by Judy Jones
So why not forget dangerous, dirty fission and get behind controllable, clean fusion? Because fusion, while it works nicely on the sun, requires temperatures higher than we’ve in general been able to achieve here on earth except, so far, in the hydrogen bomb, which is triggered by fission—in the form of an atomic bomb—at its core anyway. It’s true that in late 1993 an experimental fusion reactor at Princeton produced a few megawatts of power for a fraction of a second; while doing so, though, it used up more power than it produced. Nevertheless, a number of countries, including Japan, China, the United States, Russia, and members of the European Union, are currently collaborating on an International Thermonuclear Experimental Reactor (ITER). Unfortunately, nobody can agree on the site. Experts say economical fusion is still fifty years off, as it has been for decades. (Some scientists are still on the trail of “cold fusion,” the alleged result of a 1989 experiment by two researchers in Utah who claimed to have seen nuclear fusion in a room-temperature test tube. Their success has never been duplicated, however, and was widely dismissed as equal parts wishful thinking and sloppy science.) Still, given that fusion, once perfected, could churn out energy equivalent to 300 gallons of gasoline from a gallon of seawater, you can expect the scientists to stay on the case.
In the meantime, bear in mind that fusion is both more natural and more powerful than fission, packing the kind of wallop and carrying with it the degree of conviction that, in life as in the lab, results from putting things together, not tearing them apart.
Half-life
The fixed, invariable amount of time it takes half of an original sample of a radioactive substance like uranium, radium, or carbon-14, to break down, decay, fall to pieces—which all such substances do, nucleus by nucleus. Although scientists can never tell which specific nucleus is going to end it all next, they are surprisingly exact when it comes to predicting the overall rate of change. (It’s a little like demographers noting that Buffalo or Detroit is losing population at such-and-such a rate without being able to say which family is going to leave town next.) For instance, the half-life of uranium 238 is 4.5 billion years, which means that at the end of that time a pound will have dwindled to half a pound; the rest will have decayed into thorium. After another 4.5 billion years, there will be a quarter of a pound of the original uranium left; after yet another 4.5 billion years, an eighth of a pound, and so on. Useful to geologists in determining the age of rock specimens (and, by extension, of the planet), half-life also has popular applications: Girls with streaked blonde hair may speak of the half-life of meaningful relationships in their crowd.
Mass
Forget about weight. Forget about volume. Mass—which physicists define as the quantity of matter in a body—is the adult way of coming to grips with the question “How big?” (Weight is simply the measure of the force of gravity acting on that body and, unlike mass, tends to vary, sometimes inconveniently, from place to place. As for volume, some make do without: Electrons, for instance, have mass and no volume at all.) Of course, mass and energy have been shown—by Einstein, in his formula E = mc2—to be roughly the same thing. Which brings us to the dogeared phrase “critical mass”: In a nuclear chain reaction it’s the minimum quantity of fissionable material (see previous page) necessary to keep those neutrons popping and those nuclei alert. In Business Week, by analogy, it’s the minimum level of potency or density you have to be at if you’re really going to perform. Thus marketing types might pinpoint a magazine’s critical mass at the moment its circulation becomes large enough to attract national advertisers.
Matrix
From a Latin word that meant first “pregnant animal” and later “womb,” a matrix (plural, “matrices”) is the place where something is generated, contained, and/or developed. The word is used of, among other things, the rock that a fossil or gemstone is found embedded in; the band of formative cells in your nails and teeth; an industrial mold; and, in mathematics, a rectangular array of elements, for example,
where those elements are shorthand for some larger picture (they may, for instance, be the coefficients in a pair of linear equations that are meant to be considered together), and where they are less significant taken one by one than as a composite. Eventually, computer nerds picked up on the word, too, applying it to the point at which input and output leads intersect. It was only a matter of time before ambitious younger persons started using it as a verb, a kind of fancy synonym for networking, for example the woman who declares at a party, “I’m not here to meet men, just to do a little matrixing.” From here to the malevolent cyberintelligence that’s out to get Neo, Trinity, Morpheus, et al. is, however, a bit of a leap.
Osmosis
When fluid passes through a membrane from one side, where there’s a lower concentration of a particular particle, to the other, where there’s a higher concentration of the same particle, that’s osmosis. Essentially, it’s an attempt to reach equilibrium, which biological systems, not unlike yourself, find to be a highly desirable state; in this case, equilibrium will ensure the identical number of particles per cubic whatever of fluid on both sides of that semipermeable (but selective) membrane without any of the particles having to move a muscle. “Learning by osmosis” is likewise automatic, imperceptible, effortless.
Parameter
In mathematics—economics, too—a quantity that varies with the conditions under which it recurs, but that is, for the time being and within the context of the current problem, both constant and knowable. In life, a parameter is the measuring stick we have at hand, whose own length isn’t exactly set (it may be a yardstick today and a foot-rule tomorrow) but which nevertheless helps us define, estimate, or describe the totally unknown quantity in the next room. Take the queuing consultant called in by the Museum of Modern Art to help with “flow” during a Picasso retrospective. “Using parametric analysis of the number of people per painting and square feet per person,” he explained, “I advised the museum on queuing line layouts and admissions-per-hour.” A good use of the word: The parameters here were the existing estimates of how many people could, at a major museum exhibit, look at a painting at the same time and how much space they needed to do it; those guidelines, however, were understood to be subject to change (the mark of a good parameter), depending on canvas size, hanging technique, desirability of standing close to or away from the work, intrinsic interest of a particular painting or roomful of them, etc. Not everybody does so well with the word, however: Press secretaries, for instance, tend to speak of the “parameters” of a problem when all they mean is that problem’s distinguishing features. And even careful speakers sometimes use it as a substitute for “outer limit,” when the word they really want may be “perimeter.”
Quantum
Originally, anything that could be counted or measured (from a Latin word meaning “how much”). In physics, quanta—the plural form—came to refer to the discontinuous series of little packets in which light sometimes travels. Quantum theory, which dates from 1900, when Max Planck proposed it as a way of accounting for the emission of light by a body so hot that it’s luminous (a poker thrust into a fire, for instance), and which underlies quantum mechanics, was in complete contradiction to the then-prevailing wave theory of light. Later, both theories would prove to be right, neither alone sufficing to explain light, which sometimes travels in waves (like a river) and sometimes travels in quanta (like raindrops), but never does both at the same time; think of it as the difference between a solid line and a dotted one. As for the phrase “quantum leap,” it’s an abrupt, usually unpredictable change or step—as with an electron’s sudden transition from one fixed orbit to another as it circles an atom’s nucleus—but it’s not necessarily an enormous one. Properly, a quantum leap (or jump) in, say, the number of terrorist incidents is not about size but suddenness.
Quark
Of the over two hundred subatomic particles out of which physicists tell us all matter is made, the quark is the most evasive, the most piquing, and th
e most basic—so small as to have no size, so simple as to have no internal structure. Of course, nobody’s managed to shake a quark loose for closer inspection (the most they’ve been able to do is hit a few over the head with beams of electrons), but that hasn’t stopped scientists from insisting that quarks, like Charlie’s Angels, usually travel in threes; from positing that they carry electrical charges that are multiples of one-third; from attributing to them properties they call “color” and “flavor”; from giving them such first names as “up,” “down,” “strange,” “charm,” “bottom,” and “top”; or from positing the existence of mirror-image, or anti-, quarks. Quarks bond with other quarks in such standard combinations as protons (two up quarks and a down quark), neutrons (two down quarks and an up quark), mesons, baryons, kaons, and so on(s)—all the other subatomic particles, in fact, except leptons (a category that includes electrons, muons, and neutrinos), which are themselves so “elementary” as not to be able to be further broken down. Despite the whimsicality (the word itself is borrowed from a song in Joyce’s Finnegans Wake, “Three quarks for Muster Mark,” where it may refer to the squawking of birds, their excrement, or both), quarks pack a mean intellectual wallop. They imply that nature is three-sided, and that such dualist constructions as time/space, mind/body, and either/or miss the point. Specks of infinity on the one hand, building blocks of the universe on the other, quarks represent science at its most ambitious—also its coyest.
Symbiosis
The perfect relationship—assuming you’re not all that interested in relating to whomever it is you’ve chosen to settle down with. Take, for instance, the case of the rhinoceros and the yellow tickbird. The tickbird dines on parasites infesting the rhinoceros’ horny skin; the rhinoceros itches less and is warned of danger when the tickbird, sharp-eyed and skittish, abandons him for the nearest tree. Or the lichen, that exemplary union of alga, which brings home the bacon (it knows how to photosynthesize), and fungus, which keeps the house (it stores moisture the alga needs and scoops out the rock they’re living on to make a bungalow). In such classic instances of symbiosis (“life together”), both parties benefit but in very different ways, each compensating for the other’s shortcomings, rather than duplicating his talents. Although it’s tempting to apply the word to, say, the S &1M relationship being worked out nightly in the apartment down the hall, you weaken its meaning when you do so. The sadist and the masochist complement each other, all right, but they’re deriving too much the same benefit—sexual gratification—from their joint undertaking to qualify as a bona-fide symbiosis, a label that should be saved for arrangements between partners with widely divergent priorities.
Synapse
It’s the junction—a microscopic gap, actually—of two neighboring neurons, or nerve cells. And there are loads of them: An average neuron in the human brain has somewhere between one thousand and ten thousand synapses with nearby neurons, some of which are responsible for thinking, some of which are responsible for moving, and some of which are, for better or for worse, simply blank. When a nerve impulse reaches the synapse, there to jump across to the adjacent nerve cell, it’s given a nudge along by an electrically triggered squirt of a chemical. Some chemicals enhance, others inhibit; ditto painkillers, tranquilizers, and recreational drugs. The adjacent nerve cell reacts accordingly, either getting all excited itself and relaying the message to a muscle, a gland, or yet a third nerve cell, or giving it the cold shoulder. Caution when using the word: A synapse is properly a place, at most a transaction. It is not in itself a full-scale neural event, and it is even less a good synonym for what is portrayed in comic books as a little lightbulb going off over somebody’s head.
Synergy
Like Gestalt, another the-whole-is-greater-than-the-sum-of-its-parts manifesto. But at least this one is backed up by lab reports and an etymology you can understand: the Greek syn- + ergos, “together working.” At its most scientific, synergy refers, in biology, to the relationship between “agents” whose combined physiological clout outweighs the sum of their individual jabs; thus booze and barbiturates, ingested together, will knock you out faster and more totally than can be predicted by adding up what each of them does to you on its own. From biology, it’s a short step to the boardroom, where executives decide that, by merging with the like-minded types across town, they can pull in a market share in excess of their two individual ones put together.
Valence
In chemistry, a measure of the combining power of a specific element, equal to the number of different chemical bonds one atom of that element can form at any given time. All atoms feel most secure when they have a complete outermost electron shell, and they’ll go to great lengths to achieve one, borrowing elements from or sharing them with other atoms. For this reason neon, with an outer shell that’s full-up at birth, is highly unreactive—so chemically aloof, in fact, that, along with helium and argon (among others), it’s been dubbed one of the “noble gases.” Carbon, by contrast, with an outer shell of eight electrons only half filled, is a born joiner and an unabashed swinger, almost always requiring more than a single relationship to feel safe and provided for. It’s largely as a result of this capacity for interaction that you hear so much about carbon in chemistry circles. As for your valence, broadly speaking it’s your capacity—or tendency—to interact with the others out there. Just remember, you don’t have to go to bed with them.
Keeping Up with Cosmology
In the second century a.d., Ptolemy, a Greek working out of Alexandria, Egypt, codified all ancient astronomical beliefs and made a momentous pronouncement: The earth was the center of the universe, around which the sun, the planets, and the stars all revolved, and beyond the orbit of the most distant star lay the empyrean, the place where angels and immortal spirits dwelled. Rigorously mathematical and highly persuasive, the Ptolemaic system was accepted by virtually all educated Europeans until Copernicus’ treatise On the Revolution of the Heavenly Spheres (published posthumously in 1543) broke the news that, far from nestling cozily at the center of things, it was the earth that was doing the revolving, a theory that was soon to be embroidered and enlarged upon by Tycho Brahe, Kepler, Galileo, and Newton. Exit angels and immortal spirits. Enter uncertainty, relativity, quarks, leptons, gluons, the strong and weak forces, the Big Bang, and the search for our cosmic roots. Here, with an update: contributor James Trefil.
Since the late 1920s, we’ve known that other galaxies are moving away from our own. The obvious explanation for this is that the universe as a whole is expanding. Because every expansion has to start somewhere, it’s also obvious that if we reverse the expansion and follow the galaxies backward in time, to the tune of some fifteen billion years, there will come a point at which all the matter in the universe is crammed into a very tiny space. The appearance of the universe from a single infinitely dense point of matter is what we call the Big Bang.
Astrophysicists tend to dislike obvious explanations like this, which is why, throughout the Fifties and Sixties, there were all sorts of theories that attempted to explain expansion without the Big Bang scenario. But new evidence came in, these alternate theories bit the dust, one by one, and today hardly anyone disputes the Big Bang.
The thing about the Big Bang as far as modern physics is concerned is that when the universe was younger, it must have been hotter. Compressing matter always makes it heat up (try touching the barrel of a tire pump after it’s been used). Higher temperatures also mean that the building blocks of matter, such as atoms, move faster and collide more violently. Thus, when the universe was younger, its constituent parts were bumping into each other with much higher energy than they do in our own relatively frigid era.
When matter is subjected to high temperatures, two important things happen. First, it changes form. Heat an ice cube and you get water; heat the water and you get steam. If you heat a collection of atoms enough, the collision will become so violent that their electrons will be torn loose and you’ll have a new form of matte
r—a collection of negatively charged electrons and positively charged nuclei. The sun is made up of this sort of matter.
The Ptolemaic concept of the universe.
The second important temperature-induced change has to do with the creation of new particles via Einstein’s famous formula, E = mc2. The theory of relativity tells us that matter and energy are interchangeable—given enough of one, you can convert it into the other. Thus, when a bit of uranium nucleus is converted into energy in a nuclear reactor, the end result is sufficient electrical current to run your house. Conversely, every day, in giant particle accelerators throughout the world protons and electrons are brought up to almost the speed of light and allowed to collide with a target. The result: The energy of the particle is converted into mass and new particles are created in the collision.
A twentieth-century view of the solar system.
In this early, high-temperature universe, then, we expect two things to happen: Existing forms of matter will change form and exotic new forms of matter will be created from the available energy. But there’s one other result we might also expect: that the fundamental forces—the way bits of matter interact with one another—will also change.
The Early Universe
