The Most Beautiful Theory: Physicist Carlo Rovelli on the Aesthetic Enchantment and Scientific Impact of Einstein’s Relativity
By Maria Popova
In what remains the most beautiful love letter to the mesmerism of mathematics, James Joseph Sylvester wrote that the eternal aim of the mathematician is “to condense the Maximum of meaning into the Minimum of language.” A generation later, a man came along who condensed more meaning in more elegant economy of language than any human being before or since — Albert Einstein, who believed that “the most beautiful experience we can have is the mysterious” and went on to capture the beauty of that mystery with exquisite simplicity in his 1915 theory of relativity, which shaped our understanding of time and profoundly changed the course of science.
The source of Einstein’s genius as revealed by that theory is among the septet of scientific cornerstones which Italian theoretical physicist and writer Carlo Rovelli illuminates in his slim and stimulating Seven Brief Lessons on Physics (public library).
Rovelli writes of Einstein’s seminal masterwork:
There are absolute masterpieces that move us intensely: Mozart’s Requiem, Homer’s Odyssey, the Sistine Chapel, King Lear. To fully appreciate their brilliance may require a long apprenticeship, but the reward is sheer beauty — and not only this, but the opening of our eyes to a new perspective upon the world. Einstein’s jewel, the general theory of relativity, is a masterpiece of this order.
I remember the excitement I felt when I began to understand something about it. It was summer. I was on a beach at Condofuri in Calabria, immersed in the sunshine of the Hellenic Mediterranean, and in the last year of my university studies. Undistracted by schooling, one studies best during vacations. I was studying with the help of a book that had been gnawed at the edges by mice because at night I’d used it to block the holes of these poor creatures in the rather dilapidated, hippie-ish house on an Umbrian hillside where I used to take refuge from the tedium of university classes in Bologna. Every so often I would raise my eyes from the book and look at the glittering sea: it seemed to me that I was actually seeing the curvature of space and time imagined by Einstein. As if by magic: as if a friend were whispering into my ear an extraordinary hidden truth, suddenly raising the veil of reality to disclose a simpler, deeper order. Ever since we discovered that Earth is round and turns like a mad spinning-top, we have understood that reality is not as it appears to us: every time we glimpse a new aspect of it, it is a deeply emotional experience. Another veil has fallen.
Einstein had arrived at his magical insight by way of what he once described to a colleague as “combinatory play” — the fusion of existing logical concepts into an unexpected and utterly novel combination, in this case Newton’s concept of space and Faraday and Maxwell’s discovery of the electromagnetic field. It suddenly occurred to Einstein, as he was toying with these two previously unrelated ideas, that they belonged together — that gravity, like electricity, must exist in a field, and this gravitational filed isn’t spread throughout space but is space. This was the essence of Einstein’s general theory of relativity, the impact of which Rovelli captures in a wonderfully poetic passage:
It’s a moment of enlightenment. A momentous simplification of the world: space is no longer something distinct from matter — it is one of the “material” components of the world. An entity that undulates, flexes, curves, twists. We are not contained within an invisible, rigid infrastructure: we are immersed in a gigantic, flexible snail shell. The sun bends space around itself, and Earth does not turn around it because of a mysterious force but because it is racing directly in a space that inclines, like a marble that rolls in a funnel. There are no mysterious forces generated at the center of the funnel; it is the curved nature of the walls that causes the marble to roll. Planets circle around the sun, and things fall, because space curves.
Indeed, at the heart of Einstein’s theory is a groundbreaking explanation of why and how space bends around a star. Rovelli considers the enormous implications:
Due to this curvature, not only do planets orbit around the star but light stops moving in a straight line and deviates. Einstein predicted that the sun causes light to deviate. In 1919 this deviance was measured and the prediction verified. But it isn’t only space that curves; time does too. Einstein predicted that time passes more quickly high up than below, nearer to Earth. This was measured and turned out to be the case. If a person who has lived at sea level meets up with his twin who has lived in the mountains, he will find that his sibling is slightly older than he.
The theory describes a colorful and amazing world 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.
In the remainder of Seven Brief Lessons on Physics, Rovelli goes on to explore the beauty and intellectual enchantment of quantum mechanics, the architecture of the universe, quantum gravity, black holes, and more. Complement it with physicist Paul Davies on the puzzlement of why we experience time as linear, then revisit Einstein on the common language of science and the childhood epiphany that made him a scientist.
Published March 4, 2016