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  • My name is Professor Michio Kaku.  I'm a professor of theoretical physics at the City

  • University of New York and I specialize in something called string theory.  I'm a physicist.

  •   Some people ask me the question, "What has

  • physics done for me lately?  I mean, do I get better color television, do I get better

  • internet reception with physics?"  And the answer is yes.  You see, physics is at the

  • very foundation of matter and energy.  We physicists invented the laser beam, we invented

  • the transistor.  We helped to create the first computer.  We helped to construct the

  • internet.  We wrote the World Wide Web.  In addition, we also helped to invent television,

  • radio, radar, microwaves, not to mention MRI scans, PET scans, x-rays.  In other words,

  • almost everything you see in your living room, almost everything you see in a modern hospital,

  • at some point or other, can be traced to a physicist.

  • Now, I got interested in physics when I was a child.  When I was a child of eight, something

  • happened to me that changed my life and I wanted to be part of this grand search for

  • a theory of everything.  When I was eight, a great scientist had just died.  I still

  • remember my elementary school teacher coming into the room and announcing that the greatest

  • scientist of our era has just passed away.  And that day, every newspaper published

  • a picture of his desk.  The desk of Albert Einstein.  And the caption said, I'll never

  • forget, "The unfinished manuscript of the greatest work of the greatest scientist of

  • our time."  And I said to myself, "Why couldn't he finish it?  I mean, what's so hard?  It's

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

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

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

  • Theory.  

  • Unified Field Theory: A Theory of Everything  

  • An equation one inch long that would summarize all the physical forces in the universe.  An

  • equation like E=mc².  That equation is half an inch long and that equation unlocks the

  • secret of the stars.  Why do the stars shine?  Why does the galaxy light up?  Why do we

  • have energy on the earth?  All of it tied to an equation half an inch long.

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

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

  • hooked.  I mean, every Saturday morning watching programs about alien from outer space, star

  • ships, ray guns, invisibility shields, cities in the sky, that was for me.  But after a

  • few years, I began to notice something.  First of all, I began to notice that well, I didn't

  • have blond hair and blue eyes, I didn't have muscles like Flash Gordon, but it was a scientist

  • who made the series work.  In particular, a physicist.  He was the one who discovered

  • the ray gun, the star ships.  He was the one who created the city in the sky.  He

  • was the one who created the invisibility shield.  And then I realized something else.  If

  • you want to understand the future, you have to understand physics.  Physics is at the

  • foundation of all the gadgetry, the wizardry, all the marvels of the technological age,

  • all of it can be traced to the work of a physicist.  Including computers, also biotechnology.

  •  All of that can eventually traced down to physics.

  •   Physics and the Impossible

  • Most of science fiction is in fact well within the laws of physics, but possible within maybe

  • 100 years.  And then we have type two impossibilities, impossibilities that may take 1,000 years

  • or more.  That includes time travel, warp drive, higher dimensions, portals through

  • space and time, star gates, worm holes.  That's type two.  And then we have type three, and

  • those are things which simply violate all the known laws of physics, and they're very

  • few of them.

  • So in my life I've had two great passions.  First is to help complete Einstein's dream

  • of a theory of everything.  An equation one inch long that would allow us to, "Read the

  • mind of God."  

  • But the second passion of my life is to see the future.

  • You know, if you were to meet your grandparents at the year 1900, they were dirt farmers back

  • then.  They didn't live much beyond the age of 40, on average.  Long distance communication

  • in the year 1900 was yelling at your neighbor.  And yet, if they could see you now, with

  • iPads and iPods and satellites and GPS and laser beams, how would they view you?  They

  • would view you as a wizard or sorcerer.

  • However, if we can now meet our grandkids of the year 2100, how would we view them?

  •  We would view them as gods, like in Greek mythology.  Zeus could control objects around

  • him by pure thought.  Materialize objects just by thinking.  And there're perks to

  • being a Greek god, Venus had a perfect body, a timeless body.  And we are beginning now

  • to unravel the genetics at the molecular level, of the aging process.  And then Apollo, he

  • had a chariot that he could ride across the heavens.  We will finally have that flying

  • horse, I mean, that, we will have that flying car that we've always wanted to have in our

  • garage.  We will be able to create life forms that don't exist today.

  • And so in other words, if you want to see the future, you have to understand physics,

  • and you have to realize that by the year 2100, we will have the power of the gods.  

  • To paraphrase Arthur C. Clark, "Any sufficiently advanced technology is indistinguishable from

  • divinity."

  • So let's now begin our story.    

  • The History of Physics

  • The history of physics is the history of modern civilization.  Before Isaac Newton, before

  • Galileo, we were shrouded with the mysteries of superstition.  People believed in all

  • sorts of different kinds of spirits and demons.  What made the planets move?  Why do things

  • interact with other things?  It was a mystery.

  • So, back in the Middle Ages, for example, people read the works of Aristotle.  And

  • Aristotle asked the question, "Why do objects move toward the earth?  And that's because,"

  • he said, "objects yearn, yearn to be united with the earth.   And why do objects slow

  • down when you put them in motion?  Objects in motion slow down because they get tired."

  •  These are the works of Aristotle, which held sway for almost 2,000 years until the

  • beginning of modern physics with Galileo and Isaac Newton.

  • So, when the ancients looked at the sky, the sky was full of mystery and wonder, and in

  • the year 1066, the most important date on the British calendar, there was a comet, a

  • comet which sailed over the battlefield of Hastings.  It frightened the troops of King

  • Harold, and a young man from Normandy, swept into England and defeated King Harold at the

  • Battle of Hastings, creating the modern British monarchy.  In fact, British history dates

  • to 1066 with William the Conqueror.

  • But the question is, where did the comet come from?  What was this comet that mysteriously

  • paved the way for the coming of the British monarchy?

  • Well, believe it or not, that same comet, the very same comet that initiated the British

  • monarchy, sailed over London once again in 1682.  This time, everyone was asking the

  • question, "Where do comets come from?  Do they signal the death of the king?  Why do

  • we have messengers from heavens in the sky?"  Well, one man dared to penetrate the secrets

  • of comets, and that was Isaac Newton.  In fact, when Isaac Newton was only 23 years

  • old, he stumbled upon the universal force of gravitation.

  • According to one story, he was walking on his estate in Woolsthorpe, and he saw an apple

  • fall.  And then Isaac Newton saw the moon, and then he asked the key question which helped

  • to unlock the heavens.  If apples falls, does the moon also fall?  And the answer

  • was, "Yes."  And answer overturned thousands of years of mystery and speculation about

  • the motions of the heavens.  The moon is in freefall, just like an apple.  The moon

  • is constantly falling toward the earth.  It doesn't hit the earth, because it spins around

  • the earth, and the earth is round, but it's acting under a force, a force of gravity.

  • So Newton immediately tried to work out the mathematics and he realized that the mathematics

  • of the 1600's was not sufficient to work out the motion of a falling moon.  So what did

  • Isaac Newton do?  When he was 23 years old, not only did he stumble upon the force of

  • gravity, but he also created calculus.  In fact, he created at the rate at which you

  • learn it, when you are a freshman in college.  And why did he create calculus?  To calculate

  • the motion of a falling moon.  The mathematics of his age was incapable of calculating the

  • trajectories of objects moving under an inverse square force field, and that's what Isaac

  • Newton did.  He worked out the motion of the moon.  And then he realized that if he

  • understands the moon, he also understands the motion of the planets in the solar system.

  •  And Isaac Newton invented a new telescope.  It was the reflecting telescope and he was

  • tracking the motion of this comet.

  • Well, it turns out that everyone was talking about the comet, including a rather wealthy

  • Englishman by the name of Edmund Haley.  Everyone was talking about the comet, so Edmund Haley,

  • being a wealthy merchant, decided to make a trip to Cambridge to talk to England's illustrious

  • scientist, Sir Isaac Newton.  Well, Edmund Haley asked Newton, "What do you make of this

  • comet?  No one understands comets, they're a mystery.  They've been fascinating people

  • for centuries, for millennia, what are your thoughts?"  And then, I paraphrase, but Isaac

  • Newton said something like this, he said, "Oh, that's easy.  That comet is moving at

  • a perfect ellipse.  It's moving in an inverse square force field.  I've been tracking it

  • every day with my reflecting telescope and the path of that comet conforms to my mathematics

  • exactly."  And of course, we don't know what Edmund Haley's reaction was, but I paraphrase,

  • he must have said something like this, he said, "For God's sake, man, why don't you

  • publish the greatest work in all of scientific history?  If correct, you have decoded the

  • secret of the stars, the secret of the heavens.  Nobody understands where comets come from."

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

  • a wealthy man, it would cost too much to summarize this calculus that I've invented and to work

  • out all the motion of the stars."  And then Haley must have said this, he must have said,

  • "Mr. Newton, I am a wealthy man.  I have made my fortune in commerce.  I will pay

  • for the publication of the greatest scientific work in any language."  And it was Principia.

  •  The principals, the mathematical principals that guide the heavens.  

  • Believe it or not, this is perhaps one of the most important works ever written by a

  • human being in the 100,000 years since we evolved from Africa.  Realize that this book

  • sets into motion a physics of the universe.  Forces that control the motion of the planets,

  • forces which can be calculated, forces which govern the motion of cannonballs, rockets,

  • pebbles, everything that moves, moves according to the laws of motion and the calculus of

  • Sir Isaac Newton.

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

  • they only apply when you get near the speed of light or near a black hole.  We use Newton's

  • laws of gravity.  They are so precise that when we shoot a space probe right past the

  • rings of Saturn, we use exactly the same equations that Isaac Newton unraveled in the 1600's.

  •  That's why we have glorious photographs of the rings of Saturn.  That's why we have

  • fly-by's right past Neptune.  That's why we've been able to unravel the secrets of

  • the solar system, compliments of the laws of motion of Isaac Newton.

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

  • he also set into motion a mechanics.  Machines now operated upon well-defined laws.  Newton's

  • three laws of motion.  The first law of motion says that objects in motion stay in motion

  • forever, unless acted on by an outside force.  You see that in an ice skating rink.  You

  • should a puck and it goes all the way down forever, unless acted upon by an outside force.

  •  That's different from Aristotle's law of motion.  Aristotle said, "Objects in motion

  • eventually stop, because they get tired."  Newton says, "Objects in motion stay in

  • motion forever."  Sailing past Pluto, unless acted on by an outside force.

  • The second law of motion says, force is mass times acceleration.  And that equation made

  • possible the Industrial Revolution.  Steam engines, locomotives, factories, machines,

  • all of it due to the mechanics set into motion by Isaac Newton's second law of motion, force

  • is equal to mass times acceleration.

  • And then Newton had a third law of motion.  For every action, there's an equal and opposite

  • reaction, that's the law of rockets.  That's why we have rockets that can sail into outer

  • space.  In fact, Newton was the first human who could actually calculate how fast you

  • have to run to jump to the moon.  That was a number that mystified ancients.  How do

  • you get to the moon?  Can you jump to the moon?  Well, Newton could have calculated

  • that number, 25,000 miles per hour, that's the escape velocity of the earth, a number

  • which could have been calculated by Isaac Newton himself.

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

  • that set into motion the Industrial Revolution.  A revolution which toppled the kings and

  • queens of Europe, which displaced feudalism, ushering in the modern age.  All because

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

  • So, rockets, the motion of planets, and even buildings in Manhattan, all of them owe their

  • existence to Newton's laws of motion.

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

  •  And I said to myself, "How could that possibly build such a big building and not know that

  • it's going to fall?  I mean, why doesn't it fall?  They didn't build scale models

  • of the thing, you couldn't have an Empire State Building that big to test whether it's

  • going to fall or not.  How did they know ahead of time that that building wouldn't

  • fall?  And the answer is:  Newton's laws of motion.

  • In fact, today, I teach Newton's laws of motion, and you can actually calculate the forces

  • on every single brick of the empire state building.  Every screw, every bolt, you can

  • calculate precisely the tension on every single fragment of the Empire State Building, using

  • Newton's second law of motion, force is mass times acceleration.

  • That was the first force, when Newton unraveled the force of gravity, it ushered in the Industrial

  • Revolution.  Now, let's take a look at the second force, an even greater force which

  • has touched all of our lives, and that is the electromagnetic force.  

  • Ever since humans saw lightening bolts light up the sky, ever since they were terrified

  • by the sound of thunder, they've been asking, "Do the gods propel lightening bolts and create

  • thunder?  Are they angry at us?"

  • Well, as time went by, scientists began to realize that the lightening bolts and the

  • thunder can be duplicated on the earth.  That we can actually create many lightening bolts

  • using electricity.  And with magnets, we can also unleash a new kind of force, the

  • force of electricity and magnetism.

  • But it wasn't until the 1800's that finally we begin to unlock the second great force

  • which rules the universe, the electromagnetic force.

  • So this helped to usher in the age of discovery.  Realize that before the compass, if you

  • sailed the ocean blue, you would get lost.  With the compass knowing the position of

  • the stars, you can then begin to navigate over hundreds, thousands of miles in the ocean.

  •  So the discovery of compasses by the Chinese helped to usher in the Age of Discovery.

  • And when people like Michael Faraday, who did this, Michael Faraday would give Christmas

  • lectures in London, fascinating everyone from adults to children.  And he would demonstrate

  • the incredible properties of electricity.

  • Some people, for example, ask a simple question.  If you're in a car or an airplane, you get

  • hit by a lightening bolt, why don't you all get electrocuted?  Why don't you all die?

  • Well, Faraday answered the question.  He would create a cage for children.  He would

  • walk into this steel cage, electrify it, and he wouldn't get electrocuted at all.  That's

  • called a Faraday cage and every time you walk into  metal structure, you get shielded by

  • this metal object and that's called a Faraday cage.  Well, what Michael Faraday did was,

  • he helped to unleash the second great revolution with something calls Faraday's Law.  If I

  • take a wire and I move a wire in a magnetic field, the magnetic field pushes the electrons

  • in the magnet, creating an electrical current.  That simple idea unleashed the electric

  • revolution.  A moving wire in a magnetic field, has this electrons pushed, creating

  • a current, and that's why we have hydro-electric generators.  That's why we have dams that

  • can produce enormous amounts of power.  That's why people build nuclear power plants.  That's

  • why we have room(?) right now.  All of it due to the simple observation that a wire

  • moving at a magnetic field, has its electrons pushed, creating an electric current.

  • On a very small scale, you use that in your bicycle.  When you put a bicycle lamp on

  • your bicycle, the turning of the wheel spins a magnet.  The magnet then pushes electrons

  • in a wire and that's why electricity lights up in your bicycle lamp.  That's exactly

  • the same principal that lights up your house via a hydroelectric dam.  So in other words,

  • electricity and magnetism were unified into a single force.  We once thought that electricity

  • and magnetism were separate.  Now we know they are in fact the same force.

  • So if a moving magnet can create an electric field, this means that a moving electric field

  • can create a magnetic field.  But if they can create each other, why can't they oscillate

  • and create a wave?  So that moving electric fields create magnetic fields, create electric

  • fields, create magnetic fields, infinitum to create a wave?