11 October 2015

Seven Brief Lessons on Physics makes physics sound like Romantic poetry

With his new book of popular science, Carlo Rovelli has struck gold.

Carlo Rovelli has struck gold. This book began life as a series of articles in the Italian newspaper Il Sole 24 Ore. The series was popular enough to be assembled into a slim volume and it became the bestselling book in Italy this year, beating the Pope’s encyclical and Fifty Shades of Grey. It has already won a slew of prizes and it is easy to see why.

Though in no way a comprehensive overview of physics – the English edition is a beautifully bound 83 pages, including index – it feels like a substantial contribution. Here you will find brief but masterful expositions of quantum mechanics, relativity, particle physics and thermodynamics, among other fields. If you want to understand what gets physicists out of bed in the morning, there is no better guide than Rovelli.

The translation into English was accomplished with the help of two poets, whose touch shines through. The prose is irresistible. Einstein’s equation encapsulating the general theory of relativity contains a “teeming universe” and the “magical richness of the theory opens up into a phantasmagorical succession of predictions that resemble the delirious ravings of a madman, but which have all turned out to be true”. Einstein created a universe “where universes explode, space collapses into bottomless holes, time sags and slows near a planet, and the unbounded extensions of interstellar space ripple and sway like the surface of the sea”.

Rovelli doesn’t pretend that physicists are on top of it all, however. A whole suite of posited particles has failed to appear as predicted, for instance. “Days, months, years and decades have passed – but the supersymmetric particles have not yet manifested themselves,” Rovelli writes. “Physics is not only a history of successes.” He admits that he cannot construct a clear, communicable notion of the nature of time (“There is so much still to be understood”) and the intersection of gravity, quantum mechanics and thermodynamics has raised “a tangle of problems where we are still in the dark . . . We do not yet have a theory capable of drawing together all three pieces of our fundamental knowledge of the world.”

Since Einstein and quantum theory, physics has been somewhat stuck. Our understanding of the cosmos has moved on a little but Rovelli clearly envies the youth of other fields – neuroscience, in particular. Rovelli is too old to shift fields now but he gives the impression that he is as fascinated by what we are discovering about the brain as he is about the details that we are failing to uncover about the universe. Neuroscience stands now where physics stood when Einstein was still learning his craft: it is, Rovelli writes, “one of the most interesting frontiers of science, where major progress is about to be made”.

This Proustian sigh comes in the last chapter. The title is slightly misleading: the book contains six lessons on physics and one on “ourselves”. This last entry is an essay that encourages us to be more self-aware, before it is too late. “We belong to a short-lived genus of species. All of our cousins are already extinct,” he points out.

Seven Brief Lessons on Physics is an absorbing, lovely book. It is also a good example of what the Nobel laureate Peter Medawar called “the postures we choose to be seen in when the curtain goes up and the public sees us”. If you want to keep a noble, romantic view of science, Medawar said, don’t ask a scientist what goes on behind the scenes. Rovelli is certainly keeping the curtain firmly down; if we don’t ask, he won’t tell. And so, in these pages, the pursuit of physics is almost chivalrous, its practitioners reminiscent of the knights of legend. There is no sense of the competition or personal ambition that haunts the university physics departments of the world. In the chapter devoted to the pursuit of a theory that will unite relativity and quantum physics, for instance, Rovelli discusses only one path: loop quantum gravity, the contender he helped devise. Its more popular rival, string theory, doesn’t even get a mention.

Such tactics are forgivable. The book was written for those who know little or nothing about modern science, Rovelli notes. They are unlikely to care that the light of these lessons is carried to them through a soft-focus lens. What’s more, there is something appealing about physicists who peer steadfastly though the fog, or stand on the beach and gaze out at the “ocean of the unknown”, humbly probing the “mystery and beauty of the world”. This is physics as romantic poetry and, by God, it’s beguiling.

Seven Brief Lessons on Physics by Carlo Rovelli, translated by Simon Carnell and Erica Segre, is out now from Allen Lane (£9.99, 83pp)