into physical insights that others have missed. Most mathematicians and physicists will have come across a concept of his making, from the Penrose diagrams, which provide a graphic representation of the past, present and future of a universe, to the ‘tensor networks’ that have become a foundational tool in machine learning.

A central theme in Penrose’s work — since an epiphany during a road trip in Texas in 1963 — has been the development of the theory of ‘twistors’. In this, Penrose was motivated, in part, by his love of complex numbers, which are needed to solve otherwise impossible equations such as x² = –1. The algebra of complex numbers finds its most natural expression in the pleasingly symmetrical geometry of curves on a sphere. Penrose’s twistors attach a deeper meaning to them, by reinterpreting every point of space-time as a complex sphere.

Penrose and his school of ‘Twistorians’ hope that this concept will ultimately allow them to reconcile gravity with quantum physics. That goal might still be far away, but some of the mathematical ideas are slowly becoming part of theoretical physicists’ toolkit.

On the fringes

Barss recounts with increasing frustration how Penrose also began to put a lot of his energies into the pursuit of ideas that most other researchers either ignored or derided. That dualism between canon and heresy is epitomized by Penrose’s Nobel lecture in 2020.

In the first ten minutes, he described the theory for which he had won the prize: the first mathematically inescapable scenario² in which the collapse of a star becomes unstoppable and leads to a region of space-time so tightly curved that it paradoxically violates the theory itself. (The theorem applies to the conditions inside a black hole, but — contrary to how it’s often described — does not prove that black holes must form in the first place.) Penrose’s result was revolutionary because it introduced mathematical ideas from the field of topology into the study of Einstein’s theory, and it was the basis of his subsequent collaboration with Stephen Hawking on black holes and the Big Bang.

But Penrose chose to spend the remaining 30 minutes of his talk outlining a more controversial idea — his signature ‘cyclic’ cosmological theory, in which the Big Bang, although real, is a matter of perspective. In the distant future, the Universe will still be expanding, stretching out and cooling down, until measures of space and time cease to have meaning. But, Penrose argues, this — seen on an unimaginably large scale — will reveal the conditions for a new beginning and a new big bang, followed by a new expansion, in an endless cycle.

That theory, which Penrose popularized in a 2010 book, Cycles of Time, relies on a number of unproven assumptions, and has not gathered much of a following among cosmologists. But the longer the community has gone on ignoring it, the more tenacious Penrose has become in his attempts to disseminate it.

And, beginning with his 1989 bestselling book The Emperor’s New Mind, Penrose promoted an even more controversial idea: that human consciousness is the result of quantum phenomena in the brain. In spite of — or perhaps because of — other researchers’ grave reservations, Penrose dug in his heels and “became hyper-focused on finding anyone who would give his ideas a sympathetic hearing”, Barss writes. This outlook might have contributed to Penrose’s separation, three decades later, from his second wife, his former PhD student Vanessa Thomas.

One thing that’s missing from The Impossible Man is book plates. These could have included colour reproductions of Penrose’s celebrated aperiodic tilings³. These involve covering a plane using two types of geometric figure, to make designs that — unlike periodic patterns — do not look identical after being translated in any direction. It is also a missed opportunity to show some of the artful handwritten and hand-drawn transparencies that Penrose (no fan of PowerPoint) famously uses in his talks. Disappointingly for readers who might want to know more, the book also lacks a proper bibliography, and its notes do not always contain references to the many pieces of work alluded to in the text.

The Impossible Man is not a scientific biography. But this remarkable, smooth-reading book fills a major gap in the literature. Barss covers territory that scientist authors might have tiptoed over with obsequiousness — especially in regard to a living subject — and with less psychological acumen. As for the full significance of Penrose’s legacy, that will take many more decades — and more books — to become clear.

Nature 636, 34-36 (2024)

doi: https://doi.org/10.1038/d41586-024-03917-x

This story originally appeared on: Nature - Author:Davide Castelvecchi