MY NEXT GUEST IS A PROFESSOR OF PHYSICS AND MATHEMATICS AT

COLUMBIA UNIVERSITY AND COFOUNDER OF THE WORLD SCIENCE

FESTIVAL.

PLEASE WELCOME PROFESSOR BRIAN GREENE.

♪ ♪ ♪ >> THANK YOU, MAN.

GOOD DRIVING.

>> Stephen: THANK YOU FOR BEING HERE, THANK YOU.

( CHEERS ) HOW DO YOU-- HOW DO YOU LIKE THE

SCIENCE MOBILE?

>> OH, MAN, WAS THAT THE THE INAUGURAL RUN OF IT.

>> Stephen: THAT WAS THE FIRST TIME WE USED THE SCIENCE MOBILE.

YOU CAN RENT THAT FOR CONVENTIONS.

TELL YOUR SCIENCE FRIENDS.

>> I WILL LET THEM ALL KNOW.

>> Stephen: IT'S AVAILABLE.

YOU ARE HERE NOT ONLY BECAUSE YOU'RE A FASCINATING GUY TO TALK

TO-- THANK YOU FOR BEING AT MY LAST SHOW AT THE OLD GIG.

>> I LOVED IT.

THANK YOU.

>> Stephen: BUT, ALSO, THIS IS THE 100th ANNIVERSARY, THIS

MONTH, OF EINSTEIN PRESENTING HIS GENERAL THEORY OF

RELATIVITY.

ALL RIGHT.

I KNOW IT'S FAMOUS.

OKAY?

( LAUGHTER ) WHY IS IT EPOCH MAKING?

WHY DID IT CHANGE EVERYTHING?

>> SO WE DID NOT UNDERSTAND HOW THE FORCE OF GRAVITY WORKED

BEFORE EINSTEIN GAVE US THE GENERAL THEORY.

>> Stephen: DID NEWTON TEACH US THAT GRAVITY COMES FROM

APPLES?

>> THAT'S WHAT YOU WOULD THINK.

( LAUGHTER ) THAT'S WHAT YOU WOULD THINK.

BUT ACTUALLY, WHAT NEWTON GAVE US IS A FORMULA THAT TELLS US

THE STRENGTH OF GRAVITY, BUT HE NEVER TOLD US HOW GRAVITY

ACTUALLY EXERTS ITS PULL.

>> Stephen: DID HE NOT CARE?

>> HE CARED.

IN FACT IN HIS OWN WRITING HE SAID THAT IT WAS A CRITICAL

QUESTION THAT NEEDED TO BE ADDRESSED BUT HE SAID, "I WILL

LEAVE IT TO THE CONSIDERATION OF THE READER."

HE COULDN'T FIGURE IT OUT.

>> Stephen: SO THEN EINSTEIN READ THAT AND SAID, "I GOT THIS

ONE.

I GOT THIS ONE."

>> THAT'S RIGHT, THAT'S EXACTLY RIGHT.

>> Stephen: STAND BACK, GUYS, ALBY IS HERE.

SO WHEN DOES SPECIAL RELATIVITY COME OUT?

>> 1905.

>> Stephen: WHAT IS WHAT YOU CALL ANAS MIRABULOUS.

>> RELATIVITY IS THE MOST FAMOUS WHERE HE REDEFINED OUR

UNDERSTANDING OF SPACE AND TIME.

>> Stephen: IS THAT E.EQUALS MC SQUARED.

>> IT WAS AN AFTERTHOUGHT OF THE SPECIAL THEORY OF RELATIVITY.

>> Stephen: BY THE WAY, E.

EQUALS MC SQUARED.

>> HE PUBLISHED SPECIAL RELATIVITY AND IN SEPTEMBER HE

HAS A LITTLE EXTRA IDEA, WHICH IS E. EQUALS MC SQUARED.

>> Stephen: SO THIS IS 10 YEARS LATER.

AND HAS HE GOT ANY HITS IN BETWEEN THOSE TWO?

>> HE PUBLISHED ENORMOUS NUMBERS OF PAPERS BUT HIS REAL FOCUS,

THE PASSION OF HIS LIFE'S WORK, WAS TO FIGURE OUT GRAVITY.

>> Stephen: AND HOW DID-- HOW DID IT COME TO HIM THAT-- HOW

THIS WORKS?

( LAUGHTER ).

>> WELL, YOU KNOW-- >> Stephen: I DON'T EVEN KNOW

HOW TO FORM THE QUESTION.

>> HE WAS DEEPLY PUZZLED.

HOW DOES THE SUN KEEP THE EARTH IN ORBIT?

WHAT IS GRAVITY.

AND HE'S THINKING ABOUT THIS, THINKING ABOUT THIS.

AND ONE DAY IN 1907, HE'S IN THE PATENT OFFICE IN SWITZERLAND

WHERE HE WORKED, AND HE HAD WHAT HE CALLED THE HAPPIEST THOUGHT

OF HIS LIFE.

>> Stephen: WOW.

>> AND THE THOUGHT -- >> IS THAT SOMETHING THAT WE CAN

SAY?

>> WE CAN TALK ABOUT IT.

I DON'T KNOW ABOUT YOUR HAPPIEST THOUGHT, BUT HIS WE WITH TALK

ABOUT.

( LAUGHTER ) ( APPLAUSE )

SO HE IMAGINES A MAN FALLING FROM THE ROOF OF A HOUSE.

( LAUGHTER ).

>> Stephen: HAPPY!

YAY!

>> AND HE REALIZES THAT THAT MAN WOULD NOT FEEL HIS OWN WEIGHT.

HE WOULD FEEL WEIGHTLESS.

>> Stephen: IN FREEFALL.

>> FREEFALL.

HE'S ON A SCALE.

AND THE SCALE'S READING WOULD FALL TO ZERO BECAUSE HE'S NO

LONGER PUSHING ON THE SCALE.

HE'S FALLING WITH IT.

>> Stephen: I UNDERSTAND THERE'S AN EXPERIMENT TO

DEMONSTRATE THAT.

>> YES, A SIMPLE DEMONSTRATION.

( APPLAUSE ).

>> Stephen: YEAH!

OKAY.

DO I HAVE TO DO ANYTHING?

>> NO, IT'S VERY SIMPLE.

ALL WE HAVE HERE IS A BOTTLE OF WATER THAT HAS HOLES IN IT,

RIGHT?

SO, OF COURSE, THE WATER IS SPRAYING OUT OF THE HOLES

BECAUSE GRAVITY IS PULLING ON THE WATER, RIGHT?

>> Stephen: RIGHT.

>> BUT IF EINSTEIN IS RIGHT, IF I DROP THIS BOTTLE, THE WATER

WILL NO LONGER FEEL GRAVITY, SO THE WATER SHOULD STOP SPRAYING

OUT.

LET'S SEE IT, THREE, TWO, ONE.

>> Stephen: WHOA!

( CHEERS AND APPLAUSE ) WOW.

OKAY.

NOW, DID EINSTEIN-- DID EINSTEIN HAVE ANY THEATERIES ABOUT WHO'S

GOING TO CLEAN THAT UP RIGHT NOW?

SO HE SAW, THAT HE THOUGHT OF THAT, AND THEN GENERAL

RELATIVITY.

>> EIGHT YEARS IN THE MIND OF ALBERT EINSTEIN.

>> Stephen: SO HE THINKS ABOUT IT FOR EIGHT YEARS.

WHAT'S NEXT?

>> THEN HE REALIZES THAT THERE'S A LINK BETWEEN GRAVITY AND

MOTION.

>> Stephen: LET'S-- WE HAVE ANOTHER EXPERIMENT.

>> HE COMES UP WITH THIS IDEA FOR HOW GRAVITY WORKS.

THIS IS MEANT TO BE THE FABRIC OF SPACE.

>> Stephen: OKAY.

IT'S BLARK IT'S BLACK.

>> IT'S BLACK, RIGHT, EXACTLY.

HE SAYS IF THERE'S NO MATTER, NO ENERGY IN SPACE AND IT'S FLAT

WHICH WOULD MEAN IF YOU ROLL SOMETHING-- SAY A PLANET IS

MOVING THROUGH SPACE, IT GOES ON A STRAIGHT LINE.

BUT NOW LET'S BRING IN THE SUN.

THIS IS THE SUN RIGHT HERE.

AND HE SAYS IN THE GENERAL THEORY OF RELATIVITY, THAT THE

SUN, MERELY BY VIRTUE OF BEING IN SPACE, WARPS THE FABRIC OF

SPACE, ACTUALLY AND TIME.

AND THAT'S VITAL.

>> Stephen: IT MAKES LIKE A >> A WELL IN A SENSE.

BECAUSE NOW IF WE TAKE THE EARTH, RIGHT, AND SET IT IN

MOTION, IT NOW GOES INTO ORBIT, BECAUSE THE FABRIC OF SPACE IS

NUDGING IT AROUND.

AND THAT IS, ACCORDING TO EINSTEIN, HOW GRAVITY WORKS.

SO IF WE GET THESE GUYS MOVING, ALL OF THESE PLANETS, OBJECTS--

I THINK I JUST THREW SOMETHING OFF THE EDGE OF THE UNIVERSE.

( LAUGHTER ) THIS ACCORDING TO EINSTEIN IS

HOW THE FORCE OF GRAVITY ACTUALLY WORKS.

WE CAN PUT SOME, LET'S SAY ASTROADSIDE, IN THERE, AND LET

THEE GUYS GO IN MOTION.

GO CRAZY.

GO CRAZY.

>> Stephen: DO I HAVE TO GO IN THE SAME DIRECTION?

>> IT'S UP TO YOU, MAN.

GO NUTS.

RIGHT OFF THE EDGE OF THE UNIVERSE AGAIN!

>> Stephen: I THINK I'VE TORN THE FABRIC OF SPACE TIME.

>> AND THEN WE HAVE SOME OF THESE GUYS OVER HERE.

>> Stephen: WOW.

AND THOSE PLANETS ARE ON FIRE?

( LAUGHTER ) >> THERE THEY ARE.

>> Stephen: I'VE GOT ONE MORE QUESTION FOR YOU.

EVERYBODY ALWAYS SAYS THIS IS-- THIS IS A BEAUTIFUL

DEMONSTRATION.

EVERYONE ALWAYS SAYS TO GUYS LIKE YOU, "CAN YOU DUMB IT DOWN

TO THE LEVEL OF, LIKE, A FIVE-YEAR-OLD?"

I WOULD LIKE YOU TO NOT DUMB IT DOWN.

I WOULD LIKE YOU TO SAY IT TO ME AS IF I WERE MY AGE, 51, BUT HAD

AN ADVANCED DEGREE IN PHYSICS AND HIGH MATHEMATICS.

GIVE IT TO ME IN LESS THAN 30 SECONDS, BUT LET ME JUST LEAN

INTO MY IGNORANCE OF WHAT YOU'RE SAYING TO ME.

>> SO ALBERT EINSTEIN SAYS THAT SPACE TIME IS A FOUR-DIMENSIONAL

HOUSES DIFFERENTIAL MANIFOLD ON WHICH A METRIC TENSOR IS IMPOSED

THAT SOLVES THE EINSTEIN FIELD EQUATIONS, AND THAT METRIC

TENSOR GIVES RISE TO GEODESICS AND OBJECTS NOT EXPERIENCE

ANYTHING OTHER FORCE MOVE ALONG THE GEODESICCS DESCRIBED BY THAT

METRIC.

( CHEERS AND APPLAUSE ) >> Stephen: THAT'S-- THAT'S--

THAT'S ( BLEEP ) RIGHT THERE!

BRIAN GREENE, EVERYBODY.

THANK YOU SO MUCH.

HAPPY BIRTHDAY, GENERAL RELATIVITY.

WE'LL BE RIGHT BACK.