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[Music]

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My name is Professor Michio Kaku.

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I'm a professor of theoretical physics at the City University of New York,

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and I specialize in something called String Theory.

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I'm a physicist, and some people ask me the question:

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"What has physics done for me lately? I mean, do I get better color television?

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Do I get better internet reception with physics?"

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And the answer is: yes.

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You see, physics is at the very foundation of matter and energy.

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We physicists invented the laser beam, we invented the transistor,

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we helped to create the first computer, we helped to construct the internet,

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we wrote the World Wide Web.

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In addition, we also helped to invent television, radio, radar, microwaves,

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not to mention MRI scans, PET scans, X rays.

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In other words, almost everything you see in your living room,

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almost everything you see in a modern hospital, at some point or other, can be traced to a physicist.

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Now, I got interested in physics when I was a child.

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When I was 8, a great scientist had just died.

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I still remember my elementary school teacher coming into the room and announcing that

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the greatest scientist of our era has just passed away.

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And that day, every newspaper published a picture of his desk,

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the desk of Albert Einstein.

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And the caption said -- I'll never forget--

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"The unfinished manuscript of the greatest work of the greatest scientist of our time."

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And I said to myself: "Why couldn't he finish it? I mean, what's so hard?

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It's a homework problem, right? Why didn't he ask his mother? Why can't he finish this problem?"

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So, as a child of eight, I decided to find out what was this problem?

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Years later, I began to realize that it was the theory of everything: the Unified Field Theory.

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An equation that would summarize all the physical forces in the universe.

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An equation like e = mc^2. That equation is half an inch long,

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and that equation unlocks a secret of the stars.

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Why do the stars shine? Why does the galaxy light up?

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Why do we have energy on the earth?

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But then there was another thing that happened to me when I was around eight years old.

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I got hooked on the Saturday morning TV shows. In particular, Flash Gordon.

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And I was hooked. I mean, every Saturday morning, watching programs about aliens from outer space:

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Starships, ray guns, invisibility shields, cities in the sky--that was for me.

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But after a few years, I began to notice something.

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First of all, I began to notice that, well, I didn't have blonde hair and blue eyes,

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I didn't have muscles like Flash Gordon, but it was a scientist who made the series work.

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In particular, a physicist.

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He was the one who discovered the ray gun, the starships.

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He was the one who created the invisibility shield.

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And then I realized something else: If you want to understand the future,

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you have to understand physics.

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Physics is at the foundation of all, the gadgetry, the wizardry,

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all the marvels of the technological age, all of it can be traced

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to the work of a physicist.

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Most of science fiction is, in fact, well within the laws of physics,

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but possible within maybe a hundred years.

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Then we have impossibilities that may take a thousand years or more.

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That includes time travel, warp drive, higher dimensions,

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portals through space and time, stargates, wormholes.

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You know--if you were to meet your great grandparents of the year 1900,

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they were dirt farmers back then.

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They didn't live much beyond the age of 40, on average.

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Long distance communication in the year 1900 was yelling at your neighbor,

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and yet, if they could see you now,

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with iPads and iPods and satellites and GPS and laser beams,

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how would they view you?

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They may view you as a wizard or sorcerer.

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However, if we can now meet our grand kids of the year 2100,

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how would we view them?

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We would view them as gods like in Greek mythology.

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Zeus could control objects around him by pure thought,

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materialize objects just by thinking,

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and there are perks to being a Greek god.

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Venus had a perfect body, a timeless body,

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and we are beginning now to unravel the genetics at the molecular level of the aging process.

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And then Apollo, he had a chariot that he could ride across the heavens.

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We will finally have that flying car that we have always wanted to have in our garage by the year 2100.

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We will have the power of the gods.

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To paraphrase Arthur C. Clarke,

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"Any sufficiently advanced technology is indistinguishable from divinity."

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[Music]

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So, let's now begin our story.

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The history of physics is the history of modern civilization.

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Before Isaac Newton, before Galileo

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we were shrouded with the mysteries of superstition.

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People believed in all sorts of different kinds of spirits and demons.

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What made the planets move?

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Why do things interact with other things? It was a mystery.

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So, back in the middle ages, for example,

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people read the works of Aristotle, and Aristotle asked a question

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"Why do objects move toward the earth?"

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And that's because, he said, "Objects yearn--yearn to be united with the earth."

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And why do objects slow down when you put them in motion?

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"Objects in motion slow down because they get tired."

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These are the works of Aristotle, which held sway for almost 2,000 years until the beginning of modern with Galileo and Isaac Newton.

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[Music]

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When the ancients looked at the sky, the sky was full of mystery and wonder.

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And in the year 1066, the most important date on the British calendar,

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there was a comet--a comet would sail over the battlefield of Hastings.

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It frightened the troops of King Harold, and a young man from Normandy

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swept into England and defeated King Harold at the Battle of Hastings,

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creating the modern British monarchy.

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But the question is, where did the comet come from?

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What was this comet that mysteriously paved the way for the coming of the British monarchy?

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Well, believe it or not, that same comet--the very same comet

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that initiated the British monarchy

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sailed over London once again in 1682.

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This time, everyone was asking the question, where do comets come from?

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Do they signal the death of the king?

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Why do we have messengers from the heavens in the sky?

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Well, one man dared to penetrate the secrets of comets,

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and that was Isaac Newton.

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In fact, when Isaac Newton was only 23 years old, he stumbled upon the universal force of gravitation.

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According to one story, he was walking on his estate in Wilsthorpe and he saw an apple fall.

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And then Isaac Newton saw the moon.

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And then he asked the key question which helped to unlock the heavens:

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"If apples fall, does the moon also fall?"

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And the answer was: Yes.

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And that answer overturned thousands of years of mystery and speculation about the motions of the heavens.

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The moon is in free fall just like an apple.

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The moon is constantly falling toward the earth.

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It doesn't hit the Earth because it spins around the Earth, and the Earth is round,

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but it's acting under a force--a force of gravity.

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So, Newton immediately tried to work out the mathematics.

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And he realized that the mathematics of this 1600's was not sufficient to work out the motion

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of a falling moon.

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So, what did Isaac Newton do?

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When he was 23 years old, not only did he stumble upon the force of gravity,

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but he also created Calculus.

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In fact, he created Calculus at the rate at which you learn it when you are a freshman in college.

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And why did he create Calculus?

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To calculate the motion of a falling moon.

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The mathematics of this age was incapable of calculating

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the trajectories of objects moving under an inverse square force field.

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And that's what Isaac Newton did; he worked out the motion of the moon,

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and then he realized that if he understands the moon,

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he also understands the motion of the planets in the solar system.

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And Isaac Newton invented a new telescope.

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It was the reflecting telescope, and he was tracking the motion of this comet.

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Well, it turns out that everyone was talking about the comet, including a rather wealthy Englishman by the name of Edmund Halley.

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So, Edmund Halley, being a wealthy merchant, decided to make a trip to Cambridge

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to talk to England's illustrious scientist, Sir Isaac Newton.

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Well, Edmund Halley asked Newton, "What do you make of this comet?"

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"No one understands comets, they're a mystery."

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"They've been fascinating people for centuries, for millennia--what are your thoughts?"

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And then, I paraphrase, but Isaac Newton said something like this.

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He said, "Oh, that's easy. That comet is moving at a perfect ellipse. It's moving in an inverse square force field."

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"I've been tracking it every day with my reflecting telescope, and the path of that comet

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conforms to my mathematics exactly."

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And, of course, we don't know what Edmund Halley's reaction was, but I paraphrase.

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He must have said something like this, "For God's sake, man, why don't you publish the greatest work

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in all of scientific history?

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If correct, you have decoded the secret of the stars, the secret of the heavens.

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Nobody understands where comets come from!"

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And then Newton responded and said, "Oh, well, it costs too much. I mean, I'm not a wealthy man."

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"It would cost too much to summarize this calculus that I've invented and to work out all the motion of the stars."

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And then Halley must have said this, "Mister Newton, I am a wealthy man."

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"I have made my fortune in congress. I will pay for the publication of the greatest scientific work in any language."

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And it was "Principia" the principles--the mathematical principles that guide the heavens.

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Believe it or not, this is perhaps one of the most important works

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ever written by a human being in the hundred thousand years since we evolved from Africa.

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Realize that this book sets into motion a physics of the universe.

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Forces that control the motion of the planets, forces which can be calculated, forces which govern

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the motion of cannonballs, rockets, pebbles--everything that moves moves according to the Laws of Motion

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and the Calculus of Sir Isaac Newton.

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In fact, even today when we launch our space probes, we don't use Einstein's equations,

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they only apply when you get near the speed of light or near a black hole.

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We use Newton's Laws of Gravity.

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They are so precise that when we shoot a space probe right past the rings of Saturn,

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we use exactly the same equations that Isaac Newton unraveled in the 1600's.

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That's why we've been able to unravel the secrets of the solar system--

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complements of the Laws of Motion of Isaac Newton.

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So, what Newton did was not only did he set into motion the ability to calculate planets,

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he also set into motion a mechanics.

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Machines now operated upon well-defined laws.

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Newton's three laws of motion: the first law of motion says that objects in motion stay in motion forever

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unless acted upon by an outside force.

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You see that in an ice skating rink.

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You shoot a puck and it goes all the way down forever, unless acted on by an outside force.

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That's different from Aristotle's Law of Motion.

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Aristotle said, "Objects in motion eventually stop because they get tired."

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The second law of motion says, "Force is mass times acceleration."

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And that equation made possible the Industrial Revolution.

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Steam engines, locomotives, factories, machines, all of it due to the mechanics

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set into motion by Isaac Newton's second law of motion, "Force is equal to mass times acceleration."

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And then Newton had a third law of motion, "For every action there is an equal and opposite reaction."

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That's the law of rockets.

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That's why we have rockets that can sail into outer space.

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So, the lesson here is when scientists unraveled the first force of the universe, gravity,

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that set into motion the industrial revolution--a revolution which toppled the kings and queens of Europe,

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which displaced Feudalism, ushering in the Modern Age.

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All because a 23 year old gentleman looked up and asked the question, "Does the moon also fall?"

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You know--when I was a kid growing up in California, I would see pictures of the Empire State Building,

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and I said to myself, "How could they possibly build such a big building and not know that it's going to fall?"

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Why doesn't it fall? They didn't build scale models of the thing.

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You couldn't have an Empire State Building that big to test whether it's going to fall or not.

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How did they know ahead of time that that building wouldn't fall?

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And the answer is: Newton's Laws of Motion.

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In fact, today I teach Newton's Laws of Motion and you can actually calculate

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the forces on every single brick of the Empire State Building.

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Using Newton's second law of motion, "Force is mass times acceleration."

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When Newton unraveled the force of gravity, that was the first force.

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Now let's take a look at the second force--

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an even greater force, which has touched all of our lives.

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And that is the electromagnetic force.

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Ever since humans saw lightning bolts light up the sky, ever since they were terrified by the sound of thunder,

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they've been asking, "Do the gods propel lightning bolts and create thunder? Are they angry at us?" [Crashing thunder]

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Scientists began to realize that the lightning bolts and the thunder can be duplicated on the earth,

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that we can actually create mini-lightning bolts using electricity. [Buzzing]

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But it wasn't until the 1800's that finally we began to unlock the second great force which rules the universe--

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the electromagnetic force.

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Michael Faraday would give Christmas lectures in London, fascinating everyone from adults to children

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and he would demonstrate the incredible properties of electricity.

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Some people, for example, ask a simple question, "If you're in a car or an airplane and you get hit by a lightning bolt,

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why don't you all get electrocuted, why don't you all die?"

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Well, Faraday answered the question.

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He would create a cage.

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He would walk into this steel cage, electrify it, and he wouldn't get electrocuted at all.

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That's called a Faraday Cage, and every time you walk into a metal structure, you get shielded by this metal object.

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Well, what Michael Faraday did was he helped to unleash the second great revolution

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with something called Faraday's Law.

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A moving wire in a magnetic field has its electrons pushed, creating an electrical current.

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That simple idea, unleashed the electric revolution, and that's why we have hydro-electric generators,

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dams that can produce enormous amounts of power, that's why people build nuclear power plants,

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that's why we have electricity in this room right now.

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On a very small scale, you use that in your bicycle.

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When you put a bicycle amp on your bicycle, the turning of the wheel spins a magnet.

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The magnet then pushes electrons in a wire, and that's why electricity lights up in your bicycle lamp.

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So, in other words, electricity and magnetism were unified into a single force.

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We once thought that electricity and magnetism were separate.

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Now we know that they are, in fact, the same force.

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So, if a moving magnet can create an electric field,

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this means that the moving electric field can create a magnetic field.

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But if they can create each other, why can't they oscillate and create a wave

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so that moving electric fields create magnetic fields create electric fields create magnetic fields infinitum

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to create a wave?

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Well, around the time of the American Civil War, a mathematical physicist, James Clerk Maxwell,

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calculated using the work of Faraday the velocity of this wave.

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In one of the greatest breakthroughs of all time, James Clerk Maxwell calculated the velocity of this wave

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and found that it was the velocity of light.

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And then he made this incredible discovery.

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This is light.

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That's what light is.

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It doesn't by accident travel at the speed of electricity, it is light itself.

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And the equations were written down by James Clerk Maxwell.

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Unfortunately, Michael Faraday himself did not have a formal education.

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He could not put into mathematical form his own work.

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James Clerk Maxwell was a theoretical physicist, just like myself.

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He wrote down the mathematical physics of oscillating electric fields and magnetic fields,

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and they are called Maxwell's Equations.

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These equations have to be memorized by every physicist in grad school.

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You can not get your PhD without memorizing these equations.

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Every engineer who deals with radar and radio has to memorize these equations.

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And so, if you go to Berkeley, where I got my PhD, you can buy a t-shirt which says,

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"In the beginning God said the four dimensional divergence of an anti-symmetric, second rank tensor = 0, and there was light."

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Ladies and gentleman, this is the equation for light. [Music]

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The consequences of the electromagnetic revolution touched all of us.

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This is a picture of the Earth from outer space.

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Look at this picture!

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Europe electrified! You can actually see the fruits of all of our efforts to create electricity

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to energize our lives in one picture--seeing the Earth from outer space.

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So, let's now talk about how Faraday and Maxwell's work touches your life as well.

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This is the internet. The internet is a simple byproduct of the electromagnetic force,

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and you can see that where there is the internet, there is prosperity,

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there's science, there's entertainment, there's economic activity.

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Where there's no internet, there's poverty.

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And in the future, the internet will be miniaturized and will be placed in your glasses.

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Your glasses will recognize people's faces and display their biography next to the image as you talk to them,

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and then when they speak Chinese to you, your glasses will translate Chinese into English

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and print out subtitles right beneath their image.

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So, in the future, you will know exactly who you are talking to without even talking to them,

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and this means that at a cocktail party, if you're looking for a job, but you don't know who the heavy hitters are,

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in the future, you will know exactly who to suck up to.

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In the future, chips will only cost a penny, because we can manufacture tinier and tinier transistors.

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You will have Faraday's electromagnetic force inside your body.

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This is a pill. It has a chip in it.

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The chip is smaller than an aspirin pill.

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It also has a TV camera and a magnet.

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When you swallow it, the magnet guides the camera, taking pictures of your stomach, your intestines--

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because we all know what middle-aged men fear the most--colonoscopies.

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And this gives new meaning to the expression "Intel Inside." [Eerie music]

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Now, let's talk about the next great forces which rule the universe.

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We talked about gravity, which allows us to calculate the motion of the planets.

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The mechanics created by Newton helped to unleash the Industrial Revolution.

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Michael Faraday worked out the electromagnetic force, which gave us the wonders of the Electric Age.

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Now, let's talk about the Nuclear Age, the stars, and the sun. [Music]

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People have been fascinated by the sun.

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Apollo was a god that strode across the heavens in his fiery chariot--but hey--

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when you calculate how long coal or oil will burn like the sun,

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you'll realize that just in a few hundred years, the sun would burn to a crisp.

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What could possibly last for billions of years?

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There must be a new force--

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a nuclear force.

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Einstein and others helped to unravel the secret of the stars.

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The nuclear force comes in two types: weak and strong.

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The weak nuclear force governs radioactive decay.

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The strong nuclear force is one of the strongest forces in the entire universe.

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It's so strong it holds our protons together ever since genesis, the beginning of time.

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The equation which allows for the liberation of energy is Einstein's famous equation:

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E=mc^2

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What Einstein showed was that the faster you move the heavier you get.

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So, your weight is not a constant.

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When you move very rapidly you get heavier--something which we measure every day in the laboratory.

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Now, this means that the energy of motion transformed into mass--cause you get heavier.

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Now, listen carefully. The faster you move, the heavier you get,

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which means the energy of motion E turns into M, your mass, and the relationship

301
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between E and M is very simple--it takes one second to write it down on a sheet of paper--

302
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it is exactly e=mc^2.

303
00:25:02,701 --> 00:25:09,455
So, the nuclear force helped to explain the secret of the sun, but it also created a Pandora's box,

304
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because inside the nucleus of the atom are particles,

305
00:25:15,386 --> 00:25:17,948
and when you smash these particles, what do you get?

306
00:25:17,948 --> 00:25:20,934
More particles. And when you smash them, what do you get?

307
00:25:20,934 --> 00:25:29,762
More particles. In fact, we are drowning in subatomic particles--hundreds, thousands of subatomic particles

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00:25:29,762 --> 00:25:31,870
every time we smash atoms.

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00:25:31,870 --> 00:25:37,277
Now, we smash atoms using something called atom smashers, or particle accelerators.

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I built my own particle accelorater when I was in high school.

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When I was in high school, I went to my mom one day, and I said, "Mom, can I have permission to build

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a 2.3 million electron volt betatron particle accelerator in the garage?"

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And my mom said, "Sure, why not? And don't forget to take out the garbage."

314
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So, I went to Westinghouse, and as high school kid, I asked for 400 pounds of transformer steel.

315
00:26:03,795 --> 00:26:07,562
I asked for 22 miles of copper wire--cause I wanted to create

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a 6 kilowatt, 10,000 gauss magnetic field to energize my atom smasher.

317
00:26:11,870 --> 00:26:15,076
With 22 miles of copper wire, how can you wind it?

318
00:26:15,076 --> 00:26:17,359
We did it on the high school football field.

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I put 22 miles of copper wire on the goal post, gave it to my mother, she ran to the 50 yard line,

320
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unraveling the spool of wire.

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She gave it to my father, who then ran to the goal post,

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and we wound 22 miles of copper wire on the high school football field.

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00:26:33,824 --> 00:26:37,103
Well, finally my atom smasher was ready.

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It consumed 6 kilowatts of power--that's every single ounce of power that my house could deliver.

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00:26:42,678 --> 00:26:52,379
I plugged my ears, I closed my eyes, I turned on the power, and I heard this huge crackling sound

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as 6 kilowatts of power surged through my capacitor bank.

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And then I heard a pop-pop-pop sound as I blew out every single circuit breaker in the house.

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The whole house was plunged in darkness.

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My poor mom--every time she'd come home, she would see the lights flicker and die.

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And she must have wondered, "Why couldn't I have a son who plays baseball. Why can't he learn basketball?

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And, for God's sake, why can't he find a nice Japanese girl?"

332
00:27:22,934 --> 00:27:27,873
"I mean--why does he have to build these machines in the garage?"

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Well, these machines I built in my garage are in the attention of a physicist, Edward Teller, father of the hydrogen bomb.

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And he arranged for me to get a scholarship to Harvard, and my career got a head start.

335
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He knew exactly what I was doing.

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I didn't have to explain to him that I was experimenting with antimatter.

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I was creating anti-electrons in my mom's garage and using atom smashers to, eventually, create beams of antimatter.

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Antimatter is the opposite of matter. It has the opposite charge.

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So, an electron has negative charge.

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The positron, or anti-electron, has positive charge.

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This means that you can now create anti-molecules and anti-atoms.

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Anti-hydrogen was made at CERN outside Geneva, Switzerland and also at Fermilab outside Chicago,

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where they have anti-electrons circulating around anti-protons.

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And in Brookhaven National Laboratory in Long Island just recently, they detected anti-helium.

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We have two anti-protons with two anti-neutrons to create anti-helium.

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For every piece of matter, there's a counterpart which is made out of antimatter.

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And, when the two collide, by the way, it releases the greatest energy source in the universe. [Beaming sounds]

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It is 100% conversion of matter to energy by Einstein's equations: e=mc^2. [Phasing sounds]

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Inside the nucleus of the atom, we have particles upon particles when you smash them apart.

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In the 1950's, we were drowning in subatomic particles.

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In fact, J. Robert Oppenheimer, the father of the atomic bomb once made a statement.

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He declared that "The Nobel Prize in physics should go to the physicist who does not discover a new particle this year."

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That's how many particles were being discovered. [Music]

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So, let's talk about the particle zoo.

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00:29:31,564 --> 00:29:38,912
Right now, we physicists have unlocked hundreds, thousands of subatomic particles,

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and we've been able to piece them together into a jigsaw puzzle.

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It's called the Standard Model.

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It has 36 quarks, 19 free parameters, 3 generations of quarks, no rhyme, no reason,

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but this is the most fundamental basis of reality that we physicists have been able to construct.

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Billions of dollars, 20 Nobel Prizes have gone into the creation of the Standard Model,

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and it is the ugliest theory known to science, but it works.

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There is one piece missing, and the one piece that is missing is called the higgs boson.

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00:30:18,491 --> 00:30:23,890
We expect to find it. We want to create a higher version of this theory.

364
00:30:23,890 --> 00:30:28,393
And that theory, we think, is String Theory.

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00:30:29,332 --> 00:30:35,274
String theory is based on the simple idea that all the four forces of the universe--

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Gravity, the electromagnetic force, and the two nuclear forces--can be viewed as music. [Music]

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Music of tiny little rubber bands.

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So, if I had a super microscope and I could look right into the heart of an electron, what would I see?

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I would see a vibrating rubber band, and if I twang it, it turns into a neutrino.

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If I twang it again, it turns into a quark.

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I twang it again, it turns into a Yang-Mills particle.

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In fact, if I twang it enough times, I get thousands of subatomic particles

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that have been cataloged patiently by physicists.

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00:31:13,923 --> 00:31:18,107
String theory, we think, is a theory of everything.

375
00:31:18,107 --> 00:31:25,491
Now, string theory, in turn, can be summarized in an equation about an inch long--that's my equation.

376
00:31:25,491 --> 00:31:29,664
This is called String Field Theory, and how will we test it?

377
00:31:29,664 --> 00:31:38,420
We are building a machine--the biggest machine of science ever built in the history of the human race--

378
00:31:38,420 --> 00:31:41,111
outside Geneva, Switzerland.

379
00:31:41,111 --> 00:31:45,589
It is the Large Hadron Collider.

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So, the higgs boson,we think, will be created by the Large Hadron Collider.

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00:31:50,350 --> 00:31:55,956
A tube with 17 miles in circumference with two beams of protons circulating in opposite directions

382
00:31:55,956 --> 00:32:02,914
then slamming together, creating a shower of particles, and among these particles

383
00:32:02,914 --> 00:32:05,659
we hope to find the higgs boson, but not only that.

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00:32:05,659 --> 00:32:09,286
We hope to find particles even beyond the higgs boson.

385
00:32:09,286 --> 00:32:13,285
The next set of particles beyond the higgs boson are sparticles.

386
00:32:13,285 --> 00:32:17,661
The next layer of the jigsaw puzzle are called sparticles, super particles--

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00:32:17,661 --> 00:32:23,176
nothing but higher vibrations, higher musical notes of a vibrating string.

388
00:32:23,176 --> 00:32:25,077
And what else could we do?

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00:32:25,077 --> 00:32:28,140
We can also unlock the secrets of the Big Bang.

390
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You see, Einstein's equations break down at the instant of the big bang and the center of a black hole.

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The two most interesting places in the universe are beyond our reach using Einstein's equations.

392
00:32:44,347 --> 00:32:47,692
We need a higher theory, and that's where string theory comes in.

393
00:32:47,692 --> 00:32:53,675
String theory takes you before the big bang, before genesis itself.

394
00:32:53,675 --> 00:32:55,935
And what does string theory say?

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It says that there is a multiverse of universes.

396
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Where did the big bang come from?

397
00:33:04,512 --> 00:33:12,652
Well, Einstein's equations give us this compelling picture that we are like insects on a soap bubble--

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a gigantic soap bubble just expanding, and we are trapped like flies on fly paper, we can't escape the soap bubble.

399
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That's called the Big Bang Theory.

400
00:33:23,442 --> 00:33:28,375
String theory says there should be other bubbles out there.

401
00:33:28,375 --> 00:33:32,609
In a multiverse of bubbles when two universes collide,

402
00:33:32,609 --> 00:33:36,176
it can form another universe.

403
00:33:36,176 --> 00:33:43,770
When a universe splits in half, it can create two universes, and that, we think, is the big bang.

404
00:33:43,770 --> 00:33:51,559
The big bang is caused either by the collision of universes or by the fissioning of universes.

405
00:33:53,559 --> 00:34:00,315
If there are other dimensions, if there are other universes, can we go between universes?

406
00:34:00,315 --> 00:34:02,493
Well, that, of course, is very hard.

407
00:34:02,493 --> 00:34:07,843
However, Alice in Wonderland gives us a possibility that,

408
00:34:07,843 --> 00:34:12,580
maybe one day, we might create a worm hole between universes.

409
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This is a wormhole.

410
00:34:16,379 --> 00:34:21,033
Think of taking a sheet of paper and putting two dots on it.

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00:34:21,033 --> 00:34:24,971
The shortest distance between two points is a straight line,

412
00:34:24,971 --> 00:34:32,649
but if I can fold--if I can fold that sheet of paper, then perhaps I can create a shortcut,

413
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a shortcut through space and time called the wormhole.

414
00:34:36,942 --> 00:34:40,100
This is a genuine solution of Einstein's equations.

415
00:34:40,100 --> 00:34:42,527
We can actually see this in string theory.

416
00:34:42,527 --> 00:34:47,578
The question is how practical is it to go through one of these things?

417
00:34:47,578 --> 00:34:51,451
We don't know. In fact there's a debate among physicists today--

418
00:34:51,451 --> 00:34:54,497
Steven Hawking, many physicists are jumping into the game,

419
00:34:54,497 --> 00:35:01,751
trying to figure out whether it's physically possible to go all the way through a wormhole.

420
00:35:04,087 --> 00:35:09,030
Because if you could, then you might be able to use this as a time machine.

421
00:35:09,030 --> 00:35:14,014
Since string theory is the theory of everything, it's also a theory of time,

422
00:35:14,014 --> 00:35:17,506
and time machines are allowed in Einstein's equations,

423
00:35:17,506 --> 00:35:22,415
but to build one is extremely difficult.

424
00:35:22,415 --> 00:35:27,745
Far more energy is required than a simple Delorean with plutonium.

425
00:35:31,803 --> 00:35:36,171
You know--trillions of years from now, the universe is going to get awfully cold.

426
00:35:36,171 --> 00:35:38,942
We think the universe is headed for a big freeze.

427
00:35:38,942 --> 00:35:43,190
All the stars will blink out. Stars will cease to twinkle.

428
00:35:43,190 --> 00:35:47,294
The universe will be so big, it'll be very cold.

429
00:35:47,294 --> 00:35:53,125
At that point, all intelligent life in the universe must die.

430
00:35:53,125 --> 00:35:59,171
The laws of physics are a death warrant to all intelligent life.

431
00:35:59,171 --> 00:36:02,829
There's only one way to escape the death of the universe,

432
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and that is: leave the universe.

433
00:36:06,695 --> 00:36:11,902
Well, you're now, of course, entering the realm of science fiction, but at least we now have equations--

434
00:36:11,902 --> 00:36:18,871
the equations of string theory, which will allow us to calculate if it is possible to go through a wormhole

435
00:36:18,871 --> 00:36:24,554
to go to another universe where it's warmer, and perhaps we can start all over again.

436
00:36:28,311 --> 00:36:33,916
If you were to summarize the march of physics over the last ten thousand years,

437
00:36:33,916 --> 00:36:40,424
it would be the distillation of the laws of nature into four fundamental forces:

438
00:36:40,424 --> 00:36:44,533
Gravity, electricity and magnetism, and the two nuclear forces.

439
00:36:44,933 --> 00:36:47,646
But then the question is, is there a fifth force--

440
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a force beyond the forces that we can measure in the laboratory?

441
00:36:51,803 --> 00:36:57,104
And, believe it or not, there are physicists who have actually looked very carefully for a fifth force.

442
00:36:57,104 --> 00:37:00,068
Some people think maybe it's a psychic phenomena.

443
00:37:00,068 --> 00:37:06,792
Maybe it's telepathy, maybe it's something called psy-power, maybe it's the power of the mind, maybe consciousness.

444
00:37:07,453 --> 00:37:13,443
Well, I'm a physicist. We believe in testing theories to make sure that they are:

445
00:37:13,443 --> 00:37:16,492
Falsifiable and reproducible.

446
00:37:16,815 --> 00:37:22,620
We want to make sure that on demand, your theory works every single time without exception.

447
00:37:22,620 --> 00:37:26,695
and if your theory fails one time, it's wrong.

448
00:37:26,695 --> 00:37:32,335
In other words, Einstein's theory has to work every single time without exception.

449
00:37:32,335 --> 00:37:37,448
One time, Einstein's theory is proven to be wrong, the whole theory is wrong.

450
00:37:37,448 --> 00:37:41,215
Well, so far we can reproduce these four physical theories,

451
00:37:41,215 --> 00:37:45,845
but a fifth theory can not be reproduced--we've looked for it.

452
00:37:45,845 --> 00:37:51,316
Some people think that maybe a fifth force may be short range, like not over the nucleus over the atom,

453
00:37:51,316 --> 00:37:53,609
but ranging over several feet.

454
00:37:53,609 --> 00:37:55,652
And we can't find any.

455
00:37:58,068 --> 00:38:02,966
We physicists in the last ten years have discovered a new energy source

456
00:38:02,966 --> 00:38:08,033
larger than the galaxy itself--dark energy.

457
00:38:08,033 --> 00:38:14,192
Realize in our universe today, 73% of our universe--the matter and energy--

458
00:38:14,192 --> 00:38:18,979
73% is in the form of dark energy--the energy of nothing.

459
00:38:18,979 --> 00:38:22,300
That's what's blowing galaxies farther and farther apart.

460
00:38:22,300 --> 00:38:25,943
That's the energy of the big bang itself.

461
00:38:25,943 --> 00:38:30,342
Kids ask the question, "If the universe banged, then what made it bang?"

462
00:38:30,342 --> 00:38:32,209
And the answer is: Dark energy.

463
00:38:32,209 --> 00:38:35,943
73% of the universe's energy is dark energy.

464
00:38:35,943 --> 00:38:40,028
23% is dark matter. Dark matter is invisible matter.

465
00:38:40,028 --> 00:38:42,728
If I held it in my hand, it would go right through my hand.

466
00:38:42,728 --> 00:38:47,924
It holds the galaxy together--23% of the universe is dark matter.

467
00:38:47,924 --> 00:38:52,228
Stars, made out of hydrogen and helium, make up 4% of the universe.

468
00:38:52,228 --> 00:39:00,923
And then what about us? We, the higher elements--we, made out of oxygen, carbon, nitrogen, tungsten, iron.

469
00:39:00,923 --> 00:39:06,945
We make up 0.03% of the universe.

470
00:39:06,945 --> 00:39:09,945
In other words, we are the exception.

471
00:39:09,945 --> 00:39:16,013
The universe is mainly made out of dark energy. The universe is mainly made out of dark matter--

472
00:39:16,013 --> 00:39:20,224
overwhelming the stars, overwhelming the galaxies, in fact.

473
00:39:20,224 --> 00:39:25,429
Now, what is dark matter, which makes up 23% of the universe.

474
00:39:25,429 --> 00:39:31,070
No one knows. String theory gives us a clue, but there is no definitive answer.

475
00:39:33,594 --> 00:39:38,789
So, in other words, for you young, aspiring physicists in the audience,

476
00:39:38,789 --> 00:39:42,653
you might be saying to yourself now, "Why should I go into physics,

477
00:39:42,653 --> 00:39:46,222
because you guys already have a candidate for the unified field theory, right?"

478
00:39:46,222 --> 00:39:52,465
Just realize that every single physics textbook is wrong.

479
00:39:52,465 --> 00:39:57,355
Every single physics textbook on the Earth says that the universe is mainly made out of atoms, right?

480
00:39:57,355 --> 00:40:00,158
There it is, the universe is mainly made out of atoms.

481
00:40:00,158 --> 00:40:01,575
Wrong!

482
00:40:01,575 --> 00:40:07,802
In the last ten years, we have come to the realization that most of the universe is dark.

483
00:40:08,187 --> 00:40:12,352
And there's a whole shelf full of Nobel Prizes for the young people

484
00:40:12,352 --> 00:40:18,315
who can figure out the secret of dark matter and dark energy.

485
00:40:20,284 --> 00:40:25,875
Let me give some advice to you if you are a young physicist, perhaps just getting out of high school.

486
00:40:25,875 --> 00:40:31,662
You have dreams of being Einstein, dreams of working on string theory, and stuff like that.

487
00:40:31,662 --> 00:40:34,192
And then you hit freshman physics.

488
00:40:34,192 --> 00:40:35,812
Let me be blunt.

489
00:40:35,812 --> 00:40:39,921
We physicists flunk most students taking elementary physics,

490
00:40:39,921 --> 00:40:43,584
and we are more or less encouraged to do so by the engineering department.

491
00:40:43,584 --> 00:40:47,969
We don't want to train engineers who make bridges that fall down.

492
00:40:47,969 --> 00:40:51,715
We don't want to create engineers that create sky scrapers that fall over.

493
00:40:51,715 --> 00:40:55,803
There's a bottom line--you have to know the laws of mechanics.

494
00:40:55,803 --> 00:41:02,336
So, before you can work with the laws of Einstein, you have to work with the laws of friction, leavers, pullies, and gears.

495
00:41:02,336 --> 00:41:06,203
As a consequence, we have a very high flunk-out rate in elementary physics.

496
00:41:06,203 --> 00:41:10,449
So, if you're a young physicist graduating from high school with stars in your eyes,

497
00:41:10,449 --> 00:41:15,034
and you encounter freshman physics for the first time, watch out.

498
00:41:15,034 --> 00:41:18,309
If you have a rough time, that's the way it is.

499
00:41:19,262 --> 00:41:26,150
I started out my life as an experimental physicist, then I went to Harvard, and then I talked to my adviser,

500
00:41:26,150 --> 00:41:29,146
one of the world's greatest experimental physicists, Professor Pound,

501
00:41:29,485 --> 00:41:32,925
and he told me that maybe it's time to give it a rest.

502
00:41:32,925 --> 00:41:37,798
He said to me, "Your skills are much better suited to what you love the most,

503
00:41:37,798 --> 00:41:42,372
which is theory, mathematics, the world of higher dimensions."

504
00:41:42,372 --> 00:41:44,791
And I realized that he was probably right.

505
00:41:44,791 --> 00:41:49,744
The thing about physics, or even science that really intrigues me the most

506
00:41:49,744 --> 00:41:58,298
is to find the most fundamental basis for everything rather than trying to massage a theory or make a theory prettier,

507
00:41:58,298 --> 00:42:03,315
why not find out why it works, what makes it tick, and that's what I do for a living.

508
00:42:03,315 --> 00:42:04,882
I'm a theoretical physicist.

509
00:42:05,143 --> 00:42:06,999
Thank you very much.

510
00:42:06,999 --> 00:42:10,244
[Music]