When atoms are "coherent" and vibrating in phase with one another, the tiniest disturbances from the outside world can ruin this delicate balance and make the atoms "decohere," so they no longer vibrate in unison. Even the pa.s.sing of a cosmic ray or the rumble of a truck outside the lab can destroy the delicate spinning alignment of these atoms and destroy the computation.

The decoherence problem is the single most difficult barrier to creating quantum computers. Anyone who can solve the problem of decoherence will not only win a n.o.bel Prize but also become the richest man on earth.

As you can imagine, creating quantum computers out of individual coherent atoms is an arduous process, because these atoms quickly decohere and fall out of phase. So far, the world"s most complex calculation done on a quantum computer is 3 5 = 15. Although this might not seem much, remember that this calculation was done on individual atoms.

In addition, there is another bizarre complication coming from the quantum theory, again based on the uncertainty principle. All calculations done on a quantum computer are uncertain, so you have to repeat the experiment many times. So 2 + 2 = 4, at least sometimes. If you repeat the calculation of 2 + 2 a number of times, the final answer averages out to 4. So even arithmetic becomes fuzzy on a quantum computer.

No one knows when one might solve this problem of decoherence. Vint Cerf, one of the original creators of the Internet, predicts, "By 2050, we will surely have found ways to achieve room-temperature quantum computation."

We should also point out that the stakes are so high that a variety of computer designs have been explored by scientists. Some of these competing designs include: *optical computers: These computers calculate on light beams rather than electrons. Since light beams can pa.s.s through each other, optical computers have the advantage that they can be cubical, without wires. Also, lasers can be fabricated using the same lithographic techniques as ordinary transistors, so you can in theory pack millions of lasers onto a chip. These computers calculate on light beams rather than electrons. Since light beams can pa.s.s through each other, optical computers have the advantage that they can be cubical, without wires. Also, lasers can be fabricated using the same lithographic techniques as ordinary transistors, so you can in theory pack millions of lasers onto a chip.

*quantum dot computers: Semiconductors used in chips can be etched into tiny dots so small they consist of a collection of perhaps 100 atoms. At that point, these atoms can begin to vibrate in unison. In 2009, the world"s smallest quantum dot was built out of a single electron. These quantum dots have already proven their worth with light-emitting diodes and computer displays. In the future, if these quantum dots are arranged properly, they might even create a quantum computer. Semiconductors used in chips can be etched into tiny dots so small they consist of a collection of perhaps 100 atoms. At that point, these atoms can begin to vibrate in unison. In 2009, the world"s smallest quantum dot was built out of a single electron. These quantum dots have already proven their worth with light-emitting diodes and computer displays. In the future, if these quantum dots are arranged properly, they might even create a quantum computer.

*DNA computers: In 1994, the first computer made of DNA molecules was created at the University of Southern California. Since a strand of DNA encodes information on amino acids represented by the letters A,T,C,G instead of 0s and 1s, DNA can be viewed as ordinary computer tape, except it can store more information. In the same way that a large digital number can be manipulated and rearranged by a computer, one can also perform a.n.a.logous manipulations by mixing tubes of fluids containing DNA, which can be cut and spliced in various ways. Although the process is slow, there are so many trillions of DNA molecules acting simultaneously that a DNA computer can solve certain calculations more conveniently than a digital computer. Although a digital computer is quite convenient and can be placed inside your cell phone, DNA computers are more awkward, involving mixing tubes of liquid containing DNA. In 1994, the first computer made of DNA molecules was created at the University of Southern California. Since a strand of DNA encodes information on amino acids represented by the letters A,T,C,G instead of 0s and 1s, DNA can be viewed as ordinary computer tape, except it can store more information. In the same way that a large digital number can be manipulated and rearranged by a computer, one can also perform a.n.a.logous manipulations by mixing tubes of fluids containing DNA, which can be cut and spliced in various ways. Although the process is slow, there are so many trillions of DNA molecules acting simultaneously that a DNA computer can solve certain calculations more conveniently than a digital computer. Although a digital computer is quite convenient and can be placed inside your cell phone, DNA computers are more awkward, involving mixing tubes of liquid containing DNA.

SHAPE-SHIFTING.

In the movie Terminator 2: Judgment Day, Terminator 2: Judgment Day, Arnold Schwarzenegger is attacked by an advanced robot from the future, a T-1000, which is made of liquid metal. Resembling a quivering ma.s.s of mercury, it can change shape and slither its way through any obstacle. It can seep through the tiniest cracks and fashion deadly weapons by reshaping its hands and feet. And then it can suddenly re-form into its original shape to carry on its murderous rampage. The T-1000 appeared to be unstoppable, the perfect killing machine. Arnold Schwarzenegger is attacked by an advanced robot from the future, a T-1000, which is made of liquid metal. Resembling a quivering ma.s.s of mercury, it can change shape and slither its way through any obstacle. It can seep through the tiniest cracks and fashion deadly weapons by reshaping its hands and feet. And then it can suddenly re-form into its original shape to carry on its murderous rampage. The T-1000 appeared to be unstoppable, the perfect killing machine.

All this was science fiction, of course. The technology of today does not allow you to change a solid object at will. Yet by midcentury a form of this shape-shifting technology may become commonplace. In fact, one of the main companies driving this technology is Intel.

Ironically, by 2050, most of the fruits of nanotechnology will be everywhere, but hidden from view. Almost every product will be enhanced via molecular manufacturing techniques, so they will become superstrong, resistant, conductive, and flexible. Nanotechnology will also give us sensors that constantly protect and help us, distributed in the environment, hidden away, beneath the surface of our consciousness. We will walk down the street and everything will appear to be the same, so we will never know how nanotechnology has changed the world around us.

But there is one consequence of nanotechnology that will be obvious.

The Terminator Terminator T-1000 killer robot is perhaps the most dramatic example of an object from the field called programmable matter, which may allow us one day to change the shape, color, and physical form of an object with the push of a b.u.t.ton. On a primitive level, even a neon sign is a form of programmable matter, since you can flick a light switch and send electricity through a tube of gas. The electricity excites the gas atoms, which then decay back to their normal state, releasing light in the process. A more sophisticated version of this is the LCD display found on computer screens everywhere. The LCD contains a liquid crystal that becomes opaque when a small electrical current is applied. Thus, by regulating the electrical current flowing inside a liquid crystal, one can create colors and shapes on a screen with the push of a b.u.t.ton. T-1000 killer robot is perhaps the most dramatic example of an object from the field called programmable matter, which may allow us one day to change the shape, color, and physical form of an object with the push of a b.u.t.ton. On a primitive level, even a neon sign is a form of programmable matter, since you can flick a light switch and send electricity through a tube of gas. The electricity excites the gas atoms, which then decay back to their normal state, releasing light in the process. A more sophisticated version of this is the LCD display found on computer screens everywhere. The LCD contains a liquid crystal that becomes opaque when a small electrical current is applied. Thus, by regulating the electrical current flowing inside a liquid crystal, one can create colors and shapes on a screen with the push of a b.u.t.ton.

The scientists at Intel are much more ambitious. They visualize using programmable matter to actually change the shape of a solid object, just like in science fiction. The idea is simple: create a computer chip in the shape of a tiny grain of sand. These smart grains of sand allow you to change the static electric charge on the surface, so that these grains can attract and repel each other. With one set of charges, these grains can line up to form a certain array. But you can reprogram these grains so that their electrical charges change. Instantly, these grains rearrange themselves, forming an entirely different arrangement. These grains are called "catoms" (short for claytronic atoms) since they can form a wide range of objects by simply changing their charges, much like atoms. (Programmable matter has much in common with the modular robots we saw in Chapter 2 Chapter 2. While the modular robots contain smart blocks, about 2 inches in size, that can rearrange themselves, programmable matter shrinks these building blocks to submillimeter size and beyond.) One of the promoters of this technology is Jason Campbell, a senior researcher at Intel. He says, "Think of a mobile device. My cell phone is too big to fit comfortably in my pocket and too small for my fingers. It"s worse if I try to watch movies or do my e-mail. But if I had 200 to 300 milliliters of catoms, I could have it take on the shape of the device that I need at that moment." So one moment, I have a cell phone in my hand. The next moment, it morphs into something else. This way, I don"t have to carry so many electronic gadgets.

In its laboratories, Intel has already created an array of catoms that are about an inch in size. The catom resembles a cube with scores of tiny electrodes spread evenly on its surfaces. What makes the catom unique is that you can change the charge on each of its electrodes, so that catoms bind to each other in different orientations. With one set of charges, these cubes might combine to create a large cube. Change the charges on each cube"s electrode, and then the catoms disa.s.semble and quickly rearrange themselves into an entirely different shape, such as a boat.

The point is to shrink each catom to the size of a grain of sand, or even smaller. If one day silicon-etching techniques allow us to create catoms that are as small as a cell, then we might be able to realistically change one shape into another, simply by pushing a b.u.t.ton. Justin Rattner, a senior fellow at Intel, says, "Sometime over the next forty years, this will become everyday technology." One immediate application would be for automobile designers, airline engineers, artists, architects, and anyone who has to design three-dimensional models of their projects and then continually modify them. If one has a mold of a four-door sedan, for example, one can grab the mold, stretch it, and it suddenly morphs into a hatchback. Compress the mold a bit more and it turns into a sports car. This is far superior to molding clay, which has no memory or intelligence. Programmable matter has intelligence, can remember previous shapes, adapt to new ideas, and respond to the designers" wishes. Once the mold is finalized, the design can simply be e-mailed to thousands of other designers, who can then create exact copies.

This could have a profound effect on consumer products. Toys, for example, can be programmed to change shape by inserting new software instructions. So for Christmas, one need only download the software for a new toy, reprogram the old toy, and an entirely new toy appears. Children might celebrate Christmas not by opening presents under the tree but by downloading software for their favorite toy that Santa has e-mailed them, and the catoms making up last year"s toy become the hottest thing on the market. This means that a wide array of consumer products may eventually be reduced to software programs sent over the Internet. Instead of hiring a truck to deliver your new furniture and appliances, you may simply download the software off the net and recycle your old products. Renovating homes and apartments won"t be such a ch.o.r.e with programmable matter. In your kitchen, replacing the tiles, tabletops, appliances, and cabinets might simply involve pushing a b.u.t.ton.

In addition, this could cut down on waste disposal. You don"t have to throw out many of your unwanted things if you can simply reprogram them. If an appliance or piece of furniture breaks, you have only to reprogram it and it becomes new again.

Despite its enormous promise, there are also numerous problems facing the Intel team. One is how to orchestrate the movements of all these millions of catoms. There will be bandwidth problems when we try to upload all this information into the programmable matter. But there are also shortcuts one can take.

For example, in science fiction movies it is common to see "morphing," that is, one person suddenly changing into a monster. This used to be a very complex, tedious process to create on film, but can now be done easily by computer. First, you identify certain vectors that mark different key points on the face, such as the nose and eyes, for both the human and the monster. Each time a vector is moved, the face changes gradually. Then computers are programmed to move these vectors, from one face to the next, thereby slowly changing one face into another. In the same way, it might be possible to use shortcuts when shape-shifting a 3-D object.

Another problem is that the static electrical forces between the catoms are weak when compared to the tough interatomic forces that hold most solids together. As we have seen, quantum forces can be quite powerful, responsible for the tough properties of metals and the elastic properties of plastic. Duplicating these quantum forces with static electrical forces to ensure that these products remain stable is going to be an issue in the future.

I had a chance to witness firsthand the remarkable, rapid advances in programmable matter when I took a Science Channel film crew to visit Seth Goldstein at Carnegie Mellon University. In his laboratory you could see large stacks of cubes scattered all over a table in various sizes, each with chips inside. I saw two of these cubes bound tightly together by electrical forces, and he asked me to try to rip them apart by hand. Surprisingly, I couldn"t. I found that the electrical forces binding these two cubes were quite powerful. Then he pointed out that these electrical forces would be correspondingly greater if you miniaturized the cubes. He took me to another lab, where he showed me just how small these catoms can become. By employing the same techniques used to carve out millions of transistors on silicon wafers, he could carve out microscopic catoms that were only millimeters across. In fact, they were so small that I had to look at them under a microscope to see them clearly. He hopes that eventually, by controlling their electrical forces, he can get them to arrange in any shape with a push of a b.u.t.ton, almost like a sorcerer conjuring up anything he wants.

Then I asked him, How can you give detailed instructions to billions upon billions of catoms, so that a refrigerator, say, might suddenly transform into an oven? It seems like a programming nightmare, I said. But he replied that it wasn"t necessary to give detailed instructions to every single catom. Each catom has to know only which neighbors it must attach to. If each catom is instructed to bind with only a tiny set of neighboring catoms, then the catoms would magically rearrange themselves into complex structures (much like the neurons of a baby"s brain need to know only how to attach themselves to neighboring neurons as the brain develops).

a.s.suming that the problem of programming and stability can be solved, then by late century there is the possibility that entire buildings or even cities may rise at the push of a b.u.t.ton. One need only lay out the location of the buildings, dig their foundations, and allow trillions of catoms to create entire cities rising from the desert or forest.

However, these Intel engineers envision the day when the catoms may even take human form. "Why not? It"s an interesting thing to speculate on," says Rattner. (Then perhaps the T-1000 robot may become a reality.)

HOLY GRAIL: THE REPLICATOR.

By 2100, advocates of nanotechnology envision an even more powerful machine: a molecular a.s.sembler, or "replicator," capable of creating anything. It would consist of a machine perhaps the size of a washing machine. You would put the basic raw materials into the machine and then push a b.u.t.ton. Trillions upon trillions of nan.o.bots would then converge on the raw materials, each one programmed to take them apart molecule by molecule and then rea.s.semble them into an entirely new product. This machine would be able to manufacture anything. The replicator would be the crowning achievement of engineering and science, the ultimate culmination of our struggles ever since we picked up the first tool back in prehistory.

One problem with the replicator is the sheer number of atoms that must be rearranged in order to copy an object. The human body, for example, has over 50 trillion cells and in excess of 1026 atoms. That is a staggering number, requiring a colossal amount of memory s.p.a.ce just to store the locations of all these atoms. atoms. That is a staggering number, requiring a colossal amount of memory s.p.a.ce just to store the locations of all these atoms.

But one way to overcome this problem is to create a nan.o.bot, a still- hypothetical molecular robot. These nan.o.bots have several key properties. First, they can reproduce themselves. If they can reproduce once, then they can, in principle, create an unlimited number of copies of themselves. So the trick is to create just the first nan.o.bot. Second, they are capable of identifying molecules and cutting them up at precise points. Third, by following a master code, they are capable of rea.s.sembling these atoms into different arrangements. So the task of rearranging 1026 atoms is reduced to making a similar number of nan.o.bots, each one designed to manipulate individual atoms. In this way, the sheer number of atoms of the body is no longer such a daunting obstacle. The real problem is creating just the first one of these mythical nan.o.bots and letting it reproduce by itself. atoms is reduced to making a similar number of nan.o.bots, each one designed to manipulate individual atoms. In this way, the sheer number of atoms of the body is no longer such a daunting obstacle. The real problem is creating just the first one of these mythical nan.o.bots and letting it reproduce by itself.

However, the scientific community is split on the question of whether the full-blown dream of a nanofabricator is physically possible. A few, like Eric Drexler, a pioneer in nanotechnology and author of The Engines of Creation, The Engines of Creation, envision a future where all products are manufactured at the molecular level, creating a cornucopia of goods that we can only dream of today. Every aspect of society would be turned upside down by the creation of a machine that can create anything you want. Other scientists, however, are skeptical. envision a future where all products are manufactured at the molecular level, creating a cornucopia of goods that we can only dream of today. Every aspect of society would be turned upside down by the creation of a machine that can create anything you want. Other scientists, however, are skeptical.

The late n.o.bel laureate Richard Smalley, for example, raised the problem of "sticky fingers" and "fat fingers" in an article in Scientific American Scientific American in 2001. The key question is: Can a molecular nan.o.bot be built that is nimble enough to rearrange molecules at will? He said the answer was no. in 2001. The key question is: Can a molecular nan.o.bot be built that is nimble enough to rearrange molecules at will? He said the answer was no.

This debate spilled open when Smalley squared off with Drexler in a series of letters, reprinted in the pages of Chemical and Engineering News Chemical and Engineering News in 2003 to 2004. The repercussions of that debate are being felt even today. Smalley"s position was that the "fingers" of a molecular machine would not be able to perform this delicate task for two reasons. in 2003 to 2004. The repercussions of that debate are being felt even today. Smalley"s position was that the "fingers" of a molecular machine would not be able to perform this delicate task for two reasons.

First, the "fingers" would face tiny attractive forces that would make them stick to other molecules. Atoms stick to each other, in part, because of tiny electrical forces, like the van der Waals force, that exist between their electrons. Think of trying to repair a watch when your tweezers are covered with honey. a.s.sembling anything as delicate as watch components would be impossible. Now imagine a.s.sembling something even more complicated than a watch, like a molecule, that constantly sticks to your fingers.

Second, these fingers might be too "fat" to manipulate atoms. Think of trying to repair that watch wearing thick cotton gloves. Since the "fingers" are made of individual atoms, as are the objects being manipulated, the fingers may simply be too thick to perform the delicate operations needed.

Smalley concluded, "Much like you can"t make a boy and a girl fall in love with each other simply by pushing them together, you cannot make precise chemistry occur as desired between two molecular objects with simple mechanical motion.... Chemistry, like love, is more subtle than that."

This debate goes to the very heart of whether a replicator will one day revolutionize society or be treated as a curiosity and relegated to the trash bin of technology. As we have seen, the laws of physics in our world do not easily translate to the physics of the nanoworld. Effects that we can ignore, such as van der Waals forces, surface tension, the uncertainty principle, the Pauli exclusion principle, etc., become dominant in the nanoworld.

To appreciate this problem, imagine that the atom is the size of a marble and that you have a swimming pool full of these atoms. If you fell into the swimming pool, it would be quite different from falling into a swimming pool of water. These "marbles" would be constantly vibrating and hitting you from all directions, because of Brownian motion. Trying to swim in this pool would be almost impossible, since it would be like trying to swim in mola.s.ses. Every time you tried to grab one of the marbles, it would either move away from you or stick to your fingers, due to a complex combination of forces.

In the end, both scientists agreed to disagree. Although Smalley was unable to throw a knockout punch against the molecular replicator, several things became clear after the dust settled. First, both agreed that the naive idea of a nan.o.bot armed with molecular tweezers cutting and pasting molecules had to be modified. New quantum forces become dominant at the atomic scale.

Second, although this replicator, or universal fabricator, is science fiction today, a version of it already exists. Mother Nature, for example, can take hamburgers and vegetables and turn them into a baby in just nine months. This process is carried out by DNA molecules (which encode the blueprint for the baby) that guide the actions of ribosomes (which cut and splice the molecules into correct order) using the proteins and amino acids present in your food.

And third, a molecular a.s.sembler might work, but in a more sophisticated version. For example, as Smalley pointed out, bringing two atoms together does not guarantee a reaction. Mother Nature often gets around this problem by employing a third party, an enzyme in a water solution, to facilitate a chemical reaction. Smalley pointed out that many chemicals found in computers and the electronics industry cannot be dissolved in water. But Drexler countered by saying that not all chemical reactions involve water or enzymes.

One possibility, for example, is called self-a.s.sembly, or the bottom-up approach. Since antiquity, humans have used the top-down approach to building. With tools like a hammer and saw, one begins to cut wood and then piece together boards to create larger structures like a house according to a plan. You have to carefully guide this process from above at every step of the way.

In the bottom-up approach, things a.s.semble by themselves. In nature, for example, beautiful snowflakes crystallize all by themselves in a thunderstorm. Trillions upon trillions of atoms rearrange to create novel forms. No one has to design each snowflake. This often occurs in biological systems as well. Bacterial ribosomes, which are complex molecular systems containing at least fifty-five different protein molecules and several RNA molecules, can spontaneously self-a.s.semble in a test tube.

Self-a.s.sembly is also used in the semiconductor industry. Components used in transistors sometimes a.s.semble by themselves. By applying various complex techniques and processes in a precise sequence (such as quenching, crystallization, polymerization, vapor deposition, solidification, etc.) one can produce a variety of commercially valuable computer components. As we saw earlier, a certain type of nanoparticle used against cancer cells can be produced using this method.

However, most things do not create themselves. In general, only a tiny fraction of nanomaterials have been shown to self-a.s.semble properly. You cannot order a nanomachine using self-a.s.sembly like you can order from a menu. So progress in creating nanomachines this way will be steady but slow.

In sum, molecular a.s.semblers apparently violate no law of physics, but they will be exceedingly difficult to build. Nan.o.bots do not exist now, and will not in the near future, but once (and if) the first nan.o.bot is successfully produced, it might alter society as we know it.

BUILDING A REPLICATOR.

What might a replicator look like? No one knows exactly, since we are decades to a century away from actually building one, but I got a taste of how a replicator might appear when I had my head examined (literally). For a Science Channel special, they created a realistic 3-D copy of my face out of plastic by scanning a laser beam horizontally across my face. As the beam bounced off my skin, the reflection was recorded by a sensor that fed the image into a computer. Then the beam made the next pa.s.s across my face, but slightly lower. Eventually, it scanned my entire face, dividing it up into many horizontal slices. By looking at a computer screen, you could see a 3-D image of the surface of my face emerge, to an accuracy of perhaps a tenth of a millimeter, consisting of these horizontal slices.

Then this information was fed into a large device, about the size of a refrigerator, that can create a plastic 3-D image of almost anything. The device has a tiny nozzle that moves horizontally, making many pa.s.ses. On each pa.s.s, it sprays out a tiny amount of molten plastic, duplicating the original laser image of my face. After about ten minutes and numerous pa.s.ses, the mold emerged from this machine, bearing an eerie resemblance to my face.

The commercial applications of this technology are enormous, since you can create a realistic copy of any 3-D object, such as complicated machine parts, within a matter of a few minutes. However, one can imagine a device that, decades to centuries from now, may be able to create a 3-D copy of a real object, down to the cellular and atomic level.

At the next level, it is possible to use this 3-D scanner to create living organs of the human body. At Wake Forest University, scientists have pioneered a novel way to create living heart tissue, with an ink-jet printer. First, they have to carefully write a software program that successively sprays out living heart cells as the nozzle makes each pa.s.s. For this, they use an ordinary ink-jet printer but one whose ink cartridge is filled with a mixture of fluids containing living heart cells. In this way, they have control over the precise 3-D placement of every cell. After multiple pa.s.ses, they can actually create the layers of heart tissue.

There is another instrument that might one day record the location of every atom of our body: the MRI. As we observed earlier, the accuracy of the MRI scan is about a tenth of a millimeter. This means that every pixel of a sensitive MRI scan may contain thousands of cells. But if you examine the physics behind the MRI, you find that the accuracy of the image is related to the uniformity of the magnetic field within the machine. Thus, by making the magnetic field increasingly uniform, one can even go below a tenth of a millimeter.

Already, scientists are envisioning an MRI-type machine with a resolution down to the size of a cell, and even smaller, one that can scan down to the individual molecules and atoms.

In summary, a replicator does not violate the laws of physics, but it would be difficult to create using self-a.s.sembly. By late in this century, when the techniques of self-a.s.sembly are finally mastered, we can think about commercial applications of replicators.

GRAY GOO?.

Some people, including Bill Joy, a founder of Sun Microsystems, have expressed reservations about nanotechnology, writing that it"s only a matter of time before the technology runs wild, devours all the minerals of the earth, and spits out useless "gray goo" instead. Even Prince Charles of England has spoken out against nanotechnology and the gray-goo scenario.

The danger lies in the key property of these nan.o.bots: they can reproduce themselves. Like a virus, they cannot be recalled once they are let loose into the environment. Eventually, they could proliferate wildly, taking over the environment and destroying the earth.

My own belief is that there are many decades to centuries before this technology is mature enough to create a replicator, so concerns about the gray goo are premature. As the decades pa.s.s, there will be plenty of time to design safeguards against nan.o.bots that run amok. For example, one can design a fail-safe system so that, by pressing a panic b.u.t.ton, all the nan.o.bots are rendered useless. Or one could design "killer bots," specifically designed to seek out and destroy nan.o.bots that have run out of control.

Another way to deal with this is to study Mother Nature, who has had billions of years of experience with this problem. Our world is full of self-replicating molecular life-forms, called viruses and bacteria, that can proliferate out of control and mutate as well. However, our body has also created "nan.o.bots" of its own, antibodies and white blood cells in our immune system that seek out and destroy alien life-forms. The system is certainly not perfect, but it provides a model for dealing with this out-of-control-nan.o.bot problem.

SOCIAL IMPACT OF REPLICATORS.

For a BBC/Discovery Channel special I once hosted, Joel Garreau, author of Radical Evolution, Radical Evolution, said, "If a self-a.s.sembler ever does become possible, that"s going to be one of history"s great "holy s-!" moments. Then you are really talking about changing the world into something we"ve never recognized before." said, "If a self-a.s.sembler ever does become possible, that"s going to be one of history"s great "holy s-!" moments. Then you are really talking about changing the world into something we"ve never recognized before."

There is an old saying, Be careful what you wish for, because it may come true. The holy grail of nanotechnology is to create the molecular a.s.sembler, or replicator, but once it is invented, it could alter the very foundation of society itself. All philosophies and social systems are ultimately based on scarcity and poverty. Throughout human history, this has been the dominant theme running through society, shaping our culture, philosophy, and religion. In some religions, prosperity is viewed as a divine reward and poverty as just punishment. Buddhism, by contrast, is based on the universal nature of suffering and how we cope with it. In Christianity, the New Testament reads: "It is easier for a camel to go through the eye of a needle than for a rich man to enter into the kingdom of G.o.d."

The distribution of wealth also defines the society itself. Feudalism is based on preserving the wealth of a handful of aristocrats against the poverty of the peasants. Capitalism is based on the idea that energetic, productive people are rewarded for their labors by starting companies and getting rich. But if lazy, nonproductive individuals can get as much as they want almost for free by pushing a b.u.t.ton, then capitalism no longer works. A replicator upsets the entire apple cart, turning human relations upside down. The distinctions between the haves and have-nots may disappear, and along with it the notion of status and political power.

This conundrum was explored in an episode in Star Trek: The Next Generation, Star Trek: The Next Generation, in which a capsule from the twentieth century is found floating in outer s.p.a.ce. Inside the capsule are the frozen bodies of people who suffered from incurable diseases of that primitive time period, hoping to be revived in the future. The doctors of the starship in which a capsule from the twentieth century is found floating in outer s.p.a.ce. Inside the capsule are the frozen bodies of people who suffered from incurable diseases of that primitive time period, hoping to be revived in the future. The doctors of the starship Enterprise Enterprise quickly cure these individuals of their diseases and revive them. These fortunate individuals are surprised that their gamble paid off, but one of them is a shrewd capitalist. The first thing he asks is: What time period is this? When he finds out that he is now alive in the twenty-fourth century, he quickly realizes that his investments must today be worth a fortune. He immediately demands to contact his banker back on earth. But the crew of the quickly cure these individuals of their diseases and revive them. These fortunate individuals are surprised that their gamble paid off, but one of them is a shrewd capitalist. The first thing he asks is: What time period is this? When he finds out that he is now alive in the twenty-fourth century, he quickly realizes that his investments must today be worth a fortune. He immediately demands to contact his banker back on earth. But the crew of the Enterprise Enterprise is bewildered. Money? Investments? These do not exist in the future. In the twenty-fourth century, you simply ask for something, and it is given to you. is bewildered. Money? Investments? These do not exist in the future. In the twenty-fourth century, you simply ask for something, and it is given to you.

This also calls into question the search for the perfect society, or utopia, a word coined in the novel written by Sir Thomas More in 1516 t.i.tled Utopia. Utopia. Appalled by the suffering and squalor he saw around him, he envisioned a paradise on a fictional island in the Atlantic Ocean. In the nineteenth century, there were many social movements in Europe that searched for various forms of utopia, and many of them eventually found sanctuary by escaping to the United States, where we see evidence of their settlements even today. Appalled by the suffering and squalor he saw around him, he envisioned a paradise on a fictional island in the Atlantic Ocean. In the nineteenth century, there were many social movements in Europe that searched for various forms of utopia, and many of them eventually found sanctuary by escaping to the United States, where we see evidence of their settlements even today.

On one hand, a replicator could give us the utopia that was once envisioned by nineteenth-century visionaries. Previous experiments in utopia failed because of scarcity, which led to inequalities, then bickering, and ultimately collapse. But if replicators solve the problem of scarcity, then perhaps utopia is within reach. Art, music, and poetry will flourish, and people will be free to explore their fondest dreams and wishes.

On the other hand, without the motivating factor of scarcity and money, it could lead to a self-indulgent, degenerate society that sinks to the lowest level. Only a tiny handful, the most artistically motivated, will strive to write poetry. The rest of us, the critics claim, will become good-for-nothing loafers and slackers.

Even the definitions used by the utopians are called into question. The mantra for socialism, for example, is: "From each according to his ability, to each according to his contribution." The mantra for communism, the highest stage of socialism, is: "From each according to his ability, to each according to his need."

But if replicators are possible, then the mantra simply becomes: "To each according to his desire."

There is, however, a third way of looking at this question. According to the Cave Man Principle, people"s basic personalities have not changed much in the past 100,000 years. Back then, there was no such thing as a job. Anthropologists say that primitive societies were largely communal, sharing goods and hardships equally. Daily rhythms were not governed by a job and pay, since neither of them existed.

Yet people back then did not become loafers, for several reasons. First, they would starve to death. People who did not do their share of the work were simply thrown out of the tribe, and they soon perished. Second, people became proud of their work, and even found meaning in their tasks. Third, there was enormous social pressure to remain a productive member of society. Productive individuals could marry to pa.s.s their genes onto the next generation, while the genes of loafers usually died with them.

So why will people live productive lives when replicators are invented and everyone can have anything they want? First of all, replicators would guarantee that no one starves. But second, most people will probably still continue to work because they are proud of their skills and find meaning in their labor. But the third reason, social pressure, is harder to maintain without infringing on personal liberties. Instead of social pressure there would probably have to be a major shift in education to change people"s att.i.tudes toward work and reward, so that the replicator is not abused.

Fortunately, since progress will be slow and the replicator is a century or so away, society will have plenty of time to debate the merits and implications of this technology and adjust to this new reality so that society does not disintegrate.

More than likely, the first replicators will be expensive. As MIT robotics expert Rodney Brooks says, "Nanotechnology will thrive, much as photolithography thrives-in very expensive, controlled situations rather than as a freestanding ma.s.s-market technology." The problem of unlimited free goods will not be so much a problem. Given the sophistication of these machines, it may take many decades after they are first created to bring down the cost.

I once had an interesting conversation with Jamais Cascio, a leading futurist with a long career of thoughtfully contemplating the outlines of tomorrow. First, he told me that he doubted the singularity theory mentioned in Chapter 2 Chapter 2, observing that human nature and social dynamics are much too messy, complicated, and unpredictable to be fit into a simple neat theory. But he also admitted that remarkable advances in nanotechnology might eventually create a society in which there was an overabundance of goods, especially with replicators and robots. So I asked him: How will society behave when goods are nearly for free, when society is finally so rich that there is no necessity to work?

Two things would happen, he said. First, he thought there would be enough wealth to guarantee a decent, minimum income for everyone, even if they did not work. So there probably would be a fraction of the population who become permanent slackers. He foresaw a permanent safety net for society. This might be undesirable, but it is unavoidable, especially if replicators and robots meet all our material needs. Second, this would be compensated for, he thought, by unleashing a revolution in the entrepreneurial spirit. Freed from the fear of plunging into poverty and ruin, the more industrious individuals would have more initiative and take on additional risks to create new industries and new opportunities for others. He foresaw a new renaissance of society, as the creative spirit was unleashed from the fear of bankruptcy.

In my own field, physics, I see that most of us engage in physics not for the money but for the sheer joy of discovery and innovation. Often, we pa.s.sed up lucrative jobs in other fields because we wanted to pursue a dream, not the dollar. The artists and intellectuals I know also feel the same way-that their goal is not to ama.s.s as big a bank account as possible but to be creative and enn.o.ble the human spirit.

Personally, if by 2100 society becomes so rich that we are surrounded by material wealth, I feel that society may react in a similar way. A fraction of the population will form a permanent cla.s.s of people who simply refuse to work. Others may be liberated from the constraints of poverty and pursue creative scientific and artistic achievement. For them, the sheer joy of being creative, innovative, and artistic will outweigh the lure of a materialistic world. But the majority will continue to work and be useful simply because it is part of our genetic heritage, the Cave Man Principle within us.

But there is one problem that even replicators cannot solve. And this is the problem of energy. All these miraculous technologies need vast amounts of energy to drive them. Where will this energy come from?

The Stone Age did not end for lack of stone. And the Oil Age will end long before the world runs out of oil.

-JAMES CANTON In my mind, (fusion) ranks with the original gift of fire, back in the mists of prehistory.

-BEN BOVA

The stars were the energy source of the G.o.ds. When Apollo rode across the sky in a chariot drawn by fire-breathing horses, he illuminated the heavens and the earth with the infinite power of the sun. His power was rivaled only by that of Zeus himself. Once, when Semele, one of Zeus"s numerous mortal lovers, begged to see him in his true form, he reluctantly obliged. The resulting burst of blinding, cosmic energy burned her to a crisp.

In this century, we will harness the power of the stars, the energy source of the G.o.ds. In the short term, this means ushering in an era of solar/hydrogen power to replace fossil fuels. But in the long term, it means harnessing the power of fusion and even solar energy from outer s.p.a.ce. Further advances in physics could usher in the age of magnetism, whereby cars, trains, and even skateboards will float through the air on a cushion of magnetism. Our energy consumption could be drastically reduced, since almost all the energy used in cars and trains is simply to overcome the friction of the road.