Physics of the Future

by Michio Kaku

  So Peck’s vision of a starship is a sharp departure from the usual one found in science fiction, where huge starships lumber into space piloted by a crew of daring astronauts. For example, if a base were set up on a moon of Jupiter, then scores of these tiny chips could be fired into orbit around that giant planet. If a battery of laser canons were also built on this moon, then these chips could be accelerated by hitting them with laser light, increasing their velocity until they reached a fraction of the speed of light.

  I then asked him a simple question: Can you reduce your chips to the size of molecules using nanotechnology? Then, instead of using Jupiter’s magnetic fields to accelerate these chips, you could use atom smashers based on our own moon to fire molecular-sized probes at near the speed of light. He agreed that this would be a real possibility, but that he hadn’t worked out the details yet.

  So, we took out a sheet of paper and together began to crank out the equations for this possibility. (This is how we research scientists interact with one another, by going to the blackboard or taking out a sheet of paper to solve a problem by writing down the equations.) We wrote down the equations for the Lorentz force, which Peck uses to accelerate his chips around Jupiter, but then we reduced the chips to the size of molecules and placed them into a hypothetical accelerator similar to the Large Hadron Collider at CERN. We could quickly see that the equations allowed for such a nanostarship to accelerate to nearly the speed of light, using only a conventional atom smasher based on the moon. Because we were reducing the size of our starship from a chip to a molecule, we could reduce the size of our accelerator from the size of Jupiter to a conventional atom smasher. It seemed like this idea was a real possibility.

  But after analyzing the equations, we both agreed that the only problem was the stability of these delicate nanostarships. Would the acceleration eventually rip these molecules apart? Like a ball whipping around on a string, these molecules would experience centrifugal forces as they were accelerated to near light speed. Also, these molecules would be electrically charged, so that even electrical forces might rip them apart. We both concluded that nanoships were a definite possibility, but it might take decades of more research to reduce Peck’s chips to the size of a molecule and reinforce them so that they don’t disintegrate when accelerated to near light speed.

  So Mason Peck’s dream is to send a swarm of chips to the nearest star, hoping that some of them actually make it across interstellar space. But what do they do when they arrive?

  This is where the work of Pei Zhang of Carnegie Mellon University in Silicon Valley comes in. He has created a fleet of minihelicopters that may one day wind up on another planet. He proudly showed me his fleet of swarm-bots, which resemble toy helicopters. But looks are deceptive. I could see that at the center of each was a chip crammed with sophisticated circuitry. With one push of a button, he released four swam-bots into the air, where they flew in all directions and sent back information. Soon, I was surrounded by swarm-bots.

  The purpose of these swarm-bots, he told me, is to provide crucial assistance during emergencies, like fires and explosions, by doing reconnaissance and surveillance. Eventually, these swarm-bots could be outfitted with TV cameras and sensors that can detect temperature, pressure, wind direction, etc., information that may prove critical during an emergency. Thousands of swarm-bots could be released over a battlefield, a fire, or even an extraterrestrial terrain. These swarm-bots also communicate with one another. If one of them hits an obstacle, it radios the information to the other swarm-bots.

  So one vision of space travel might be that thousands of cheap, disposable chips devised by people like Mason Peck are fired at the nearest star at nearly the speed of light. Once a handful of them reach their destination, they sprout wings and blades and fly over the alien terrain, just like Pei Zhang’s fleet of swarm-bots. They would then radio information back to earth. Once promising planets are found, a second generation of swarm-bots might be sent to create factories on these planets that then create more copies of these swarm-bots, which then fly to the next star. Then the process continues indefinitely.

  EXODUS EARTH?

  By 2100, it is likely that we will have sent astronauts to Mars and the asteroid belt, explored the moons of Jupiter, and begun the first steps to send a probe to the stars.

  But what about humanity? Will we have space colonies to relieve the world population by finding a new home in outer space? Will the human race begin to leave the earth by 2100?

  No. Given the cost, even by 2100 and beyond, the majority of the human race will not board a spaceship to visit the other planets. Although a handful of astronauts will have created tiny outposts among the planets, humanity itself will be stuck on earth.

  Given the fact that earth will be the home of humanity for centuries to come, this raises another question: How will civilization itself evolve? How will science affect our lifestyle, our jobs, and our society? Science is the engine of prosperity, so how will it reshape civilization and wealth in the future?

  Technology and ideology are shaking the foundations of twenty-first-century capitalism. Technology is making skills and knowledge the only sources of sustainable strategic advantage.

  —LESTER THUROW

  In mythology, the rise and fall of great empires depended on the strength and cunning of one’s armies. The great generals of the Roman Empire worshipped at the temple of Mars, the god of war, before decisive military campaigns. The legendary exploits of Thor inspired the Vikings into heroic battles. The ancients built huge temples and monuments dedicated to the gods, commemorating victories in battle against their enemies.

  But when we analyze the actual rise and decline of great civilizations, we find an entirely different story.

  If you were an alien from Mars visiting earth in the year 1500 and viewed all the great civilizations, which would you think would eventually dominate the word? The answer would be easy: any civilization but the European one.

  In the east, you would see the great Chinese civilization, which had lasted for millennia. The long list of inventions pioneered by the Chinese is without parallel: paper, the printing press, gunpowder, the compass, etc. Its scientists are the best on the planet. Its government is unified and the mainland is at peace.

  In the south, you have the Ottoman Empire, which came within a hairbreadth of overrunning Europe. The great Muslim civilization invented algebra, produced advances in optics and physics, and named the stars. Art and science flourish. Its great armies face no credible opposition. Istanbul is one of the world’s great centers for scientific learning.

  Then you have the pitiful European countries, which are racked by religious fundamentalism, witch trials, and the Inquisition. Western Europe, in precipitous decline for a thousand years since the collapse of the Roman Empire, is so backward that it is a net importer of technology. It is a medieval black hole. Most of the knowledge of the Roman Empire has long since vanished, replaced by stifling religious dogma. Opposition or dissent is frequently met with torture or worse. Moreover, the city-states of Europe are constantly at war with one another.

  So what happened?

  Both the great Chinese and Ottoman empires are entering a 500-year-period of technological stagnation, while Europe is beginning an unprecedented embrace of science and technology.

  Beginning in 1405, the Yongle emperor of China ordered a massive naval armada, the largest the world had ever seen, to explore the world. (The three puny naval ships of Columbus would have fit nicely on the deck of just one of these colossal vessels.) Seven massive expeditions were launched, each larger than the previous one. This fleet sailed around the coast of Southeast Asia and reached Africa, Madagascar, and perhaps even beyond that. The fleet brought back a rich bounty of goods, delicacies, and exotic animals from the far reaches of the earth. There are remarkable ancient woodcuts of African giraffes being paraded at a Ming Dynasty zoo.

  But the rulers of China were also disappointed. Was that all there was? Where we
re the great armies that could rival the Chinese? Were exotic foods and strange animals all that the rest of the world could offer? Losing interest, the subsequent rulers of China let their great naval fleet decay and eventually burn. China gradually isolated itself from the outside world, stagnating as the world lunged forward.

  A similar attitude settled in the Ottoman Empire. Having conquered most of the world they knew, the Ottomans turned inward, into religious fundamentalism and centuries of stagnation. Mahathir Mohamad, the former prime minister of Malaysia, has said, “The great Islamic civilization went into decline when Muslim scholars interpreted knowledge acquisition, as enjoined by the Qur’an, to mean only knowledge of religion, and that other knowledge was un-Islamic. As a result, Muslims gave up the study of science, mathematics, medicine, and other so-called worldly disciplines. Instead, they spent much time debating on Islamic teachings and interpretations, on Islamic jurisprudence and Islamic practices, which led to a breakup of the Ummah and the founding of numerous sects, cults, and schools.”

  In Europe, however, a great awakening was beginning. Trade brought in fresh, revolutionary ideas, accelerated by Gutenberg’s printing press. The power of the Church began to weaken after a millennium of domination. The universities slowly turned their attention away from interpreting obscure passages of the Bible to applying the physics of Newton and the chemistry of Dalton and others. Historian Paul Kennedy of Yale adds one more factor to the meteoric rise of Europe: the constant state of war between nearly equal European powers, none of which could ever dominate the Continent. Monarchs, constantly at war with one another, funded science and engineering to further their territorial ambitions. Science was not just an academic exercise but a way to create new weapons and new avenues of wealth.

  Soon, the rise of science and technology in Europe began to weaken the power of China and the Ottoman Empire. The Muslim civilization, which had prospered for centuries as a gateway for trade between the East and the West, faltered as European sailors forged trade routes to the New World and the East—especially around Africa, bypassing the Middle East. And China found itself being carved up by European gunboats that ironically exploited two pivotal Chinese inventions, gunpowder and the compass.

  The answer to the question “What happened?” is clear. Science and technology happened. Science and technology are the engines of prosperity. Of course, one is free to ignore science and technology, but only at your peril. The world does not stand still because you are reading a religious text. If you do not master the latest in science and technology, then your competitors will.

  MASTERY OF THE FOUR FORCES

  But precisely how did Europe, the dark horse, suddenly sprint past China and the Muslim world after centuries of ignorance? There are both social and technological factors in this remarkable upset.

  When analyzing world history after 1500, one realizes that Europe was ripe for the next great advance, with the decline of feudalism, the rise of a merchant class, and the vibrant winds of the Renaissance. Physicists, however, view this great transition through the lens of the four fundamental forces that rule the universe. These are the fundamental forces that can explain everything around us, from machines, rockets, and bombs to the stars and the universe itself. Changing social trends may have set the stage for this transition, but it was the mastery of these forces in Europe that finally propelled it to the forefront of world powers.

  The first force is gravity, which holds us anchored to the ground, prevents the sun from exploding, and holds the solar system together. The second is the electromagnetic force, which lights up our cities, energizes our dynamos and engines, and powers our lasers and computers. The third and fourth forces are the weak and strong nuclear forces, which hold the nucleus of the atom together, light the stars in the heavens, and create the nuclear fire at the center of our sun. All four forces were unraveled in Europe.

  Each time one of these forces was understood by physicists, human history changed, and Europe was ideally suited to exploit that new knowledge. When Isaac Newton witnessed an apple fall and gazed at the moon, he asked himself a question that forever changed human history: If an apple falls, then does the moon also fall? In a brilliant stroke of insight when he was twenty-three years old, he realized that the forces that grab an apple are the same that reach out to the planets and comets in the heavens. This allowed him to apply the new mathematics he had just invented, the calculus, to plot the trajectory of the planets and moons, and for the first time to decode the motions of the heavens. In 1687, he published his masterpiece, Principia, arguably the most important book of science ever written, ranking among the most influential books in all human history.

  More important, Newton introduced a new way of thinking, a mechanics by which one could compute the motion of moving bodies via forces. No longer were we subject to the whims of spirits, demons, and ghosts; instead objects moved because of well-defined forces that could be measured and harnessed. This led to Newtonian mechanics, by which scientists could accurately predict the behavior of machines; this in turn paved the way for the steam engine and the locomotive. The intricate dynamics of complex steam-powered machines could be broken down systematically, bolt by bolt, lever by lever, by Newton’s laws. So Newton’s description of gravity helped to pave the way for the Industrial Revolution in Europe.

  Then in the 1800s, again in Europe, Michael Faraday, James Clerk Maxwell, and others harnessed the second great force, electromagnetism, which ushered in the next great revolution. When Thomas Edison built generators at the Pearl Street Station in Lower Manhattan and electrified the first street on earth, he opened the gateway to the electrification of the entire planet. Today, from outer space, we can view the earth at night, with entire continents set ablaze. Gazing at the earth from space, any alien would immediately realize that earthlings had mastered electromagnetism. We dearly appreciate our dependence on it any time there is a power blackout. In an instant, we are suddenly thrown over 100 years back into the past, without credit cards, computers, lights, elevators, TV, radio, the Internet, motors, etc.

  Last, the nuclear forces, also mastered by European scientists, are changing everything around us. Not only can we unlock the secrets of the heavens, revealing the power source that fires the stars, but we can also unravel inner space, using this knowledge for medicine through MRI, CAT, and PET scans; radiation therapy; and nuclear medicine. Because the nuclear forces govern the immense power stored within the atom, the nuclear forces can ultimately determine the fate of humanity, whether we will prosper by harnessing the unlimited power of fusion or die in a nuclear inferno.

  FOUR STAGES OF TECHNOLOGY

  The combination of changing social conditions and the mastery of the four forces propelled Europe to the forefront of nations. But technologies are dynamic, changing all the time. They are born, evolve, and rise and fall. To see how specific technologies will change in the near future, it is useful to see how technologies obey certain laws of evolution.

  Mass technologies usually evolve in four basic stages. This can be seen in the evolution of paper, running water, electricity, and computers. In stage I, the products of technology are so precious that they are closely guarded. Paper, when it was invented in the form of papyrus by the ancient Egyptians and then by the Chinese thousands of years ago, was so precious that one papyrus scroll was closely guarded by scores of priests. This humble technology helped to set into motion ancient civilization.

  Paper entered stage II around 1450, when Gutenberg invented printing from movable type. This made possible the “personal book,” so that one person could possess one book containing the knowledge of hundreds of scrolls. Before Gutenberg, there were only 30,000 books in all Europe. By 1500, there were 9 million books, stirring up intense intellectual ferment and stimulating the Renaissance.

  But around 1930, paper hit stage III, when the cost fell to a penny a sheet. This made possible the personal library, where one person could possess hundreds of books. Paper became an o
rdinary commodity, sold by the ton. Paper is everywhere and nowhere, invisible and ubiquitous. Now we are in stage IV, where paper is a fashion statement. We decorate our world with paper of all colors, shapes, and sizes. The largest source of urban waste is paper. So paper evolved from being a closely guarded commodity to being waste.

  The same applies to running water. In ancient times, in stage I, water was so precious that a single well had to be shared by an entire village. This lasted for thousands of years, until the early 1900s, when personal plumbing was gradually introduced and we entered stage II. After World War II, running water entered stage III and became cheap and available to an expanding middle class. Today, running water is in stage IV, a fashion statement, appearing in numerous shapes, sizes, and applications. We decorate our world with water, in the form of fountains and displays.

  Electricity also went through the same stages. With the pioneering work of Thomas Edison and others, in stage I a factory shared a single lightbulb and electric motor. After World War I, we entered stage II with the personal lightbulb and personal motor. Today, electricity has disappeared; it is everywhere and nowhere. Even the word “electricity” has pretty much disappeared from the English language. At Christmas, we use hundreds of blinking lights to decorate our homes. We assume that electricity is hidden in the walls, ubiquitous. Electricity is a fashion statement, lighting up Broadway and decorating our world.

  In stage IV, both electricity and running water have become utilities. They are so cheap, and we consume so much of them, that we meter the amount of electricity and water that runs into our home.