n the WB network's Smallville, we are introduced to Clark Kent, a young Kansas man coming to terms with more than the usual teenage angst. Although the S-word is never mentioned, Kent is of course growing into Superman, an alien of humanoid appearance but decidedly inhuman strength. His flesh is impervious to bullets, trucks, hypodermic needles and pretty much anything else the show can plausibly throw at it. Nicknames aside, the future "Man of Steel" is demonstrably a lot stronger than any known metal.
Since he's also inhumanly fast, plus impervious to heat and electric shock, I would ordinarily suspect a body reinforced with carbon nanotubes: long molecules of rolled-up graphite which are only as wide as a DNA helix but can be several millimeters long, or potentially even longer. Though chemically similar to diamond, nanotube bundles are actually tougher and more flexible than this hardest of natural substances, in the same way that fiberglass is tougher than window glass. They are, in fact, the strongest known material.
Being hollow, nanotubes are also incredibly light, with 600 times the strength-to-weight ratio of steel. A "human" built of such stuff would practically defy gravity. Nanotubes are also the best known conductors of both heat and electricity, and can't ordinarily be damaged by acids or other chemicals. Sound like our boy?
A man of no ordinary matter
Unfortunately, no. Under normal circumstances, Clark Kent walks and stands and rides like a normal human being. The wind doesn't whisk him away like a pile of dry leaves, and a punch from a strong man doesn't knock him over. In fact, steel vehicles weighing several tons simply disintegrate when they collide with him, and our buddy Clark never even budges. The normal rules of momentum and inertia don't seem to apply.
The only conclusion I can draw is that Smallville's adopted son is not made of ordinary matter. Sure, he eats ordinary food and drinks ordinary beverages (non-alcoholic, please). But somehow he's able to convert these into a different kind of substance, which is exempt from Newtonian mechanics. In many ways, Superman resembles a gigantic subatomic particle: swift, indestructible and capable of eerie feats of action-at-a-distance. The only thing that seems to affect him—to interact with him, as a physicist would say—is the radiation of his native Krypton.
Well.
Believe it or not, there is a substance which exhibits some of these properties. It's "Bose-Einstein condensate" if you're a scientist, but the stuff will always be "superatom" to its friends. I am not making this up. In the hallowed halls of the University of Colorado at Boulder (one state over from Smallville, and coincidntally where my own engineering degree was minted), a young professor named Eric Cornell first cooked up this brew in 1995, a feat which won him the 2001 Nobel Prize—modern science's highest honor.
The superatom was first proposed by Albert Einstein in the 1920s, when the quantum-mechanical rule known as Heisenberg's Uncertainty Principle made it clear that the universe, for bizarre reasons of its own, would not let both the position and the momentum of a particle be defined precisely. "If we constrain a group of atoms to very low velocity," Einstein reasoned (I'm paraphrasing here—imagine that German accent of his piping from a little cartoon professor in the corner of your screen), "then their positions should become indefinite. At some point, they should smear together and behave as a single entity. A wave, a particle, much larger than an ordinary atom. A superatom."
The idea seemed more hypothetical than real until the 1970s, when new cooling techniques made it possible to achieve absurdly low temperatures. And since "temperature" is nothing more than the average velocity of the atoms traveling or bouncing or vibrating inside a substance, absurdly low temperature at the atomic level is the same thing as absurdly low velocity. By the 1980s, half a dozen teams around the world were hotly (er, coldly) competing to create the first superatom. The race was on.
Unfortunately, most of these teams were using hydrogen, which proved difficult to cool. "It's not elastic enough," Cornell says. "The atoms stick together too well. We had reasoned that the heavy alkali metals would be superior. I'd been playing with laser cooling as a postdoc under Carl Wieman, and when I became a professor I built a special apparatus of my own, to cool a vapor of rubidium atoms."
Progress in science is often slow and painful, but Cornell was one of the lucky ones. "When we had the superatom in our cameras, we knew it right away. There it was, too imperfectly real to be a mistake. I felt remorse for all those other teams, for taking their good ideas and applying them to a better atom. But the paper was accepted by the journal Science only three days after we submitted it, and published less than six weeks later. That has to be some kind of record."
The coming science of superatoms
All right, a superatom isn't superstrong. It can't lift a bus or break up a Kansas tornado. It isn't solid at all, but a kind of cloud—a haze of probability densities, of places where an atom-like phenomenon may or may not exist. But the superatom can, in Cornell's words, "magnify the effects of quantum mechanics until you can see them with a magnifying glass." The smallest superatoms are about 0.001 millimeters across—10,000 times the diameter of a normal atom—and gobble anywhere from 100 to 1,000 atoms before "changing phase" from a vapor to a Bose-Einstein condensate. The largest superatoms to date are half a millimeter in size (with maybe a billion atoms inside them), and there's no particular reason they couldn't be made larger or shaped into human form, although at the moment we have neither the need nor the equipment to do so.
Superpowers? Kooky matter tricks? You bet. Superatoms don't have heat vision, but they have been used to slow down the speed of light, and even to stop light beams and trap them internally, for later release. That's an ability you don't see every day. Superatoms can also be squirted out in streams, which are known as "atom lasers." These streams travel a lot more slowly than light beams, and droop with gravity like the spray from a fire hose. They also contain far fewer particles; a typical light laser fires a million million times as many photons as an atom laser does atoms.
This might seem to limit the usefulness of atom lasers, but they do have one clear advantage: They operate at wavelengths up to 70,000 times smaller than optical lasers do, and 2,000 times smaller than electron beams. This means they can be used to measure or manipulate very short spans of time and space. A hologram made from atom lasers can resolve much finer detail—70,000 times finer—than the equivalent hologram taken in red light. Thus, atom lasers may be important in nanotechnology, computer chip manufacturing and other fields which call for the precise measurement and placement of very small things.
The most immediate application for superatoms, though, is as motion sensors. By sending the atom laser stream around in a ring and counting the peaks of its quantum waveform as they cross the finish line, scientists are able to detect fantastically small movements. Cornell estimates that his superatom gyroscopes—funded by the U.S. Navy for possible use in submarine navigation—will be 10 to 100 billion times more sensitive than the laser gyros used today. That'll find your way in the dark, you bet. I suspect it could lead to ultrasensitive sound detectors as well.
Although the apparatus for producing superatoms can fill a room, the labs in Boulder and elsewhere are making remarkable progress in miniaturizing it. Already there are superatom-on-a-chip devices of glass and copper which can just about fit in the palm of your hand, and they may soon be even smaller. Who knows? Someday you may have one in your cell phone, serving as a foolproof inertial compass that (unlike GPS or magnetic compasses) works indoors, underground, underwater or wherever else you happen to find yourself.
Will it get the girl? Will it save the city of Metropolis? Only time will tell. But the superatom has already done two things that Clark Kent never could: revealed its secret identity and earned a decent living in the real world.
Wil McCarthy is a rocket guidance engineer, robot designer, science-fiction author and occasional aquanaut. He has contributed to three interplanetary spacecraft, five communication and weather satellites, a line of landmine-clearing robots, and some other "really cool stuff" he can't tell us about. His short fiction has graced the pages of Analog, Asimov's, Science Fiction Age and other major publications, and his novel-length works include Aggressor Six, the New York Times notable Bloom and The Collapsium.
