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Electrons, Photons, Gluons, Quarks: A Nobel-Winning Physicist Explains It All

FUNDAMENTALS
Ten Keys to Reality
By Frank Wilczek

Whether or not you’re accustomed to reading physics for pleasure, the Nobel laureate Frank Wilczek’s “Fundamentals” might be the perfect book for the winter of this plague year. Early on, Wilczek quotes the 17th-century French physicist and philosopher Blaise Pascal’s lament, “The universe grasps me and swallows me up like a speck.” For Pascal, that thought produced intense spiritual anxiety, but for the contemporary reader it might actually provide a certain comfort: Whatever obscene amount of damage we’ve managed to do here on Earth is insignificant when seen on an astronomical scale. Wilczek has a more optimistic take, though, based on quantifying the space inside us: The number of atoms in a single human body is roughly 1028 — 1 followed by 28 zeros, “a million times the number of stars in the entire visible universe.” He sees potential in our inner vastness, too.

Another way to write that number is 10 octillion, and “Fundamentals” is filled with facts like these — the kind of question adults think they can answer until their children ask. How long until the Earth is swallowed by the sun? How does GPS work? How many thoughts can a person have in a lifetime? (Based on an average speech rate of two words per second, Wilczek estimates approximately a billion.)

Although Wilczek’s voice here is endearingly humble, it’s clear that his mind was never like that of most kids piping up from the back seat. He recalls that one of his “earliest childhood memories is of a small notebook I kept when I was first learning about relativity, on the one hand, and algebra, on the other.” Wilczek grew up in New York City and attended public school in Queens, graduating from high school in two years. As a teenager trailing his mother in the grocery store, he was taken with the brand name of a laundry detergent called Axion, and promised himself that if he ever discovered an elementary particle, he’d give it that name. Incredibly, in 1978, Wilczek did identify a hypothetical particle — one that coincidentally solved a problem related to axial currents — and was able to fulfill that fantasy.

Wilczek was still a graduate student at Princeton when he and David Gross developed the theory of asymptotic freedom, an explanation for the way quarks interact with one another inside the nucleus of an atom, clarifying the workings of the strong force, also called quantum chromodynamics. The theory explained a seeming paradox in the behavior of these elementary particles — that they attract one another more forcefully at a distance than in proximity — a discovery that earned him and Gross, along with David Politzer, the 2004 Nobel Prize.

Wilczek writes with breathtaking economy and clarity, and his pleasure in his subject is palpable. He lays out the elementary particles of matter — electrons, photons, gluons and quarks — and their strikingly short list of properties: mass, charge and spin. He then defines four principles that characterize the four basic forces in nature: electromagnetism, gravity, the strong force and the weak force. Most people vaguely remember electromagnetic fields from high school physics, but Wilczek makes very clear the way that those “space-filling” fields are contiguous with the smallest building blocks of matter: “We now understand particles as manifestations of a deeper, fuller reality. Particles are avatars of fields.” It’s a beautiful description that would be especially evocative for today’s game-fluent high school students.

Sometimes, to see if you understand a concept in physics, it helps to try to explain it to someone else. Wilczek points out that the elementary particles “aren’t even solid bodies. Indeed, though it’s convenient to call them ‘elementary particles,’ they aren’t really particles. … Our modern fundamental ingredients have no intrinsic size or shape.”

In trying to paraphrase this enchanting idea for my husband, I realized that I didn’t actually know how something with no size or shape could have mass. I thought Wilczek might not enlighten me, and then a chapter later he did, articulating the concept this way: “Quarks have very small masses, and gluons have zero mass. But inside protons they are moving around very fast, and thus they carry energy. All that energy adds up. When the accumulated energy is packaged into an object that is at rest overall, such as the proton as a whole, then that object has the mass m=E/c2.” That inverted version of Einstein’s famous formula incidentally is one of the things Wilczek remembers writing down in his childhood notebook. What a reader gets in “Fundamentals” is the native language of physics — mathematics — precisely translated by someone who has spent a lifetime (about a billion thoughts!) on these forces that shape our physical world.

Beyond the facts, “Fundamentals” is full of the kind of heady ideas that keep laypeople reading about contemporary physics: the possibility that the mysterious “dark matter” that makes up 25 percent of the mass of our universe might actually be a remnant of theoretical particles called axions in the very early universe, an invisible cousin of the cosmic microwave background radiation, also a relic of the Big Bang; or the idea that with a biological engineering technique called “modulated self-reproduction” it might be possible to “terraform” a new planet. In a book this far-reaching, it’s understandable that Wilczek spends only a few pages on climate change, focusing mostly on the enormous potential of solar energy. The optimism inherent in chapter titles like “There’s Plenty of Time” and “There’s Plenty of Space” can seem Panglossian next to the reality of what we’re facing on Earth in the next few decades.

I think Wilczek might answer that criticism by talking about complementarity, an idea that he’s elevated to an intellectual credo: “the concept that one single thing, when considered from different perspectives, can seem to have very different or even contradictory properties.” He explains that in physics, when a model becomes too complicated, an alternative model can help answer important questions.

“Fundamentals” offers readers just that sort of radical shift: the way that energy, seen from another angle, is a particle; the way that space-time could be a form of matter; the way that stepping outside a catastrophe to look at it on a cosmic scale might actually be the first step toward a solution.

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