Genius (7 page)
Authors: James Gleick
The first quantum idea—the notion that indivisible building blocks lay at the core of things—occurred to someone at least twenty-five hundred years ago, and with it physics began its slow birth, for otherwise not much can be understood about earth or water, fire or air. The idea must have seemed dubious at first. Nothing in the blunt appearance of dirt, marble, leaves, water, flesh, or bone suggests that it is so. But a few Greek philosophers in the fifth century B.C. found themselves hard pressed to produce any other satisfactory possibilities. Things change—crumble, fade, wither, or grow—yet they remain the same. The notion of immutability seemed to require some fundamental immutable parts. Their motion and recombination might give the appearance of change. On reflection, it seemed worthwhile to regard the basic constituents of matter as unchanging and indivisible:
atomos
—uncuttable. Whether they were also uniform was disputed. Plato thought of atoms as rigid blocks of pure geometry: cubes, octahedrons, tetrahedrons, and icosahedrons for the four pure elements, earth, air, fire, and water. Others imagined little hooks holding the atoms together (of what, though, could these hooks be made?).
Experiment was not the Greek way, but some observations supported the notion of atoms. Water evaporated; vapor condensed. Animals sent forth invisible messengers, their scents on the wind. A jar packed with ashes could still accept water; the volumes did not sum properly, suggesting interstices within matter. The mechanics were troubling and remained so. How did these grains move? How did they bind? “Cloudy, cloudy is the stuff of stones,” wrote the poet Richard Wilbur, and even in the atomic era it was hard to see how the physicist’s swarming clouds of particles could give rise to the hard-edged world of everyday sight and touch.
Someone who trusts science to explain the everyday must continually make connections between textbook knowledge and real knowledge, the knowledge we receive and the knowledge we truly own. We are told when we are young that the earth is round, that it circles the sun, that it spins on a tilted axis. We may accept the knowledge on faith, the frail teaching of a modern secular religion. Or we may solder these strands to a frame of understanding from which it may not so easily be disengaged. We watch the sun’s arc fall in the sky as winter approaches. We guess the time from the shadow of a lamppost. We walk across a merry-go-round and strain against the sideways Coriolis force, and we try to connect the sensation to our received knowledge of the habits of earthly cyclones: northern hemisphere, low pressure, counterclockwise. We time the vanishing point of a tall-masted ship below the horizon. The sun, the winds, the waves all join in preventing our return to a flat-earth world, where we could watch the tides follow the moon without understanding.
All things are made of atoms
—how much harder it is to reconcile this received fact with the daily experience of solid tables and chairs. Glancing at the smooth depressions worn in the stone steps of an office building, we seldom recognize the cumulative loss of invisibly small particles struck off by ten million footfalls. Nor do we connect the geometrical facets of a jewel to a mental picture of atoms stacked like cannonballs, favoring a particular crystalline orientation and so forcing regular angles visible to the naked eye. If we do think about the atoms in us and around us, the persistence of solid stone remains a mystery. Richard Feynman asked a high-school teacher (and never heard a satisfactory reply), “How do sharp things stay sharp all this time if the atoms are always jiggling?”
The adult Feynman asked: If all scientific knowledge were lost in a cataclysm, what single statement would preserve the most information for the next generations of creatures? How could we best pass on our understanding of the world? He proposed, “
All things are made of atoms
—
little particles that move around in perpetual motion, attracting each other when they are a little distance apart, but repelling upon being squeezed into one another
,” and he added, “In that one sentence, you will see, there is an enormous amount of information about the world, if just a little imagination and thinking are applied.” Although millennia had passed since natural philosophers broached the atomic idea, Feynman’s lifetime saw the first generations of scientists who truly and universally believed in it, not just as a mental convenience but as a hard physical reality. As late as 1922 Bohr, delivering his Nobel Prize address, felt compelled to remind his listeners that scientists “believe the existence of atoms to be proved beyond a doubt.” Richard nevertheless read and reread in the Feynmans’
Encyclopaedia Britannica
that “pure chemistry, even to-day, has no very conclusive arguments for the settlement of this controversy.” Stronger evidence was at hand from the newer science, physics: the phenomenon called radioactivity seemed to involve the actual disintegration of matter, so discretely as to produce audible pings or visible blips. Not until the eighties could people say that they had finally seen atoms. Even then the seeing was indirect, but it stirred the imagination to see shadowy globules arrayed in electron-microscope photographs or to see glowing points of orange light in the laser crossfire of “atom traps.”
Not solids but gases began to persuade seventeenth- and eighteenth-century scientists of matter’s fundamental granularity. In the heady aftermath of Newton’s revolution scientists made measurements, found constant quantities, and forged mathematical relationships that a philosophy without numbers had left hidden. Investigators made and unmade water, ammonia, carbonic acid, potash, and dozens of other compounds. When they carefully weighed the ingredients and end products, they discovered regularities. Volumes of hydrogen and oxygen vanished in a neat two-to-one ratio in the making of water. Robert Boyle found in England that, although one could vary both the pressure and the volume of air trapped at a given temperature in a piston, one could not vary their product. Pressure multiplied by volume was a constant. These measures were joined by an invisible rod—why? Heating a gas increased its volume or its pressure. Why?
Heat had seemed to flow from one place to another as an invisible fluid—“phlogiston” or “caloric.” But a succession of natural philosophers hit on a less intuitive idea—that heat was motion. It was a brave thought, because no one could see the things in motion. A scientist had to imagine uncountable corpuscles banging invisibly this way and that in the soft pressure of wind against his face. The arithmetic bore out the guess. In Switzerland Daniel Bernoulli derived Boyle’s law by supposing that pressure was precisely the force of repeated impacts of spherical corpuscles, and in the same way, assuming that heat was an intensification of the motion hither and thither, he derived a link between temperature and density. The corpuscularians advanced again when Antoine-Laurent Lavoisier, again with painstaking care, demonstrated that one could keep reliable account books of the molecules entering and exiting any chemical reaction, even when gases joined with solids, as in rusting iron.
“Matter is unchangeable, and consists of points that are perfectly simple, indivisible, of no extent”—that the atom could itself contain a crowded and measurable universe remained for a later century to guess—“& separated from one another.” Ruggiero Boscovich, an eighteenth-century mathematician and director of optics for the French navy, developed a view of atoms with a strikingly prescient bearing, a view that Feynman’s single-sentence credo echoed two centuries later. Boscovich’s atoms stood not so much for substance as for forces. There was so much to explain: how matter compresses elastically or inelastically, like rubber or wax; how objects bounce or recoil; how solids hold together while liquids congeal or release vapors; “effervescences & fermentations of many different kinds, in which the particles go & return with as many different velocities, & now approach towards & now recede from one another.”
The quest to understand the corpuscles translated itself into a need to understand the invisible attractions and repulsions that gave matter its visible qualities.
Attracting each other when they are a little distance apart, but repelling upon being squeezed into one another
, Feynman would say simply. That mental picture was already available to a bright high-school student in 1933. Two centuries had brought more and more precise inquiry into the chemical behavior of substances. The elements had proliferated. Even a high-school laboratory could run an electric current through a beaker of water to separate it into its explosive constituents, hydrogen and oxygen. Chemistry as packaged in educational chemistry sets seemed to have reduced itself to a mechanical collection of rules and recipes. But the fundamental questions remained for those curious enough to ask, How do solids stay solid, with atoms always “jiggling”? What forces control the fluid motions of air and water, and what agitation of atoms engenders fire?
By then the search for forces had produced a decade of reinterpretation of the nature of the atom. The science known as chemical physics was giving way rapidly to the sciences that would soon be known as nuclear and high-energy physics. Those studying the chemical properties of different substances were trying to assimilate the first startling findings of quantum mechanics. The American Physical Society met that summer in Chicago. The chemist Linus Pauling spoke on the implications of quantum mechanics for complex organic molecules, primitive components of life. John C. Slater, a physicist from the Massachusetts Institute of Technology, struggled to make a connection between the quantum mechanical view of electrons and the energies that chemists could measure. And then the meeting spilled onto the fairgrounds of the spectacular 1933 Chicago World’s Fair, “A Century of Progress.” Niels Bohr himself spoke on the unsettling problem of measuring anything in the new physics. Before a crowd of visitors both sitting and standing, his ethereal Danish tones often smothered by crying babies and a balking microphone, he offered a principle that he called “complementarity,” a recognition of an inescapable duality at the heart of things. He claimed revolutionary import for this notion. Not just atomic particles, but all reality, he said, fell under its sway. “We have been forced to recognize that we must modify not only all our concepts of classical physics but even the ideas we use in everyday life,” he said. He had lately been meeting with Professor Einstein (their discussions were actually more discordant than Bohr now let on), and they had found no way out. “We have to renounce a description of phenomena based on the concept of cause and effect.”
Elsewhere amid the throngs at the fairground that summer, enduring the stifling heat, were Melville, Lucille, Richard, and Joan Feynman. For the occasion Joan had been taught to eat bacon with a knife and fork; then the Feynmans strapped suitcases to the back of a car and headed off crosscountry, a seemingly endless drive on the local roads of the era before interstate highways. On the way they stayed at farmhouses. The fair spread across four hundred acres on the shore of Lake Michigan, and the emblems of science were everywhere. Progress indeed: the fair celebrated a public sense of science that was reaching a crest.
Knowledge Is Power
—that earnest motto adorned a book of Richard’s called
The Boy Scientist
. Science was invention and betterment; it changed the way people lived. The eponymous business enterprises of Edison, Bell, and Ford were knotting the countryside with networks of wire and pavement—an altogether positive good, it seemed. How wonderful were these manifestations of the photon and the electron, lighting lights and bearing voices across hundreds of miles!
Even in the trough of the Depression the wonder of science fueled an optimistic faith in the future. Just over the horizon were fast airships, half-mile-high skyscrapers, and technological cures for diseases of the human body and the body politic. Who knew where the bright young students of today would be able to carry the world? One New York writer painted a picture of his city fifty years in the future: New York in 1982 would hold a magnificent fifty million people, he predicted, the East River and much of the Hudson River having been “filled in.” “Traffic arrangements will no doubt have provided for several tiers of elevated roadways and noiseless railways—built on extended balconies flanking the enormous skyscrapers …” Nourishment will come from concentrated pellets. Ladies’ dress will be streamlined to something like the 1930s bathing suit. The hero of this fantasy was the “high-school genius (who generally knows more than anybody else).” There was no limit to the hopes vested in the young.
Scientists, too, struggled to assimilate the new images pouring into the culture from the laboratory. Electricity powered the human brain itself, a University of Chicago researcher announced that summer; the brain’s central switchboard used vast numbers of connecting lines to join brain cells, each one of which could be considered both a tiny chemical factory and electric battery. Chicago’s business community made the most of these symbols, too. In an opening-day stunt, technicians at four astronomical observatories used faint rays of starlight from Arcturus, forty light-years distant, focused by telescopes and electrically amplified, to turn on the lights of the exposition. “Here are gathered the evidences of man’s achievements in the realm of physical science, proofs of his power to prevail over all the perils that beset him,” declared Rufus C. Dawes, president of the fair corporation, as loud projectiles released hundreds of American flags in the sky over the fairgrounds. Life-size dinosaurs awed visitors. A robot gave lectures. Visitors less interested in science could pay to see an unemployed actress named Sally Rand dance with ostrich-feather fans. The Feynmans, though, took the Sky Ride, suspended on cables between two six-hundred-foot towers, and visited the Hall of Science, where a 151-word wall motto summed up the history of science from Pythagoras to Euclid to Newton to Einstein.
