At the end of "The Incredible Shrinking Man" (1957), our unfortunate hero -- having survived encounters with a house cat and a spider on the way down -- finds himself smaller than an atom, with no end in sight. We see him awaken on what looks like a planet, made up (one reckons) of even tinier atoms. Which in turn contain worlds, containing atoms, and so on.
A mystical epiphany seems totally appropriate under the circumstances. "Smaller than smallest,” he says in the closing voice-over, “I meant something too. To God there is no zero. I still exist!" A galaxy fills the screen: vaster, and more infinitesimal, than the viewer can possibly imagine. A psychedelic moment, with the 1960s not even started yet.
It works, in part, because the audience has seen the standard textbook drawing of an atom, with electrons orbiting the nucleus like planets around the sun. (A lumpy sun, to be sure, made of protons and neutrons.) All of the particles are little spheres. The obvious parallel to a solar system feels sublimely appropriate. To use the maxim alchemists once learned from Hermes Trismegistus: “As above, so below.”
But the parallelism, while convenient, is misleading. Electrons resemble clouds more than they do the billiard-ball planets in a science-fair exhibit. Protons and neutrons are waves as much as they are particles. And there’s scarcely any point to attempting a visual rendering of the still more elementary components of matter that Jeremy Bernstein writes about in A Palette of Particles (Harvard University Press). Apart from vintage photographs in which scientists discerned the trails left by a positron or an Omega-minus particle on the move, most of the entities Bernstein writes about are best “depicted” as mathematical formulae.
A professor emeritus of physics at the Stevens Institute of Technology, Bernstein is a prolific author of books on science for the lay reader -- and he brings to this popular history of particle physics the advantage of having been around when some of that history was being made. Bernstein, now in his 80s, knew Wolfgang Pauli, who hypothesized the existence of the neutrino in 1930, a quarter-century before it could be confirmed. (He also came up with two devastating remarks sometimes appropriated by people who haven’t heard of Pauli. One was to say of a theory that it “wasn’t even wrong.” The other was to refer to a colleague as “so young and already so unknown.”)
Particle physics has become staggeringly expensive (the search for the Higgs boson or “God particle” cost more than $13 billion) but Bernstein entered the field when budgets, like computation speeds, were a lot lower. He mentions being “the house theorist for the Harvard Cyclotron from 1955 to 1957,” when the machine and the building to house it “cost something like half a million dollars.”
And the old venues had their charm: he expresses a certain fondness for the Cosmotron, a particle accelerator that went into operation at Brookhaven National Laboratory in the early 1950s. “I was on the theoretical staff at Brookhaven for a couple of years in the 1960s,” he writes. “When the machine was down I used to go into the building at night to practice my trumpet. The acoustics were wonderful.”
His personal observations help ground what can prove a mind-bending tour of the infinitesimal. Physicists have discovered a whole menagerie of subatomic entities since James Chadwick identified the neutron in 1932. Some of them have hard-to-grasp qualities such as zero mass, or power that increases with distance. The distinctions among them involve terms such as “spin” or “color” that bear little or no relation to what they mean in ordinary usage.
Furthermore, particles are related to one another in various ways, and there are symmetries (and anomalous asymmetries) between them as well. Keeping it all straight is like remembering who’s who in a Russian novel.
Not a complaint, let me hasten to say: Bernstein covers the material in a sprightly manner, with only the occasional equation that will reveal the beauty of it all to the reader who can grasp it. And he takes a quick look at hypothetical particles that sound like something out of a sci-fi flick. One is the graviton: a gravitational quantum with no mass that moves at the speed of light. Another is the tachyon, which cannot move slower than the speed of light.
If tachyons do exist and could be used to transmit information (so goes the speculation) it might be possible to reverse cause and effect – to go backward in time. Bernstein does not sound optimistic about anyone proving the existence of the tachyon. Even so, the search is on. (Imagine the day that breakthrough is made. What could possibly go wrong?)
A Palette of Particles ends by comparing the domain of subatomic particles to “a series of nested Russian dolls: inside each one there is another.” Add to that the estimate by physicists that 85 percent of the matter in the universe consists of subatomic particles we don’t recognize or understand yet…. It turns out that Bernstein’s sober and lucid introduction to particle physics has an almost mystical quality, even if the author shows no interest in that kind of cosmic thinking. We’re back to what the incredible shrinking man tells us:
“So close, the Infinitesimal and the Infinite. But suddenly I knew they were the really the two ends of the same concept. The unbelievably small and the unbelievably vast eventually meet like the closing of a gigantic circle.”