Physics of the Impossible: A Scientific Exploration into the World of Phasers, Force Fields, Teleportation, and Time Travel

by Michio Kaku

Perpetual motion machines of the second type are more subtle. They obey the First Law of Thermodynamics—conserving energy—but violate the Second Law. In theory, a perpetual motion machine of the second type produces no waste heat, so it is 100 percent efficient. Yet the Second Law says that such a machine is impossible—that waste heat must always be produced—and hence disorder or chaos in the universe, or entropy, always increases. No matter how efficient a machine might be, it will always produce some waste heat, thereby raising the entropy of the universe.

  The fact that total entropy always increases lies at the heart of human history as well as mother nature. According to the Second Law, it is far easier to destroy than to build. Something that might take thousands of years to create, such as the great Aztec Empire in Mexico, can be destroyed in a matter of months; and this is what happened when a raggedy band of Spanish conquistadores, armed with horses and firearms, completely shattered that empire.

  Every time you look in a mirror and see a new wrinkle or a white hair you are observing the effects of the Second Law. Biologists tell us that the aging process is the gradual accumulation of genetic errors in our cells and genes, so that the cell’s ability to function slowly deteriorates. Aging, rusting, rotting, decay, disintegration, and collapse are also examples of the Second Law.

  Remarking on the profound nature of the Second Law, astronomer Arthur Eddington once said, “The law that entropy always increases holds, I think, the supreme position among the laws of Nature…if your theory is found to be against the second law of thermodynamics, I can give you no hope; there is nothing for it but to collapse in deepest humiliation.”

  Even today enterprising engineers (and clever charlatans) continue to announce the invention of perpetual motion machines. Recently I was asked by the Wall Street Journal to comment on the work of an inventor who had actually persuaded investors to sink millions of dollars into his machine. Breathless articles were published in major financial newspapers, written by journalists with no background in science, gushing about the potential of this invention to change the world (and generate fabulous, lucrative profits in the process). “Genius or crackpot?” the headlines blared.

  Investors threw enormous bundles of cash at this device, which violated the most basic laws of physics and chemistry taught in high school. (What was shocking to me was not that a person was trying to swindle the unwary—this has been true since the dawn of time. What was surprising was that it was so easy for this inventor to fool wealthy investors because of their lack of understanding of elementary physics.) I repeated to the Journal the proverb “A fool and his money are easily parted” and P. T. Barnum’s famous dictum “There’s a sucker born every minute.” Perhaps not surprisingly, the Financial Times, the Economist, and the Wall Street Journal have all run large feature articles on various inventors touting their perpetual motion machines.

  THE THREE LAWS AND SYMMETRIES

  But all this raises a deeper question: Why do the iron laws of thermodynamics hold in the first place? It is a mystery that has intrigued scientists since the laws were first proposed. If we could answer that question, perhaps we might find loopholes in the laws, and the implications would be earth-shattering.

  In graduate school I was left speechless one day when I finally learned the true origin of the conservation of energy. One of the fundamental principles of physics (discovered by mathematician Emmy Noether in 1918) is that whenever a system possesses symmetry, the result is a conservation law. If the laws of the universe remain the same over time, then the astonishing result is that the system conserves energy. (Furthermore, if the laws of physics remain the same if you move in any direction, then momentum is conserved in any direction as well. And if the laws of physics remain the same under a rotation, then angular momentum is conserved.)

  This was staggering to me. I realized that when we analyze starlight from distant galaxies that are billions of light-years away, at the very edge of the visible universe, we find that the spectrum of light is identical to spectra that we can find on Earth. In the relic light that was emitted billions of years before Earth or the sun was born, we see the same unmistakable “fingerprints” of the spectrum of hydrogen, helium, carbon, neon, and so forth, that we find on the Earth today. In other words, the basic laws of physics haven’t changed for billions of years, and they are constant out to the outer edges of the universe.

  At a minimum, I realized, Noether’s theorem means that the conservation of energy will probably last for billions of years, if not forever. As far as we know, none of the fundamental laws of physics have changed with time, and this is the reason that energy is conserved.

  The implications of Noether’s theorem on modern physics are profound. Whenever physicists create a new theory, whether it addresses the origin of the universe, the interactions of quarks and other subatomic particles, or antimatter, we first start with the symmetries that the system obeys. In fact, symmetries are now known to be the fundamental guiding principle in creating any new theory. In the past, symmetries were thought to be by-products of a theory—a cute but ultimately useless feature of a theory, pretty, but not essential. Today we realize that symmetries are the essential feature that defines any theory. In creating new theories, we physicists first start with symmetry, and then build the theory around it.

  (Sadly, Emmy Noether, like Boltzmann before her, had to fight tooth and nail for recognition. A woman mathematician, she was denied a permanent position at leading institutions because of her sex. Noether’s mentor, the great mathematician David Hilbert, was so frustrated in failing to secure a teaching appointment for Noether that he exclaimed, “What are we, a university or a bathing society?”)

  This raises a disturbing question. If energy is conserved because the laws of physics do not change with time, then could this symmetry be broken in rare, unusual circumstances? There is still the possibility that the conservation of energy might be violated on a cosmic scale, if the symmetry of our laws is broken in exotic and unexpected places.

  One way that might happen is if the laws of physics vary with time or change with distance. (In Asimov’s novel The Gods Themselves this symmetry was broken because there was a hole in space connecting our universe with a parallel universe. The laws of physics change in the vicinity of the hole in space, therefore allowing a breakdown in the laws of thermodynamics. Hence the conservation of energy could be violated if there are holes in space, that is, wormholes.)

  Another loophole that is hotly being debated today is whether energy may spring from nothing.

  ENERGY FROM THE VACUUM?

  A tantalizing question is: Is it possible to extract energy from nothing? Physicists have only recently realized that the “nothing” of the vacuum is not empty at all, but teaming with activity.

  One of the proponents of this idea was the eccentric genius of the twentieth century Nikola Tesla, a worthy rival to Thomas Edison. He was also one of the proponents of zero-point energy, that is, the idea that the vacuum may possess untold quantities of energy. If true, the vacuum would be the ultimate “free lunch,” capable of providing unlimited energy literally from thin air. The vacuum, instead of being considered empty and devoid of any matter, would be the ultimate storehouse of energy.

  Tesla was born in a small town in what is now Serbia and arrived penniless in the United States in 1884. Soon he became an assistant to Thomas Edison, but because of his brilliance, he became a rival. In a celebrated contest, which historians dubbed “The War of the Currents,” Tesla was pitted against Edison. Edison believed that he could electrify the world with his direct current (DC) motors, while Tesla was the originator of alternating current (AC) and successfully showed that his methods were far superior to Edison’s and incurred significantly less power loss over distance. Today the entire planet is electrified on the basis of the patents of Tesla, not Edison.

  Tesla’s inventions and patents number over seven hundred and contain some of the most important milestones in modern electrical history.
Historians have made a credible case that Tesla invented radio before Guglielmo Marconi (widely recognized as the inventor of radio) and was working with X-rays before their official discovery by Wilhelm Roentgen. (Both Marconi and Roentgen would later win the Nobel Prize for discoveries probably made by Tesla years earlier.)

  Tesla also believed that he could extract unlimited energy from the vacuum, a claim that unfortunately he did not prove in his notes. At first, “zero-point energy” (or the energy contained in a vacuum) seems to violate the First Law of Thermodynamics. Although zero-point energy defies the laws of Newtonian mechanics, the notion of zero-point energy has reemerged recently from a novel direction.

  When scientists analyze the data from satellites currently orbiting the Earth, such as the WMAP satellite, they have come to the astounding conclusion that fully 73 percent of the universe is made of “dark energy,” the energy of a pure vacuum. This means that the greatest reservoir of energy in the entire universe is the vacuum that separates the galaxies in the universe. (This dark energy is so colossal that it is pushing the galaxies away from each other, and may eventually rip the universe apart in a Big Freeze.)

  Dark energy is everywhere in the universe, even in your living room and inside your body. The amount of dark energy in outer space is truly astronomical, outweighing all the energy of the stars and galaxies put together. We can also calculate the amount of dark energy on the Earth, and it is quite small, too small to be used to power a perpetual motion machine. Tesla was right about dark energy but wrong about the amount of dark energy on the Earth.

  Or was he?

  One of the most embarrassing gaps in modern physics is that no one can calculate the amount of dark energy that we can measure via our satellites. If we use the latest theory of atomic physics to calculate the amount of dark energy in the universe, we arrive at a number that is wrong by a factor of 10120! That is “one” followed by 120 zeros! This is by far the largest mismatch between theory and experiment in all of physics.

  The point is that no one knows how to calculate the “energy of nothing.” This is one of the most important questions in physics (because it will eventually determine the fate of the universe), but at the present time we are clueless as to how to calculate it. No theory can explain dark energy, although experimental evidence for its existence is staring us in the face.

  So the vacuum does have energy, as Tesla suspected. But the amount of energy is probably too small to be used as a source of usable energy. There are vast amounts of dark energy between the galaxies, but the amount that can be found on the Earth is tiny. But the embarrassing thing is that no one knows how to calculate this energy, or where it came from.

  My point is that the conservation of energy arises from deep, cosmological reasons. Any violation of these laws would necessarily mean a profound shift in our understanding of the evolution of the universe. And the mystery of dark energy is forcing physicists to confront this question head-on.

  Because creating a true perpetual motion machine may require us to reevaluate the fundamental laws of physics on a cosmological scale, I would rank perpetual motion machines as a Class III impossibility; that is, either they are truly impossible, or we would need to fundamentally change our understanding of fundamental physics on a cosmological scale in order to make such a machine possible. Dark energy remains one of the great unfinished chapters in modern science.

  15: PRECOGNITION

  A paradox is truth standing on its head to attract attention.

  —NICHOLAS FALLETTA

  Is there such a thing as precognition, or seeing the future? This ancient concept is present in every religion, going back to the oracles of the Greeks and Romans and to the prophets of the Old Testament. But in such tales, the gift of prophecy can also be a curse. In Greek mythology there is the tale of Cassandra, the daughter of the King of Troy. Because of her beauty she attracted the attention of the sun god, Apollo. To win her over Apollo granted her the ability to see the future. But Cassandra spurned the advances of Apollo. In a fit of anger, Apollo twisted his gift, so that Cassandra would be able to see the future but no one would believe her. When Cassandra warned the people of Troy of their impending doom, no one listened. She foretold the treachery of the Trojan horse, the death of Agamemnon, and even her own demise, but instead of taking heed, the people of Troy thought she was mad and locked her up.

  Nostradamus, writing in the sixteenth century, and more recently Edgar Cayce have claimed that they could lift the veil of time. Although there have been many claims that their predictions have come true (for example, correctly predicting World War II, JFK’s assassination, and the fall of Communism), the obscure, allegorical way in which many of these seers recorded their verses allows for a variety of contradictory interpretations. The quatrains of Nostradamus, for example, are so general that one can read almost anything into them (and people have). One quatrain reads:

  Earth-shaking fires from the world’s center roar:

  Around “New City” is the Earth a-quiver

  Two nobles long shall wage a fruitless war

  The nymph of springs pour forth a new, red river.

  Some have claimed that this quatrain proved that Nostradamus foresaw the burning of the Twin Towers in New York on September 11,2001. Yet over the centuries scores of other interpretations have been given to this same quatrain. The images are so vague that many interpretations are possible.

  Precognition is also a favorite device of playwrights who write of the impending doom of kings and the fall of empires. In Shakespeare’s Macbeth, precognition is central to the theme of the play and to the ambitions of Macbeth, who encounters three witches who foresee his rise to become King of Scotland. With his murderous ambitions fired up by the witches’ prophesy, he begins a bloody and grisly campaign to wipe out his enemies, including killing the innocent wife and children of his rival Macduff.

  After committing a series of hideous deeds to seize the crown, Macbeth learns from the witches that he cannot be defeated in battle or “vanquish’d be until great Birnam Wood to high (Dunsinane Hills) shall come against him,” and that “none of woman born shall harm Macbeth.” Macbeth takes comfort in this prophecy, since a forest cannot move, and all men are born of women. But the Great Birnam forest does move, as the troops of Macduff camouflaging themselves beneath twigs from the Great Birnam forest, advance on Macbeth, and Macduff himself was born via cesarean.

  Although prophecies from the past have so many alternative interpretations, and hence are impossible to test, one set of prophecies is easy to analyze: predictions of the precise date of the end of the Earth—Doomsday. Ever since the last chapter of the Bible, Revelations, laid out in graphic detail the final days of the Earth, when chaos and destruction will accompany the arrival of the Antichrist and the final Second Coming of Christ, fundamentalists have tried to predict the precise date of the End of Days.

  One of the most celebrated of all Doomsday predictions was made by astrologers who predicted a great flood that would end the world on February 20, 1524, based on the conjunction of all the planets in the heavens: Mercury, Venus, Mars, Jupiter, and Saturn. Mass panic swept across Europe. In England, twenty thousand people fled their homes in desperation. A fortress stocked with food and water to last two months was built around St. Bartholomew’s Church. Across Germany and France, people furiously set out to build large arks to ride out the flood. Count Von Iggleheim even built a huge, three-story ark in preparation for this momentous event. But when the date finally arrived, there was only a slight rain. The mood of the crowd suddenly swung from fear into anger. People who had sold all their belongings and turned their lives upside down felt betrayed. Angry mobs began to run amok. The count was stoned to death, and hundreds were killed when the mob stampeded.

  Christians aren’t the only ones who feel the lure of prophecy. In 1648 Sabbatai Zevi, the son of a wealthy Jew in Smyrna, declared himself to be the Messiah and predicted that the world would end in 1666. Handsome, charis
matic, and well versed in the mystical texts of the Kabbalah, he quickly assembled a group of fiercely loyal followers, who spread the news across Europe. In the spring of 1666 Jews from as far away as France, Holland, Germany, and Hungary began to pack their bags and heed the call of their Messiah. But later that year Zevi was arrested by the grand vizier in Constantinople and thrown in prison in chains. Facing a possible death sentence, he dramatically cast off his Jewish clothes, adopted a Turkish turban, and converted to Islam. Tens of thousands of his devout followers left the cult in utter disillusionment.

  The prophecies of seers still resonate even today, influencing the lives of tens of millions of people worldwide. In the United States, William Miller declared that Doomsday would arrive on April 3, 1843. As news of his prophecy spread thoughout the United States, a spectacular meteor shower by chance lit up the night sky in 1833, one of the largest of its kind, further enhancing the influence of Miller’s prophecy.

  Tens of thousands of devout followers, called Millerites, awaited the coming of Armageddon. When 1843 came and went without the arrival of the End of Days, the Millerite movement split into several large groups. Because of the huge following amassed by the Millerites, each of these splinter groups would have a major impact on religion even today. One large piece of the Millerite movement regrouped in 1863 and changed their name to the Seventh-Day Adventist Church, which today has about 14 million baptized members. Central to their belief is the imminent Second Coming of Christ.

  Another splinter group of Millerites later drifted toward the work of Charles Taze Russell, who pushed back the date of Doomsday to 1874. When that date also passed, he revised his prediction, based on analyses of the Great Pyramids of Egypt, this time to 1914. This group would later be called Jehovah’s Witnesses, with a membership of over 6 million.