Part 10 (2/2)
In 2005, biologists successfully resurrected the Spanish flu virus of 1918, which killed more people than World War I. Remarkably, they were able to resurrect the virus by a.n.a.lyzing a woman who had died and was buried in the permafrost of Alaska, as well as samples taken from U.S. soldiers during the epidemic.
The scientists then proceeded to publish the entire genome of the virus on the Web, making it known to the entire world. Many scientists felt uneasy about this, since one day even a college student with access to a university laboratory might be able to resurrect one of the greatest killers in the history of the human race.
In the short term, the publication of the genome of the Spanish flu virus was a bonanza for scientists, who then could examine the genes to solve a long-standing puzzle: How did a tiny mutation cause such widespread damage to the human population? The answer was soon found. The Spanish flu virus, unlike other varieties, causes the body's immune system to overreact, releasing large amounts of fluid that eventually kills the patient. The person literally drowns in his own fluids. Once this was understood, the genes that cause this deadly effect could be compared to the genes of the H1N1 flu and other viruses. Fortunately, none of them possessed this lethal gene. Moreover, one could actually calculate how close a virus was to attaining this alarming capability, and the H1N1 flu was still far from achieving this ability.
But in the long term, there is a price to pay. Every year, it becomes easier and easier to manipulate the genes of living organisms. Costs keep plummeting, and the information is widely available on the Internet.
Within a few decades, some scientists believe that it will be possible to create a machine that will allow you to create any gene simply by typing the desired components. By typing in the A-T-C-G symbols making up a gene, the machine will then automatically splice and dice DNA to create that gene. If so, then it means that perhaps even high school students may one day do advanced manipulations of life-forms.
One nightmare scenario is airborne AIDS. Cold viruses, for example, possess a few genes that allow them to survive in droplets of aerosols, so that sneezing can infect others. At present, the AIDS virus is quite vulnerable when it is exposed to the environment. But if the cold virus genes are implanted into the AIDS virus, then it is conceivable that they might make it able to survive outside the human body. This could then cause the AIDS virus to spread like the common cold, thereby infecting a large portion of the human race. It is also known that viruses and bacteria do exchange genes, so there is also the possibility that the AIDS and common cold viruses can exchange genes naturally, although this is less likely.
In the future, a terrorist group or nation-state may be able to weaponize AIDS. The only thing preventing them from unleas.h.i.+ng it would be the fact that they, too, would also perish if the virus were to be dispersed into the environment.
This threat became real right after the tragedy of 9/11. An unknown person mailed packets of a white powder containing anthrax spores to well-known politicians around the country. A careful, microscopic a.n.a.lysis of the white powder showed that the anthrax spores had been weaponized for maximum death and destruction. Suddenly, the entire country was gripped with fear that a terrorist group had access to advanced biological weapons. Although anthrax is found in the soil and throughout our environment, only a person with advanced training and maniacal intentions could have purified and weaponized the anthrax and pulled off this feat.
Even after one of the largest manhunts in U.S. history, the culprit was never found, even to this day (although a leading suspect recently committed suicide). The point here is that even a single individual with some advanced biological training can terrorize an entire nation.
One restraining factor that has kept germ warfare in check is simple self-interest. During World War I, the efficacy of poison gas on the battlefield was mixed. The wind conditions were often unpredictable, so the gas could blow back onto your own troops. Its military value was largely in terrorizing the enemy, rather than defeating him. Not a single decisive battle was won using poison gas. And even at the height of the Cold War, both sides knew that poison gas and biological weapons could have unpredictable effects on the battlefield, and could easily escalate to a nuclear confrontation.
All the arguments mentioned in this chapter, as we have seen, involved the manipulation of genes, proteins, and molecules. Then the next question naturally arises: How far can we manipulate individual atoms?
The principles of physics, as far as I can see, do not speak against the possibility of maneuvering things atom by atom.
-RICHARD FEYNMAN, n.o.bEL LAUREATE Nanotechnology has given us the tools to play with the ultimate toy box of nature-atoms and molecules. Everything is made from these, and the possibilities to create new things appear limitless.
-HORST STORMER, n.o.bEL LAUREATE The role of the infinitely small is infinitely large.
-LOUIS PASTEUR
The mastery of tools is a crowning achievement that distinguishes humanity from the animals. According to Greek and Roman mythology, this process began when Prometheus, taking pity on the plight of humans, stole the precious gift of fire from Vulcan's furnace. But this act of thievery enraged the G.o.ds. To punish humanity, Zeus devised a clever trick. He asked Vulcan to forge a box and a beautiful woman out of metal. Vulcan created this statue, called Pandora, and then magically brought her to life, and told her never to open the box. Out of curiosity, one day she did, and unleashed all the winds of chaos, misery, and suffering in the world, leaving only hope in the box.
So from Vulcan's divine furnace emerged both the dreams and the suffering of the human race. Today, we are designing revolutionary new machines that are the ultimate tools, forged from individual atoms. But will they unleash the fire of enlightenment and knowledge or the winds of chaos?
Throughout human history, the mastery of tools has determined our fate. When the bow and arrow were perfected thousands of years ago, it meant that we could fire projectiles much farther than our hands could throw them, increasing the efficiency of our hunting and increasing our food supply. When metallurgy was invented around 7,000 years ago, it meant that we could replace huts of mud and straw and eventually create great buildings that soared above the earth. Soon, empires began to rise from the forest and the desert, built by the tools forged from metals.
And now we are on the brink of mastering yet another type of tool, much more powerful than anything we have seen before. This time, we will be able to master the atoms themselves out of which everything is created. Within this century, we may possess the most important tool ever imagined-nanotechnology that will allow us to manipulate individual atoms. This could begin a second industrial revolution, as molecular manufacturing creates new materials we can only dream about today, which are superstrong, superlight, with amazing electrical and magnetic properties.
n.o.bel laureate Richard Smalley has said, ”The grandest dream of nanotechnology is to be able to construct with the atom as the building block.” Philip Kuekes of Hewlett-Packard said, ”Eventually, the goal is not just to make computers the size of dust particles. The idea would be to make simple computers the size of bacteria. Then you could get something as powerful as what's now on your desktop into a dust particle.”
This is not just the hope of starry-eyed visionaries. The U.S. government takes it seriously. In 2009, because of nanotechnology's immense potential for medical, industrial, aeronautical, and commercial applications, the National Nanotechnology Initiative allocated $1.5 billion for research. The government's National Science Foundation Nanotechnology Report states, ”Nanotechnology has the potential to enhance human performance, to bring sustainable development for materials, water, energy, and foods, to protect against unknown bacteria and viruses....”
Ultimately, the world economy and fate of nations may depend on this. Around 2020 or soon afterward, Moore's law will begin to falter and perhaps eventually collapse. The world economy could be thrown into disarray unless physicists can find a suitable replacement for silicon transistors to power our computers. The solution to the problem may come from nanotechnology.
Nanotechnology might also, perhaps by the end of this century, create a machine that only the G.o.ds can wield, a machine that can create anything out of almost nothing.
THE QUANTUM WORLD.
The first to call attention to this new realm of physics was n.o.bel laureate Richard Feynman, who asked a deceptively simple question: How small can you make a machine? This was not an academic question. Computers were gradually becoming smaller, changing the face of industry, so it was becoming apparent that the answer to this question could have an enormous impact on society and the economy.
In his prophetic talk given in 1959 to the American Physical Society t.i.tled ”There's Plenty of Room at the Bottom,” Feynman said, ”It is interesting that it would be, in principle, possible (I think) for a physicist to synthesize any chemical substance that the chemist writes down. Give the orders and the physicist synthesizes it. How? Put the atoms down where the chemist says, and so you make the substance.” Feynman concluded that machines made out of individual atoms were possible, but that new laws of physics would make them difficult, but not impossible, to create.
So ultimately, the world economy and the fate of nations may depend on the bizarre and counterintuitive principles of the quantum theory. Normally, we think that the laws of physics remain the same if you go down to smaller scales. But this is not true. In movies like Disney's Honey, I Shrunk the Kids Honey, I Shrunk the Kids and and The Incredible Shrinking Man, The Incredible Shrinking Man, we get the mistaken impression that miniature people would experience the laws of physics the same way we do. For example, in one scene in the Disney movie, our shrunken heroes ride on an ant during a rainstorm. Raindrops fall onto the ground and make tiny puddles, just as in our world. But in reality, raindrops can be larger than ants. So when an ant encounters a raindrop, it would see a huge hemisphere of water. The hemisphere of water does not collapse because surface tension acts like a net that holds the droplet together. In our world, surface tension of water is quite small, so we don't notice it. But on the scale of an ant, surface tension is proportionately huge, so rain beads up into droplets. we get the mistaken impression that miniature people would experience the laws of physics the same way we do. For example, in one scene in the Disney movie, our shrunken heroes ride on an ant during a rainstorm. Raindrops fall onto the ground and make tiny puddles, just as in our world. But in reality, raindrops can be larger than ants. So when an ant encounters a raindrop, it would see a huge hemisphere of water. The hemisphere of water does not collapse because surface tension acts like a net that holds the droplet together. In our world, surface tension of water is quite small, so we don't notice it. But on the scale of an ant, surface tension is proportionately huge, so rain beads up into droplets.
(Furthermore, if you tried to scale up the ant so that it was the size of a house, you have another problem: its legs would break. As you increase the size of the ant, its weight grows much faster than the strength of its legs. If you increase the size of an ant by a factor of 10, its volume and hence its weight is 10 10 10 = 1,000 times heavier. But its strength is related to the thickness of its muscles, which is only 10 10 = 100 times stronger. Hence, the giant ant is 10 times weaker, relatively speaking, than an ordinary ant. This also means that King Kong, instead of terrorizing New York City, would crumble if he tried to climb the Empire State Building.) Feynman noted that other forces also dominate at the atomic scale, such as hydrogen bonding and the van der Waals force, caused by tiny electrical forces that exist between atoms and molecules. Many of the physical properties of substances are determined by these forces.
(To visualize this, consider the simple problem of why the Northeast has so many potholes in its highways. Every winter, water seeps into tiny cracks in the asphalt; the water expands as it freezes, causing the asphalt to crumble and gouging out a pothole. But it violates common sense to think that water expands when it freezes. Water does expand because of hydrogen bonding. The water molecule is shaped like a V, with the oxygen atom at the base. The water molecule has a slight negative charge at the bottom and a positive charge at the top. Hence, when you freeze water and stack water molecules, they expand, forming a regular lattice of ice with plenty of s.p.a.ces between the molecules. The water molecules are arranged like hexagons. So water expands as it freezes since there is more s.p.a.ce between the atoms in a hexagon. This is also the reason snowflakes have six sides, and explains why ice floats on water, when by rights it should sink.) WALKING THROUGH WALLS.
In addition to surface tension, hydrogen bonding, and van der Waals forces, there are also bizarre quantum effects at the atomic scale. Normally, we don't see quantum forces at work in everyday life. But quantum forces are everywhere. For example, by rights, since atoms are largely empty, we should be able to walk through walls. Between the nucleus at the center of the atom and the electron sh.e.l.ls, there is only a vacuum. If the atom were the size of a football stadium, then the stadium would be empty, since the nucleus would be roughly the size of a grain of sand.
(We sometimes amaze our students with a simple demonstration. We take a Geiger counter, place it in front of a student, and put a harmless radioactive pellet in back. The student is startled that some particles pa.s.s right through his body and trigger the Geiger counter, as if he is largely empty, which he is.) But if we are largely empty, then why can't we walk through walls? In the movie Ghost, Ghost, Patrick Swayze's character is killed by a rival and turns into a ghost. He is frustrated every time he tries to touch his former fiancee, played by Demi Moore. His hands pa.s.s through ordinary matter; he finds that he has no material substance and simply floats through solid objects. In one scene, he sticks his head into a moving subway car. The train races by with his head sticking inside, yet he doesn't feel a thing. (The movie does not explain why gravity does not pull him through the floor so he falls to the center of the earth. Ghosts, apparently, can pa.s.s through anything except floors.) Patrick Swayze's character is killed by a rival and turns into a ghost. He is frustrated every time he tries to touch his former fiancee, played by Demi Moore. His hands pa.s.s through ordinary matter; he finds that he has no material substance and simply floats through solid objects. In one scene, he sticks his head into a moving subway car. The train races by with his head sticking inside, yet he doesn't feel a thing. (The movie does not explain why gravity does not pull him through the floor so he falls to the center of the earth. Ghosts, apparently, can pa.s.s through anything except floors.) So why can't we pa.s.s through solid objects like ghosts? The answer resides in a curious quantum phenomenon. The Pauli exclusion principle states that no two electrons can exist in the same quantum state. Hence when two nearly identical electrons get too close, they repel each other. This is the reason objects appear to be solid, which is an illusion. The reality is that matter is basically empty.
When we sit in a chair, we think we are touching it. Actually, we are hovering above the chair, floating less than a nanometer above it, repelled by the chair's electrical and quantum forces. This means that whenever we ”touch” something, we are not making direct contact at all but are separated by these tiny atomic forces. (This also means that if we could somehow neutralize the exclusion principle, then we might be able to pa.s.s through walls. However, no one knows how to do this.) Not only does the quantum theory keep atoms from cras.h.i.+ng through one another, it also binds them together into molecules. Imagine for the moment that an atom is like a tiny solar system, with planets revolving around a sun. Now, if two such solar systems collided, then the planets would either crash into one another or fly out in all directions, causing the solar system to collapse. Solar systems are never stable when they collide with another solar system, so by rights, atoms should collapse when they b.u.mp into one another.
In reality, when two atoms get very close, they either bounce off each other or they combine to form a stable molecule. The reason atoms can form stable molecules is because electrons can be shared between two atoms. Normally, the idea of an electron being shared between two atoms is preposterous. It is impossible if the electron obeyed the commonsense laws of Newton. But because of the Heisenberg uncertainty principle, you don't know precisely where the electron is. Instead, it's smeared out between two atoms, which holds them together.
In other words, if you turn off the quantum theory, then your molecules fall apart when they b.u.mp into one another and you would dissolve into a gas of particles. So the quantum theory explains why atoms can bind to form solid matter, rather than disintegrate.
(This is also the reason you cannot have worlds within worlds. Some people imagine that our solar system or galaxy might be an atom in someone else's gigantic universe. This was, in fact, the final scene in the movie Men in Black, Men in Black, where the entire known universe was in fact just an atom in some alien's ball game. But according to physics, this is impossible, since the laws of physics change as we go from scale to scale. The rules governing atoms are quite different from the rules governing galaxies.) where the entire known universe was in fact just an atom in some alien's ball game. But according to physics, this is impossible, since the laws of physics change as we go from scale to scale. The rules governing atoms are quite different from the rules governing galaxies.) Some of the mind-bending principles of the quantum theory are: *you cannot know the exact velocity and location of any particle-there is always uncertainty *particles can in some sense be in two places at the same time *all particles exist as mixtures of different states simultaneously; for example, spinning particles can be mixtures of particles whose axes spin both up and down simultaneously *you can disappear and reappear somewhere else
All these statements sound ridiculous. In fact, Einstein once said, ”the more successful the quantum theory is, the sillier it looks.” No one knows where these bizarre laws come from. They are simply postulates, with no explanation. The quantum theory has only one thing going for it: it is correct. Its accuracy has been measured to one part in ten billion, making it the most successful physical theory of all time.
The reason we don't see these incredible phenomena in daily life is because we are composed of trillions upon trillions of atoms, and these effects, in some sense, average out.
MOVING INDIVIDUAL ATOMS.
Richard Feynman dreamed of the day when a physicist could manufacture any molecule, atom for atom. That seemed impossible back in 1959, but part of that dream is now a reality.
I had a chance to witness this up close, when I visited the IBM Almaden Research Center in San Jose, California. I came to observe a remarkable instrument, the scanning tunneling microscope, which allows scientists to view and manipulate individual atoms. This device was invented by Gerd Binnig and Heinrich Rohrer of IBM, for which they won the n.o.bel Prize in 1986. (I remember, as a child, my teacher telling us that we would never be able to see atoms. They are just too small, he said. By then, I had already decided to become an atomic scientist. I realized that I would spend the rest of my life studying something I would never be able to observe directly. But today, not only can we see atoms, but we can play with them, with atomic tweezers.) The scanning tunneling microscope is actually not a microscope at all. It resembles an old phonograph. A fine needle (with a tip that is only a single atom across) pa.s.ses slowly over the material being a.n.a.lyzed. A small electrical current travels from the needle, through the material, to the base of the instrument. As the needle pa.s.ses over the object, the electrical current changes slightly every time it pa.s.ses over an atom. After multiple pa.s.ses, the machine prints out the stunning outline of the atom itself. Using an identical needle, the microscope is then capable not just of recording these atoms but also of moving them around. In this way, one can spell out the letters, such as the initials IBM, and in fact even design primitive machines built out of atoms.
(Another recent invention is the atomic force microscope, which can give us stunning 3-D pictures of arrays of atoms. The atomic force microscope also uses the needle with a very small point, but it s.h.i.+nes a laser onto it. As the needle pa.s.ses over the material being studied, the needle jiggles, and this motion is recorded by the laser beam image.) I found that moving individual atoms around was quite simple. I sat in front of a computer screen, looking at a series of white spheres, each resembling a Ping-Pong ball about an inch across. Actually, each ball was an individual atom. I placed the cursor over an atom and then moved the cursor to another position. I pushed a b.u.t.ton that then activated the needle to move the atom. The microscope rescanned the substance. The screen changed, showing that the ball had moved to precisely where I wanted it.
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