[ CLOCK TICKING ]
Narrator: ON MARCH 14, 1879,
ALBERT EINSTEIN WAS BORN IN ULM, GERMANY.
AND ON MARCH 14, 2018,
STEPHEN HAWKING DIED IN CAMBRIDGE, ENGLAND.
TWO OF THE MOST RECOGNIZED SCIENTISTS IN THE WORLD,
WHO, BETWEEN THEM,
TRANSFORMED OUR UNDERSTANDING OF THE ENTIRE UNIVERSE
AND THE NATURE OF TIME.
Gates: IF ALBERT EINSTEIN HAD NOT LIVED,
IT IS HARD TO IMAGINE WHAT THE 20th CENTURY
WOULD HAVE BEEN LIKE.
[ WHISTLE BLOWS ]
Narrator: IN 1905,
ALBERT EINSTEIN HAD AN IDEA SO REVOLUTIONARY,
IT CHANGED THE COURSE OF HISTORY.
IT WAS CALLED RELATIVITY.
[ TICKING CONTINUES ]
HIS ONE GIANT LEAP OF IMAGINATION
INSPIRED STEPHEN HAWKING,
WHO WOULD DEVELOP EINSTEIN'S IDEAS
TO REVEAL THE MOST EXTRAORDINARY PHENOMENA IN THE UNIVERSE.
Hawking: BLACK HOLES ARE STRANGER THAN ANYTHING
DREAMED OF BY SCIENCE-FICTION WRITERS,
BUT THEY ARE FIRMLY MATTERS OF SCIENCE FACT.
Narrator: THIS IS THE STORY OF HOW
THESE TWO REMARKABLE SCIENTISTS
SHOWED US THAT THE UNIVERSE IS STRANGER
AND MORE WONDERFUL
THAN WE EVER IMAGINED.
-- Captions by VITAC -- www.vitac.com
CAPTIONS PAID FOR BY DISCOVERY COMMUNICATIONS
[ BELLS TOLLING ]
[ CLOCK TICKING ]
THE STORY STARTS IN THIS APARTMENT
IN BERN, SWITZERLAND.
ALBERT EINSTEIN LIVED HERE WITH HIS FIRST WIFE
AND FELLOW PHYSICIST, MILEVA,
FOR TWO YEARS WHILE HE DID HIS GREATEST WORK.
WE CAN ONLY IMAGINE THE CONVERSATIONS
THESE WALLS HAVE HEARD,
THE MOMENTS OF GENIUS THEY HAVE WITNESSED.
BUT WHEN HE ARRIVED HERE IN 1903,
THERE WAS NO SIGN AT ALL
THAT EINSTEIN WAS DESTINED FOR GREATNESS.
IN FACT, EINSTEIN'S PROGRESS HAD BEEN DISTINCTLY UNDERWHELMING.
♪
Gates: ALBERT EINSTEIN WAS A RATHER UNUSUAL CHILD.
IT WAS VERY LATE IN HIS EARLY LIFE
THAT HE BEGAN TO TALK,
AND SO HIS PARENTS, IN FACT,
WERE WORRIED ABOUT HIM FOR QUITE A WHILE.
Kaiser: SO, EINSTEIN, FROM A VERY EARLY AGE,
WAS INDEPENDENT-MINDED,
FOCUSED ON THINGS THAT CAPTURED HIS IMAGINATION,
BUT VERY QUICK TO IGNORE THINGS IN SCHOOL
THAT HE CONSIDERED LESS IMPORTANT.
HE OFTEN FOUGHT WITH HIS PROFESSORS.
HE BARELY SQUEAKED THROUGH HIS UNIVERSITY EDUCATION
AND HAD A GREAT DEAL OF DIFFICULTY
FINDING A POSITION AFTER UNIVERSITY.
♪
SO, THE ONE POSITION EINSTEIN COULD ACTUALLY ARRANGE
WAS AS AN ENTRY-LEVEL PATENT CLERK
IN THE PATENT OFFICE IN BERN, SWITZERLAND.
AND EINSTEIN ENTERED LITERALLY AT THE BOTTOM.
♪
Narrator: THIS WAS EINSTEIN'S LOT IN 1903 --
AN ACADEMIC UNDERACHIEVER IN A DEAD-END JOB.
BUT IT WAS ALSO A BLESSING IN DISGUISE.
Carroll: IT WAS A PERFECT JOB FOR HIM IN SOME WAYS,
BECAUSE HE COULD GO THROUGH THE DAY AND GET PAID
AND THEN SPEND HIS IMPORTANT TIME
DOING PHYSICS ON THE SIDE.
Greene: HE JUST WAS ABLE TO LIVE WITHIN HIS MIND,
AND THAT, FOR ALL OF HUMANITY, WAS A GREAT BOON.
♪
Narrator: ALMOST SIX DECADES LATER,
ON THE 300th ANNIVERSARY OF THE DEATH OF GALILEO,
EINSTEIN'S INTELLECTUAL HEIR WAS BORN.
UNLIKE EINSTEIN,
STEPHEN HAWKING EXCELLED ACADEMICALLY FROM A YOUNG AGE.
AND ALTHOUGH A RESPECTED SCIENTIST IN HIS OWN RIGHT,
HE FIRST HIT THE HEADLINES IN 1984
WITH THE PUBLICATION OF "A BRIEF HISTORY OF TIME,"
WHICH TRIED TO BRING THE THEORIES OF ALBERT EINSTEIN
TO A WIDER AUDIENCE.
♪
Levin: HAWKING IS SUCH A FASCINATING HUMAN BEING.
YOU CAN'T REALLY EXAGGERATE THE POWER OF THAT INTELLECT.
AND A COMPLICATED MAN, YOU KNOW, A COMPLICATED CHARACTER.
STEPHEN WAS A LOVER OF LIFE.
HE TOOK ME WITH HIM TO ANTARCTICA.
HE, OF COURSE, WENT UP IN A SUBORBITAL FLIGHT,
SO HE WAS WEIGHTLESS.
HE ENJOYED LIFE TO THE FULL.
Narrator: AS A TEENAGER,
HE WAS KNOWN TO HIS CLASSMATES AS "EINSTEIN."
AND IN COLLEGE, HE OFTEN DELIGHTED
IN DOING AS LITTLE WORK AS POSSIBLE.
Hawking: THE PHYSICS COURSE AT OXFORD AT THAT TIME
WAS RIDICULOUSLY EASY.
YOU DIDN'T NEED TO REMEMBER MANY FACTS,
JUST A FEW EQUATIONS.
♪
Narrator: BUT IN 1961, WHEN HE WAS JUST 21,
HAWKING'S HAPPY-GO-LUCKY LIFESTYLE
CAME GRINDING TO A HALT.
HE WAS DIAGNOSED WITH MOTOR NEURON DISEASE
AND GIVEN JUST TWO YEARS TO LIVE.
ITS FIRST EFFECT WAS TO DEPRESS ME.
I SEEMED TO BE GETTING WORSE FAIRLY RAPIDLY.
Narrator: BUT HAWKING WAS NOT ONE
TO LET ADVERSITY STAND IN HIS WAY.
Thorne: STEPHEN WAS THE MOST STUBBORN MAN I HAVE EVER MET.
HE JUST ABSOLUTELY REFUSED TO LET HIS PHYSICAL DISABILITY
GET IN THE WAY OF DOING ANYTHING.
Narrator: THROUGH THE POWER OF HIS MIND,
STEPHEN HAWKING JOURNEYED THROUGH THE UNIVERSE
TO THE FURTHEST CORNERS OF SPACE AND TIME.
Hawking: I CERTAINLY AM HAPPIER NOW.
BEFORE I GOT MOTOR NEURON DISEASE,
I WAS BORED WITH LIFE.
BUT THE PROSPECT OF AN EARLY DEATH
MADE ME REALIZE LIFE WAS REALLY WORTH LIVING.
Narrator: STEPHEN HAWKING AND ALBERT EINSTEIN NEVER MET,
BUT THEY WERE JOINED TOGETHER BY AN ABILITY
TO CONCEPTUALIZE THE UNIVERSE IN NEW AND RADICAL WAYS.
THIS NEW VISION OF REALITY BEGAN IN SWITZERLAND IN 1905.
[ BELL TOLLING ]
♪
Gates: 1905 -- THAT'S THE YEAR THAT WE PHYSICISTS REFER TO
AS "THE YEAR OF MIRACLES."
HE WROTE FOUR PAPERS THAT YEAR.
ANY ONE OF THEM WAS WORTHY OF A NOBEL PRIZE.
Narrator: IN MAY 1905, EINSTEIN WROTE TO A FRIEND.
Einstein: I PROMISE YOU FOUR PAPERS.
THE FIRST DEALS WITH THE RADIATION
AND ENERGY PROPERTIES OF LIGHT.
THE SECOND IS A DETERMINATION OF THE TRUE SIZE OF ATOMS.
Narrator: THE THIRD EXPLAINED THE MOTION OF PARTICLES
IN A LIQUID.
BUT IT WAS THE FOURTH PAPER,
HIS THEORY OF SPECIAL RELATIVITY,
THAT WOULD CHANGE THE WORLD.
♪
Einstein: THE FOURTH IS A MODIFICATION
OF THE THEORY OF SPACE AND TIME.
[ BELL TOLLS ]
Narrator: EINSTEIN WROTE ABOUT HOW THIS MEDIEVAL CLOCK TOWER
IN BERN INSPIRED HIM TO THINK ABOUT THE NATURE OF TIME.
[ BELL TOLLS ]
[ CLICKING ]
♪
TIME -- THE THING WE USE TO MARK THE PASSAGE OF DAYS AND YEARS,
THE ONE THING WE RELY ON TO BE CONSTANT AND UNCHANGING.
EINSTEIN WAS GOING TO SHOW
THAT WE'VE BEEN GETTING THAT ALL WRONG.
♪
HE PUBLISHED HIS PAPER ON SEPTEMBER 26, 1905.
IT WAS THE BEGINNING OF HIS RELATIVITY REVOLUTION,
AND NOTHING WOULD EVER BE THE SAME AGAIN.
Levin: THERE'S BEFORE RELATIVITY AND AFTER RELATIVITY.
ONCE YOU LEARN IT, YOUR WHOLE WORLD VIEW CHANGES.
AND THAT WAS THE IMPACT ON THE SCIENTIFIC COMMUNITY --
THAT THE WHOLE WORLD CHANGED.
Greene: THAT'S, YOU KNOW,
A SPECTACULAR MOMENT FOR THE SPECIES,
WHEN WE CAN SEE WHAT A HUMAN MIND IS CAPABLE OF
WHEN ALL OF THE PIECES COME TOGETHER IN THE RIGHT WAY.
♪
Oluseyi: MANY OF EINSTEIN'S IDEAS ARE OUT THERE.
AT BEST, THEY'RE COUNTERINTUITIVE.
♪
OTHERS ARE SIMPLY MIND-BENDING.
BUT THAT'S JUST THE REFLECTION OF A FACT
THAT EINSTEIN UNDERSTOOD VERY WELL,
WHICH IS -- WHAT IS GOING ON AT THE FUNDAMENTAL STRUCTURE
OF OUR UNIVERSE IS VERY DIFFERENT
FROM WHAT OUR EYES AND EARS ARE TELLING US.
Narrator: TO UNDERSTAND HOW EINSTEIN CHANGED
OUR CONCEPT OF TIME,
WE FIRST NEED TO UNDERSTAND SOMETHING FUNDAMENTAL
ABOUT LIGHT AND THE WAY WE SEE THE WORLD.
Oluseyi: IN THE EVERYDAY WORLD AROUND US,
EVERYTHING THAT'S NOT LIGHT
MOVES IN PRETTY MUCH THE SAME WAY.
AND I'M GONNA USE THIS TENNIS-BALL MACHINE HERE
TO SHOW YOU EXACTLY WHAT I MEAN.
♪
IF I FIRE OFF THESE BALLS FROM THE BACK
OF THIS STATIONARY PICKUP TRUCK,
THEY FLY OFF AT 25 MILES PER HOUR.
BUT HERE'S THE THING --
NO MATTER IF I'M ON THE BACK OF THIS PICKUP TRUCK
OR IF THERE IS A PERSON STANDING ON THE GROUND,
EVERYONE SEES THE SAME THING --
THE BALLS FLYING OFF INTO THE DISTANCE IN THE SAME WAY.
♪
BUT THAT CHANGES IF THE TRUCK STARTS TO MOVE.
AS WE ACCELERATE, THE MOTION OF THE TRUCK
AFFECTS THE APPARENT TRAJECTORY OF THE BALLS.
IF SOMEONE IS STANDING ON THE BACK OF THE TRUCK,
THE BALLS WOULD APPEAR TO FLY OFF WITH THE SAME SPEED
AND TAKE THE SAME PATH THROUGH THE AIR.
BUT FOR SOMEONE ON THE GROUND,
THEY SEE SOMETHING VERY DIFFERENT.
THE BALLS DON'T TRAVEL NEARLY AS FAR.
♪
AND WHEN THE SPEED OF THE TRUCK MATCHES THE SPEED OF THE BALLS,
IT DOESN'T LOOK LIKE THEY TRAVEL ANYWHERE.
FOR THE STATIONARY OBSERVER,
THE BALLS JUST DROP STRAIGHT TO THE GROUND.
AS THEY SAY, IT'S ALL RELATIVE.
Narrator: EVERYTHING IN THE UNIVERSE BEHAVES LIKE THIS --
EVERYTHING, EINSTEIN REALIZED, EXCEPT LIGHT,
WHOSE SPEED REMAINS THE SAME
NO MATTER WHERE YOU ARE OR HOW FAST YOU'RE MOVING,
A BLINDINGLY BRILLIANT INSIGHT
THAT WOULD UPEND OUR UNDERSTANDING OF THE UNIVERSE
AND THE NATURE OF TIME ITSELF.
♪
Narrator: EINSTEIN KNEW THAT IF HE COULD FIGURE OUT
THE PROPERTIES OF LIGHT,
THEN HE COULD UNDERSTAND THE WAY THE UNIVERSE REALLY WORKED.
THE FIRST PROBLEM THAT REALLY LAUNCHED EINSTEIN'S THINKING
HAD TO DO WITH LIGHT AND ITS SPEED.
THE SPEED OF LIGHT SEEMED NOT TO FOLLOW
THE TRADITIONAL BEHAVIOR OF ORDINARY SPEEDS OF BASEBALLS
OR ANY OBJECT THAT YOU TYPICALLY THROW.
AND EINSTEIN WORRIED THAT WE MAYBE DON'T REALLY UNDERSTAND
LIGHT AS CLEARLY AS WE SHOULD.
♪
Narrator: SO HE CAME UP WITH
A DECEPTIVELY SIMPLE THOUGHT EXPERIMENT.
[ TRAIN WHISTLE BLOWS ]
HE IMAGINED HIMSELF STANDING ON A TRAIN PLATFORM,
HOLDING A CLOCK THAT USES LIGHT TO TELL THE TIME.
A CLOCK TICKS AS A SINGLE PHOTON OF LIGHT
BOUNCES BACK AND FORTH BETWEEN TWO MIRRORS.
ON A NEARBY TRAIN, AN IDENTICAL CLOCK TICKS
AT AN IDENTICAL RATE.
EINSTEIN THEN IMAGINED THAT THE TRAIN STARTS TO PULL AWAY.
AND HE REALIZED THAT, AS IT DID SO,
HE WOULD SEE THE CLOCK ON THE TRAIN
START TO BEHAVE VERY DIFFERENTLY.
WHEN THE TRAIN IS MOVING,
AS WELL AS SEEING THE PHOTON BOUNCING UP AND DOWN,
HE ALSO SEES IT MOVING FORWARDS.
THE PHOTON IS TRAVELING FURTHER,
AND SINCE THE SPEED OF LIGHT IS CONSTANT,
IT MEANS THAT EACH TICK APPEARS TO TAKE LONGER.
♪
FOR EINSTEIN, THE EXPLANATION WAS SIMPLE.
TIME IS PASSING MORE SLOWLY ON THE MOVING TRAIN.
AND THE FASTER THE TRAIN GOES,
THE SLOWER TIME PASSES.
[ TRAIN WHISTLE BLOWS ]
EINSTEIN CLAIMED THAT TIME IS NOT CONSTANT.
IT IS RELATIVE.
IT CAN SPEED UP AND SLOW DOWN,
DEPENDING ON HOW YOU WERE MOVING.
IT WAS A STAGGERING CONCLUSION.
Greene: WE'RE ALL USED TO AN INTUITIVE NOTION OF TIME,
WHICH TICKS OFF THE SAME
REGARDLESS OF WHERE YOU ARE OR WHAT YOU'RE DOING,
HOW FAST YOU'RE MOVING.
THAT HAS NO IMPACT ON THE RATE
AT WHICH YOUR CLOCK TICKS FORWARD SECOND AFTER SECOND.
AND EINSTEIN SAID, "SURE, THAT'S OUR EVERYDAY EXPERIENCE OF TIME,
BUT THAT EVERYDAY EXPERIENCE IS COMPLETELY MISLEADING."
Narrator: BUT EINSTEIN'S GENIUS WENT BEYOND
SIMPLE THOUGHT EXPERIMENTS.
HE WAS ABLE TO BACK UP HIS THEORIES WITH MATH.
Dijkgraaf: IN THIS MATHEMATICAL EQUATION,
EINSTEIN WAS ABLE TO CAPTURE THE EFFECT
OF MOVING CLOCKS SLOWING DOWN.
AND THIS HAS REALLY, REALLY DRAMATIC EFFECT.
IF YOU LOOK AT THE GRAPH,
YOU SEE THAT IF THE SPEED OF THE TRAIN IS SMALL
COMPARED TO THE SPEED OF LIGHT,
THERE'S BASICALLY NO DIFFERENCE.
THE TWO TIMES ARE EQUIVALENT.
BUT IF YOU GET CLOSER AND CLOSER TO THE SPEED OF LIGHT,
YOU SEE THIS CURVE IS SHOOTING UP,
AND THE EFFECT BECOMES REALLY, REALLY DRAMATIC.
SO, AT 50%, ONE DAY ON THE TRAIN LASTS 1.15 DAYS ON THE PLATFORM,
AND 75%, IT'S ALREADY 1 1/2 DAY.
AT 99%, IT LASTS A WEEK.
AND IF YOU GET TO A SPEED OF 99 --
AND, HERE, I ADDED 12 9s
AS A PERCENTAGE OF THE SPEED OF LIGHT --
THEN ONE DAY ON THE TRAIN LASTS 20,000 YEARS ON THE PLATFORM.
Narrator: THIS TIME-DILATION EFFECT
DOESN'T JUST APPLY TO EINSTEIN'S LIGHT CLOCKS.
IT WOULD APPLY TO US, IF WE COULD TRAVEL FAST ENOUGH.
EINSTEIN EXPLAINED IT USING TWINS AS AN EXAMPLE.
HE REASONED THAT IF ONE TWIN LEFT THE EARTH
IN A SPACESHIP MOVING AT A VERY HIGH SPEED,
HE WOULD EXPERIENCE TIME MORE SLOWLY
AND WOULD AGE MUCH LESS THAN HIS TWIN
LEFT BEHIND ON EARTH.
IF YOU DO HOP IN THE SPACESHIP AND MOVE TOWARD THE NEAREST STAR
AT SOME HIGH FRACTION OF THE SPEED OF LIGHT --
99%, RIGHT? --
TO YOU, IT DOESN'T SEEM LIKE THAT LONG.
THE DOWNSIDE OF THAT IS THAT IF WE CAME BACK,
ALL OF OUR FRIENDS BACK HERE ON EARTH WOULD BE DEAD
BECAUSE MANY, MANY YEARS WOULD HAVE PASSED FOR THEM.
Narrator: IT SOUNDS LIKE A CRAZY THOUGHT EXPERIMENT,
BUT IT'S HAPPENED IN REAL LIFE.
NASA HAS IDENTICAL-TWIN ASTRONAUTS --
SCOTT AND MARK KELLY.
WHAT'S THAT? YOU WANT US TO --
WE ACTUALLY SWITCHED THE NAME TAGS.
[ LAUGHTER ] ACTUALLY...
Woman: AND ONE OF YOU SHAVED OFF THE MUSTACHE.
...HE WAS THE GUY IN SPACE.
Narrator: SCOTT, WHO WAS BORN 6 MINUTES AFTER MARK,
HAS SPENT AROUND 10 TIMES LONGER IN SPACE THAN HIS BROTHER,
ORBITING AT 17,000 MILES PER HOUR,
MEANING HE'S NOW 6 MINUTES AND 5 MILLISECONDS YOUNGER.
♪
Levin: AND, IN PRINCIPLE, TIME DILATION SHOULD HELP US
EXPLORE THE UNIVERSE.
IT WOULD ALLOW US TO TRAVEL
ARBITRARILY LARGE DISTANCES WITHOUT AGING AND DYING
BEFORE WE GOT THERE.
SO, IN PRINCIPLE, TIME DILATION IS A BENEFIT.
Narrator: IN A SINGLE MIRACLE YEAR,
THE SCIENTIFIC UPSTART IN THE PATENT OFFICE
HAD FOREVER CHANGED OUR RELATIONSHIP TO TIME.
♪
EINSTEIN TOOK AN INCREDIBLY BOLD STEP, RIGHT?
HERE'S A GUY THAT'S OUTSIDE THE TRADITIONAL ACADEMIC STRUCTURE,
WHO WRITES A PAPER --
A VERY SHORT PAPER, A VERY STRANGE PAPER,
LIKE, NO REFERENCES IN THIS PAPER --
WHICH CLAIMS THAT, FOR ALL OF HUMAN HISTORY,
WE'VE HAD THE WRONG PICTURE ABOUT WHAT TIME IS
AND HOW IT ELAPSES.
THOSE OF US WHO WIND UP AS SCIENTISTS
IN THEORETICAL PHYSICS,
WE TEND TO BE PEOPLE WHO LIKE TO SOLVE PUZZLES,
FOR EXAMPLE,
AND ALSO BRING TO BEAR THE ABILITY TO CONCENTRATE.
IN FACT, THAT'S WHAT EINSTEIN SAID
WAS HIS MOST REMARKABLE ABILITY --
THAT HE COULD CONCENTRATE ON A SINGLE QUESTION
OVER AN INCREDIBLY LONG PERIOD OF TIME.
♪
Narrator: IN 1909, EINSTEIN'S REPUTATION WAS GROWING,
AND HE WAS MADE AN ASSOCIATE PROFESSOR
AT THE UNIVERSITY OF ZURICH.
IT WAS HERE THAT HE SET TO WORK
ON THE NEXT STAGE OF HIS MISSION
TO REVOLUTIONIZE OUR UNDERSTANDING OF THE UNIVERSE.
HE WOULD DO NOTHING LESS THAN REWRITE THE LAWS OF GRAVITY.
♪
Narrator: EINSTEIN KNEW THAT SPACE AND TIME
WERE PART OF THE SAME STRUCTURE,
THAT THE WHOLE UNIVERSE WAS FILLED
WITH A FOUR-DIMENSIONAL FABRIC,
WHICH COMBINED TIME WITH THE THREE DIMENSIONS OF SPACE.
IT WAS CALLED SPACE-TIME.
AND ITS KEY FEATURE WAS THAT IT COULD BEND AND FLEX.
♪
Hawking: EINSTEIN HAD A STROKE OF GENIUS
WHEN HE SAW THAT GENERAL RELATIVITY
RELATES TO THE CURVATURE OF SPACE-TIME.
SO GENERAL RELATIVITY GIVES SPACE AND TIME A SHAPE.
Greene: EINSTEIN'S BASIC IDEA IS THAT WE NEED
TO THINK OF SPACE KIND OF LIKE A FABRIC.
AND THAT FABRIC IS NICE AND FLAT
WHEN THERE'S NO MATTER OR ENERGY,
WHICH MEANS THAT OBJECTS MOVING THROUGH SPACE
WILL MOVE IN A NICE, STRAIGHT TRAJECTORY.
NOTHING TOO COMPLICATED ABOUT THAT AT ALL.
BUT THEN THE KEY IDEA IS THAT IF WE HAVE A MASSIVE OBJECT,
LIKE THE SUN, IN SPACE,
MERELY BY VIRTUE OF BEING WITHIN THE ENVIRONMENT,
THIS MASSIVE OBJECT WILL WARP THE FABRIC.
AND THEN ANOTHER OBJECT -- THINK OF IT LIKE A PLANET --
WILL NOW GO INTO A NICE CURVED TRAJECTORY,
WILL GO INTO ORBIT...
BECAUSE IT'S ROLLING ALONG A VALLEY
IN THE CURVED ENVIRONMENT THAT THE SUN CREATES.
♪
AND THAT'S THE WAY THE FORCE OF GRAVITY WORKS --
SPACE ITSELF PUSHING PLANETS
TO GO INTO THESE NICE, CURVED TRAJECTORIES.
THIS, IN ESSENCE, IS THE ESSENTIAL IDEA
OF EINSTEIN'S GENERAL THEORY OF RELATIVITY.
♪
Narrator: IT SEEMS A SIMPLE CONCEPT,
EASY TO VISUALIZE IN TWO DIMENSIONS,
BUT SPACE ISN'T A TWO-DIMENSIONAL FABRIC.
IT'S NOT EVEN THREE-DIMENSIONAL.
IT'S A WARPED FOUR-DIMENSIONAL FABRIC
THAT CREATES COMPLEX SHAPES
THAT ARE IMPOSSIBLE FOR HUMANS TO VISUALIZE.
[ CLOCK TICKING ]
BUT EINSTEIN WAS THINKING IN FOUR DIMENSIONS --
SOMETHING THAT MAY HAVE COME
FROM HIS SLOW DEVELOPMENT AS A CHILD.
♪
Einstein: THE ORDINARY ADULT NEVER BOTHERS HIS HEAD
ABOUT THE PROBLEMS OF SPACE AND TIME.
THESE ARE THINGS HE THOUGHT OF AS A CHILD.
BUT I DEVELOPED SO SLOWLY
THAT I BEGAN TO WONDER ABOUT SPACE AND TIME
ONLY WHEN I WAS ALREADY GROWN UP.
CONSEQUENTLY, I PROBED MORE DEEPLY
THAN AN ORDINARY CHILD WOULD HAVE.
♪
Narrator: ONCE AGAIN, TO COMPLETE HIS THEORY,
EINSTEIN USED MATH.
SO, EINSTEIN IS FINALLY ABLE TO CAPTURE THE CURVATURE
OF SPACE AND TIME IN A MATHEMATICAL EQUATION,
AND IT'S QUITE A BEAUTIFUL AND ELEGANT EQUATION.
ON THE LEFT-HAND SIDE IS THE CURVATURE,
THE GEOMETRY OF SPACE-TIME.
ON THE RIGHT-HAND SIDE
IS THE DISTRIBUTION OF ENERGY AND MATTER.
BASICALLY, ON THE LEFT-HAND SIDE IS MATHEMATICS.
ON THE RIGHT-HAND SIDE IS PHYSICS.
AND IT'S QUITE REMARKABLE
THAT BOTH ARE CONNECTED IN ONE EQUATION.
AND THE WAY TO READ THIS EQUATION
IS THAT MATTER TELLS SPACE-TIME HOW TO CURVE,
AND SPACE-TIME TELLS MATTER HOW TO MOVE.
I THINK IT'S JUST ONE OF THOSE REMINDERS
ABOUT HOW REALLY ELEGANT AND SIMPLE
THE UNIVERSE IS AT ITS HEART.
Narrator: HOWEVER, WHEN EINSTEIN PUBLISHED A VITAL PAPER
ON GENERAL RELATIVITY IN 1915,
ALMOST NO ONE TOOK ANY NOTICE.
♪
BY THAT POINT, EUROPE HAD BEEN ENGULFED BY WORLD WAR
FOR MORE THAN A YEAR.
[ EXPLOSIONS ]
COMMUNICATION LINES HAD BEEN SEVERED
BETWEEN, FOR EXAMPLE, BRITAIN AND GERMANY.
TRENCH WARFARE HAD DUG IN.
THE WAR LOOKED INTERMINABLE.
SO IT WAS NOT, AT FIRST,
SEEN AS ANY PARTICULAR GREAT BREAKTHROUGH,
PARTLY BECAUSE MANY PEOPLE HAD DIFFICULTY
LEARNING THE NEWS AT ALL.
Narrator: EINSTEIN'S THEORY MIGHT HAVE BEEN LOST FOR DECADES
IF IT HAD NOT BEEN FOR THE WORK
OF ENGLISH ASTRONOMER ARTHUR EDDINGTON,
WHOSE EXPERIMENT WOULD SHAKE THE WORLD.
♪
Narrator: IN 1919,
ENGLISH ASTRONOMER ARTHUR EDDINGTON
TOOK A TELESCOPE TO THE TROPICAL ISLAND OF PRíNCIPE,
IN THE ATLANTIC OCEAN,
TO PHOTOGRAPH A SOLAR ECLIPSE.
EINSTEIN'S THEORY PREDICTED THE PASSAGE OF LIGHT
WOULD ALSO BE AFFECTED BY THE WARPING OF SPACE-TIME
AND THAT MASSIVE OBJECTS, LIKE OUR SUN,
COULD ACT LIKE A MAGNIFYING GLASS
BY BENDING LIGHT AROUND IT.
THE PHOTOS EDDINGTON TOOK OF THE ECLIPSE
SHOWED THAT STARS IN THE HYADES CLUSTER
APPEARED TO BE IN THE WRONG POSITIONS.
THE LIGHT COMING FROM THEM HAD BEEN BENT.
♪
EINSTEIN'S THEORY WAS PROVED,
AND THIS TIME, THE TIMING WAS PERFECT.
Kaiser: THE NEXT DAY, EINSTEIN IS A WORLDWIDE CELEBRITY.
THERE ARE FAMOUS FRONT-PAGE STORIES ABOUT THIS
IN THE LONDON TIMES, IN THE NEW YORK TIMES,
IN INDIA, IN JAPAN.
IT'S REALLY THAT ANNOUNCEMENT, IN NOVEMBER 1919,
THAT MAKES EINSTEIN THE CHARACTER
THAT WE'VE COME TO SEEM SO FAMILIAR TO US.
THAT'S WHY WE CAN BUY T-SHIRTS AND COFFEE MUGS
AND ALL KINDS OF SWAG WITH EINSTEIN'S FACE.
Narrator: EINSTEIN HAD BECOME THE MOST INSTANTLY RECOGNIZABLE
SCIENTIST TO HAVE EVER LIVED.
♪
WITH HIS THEORY OF A UNIVERSE
CONSTRUCTED OF WARPED SPACE-TIME,
ALBERT EINSTEIN HAD TRANSFORMED
OUR UNDERSTANDING OF THE COSMOS.
♪
[ CLOCKS TICKING ]
AND IN THE 1960s AND '70s,
A GROUP OF YOUNG SCIENTISTS, INCLUDING STEPHEN HAWKING,
STARTED USING THOSE IDEAS TO EXPLAIN
THE MOST EXTREME PHENOMENA IN THE UNIVERSE.
EINSTEIN INVENTED HIS THEORY OF GENERAL RELATIVITY
BACK IN 1915, RIGHT?
BUT IT WAS STILL KIND OF A TINY, LITTLE PART
OF THEORETICAL PHYSICS FOR A LONG TIME.
IT WASN'T UNTIL THE 1960s,
WHEN PEOPLE LIKE STEPHEN HAWKING REALLY TRAINED
THEIR MATHEMATICAL MUSCLES ON UNDERSTANDING
HOW GENERAL RELATIVITY WORKS,
THAT WE UNDERSTOOD ALL SORTS OF FEATURES
OF THE THEORY THAT EINSTEIN NEVER KNEW.
Thorne: WHEN I FIRST MET STEPHEN,
I THINK IT WAS IN JUNE OF 1965.
HE WAS IN THE MIDST OF HIS PhD WORK AT THE TIME.
HE WAS WALKING WITH A CANE.
HIS SPEECH WAS MILDLY AFFECTED BUT NOT STRONGLY AFFECTED.
HE GAVE A SEMINAR ABOUT HIS RESEARCH.
♪
HE HELD FORTH DESCRIBING HIS INSIGHTS
ABOUT THE BIRTH OF THE UNIVERSE.
♪
THERE WAS SPECULATION THAT THERE WAS A BIG BANG,
BASED ON OBSERVATIONS, BUT NO REAL PROOF.
AND STEPHEN WAS ABLE TO DO THE MATHEMATICS
TO GIVE A FIRM PROOF THAT THIS HAD TO HAVE BEEN.
♪
Narrator: THE BIG BANG THEORY HAD BEEN AROUND FOR DECADES.
SPECULATION HAD STARTED SOON AFTER EINSTEIN
HAD GIVEN HIS THEORY OF RELATIVITY TO THE WORLD.
THIS IS ONE OF THE WONDERFUL THINGS ABOUT PHYSICS
IS THAT ONCE YOU INVENT A CORRECT THEORY OF PHYSICS,
YOU DON'T OWN IT ANYMORE.
THE THEORY IS OUT THERE, RIGHT?
IT'S NOT LIKE WRITING A NOVEL,
WHERE IT'S YOUR NOVEL ONCE AND FOREVER.
ONCE EINSTEIN INVENTS HIS THEORY,
I THINK, ACTUALLY, THERE'S NO QUESTION
THAT MANY PEOPLE HAVE UNDERSTOOD AND USED EINSTEIN'S EQUATIONS
BETTER THAN HE DID.
♪
Narrator: ONCE OTHER PEOPLE STARTED EXPLORING
EINSTEIN'S THEORY,
THEY FOUND IT WAS MORE POWERFUL THAN HE HAD EVER IMAGINED.
♪
IT DIDN'T JUST TELL US ABOUT THE STRUCTURE OF THE UNIVERSE.
IT COULD TELL US ITS HISTORY, TOO.
♪
BY 1927, A CATHOLIC PRIEST AND MATHEMATICIAN, GEORGES LEMAîTRA,
HAD DECIDED TO FIGURE OUT WHAT EINSTEIN'S EQUATION SAID
ABOUT THE SHAPE OF THE ENTIRE UNIVERSE.
TO DO THAT, HE NEEDED TO KNOW
WHERE ALL THE MASS IN THE UNIVERSE WAS LOCATED.
Oluseyi: THE EASIEST WAY TO WORK WITH THE ENTIRE UNIVERSE
IS TO MAKE A BIG ASSUMPTION.
AND THAT IS THAT THE MASS OF THE UNIVERSE
IS PRETTY MUCH UNIFORMLY DISTRIBUTED.
EVERY PATCH OF THE UNIVERSE IS LIKE EVERY OTHER,
KIND OF LIKE THIS FIELD OF SAND DUNES
STRETCHING OUT BEHIND US.
ONE PATCH OF SAND IS SIMILAR TO ANY OTHER PATCH OF SAND.
AND BASED ON WHAT WE'VE OBSERVED,
THAT'S A VERY GOOD ASSUMPTION,
BECAUSE ON THE LARGER SCALES,
THE GALAXIES OF THE UNIVERSE ARE UNIFORMLY DISTRIBUTED.
♪
Narrator: BUT WHEN LEMAîTRA PUT HIS HOMOGENEOUS UNIVERSE
THROUGH EINSTEIN'S EQUATIONS,
HE MADE A VERY SURPRISING DISCOVERY.
WHATEVER VALUES HE PUT IN, THERE WERE NO STABLE SOLUTIONS.
THE UNIVERSE WAS EITHER CONTRACTING
OR, MORE LIKELY, EXPANDING.
Oluseyi: LEMAîTRA'S WORK HAD ENORMOUS IMPLICATIONS.
THE UNIVERSE IS GROWING.
BUT IF WE RUN THE CLOCK BACKWARDS,
WE SEE THAT, IN THE PAST,
THE UNIVERSE MUST HAVE BEEN SMALLER.
AND LEMAîTRA REALIZED
THAT IF YOU RUN THE CLOCK BACKWARDS FAR ENOUGH,
ALL OF THE MATTER IN THE UNIVERSE
WOULD HAVE BEEN CONCENTRATED INTO A SINGLE POINT.
LEMAîTRA CALLED THIS THE COSMIC EGG,
AND THAT REPRESENTED THE BEGINNING OF THE UNIVERSE.
TODAY, WE CALL IT THE BIG BANG.
♪
Narrator: BY FORMULATING THE BIG BANG,
LEMAîTRA, THE CATHOLIC PRIEST,
HAD GIVEN THE UNIVERSE A MOMENT OF CREATION.
LOTS OF PEOPLE HATED THIS IDEA.
ONE OF THEM WAS ALBERT EINSTEIN.
Greene: EINSTEIN, LIKE MOST EVERYBODY ELSE,
HAD HIDDEN SUPPOSITIONS
ABOUT WHAT THEY CONSIDERED TO BE NATURAL IN THE UNIVERSE,
WHAT THEY CONSIDERED TO BE SENSIBLE.
ALL OF THE WORLD'S GREATEST ASTRONOMERS
AND COSMOLOGISTS WERE ABSOLUTELY CONVINCED
THAT WE LIVED IN A STATIC UNIVERSE --
NO EXPANSION, NO CONTRACTION.
THE UNIVERSE, UNLIKE OTHER THINGS,
WOULDN'T HAVE A BEGINNING AND A MIDDLE AND AN END.
BECAUSE ONCE ONE HAS A BEGINNING, ONE MUST ASK,
"WHAT HAPPENED BEFORE THE BEGINNING?"
OR "WHAT CAUSED THINGS TO START?"
AND EINSTEIN THOUGHT, "LET'S AVOID THAT ENTIRE DISCUSSION
BY SAYING THERE WAS NO BEGINNING.
THERE ALWAYS WAS AND ALWAYS SHALL BE A UNIVERSE."
AND WHEN HIS EQUATION SEEMED TO SUGGEST THAT THE UNIVERSE,
MUCH LIKE EVERYTHING ELSE,
EVOLVES AND CHANGES AND MAY HAVE HAD A BEGINNING
AND -- WHO KNOWS? -- MAY HAVE AN END,
HE RESISTED IT.
Narrator: WITH THE FATE OF THE COSMOS AT STAKE,
THE QUESTION WAS,
WHICH UNIVERSE DID WE LIVE IN?
LEMAîTRA'S EXPANDING UNIVERSE
OR EINSTEIN'S STABLE ONE?
♪
Narrator: IN 1929,
EINSTEIN'S REJECTION OF THE BIG BANG
WENT BANG AT MOUNT WILSON, NEAR LOS ANGELES,
THEN THE LARGEST TELESCOPE IN THE WORLD.
AMERICAN ASTRONOMER EDWIN HUBBLE
HAD BEEN STUDYING DISTANT GALAXIES
AND HAD DISCOVERED THAT NEARLY ALL OF THEM
WERE MOVING AWAY FROM US.
THE FURTHER AWAY THEY WERE, THE FASTER THEY WERE RECEDING.
IT WAS COMPREHENSIVE PROOF THAT THE UNIVERSE WAS EXPANDING.
AND AT THAT MOMENT,
EINSTEIN KIND OF HITS HIMSELF IN THE HEAD
AND SAYS TO HIMSELF, LIKE,
"WHY DIDN'T I BELIEVE WHAT THE EQUATIONS
OF GENERAL RELATIVITY WERE SAYING?"
IN PRINCIPLE, HE COULD HAVE PREDICTED THIS
A DOZEN YEARS BEFORE IT ACTUALLY WAS DISCOVERED.
♪
Narrator: WHEN PRESENTED WITH THE EVIDENCE,
EINSTEIN CONCEDED HIS ERROR.
IT HAD BEEN, HE SAID, HIS GREATEST MISTAKE.
HE OFTEN SAID, "OH, DON'T WORRY ABOUT MY NAME ON WRONG PAPERS.
MY NAME IS ON PLENTY OF WRONG PAPERS."
HE WASN'T THAT SCARED OF BEING WRONG.
I THINK HE CALLED IT HIS GREATEST BLUNDER
MAYBE BECAUSE THIS RESISTANCE
WAS MORE OUT OF CHARACTER FOR HIM.
♪
Narrator: EINSTEIN'S MISTAKE BECAME EVEN CLEARER
WHEN STEPHEN HAWKING BURST ONTO THE WORLD STAGE
WITH A PAPER GIVING THEORETICAL PROOF
OF THE BIG BANG.
♪
BUT SOME OF HAWKING'S GREATEST WORK
WAS RESERVED FOR THE MOST REMARKABLE PHENOMENA
IN THE COSMOS --
BLACK HOLES.
♪
Hawking: IT IS SAID THAT FACT IS SOMETIMES STRANGER THAN FICTION.
BUT NOWHERE IS THAT MORE TRUE THAN IN THE CASE OF BLACK HOLES.
♪
THEY ARE QUITE LITERALLY HOLES IN SPACE
THAT STUFF CAN FALL INTO BUT NOT GET OUT OF.
♪
THEY ARE PLACES WHERE THE GRAVITATIONAL FIELD
IS SO STRONG THAT NOTHING, NOT EVEN LIGHT,
CAN GET AWAY.
♪
Narrator: HAWKING WASN'T THE FIRST
TO PONDER THE POSSIBILITY OF BLACK HOLES.
♪
WHILE SERVING ON THE FRONT LINE IN THE FIRST WORLD WAR IN 1916,
GERMAN ARTILLERY OFFICER KARL SCHWARZSCHILD
HAD BEEN PLAYING WITH EINSTEIN'S EQUATIONS
TO SEE HOW FAR HE COULD STRETCH SPACE-TIME.
HE DISCOVERED THAT THE DENSER MATTER BECAME,
THE MORE SPACE-TIME WARPED,
UNTIL, IF YOU TOOK A MASS THE SIZE OF OUR SUN
AND CRUSHED IT INTO A SPHERE JUST 2 MILES ACROSS,
IT WOULD CREATE A HOLE IN SPACE-TIME
THAT WAS INFINITELY DEEP.
WITHIN THAT HOLE, THE LAWS OF PHYSICS BREAK DOWN,
TIME STOPS, AND SPACE GOES ON FOREVER.
BUT IT SEEMED INCONCEIVABLE
THAT SO MUCH MATTER COULD BE SQUEEZED INTO SUCH A TINY SPACE.
Hawking: ALBERT EINSTEIN WROTE A PAPER IN 1939
CLAIMING MATTER COULD NOT BE COMPRESSED
BEYOND A CERTAIN POINT.
I THINK EINSTEIN WENT TO HIS GRAVE
THINKING THAT BLACK HOLES WERE NOT REAL.
♪
Narrator: BUT THEN, JUST BEFORE THE SECOND WORLD WAR,
SCIENTISTS FIGURED OUT WHAT HAPPENED TO STARS
AT THE END OF THEIR LIVES.
♪
Hawking: DURING MOST OF THE LIFE OF A NORMAL STAR,
OVER MANY BILLIONS OF YEARS,
IT WILL SEPARATE ITSELF AGAINST ITS OWN GRAVITY
BY THERMAL PRESSURE,
CAUSED BY NUCLEAR PROCESSES
WHICH CONVERT HYDROGEN INTO HELIUM.
EVENTUALLY, HOWEVER,
THE STAR WILL EXHAUST ITS NUCLEAR FUEL.
♪
Narrator: WHEN A STAR RUNS OUT OF FUEL,
IT CAN NO LONGER FIGHT AGAINST ITS OWN GRAVITY.
♪
GIANT-SIZED STARS WOULD COLLAPSE IN A MASSIVE EXPLOSION,
CALLED A SUPERNOVA,
LEAVING BEHIND A SUPER-DENSE REMNANT
CALLED A NEUTRON STAR.
THESE NEUTRON STARS COMPRESS ONE TO TWO TIMES
THE MASS OF OUR SUN
INTO A BALL JUST 6 MILES ACROSS.
BUT THESE WERE NOT THE MOST EXTREME OBJECTS OUT THERE,
BECAUSE THERE ARE MANY MUCH LARGER STARS
THAT WILL ALSO ONE DAY DIE.
♪
Hawking: WHAT WOULD BE THE FATE OF THOSE COUNTLESS STARS
WITH GREATER MASS THAN THE NEUTRON STAR,
WHEN THEY HAD EXHAUSTED NUCLEAR FUEL,
THEY WOULD CONSTRICT TO A SINGLE POINT OF INFINITE DENSITY,
A BLACK HOLE.
♪
Narrator: BLACK HOLES FIRED THE IMAGINATIONS OF HAWKING
AND THE NEXT GENERATION OF PHYSICISTS.
IT WAS A GOLDEN AGE, RELATIVITY, AS WE SORTED OUT,
UNDER HAWKING'S LEADERSHIP,
THE THEORY OF BLACK HOLES.
♪
Narrator: IT SOON BECAME CLEAR
THAT BLACK HOLES WERE VERY PECULIAR PLACES.
♪
WE THINK OF A BLACK HOLE AS A THING, AS AN OBJECT,
BUT, REALLY, IT'S A REGION OF SPACE-TIME.
A BLACK HOLE IS A REGION OF SPACE-TIME
WHERE GRAVITY IS SO STRONG
THAT ONCE YOU ENTER THAT REGION,
YOU JUST CANNOT EVER LEAVE IT.
Narrator: BLACK HOLES ARE THE FISSURES
IN THE FABRIC OF THE UNIVERSE.
SURROUNDED BY AN INVISIBLE BOUNDARY
CALLED THE EVENT HORIZON,
NOTHING THAT CROSSES THE HORIZON CAN GET AWAY.
Hawking: FALLING THROUGH THE EVENT HORIZON
IS A BIT LIKE GOING OVER NIAGARA FALLS IN A CANOE.
IF YOU ARE ABOVE THE FALLS,
YOU CAN GET AWAY IF YOU PADDLE FAST ENOUGH.
BUT ONCE YOU ARE OVER THE EDGE, YOU ARE LOST.
Levin: THE BLACK HOLE IS REALLY DEFINED BY THAT EVENT HORIZON.
IT SEPARATES US, FUNDAMENTALLY AND FOREVER,
FROM THE INSIDE OF THE BLACK HOLE.
YOU CAN FALL IN, BUT YOU CANNOT COME OUT.
Narrator: THE CONSEQUENCE IS --
ONCE SOMETHING HAS FALLEN INTO A BLACK HOLE,
IT APPEARS TO BE LOST FROM THE UNIVERSE FOREVER.
Hawking: FROM THE OUTSIDE,
YOU CAN'T TELL WHAT IS INSIDE A BLACK HOLE.
YOU CAN THROW TELEVISION SETS, DIAMOND RINGS,
OR YOUR WORST ENEMIES INTO A BLACK HOLE,
AND ALL THE BLACK HOLE WILL REMEMBER
IS THE TOTAL MASS AND THE STATE OF ROTATION.
BLACK HOLES ARE STRANGER
THAN ANYTHING DREAMED UP BY SCIENCE-FICTION WRITERS,
BUT THEY ARE FIRMLY MATTERS OF SCIENCE FACT.
♪
Narrator: IT WAS THESE MONSTERS THAT STEPHEN HAWKING
WAS WORKING ON IN CAMBRIDGE IN THE MID-1970s.
MOTOR NEURON DISEASE WAS TAKING ITS TOOL.
HE WAS PERMANENTLY CONFINED TO A WHEELCHAIR,
HIS SPEECH NOW SO SLURRED THAT IT COULD ONLY BE UNDERSTOOD
BY CLOSE FAMILY AND COLLEAGUES.
...AND BECOME MASTERS...
Interpreter: ON ONE VIEW, WE ARE JUST WEAK, FEEBLE CREATURES
AT THE MERCY OF THE FORCES OF NATURE.
WHEN WE DISCOVER THE LAWS WHICH GOVERN THESE FORCES,
WE RISE ABOVE THEM
AND BECOME MASTERS OF THE UNIVERSE.
Narrator: BUT BEING A MASTER OF THE UNIVERSE
CAN HAVE APOCALYPTIC CONSEQUENCES,
AS ALBERT EINSTEIN HAD LONG AGO FOUND OUT.
[ CLOCK TICKING ]
♪
Narrator: BACK IN THE 1920s,
ALBERT EINSTEIN FOUND THAT INTEREST IN HIS WORK
HAD EXTENDED BEYOND THE WORLD OF THEORETICAL PHYSICS
AND INTO THE REALM OF POPULIST POLITICS.
Kaiser: LONG BEFORE THERE WAS EVEN A FORMAL NAZI PARTY,
AS EARLY AS SPRING OF 1920,
THERE WERE RALLIES TO DENOUNCE NOT JUST ALBERT EINSTEIN,
BUT, RATHER, TO DENOUNCE GENERAL RELATIVITY.
THEY WOULD RENT OUT SPORTS ARENAS AND OPERA HOUSES
AND LARGE, LARGE STADIUMS --
THOUSANDS OF PEOPLE IN ATTENDANCE --
TO BASICALLY CHANT, "DOWN WITH WARPING SPACE-TIME."
IT WAS SEEN AS A SYMBOL OF ALL THAT HAD GONE WRONG
WITH SO-CALLED JEWISH PHYSICS.
IT BECAME CLEAR IT WAS NOT GONNA BE SAFE FOR HIM.
Narrator: AFTER THE NAZIS CAME TO POWER,
EINSTEIN FLED GERMANY IN 1933
AND SETTLED HERE, IN PRINCETON, NEW JERSEY,
WORKING AT THE INSTITUTE FOR ADVANCED STUDY.
AND, AS A LIFELONG PACIFIST,
HE WAS APPALLED AT THE PROSPECT OF ANOTHER WAR,
ESPECIALLY SINCE HE KNEW HIS OWN WORK
COULD HAVE A DEVASTATING IMPACT ON ITS OUTCOME.
EINSTEIN DID NOT WANT TO GET THAT INVOLVED IN THE WAR EFFORT.
I THINK EVERYONE WAS EXTREMELY SURPRISED
THAT THIS 1905 PAPER -- E=MC2 --
COULD HAVE AN IMPLICATION FOR KILLING PEOPLE.
SO, WE COME TO EINSTEIN'S MOST FAMOUS EQUATION --
E=MC2.
AND, LIKE MANY OF HIS EQUATIONS,
IT HAS THIS MAGICAL PROPERTY OF EQUATING TWO THINGS
THAT YOU WOULDN'T EXPECT TO BE EQUAL.
ON THE LEFT-HAND SIDE, WE FIND "E," THE ENERGY.
ON THE RIGHT-HAND SIDE, "M," THE MASS.
AND SO THIS EQUATION TELLS US THAT ENERGY AND MASS
ARE ESSENTIALLY THE SAME.
THEY'RE EQUIVALENT. THEY CAN BE EXCHANGED.
AND THE EXCHANGE RATE IS "C" SQUARED.
WELL, "C" IS THE SPEED OF LIGHT.
IT'S HUGE. SO "C" SQUARED IS A TREMENDOUSLY LARGE NUMBER.
SO, ONE WAY TO READ THE EQUATION
IS THAT A HUGE AMOUNT OF ENERGY CAN BE CONVERTED
INTO A SMALL AMOUNT OF MATTER.
BUT READING THE EQUATION FROM THE OPPOSITE END,
IT TELLS US THAT A SMALL AMOUNT OF MATTER
CAN BE CONVERTED INTO A HUGE AMOUNT OF ENERGY.
♪
Narrator: BUT THE POWER OF E=MC2 WENT FAR BEYOND THE THEORETICAL.
IN THE EARLY 1920s,
EINSTEIN'S FRIEND ARTHUR EDDINGTON
REALIZED THAT THE FAMOUS EQUATION
WAS THE SECRET TO HOW STARS, LIKE OUR SUN,
PRODUCE SUCH VAST AMOUNTS OF HEAT AND LIGHT.
Oluseyi: DEEP IN THE HEARTS OF STARS,
PRESSURES AND TEMPERATURES ARE SO HIGH
THAT HYDROGEN NUCLEI SLAM INTO EACH OTHER, FUSING,
AND EVENTUALLY CREATING HELIUM NUCLEI.
AND IN THAT PROCESS, A TINY AMOUNT OF MASS
IS CONVERTED INTO ENERGY.
ALBERT EINSTEIN REALIZED THAT, PERHAPS,
WE COULD HARNESS THAT PROCESS HERE ON EARTH
AND CREATE ENERGY OF OUR OWN...
OR CREATE A WEAPON.
♪
Narrator: WORRIED THE GERMANS HAD ALREADY STARTED
A NUCLEAR PROGRAM,
EINSTEIN AND FELLOW PHYSICIST LEO SZILARD
WROTE TO PRESIDENT ROOSEVELT,
URGING HIM TO DEVELOP A BOMB.
ROOSEVELT RESPONDED BY SETTING UP THE MANHATTAN PROJECT.
THEY ACHIEVED THEIR GOAL IN JUST THREE YEARS.
Oluseyi: THIS IS THE TRINITY MONUMENT.
ON JULY 16, 1945,
THE WORLD'S VERY FIRST NUCLEAR BOMB
WAS SET OFF RIGHT HERE IN THIS SPOT.
THE BOMB, NICKNAMED "GADGET,"
WAS WINCHED TO THE TOP OF A 100-FOOT TOWER
THAT STOOD RIGHT HERE.
THE OBSERVERS RETREATED.
AND JUST BEFORE DAWN,
THE BOMB WAS DETONATED.
♪
AT 5:29 A.M.,
THE DEVICE EXPLODED WITH AN ENERGY EQUIVALENT
TO 20 KILOTONS OF TNT.
THE ROAR OF THE SHOCK WAVE WAS FELT OVER 100 MILES AWAY.
THE SURROUNDING MOUNTAINS
WERE ILLUMINATED BRIGHTER THAN DAYTIME.
AND THE MUSHROOM CLOUD REACHED 7 1/2 MILES IN HEIGHT.
ALL THAT POWER WAS RELEASED WHEN, INSIDE THE BOMB,
JUST 0.9 GRAMS OF MATTER WERE CONVERTED INTO ENERGY.
AND THAT'S THE POWER OF E=MC2.
Narrator: JUST THREE WEEKS LATER,
ON AUGUST 6, 1945,
ANOTHER BOMB WAS DETONATED
OVER THE JAPANESE CITY OF HIROSHIMA.
AT EXACTLY 8:15 IN THE MORNING,
0.6 GRAMS OF MATTER WAS CONVERTED INTO ENERGY,
INCINERATING 70,000 PEOPLE.
♪
THE DEVASTATING POWER OF EINSTEIN'S EQUATION
HAD BEEN UNLEASHED.
NOW, IT'S ALWAYS BEEN A MIXED LEGACY
FOR THE HISTORY OF PHYSICS, RIGHT?
LIKE, WE LIKE TO THINK OF OURSELVES
AS DISCOVERING SECRETS OF THE UNIVERSE,
NOT AS BLOWING THINGS UP.
BUT THERE IS THIS NECESSARY INTERPLAY
BETWEEN THE DISCOVERIES WE MAKE
AND THE TECHNOLOGICAL CAPABILITIES
THAT WE HAVE HERE ON EARTH THAT PHYSICISTS HAVE TO ACCEPT.
AND, OF COURSE, EINSTEIN ALWAYS HAD MIXED FEELINGS
ABOUT IT LATER ON, 'CAUSE HE WAS, AT HEART, A PACIFIST.
Narrator: FOR THE REST OF HIS LIFE,
EINSTEIN CAMPAIGNED FOR NUCLEAR DISARMAMENT
AND PEACE.
♪
Narrator: OUR ABILITY TO ANNIHILATE OURSELVES
WEIGHED HEAVILY UPON STEPHEN HAWKING
TOWARD THE END OF HIS LIFE,
BUT FOR HIM, EINSTEIN'S THEORIES
ALSO POINTED A WAY TO SALVATION.
Hawking: WE SHOULD BEGIN TO MOVE INTO SPACE.
THE BIGGEST CHALLENGE OF THE HUMAN RACE
IN THE COMING CENTURY
WILL BE TO SURVIVE TO THE END OF IT.
WE ARE LIKE CHILDREN PLAYING WITH STICKS OF DYNAMITE.
SOMETHING COULD WIPE US ALL OUT.
BUT ONCE THE HUMAN RACE HAS SPREAD THROUGH THE GALAXY,
IT SHOULD BE SAFE.
Narrator: BUT TO DO THAT,
WE WOULD NEED TO DEVELOP A WAY TO TRAVEL
AT CLOSE TO THE SPEED OF LIGHT,
A THING ONCE THOUGHT IMPOSSIBLE,
BUT SOMETHING THAT HAWKING SET OUT TO MAKE A REALITY.
♪
GOOD AFTERNOON.
WE ARE HERE TODAY TO TALK ABOUT BREAKTHROUGH STARSHOT
AND OUR FUTURE IN SPACE.
Narrator: IN 2016,
ALONG WITH INTERNET BILLIONAIRE YURI MILNER,
STEPHEN HAWKING LAUNCHED A VENTURE
CALLED BREAKTHROUGH STARSHOT.
Hawking: I BELIEVE WHAT MAKES US UNIQUE
IS TRANSCENDING OUR LIMITS.
THE LIMIT THAT CONFRONTS US NOW
IS THE GREAT VOID BETWEEN US AND THE STARS.
BUT NOW WE CAN TRANSCEND IT.
TODAY, WE COMMIT TO THIS NEXT GREAT LEAP INTO THE COSMOS,
BECAUSE WE ARE HUMAN, AND OUR NATURE IS TO FLY.
Narrator: THE AIM OF BREAKTHROUGH STARSHOT
IS TO DEVELOP THE FIRST SPACECRAFT
THAT CAN TRAVEL AT A SIGNIFICANT FRACTION OF THE SPEED OF LIGHT.
♪
IN VIRGINIA, AEROSPACE ENGINEER ZAC MANCHESTER
IS TRYING TO TURN STEPHEN HAWKING'S DREAM
OF INTERSTELLAR FLIGHT INTO A REALITY.
GPS: TURN RIGHT NOW.
♪
Narrator: TODAY, HE'S DRIVING TO NASA's WALLOPS ISLAND
FLIGHT FACILITY.
AND, LIKE MANY OF US,
HE HAS GPS NAVIGATION.
SO, GPS OBVIOUSLY RELIES ON SUPER-PRECISE TIME-KEEPING
BETWEEN THE SATELLITES AND US ON THE GROUND.
AND IT'S THE ONLY SORT OF CONSUMER-FACING APPLICATION
OF GENERAL RELATIVITY I KNOW OF THAT WE ACTUALLY USE EVERY DAY.
IT TURNS OUT, BECAUSE THE SATELLITES
ARE SO HIGH ABOVE THE EARTH,
THEY'RE IN A VERY DIFFERENT PART
OF THE EARTH'S GRAVITATIONAL FIELD,
AND THAT ACTUALLY AFFECTS THE RATE
AT WHICH THEIR CLOCKS RUN.
IF WE DIDN'T CORRECT FOR GENERAL RELATIVITY,
THEIR CLOCKS WOULD ACTUALLY DRIFT SO MUCH
THAT WE'D BE OFF BY 10 KILOMETERS A DAY
IN OUR POSITIONS.
Narrator: IN THE '60s,
THE WALLOPS ISLAND FLIGHT FACILITY
WAS USED TO TEST THE CAPSULES
FOR THE FIRST MANNED SPACE FLIGHTS
THAT WOULD LEAD THE WAY TO THE MOON.
Kennedy: WE CHOOSE TO GO TO THE MOON.
[ APPLAUSE ]
WE CHOOSE TO GO TO THE MOON IN THIS DECADE
AND DO THE OTHER THINGS --
NOT BECAUSE THEY ARE EASY,
BUT BECAUSE THEY ARE HARD.
SO, THIS IS THE ANTARES ROCKET.
AND AT THE TOP, BEHIND THAT AMERICAN FLAG,
IS A VEHICLE CALLED THE CYGNUS.
AT THE BACK OF THE CYGNUS, IN KIND OF A TRUNK,
WE HAVE A SPACECRAFT THAT I BUILT.
UNFORTUNATELY, AS YOU CAN TELL, THE WEATHER'S NOT GREAT.
AND THE LAST 2 OR 3 TIMES I'VE TRIED WATCHING ROCKET LAUNCHES,
IT'S BEEN THE SAME THING.
I'VE NEVER ACTUALLY GOTTEN TO SEE
SOMETHING I'VE BUILT LAUNCHED.
♪
Narrator: ZAC'S SPACECRAFT WILL BE THE FIRST TEST
OF A COMPLETELY NEW CONCEPT IN SPACE TRAVEL
AND WILL BRING STEPHEN HAWKING'S DREAM
JUST A LITTLE CLOSER.
ON THIS MISSION, WE'RE TESTING THIS LITTLE GUY.
WE CALL THIS THE SPRITE.
IT'S CURRENTLY THE WORLD'S SMALLEST SPACECRAFT.
IT'S 3 1/2-BY-3 1/2 CENTIMETERS AND WEIGHS 4 GRAMS.
IT'S BASICALLY JUST A LITTLE CIRCUIT BOARD.
AND ON HERE, WE'VE GOT A TINY COMPUTER
WE CALL A MICROCONTROLLER,
A RADIO TRANSCEIVER,
AN ANTENNA HERE FOR THE RADIO,
AND A COUPLE OF SENSORS.
SO, THE PLAN HERE, IF THIS ROCKET FLIES,
IS TO DEPLOY 100 OF THESE IN LOW EARTH ORBIT.
THEY'RE GONNA NETWORK WITH EACH OTHER,
TALK TO EACH OTHER, AND THEN TRANSMIT
A BUNCH OF SENSOR DATA BACK DOWN TO THE GROUND.
Narrator: IF IT IS SUCCESSFUL, WITHIN A FEW YEARS,
WE COULD BE SENDING SPRITES LIKE THESE ACROSS THE UNIVERSE,
TRAVELING AT 1,000 TIMES FASTER
THAN ANYTHING WE HAVE BUILT BEFORE.
EVENTUALLY, WE'D LIKE TO BE ABLE TO SEND SPACECRAFT
OUT TO OUR NEIGHBORING SOLAR SYSTEMS -- RIGHT? --
OUT TO THE STARS.
AND THE CLOSEST STAR TO US IS CALLED PROXIMA CENTAURI.
BUT PROXIMA CENTAURI IS 4 LIGHT-YEARS AWAY FROM US,
AND WITH CONVENTIONAL ROCKETS,
IT MIGHT TAKE US 10,000 YEARS TO GET THERE.
SO WE HAVE IN MIND A DIFFERENT PLAN.
WE'RE GONNA BUILD A GIANT LASER ON THE GROUND.
THIS LASER WOULD BE A KILOMETER ACROSS
AND HAVE 100 GIGAWATTS OF POWER.
AND THEN WE'RE GONNA BUILD A REALLY, REALLY SMALL,
LIGHTWEIGHT SPACECRAFT TO RIDE ON IT.
IF WE PUSH A SPRITE WITH THIS 100-GIGAWATT LASER,
WE CAN ACCELERATE IT ABOUT AS FAST
AS A SHELL COMING OUT OF A CANNON --
60,000 G's.
AND WITHIN A FEW MINUTES,
WE COULD PUSH THIS UP TO 20% THE SPEED OF LIGHT.
♪
Narrator: AT 20% THE SPEED OF LIGHT,
THE TIME-DILATION EFFECTS DESCRIBED BY EINSTEIN
START TO COME INTO PLAY.
TIME WOULD PASS MORE SLOWLY ON THE SPACECRAFT
THAN IT DOES FOR OBSERVERS ON EARTH,
WHO WOULD BE WAITING A LONG TIME TO SEE THE RESULTS.
Manchester: KEEP IN MIND, AT 4 LIGHT-YEARS,
IT TAKES THE SIGNALS FOUR YEARS TO GET BACK TO EARTH.
SO, ALTOGETHER, THIS MISSION MIGHT TAKE 25 YEARS.
THAT'S NOT ACTUALLY THAT LONG COMPARED TO MISSIONS
WE'VE SENT TO THE OUTER SOLAR SYSTEM ALREADY.
♪
Man: THIS IS MISSION CONTROL, HOUSTON.
EVERYTHING IS SET, READY TO GO FOR AN ON-TIME LAUNCH TODAY.
Narrator: FINALLY, THE ANTARES ROCKET TOOK TO THE SKIES,
ALONG WITH ZAC'S AND HAWKING'S DREAMS.
Man: 3, 2, 1...
LAUNCH HAS BEEN INITIATED.
Man #2: AND WE HAVE LIFTOFF OF THE NG-10 MISSION,
TAKING CYGNUS TO THE ISS.
Narrator: AND WITH IT,
WE MAY HAVE TAKEN OUR FIRST GIANT LEAP
TOWARDS THE STARS,
A TRIUMPH INSPIRED BY ALBERT EINSTEIN'S
DAZZLING INSIGHTS.
BUT ONE OF EINSTEIN'S LAST GREAT PREDICTIONS
HAD DEFIED SCIENCE FOR A FULL CENTURY
THAT ONLY THE BIGGEST COLLISION IN THE UNIVERSE
COULD CONFIRM.
♪
Narrator: IN 1916,
ALBERT EINSTEIN ENVISIONED A PHENOMENON
SO DIFFICULT TO CONFIRM THAT EVEN HE DOUBTED IT.
BUT ONE MAN DID NOT.
♪
THESE ARE OFFICES AT LIGO.
WE CAN USE ANY OF THESE ROOMS, IF YOU WANT.
BUT IF YOU WANT MY OFFICE, WE'RE HEADING THERE.
[ CHUCKLES ]
IT'S FULL OF JUNK. [ LAUGHS ]
THIS IS THE OFFICE THEY GIVE EMERITUS OLD PROFESSORS.
THAT'S WHAT THEY GIVE US.
SO, A LOT OF MY PAPERS AND JUNK IS ALL AROUND.
♪
THERE'S A PICTURE OF MY MENTOR RIGHT OVER THERE.
YOU CAN SEE HIM. HIS NAME IS JERROLD ZACHARIAS.
HE'S THE FIRST GUY WHO EVER SAID TO ME THAT,
YOU KNOW, "YOU'RE NOT AS DUMB AS YOU LOOK."
THAT WAS VERY IMPORTANT.
YOU NEED SOMEBODY IN YOUR LIFE TO TELL YOU THAT.
Narrator: RAINER WEISS, RAI TO HIS FRIENDS,
IS NOW A NOBEL PRIZE-WINNING EMERITUS PROFESSOR AT M.I.T.
BUT IN 1967, HE WAS JUST A JUNIOR FACULTY MEMBER
WHO WAS FASCINATED BY A PARTICULAR PIECE
OF EINSTEIN'S THEORY --
GRAVITATIONAL WAVES.
50 YEARS EARLIER,
EINSTEIN HIMSELF HAD CALCULATED
THAT OBJECTS MOVING THROUGH THE FABRIC OF SPACE-TIME
SHOULD CAUSE IT TO RIPPLE,
LIKE WAVES ON A POND.
AT FIRST, EINSTEIN THOUGHT THAT THESE WAVES WOULD BE SO TINY,
THEY WOULD BE IMPOSSIBLE TO MEASURE.
LATER IN LIFE, HE WAS NOT SURE THEY EXISTED AT ALL.
Einstein: IF YOU ASK ME WHETHER THERE ARE GRAVITATIONAL WAVES
OR NOT,
I MUST ANSWER THAT I DON'T KNOW,
BUT IT IS A HIGHLY INTERESTING PROBLEM.
Narrator: RAI THOUGHT GRAVITATIONAL WAVES DID EXIST
AND HAS SPENT A LIFETIME TRYING TO FIND THEM.
SO HE CAME UP WITH A SYSTEM
THAT COULD POTENTIALLY DETECT
THE MOST MINISCULE WAVES IN SPACE-TIME.
IT WAS CALLED LASER INTERFEROMETRY.
Weiss: SO, HERE'S THE IDEA.
THERE'S A LASER, WHICH IS THIS CYLINDER.
THERE'S SOMETHING CALLED A BEAM SPLITTER,
WHICH DIVIDES THE LIGHT.
♪
HALF OF THE LIGHT WILL GET REFLECTED TO A MIRROR
THAT'S OVER HERE
AND THEN SENT BACK TO THIS BEAM SPLITTER.
AND THE OTHER HALF HITS THIS MIRROR
AND COMES BACK TO THE BEAM SPLITTER.
THEN TWO BEAMS WILL HEAD TOWARD A PHOTO DETECTOR,
AND YOU'LL SEE SOMETHING INTERESTING.
NO LIGHT GOES THROUGH THE PHOTO DETECTOR.
LIGHT CANCELS.
NOW WHAT HAPPENS IS --
YOU CHANGE THE LENGTH ON ONE ARM,
MAKE IT LONGER,
MAKE THE LIGHT SHORTER ON THE OTHER ARM.
YOU SEE LIGHT DOES GO TO THE PHOTO DETECTOR
WHEN THE PATHS ARE NOT EQUAL ANYMORE.
AND THAT, THE FACT THAT LIGHT GOES THROUGH
THE PHOTO DETECTOR HERE
WHEN THE PATHS ARE NO LONGER EQUAL
AND THEY HAVE BEEN DISTURBED
BY THAT GRAVITATIONAL WAVE TO DO THIS,
THAT'S THE WAY THE DETECTION IS MADE.
IT'S REALLY AS SIMPLE AS THAT.
Narrator: IF RAI'S CALCULATIONS WERE RIGHT,
HIS SYSTEM WOULD BE ABLE TO PICK UP MOVEMENTS
IN THE MIRRORS OF JUST A FEW TRILLIONTHS OF A FOOT.
I HEARD ABOUT THE IDEA. I DID SOME NUMBERS,
AND IT WAS OBVIOUS THAT RAI HAD GONE CRAZY OR SOMETHING.
I JUST COULDN'T BELIEVE THAT HE COULD REALLY --
ANYONE COULD REALLY PULL THIS OFF.
AND THEN I SPENT THE REST OF MY CAREER EATING CROW
AND TRYING TO HELP HIM PULL IT OFF.
♪
Narrator: WHEN KIP THORNE, A THEORETICAL PHYSICIST
AND CLOSE FRIEND OF STEPHEN HAWKING,
JOINED THE PROJECT,
HIS JOB WAS TO FIGURE OUT WHETHER THERE WERE ANY EVENTS
IN THE UNIVERSE POWERFUL ENOUGH
TO PRODUCE GRAVITATIONAL WAVES THAT RAI'S SYSTEM COULD DETECT.
♪
AS A THEORIST, I HAD THE BEST HANDLE ANYONE HAD.
IT WAS NOT A GREAT HANDLE, BUT THE BEST HANDLE ANYONE HAD
ON THE STRENGTHS OF THE SOURCES.
♪
Narrator: WHAT KIP NEEDED WAS A SOURCE OF GRAVITATIONAL ENERGY
SO STRONG THAT IT WOULD SHAKE
THE FABRIC OF THE ENTIRE UNIVERSE,
THE SORT OF ENERGY THAT WOULD BE RELEASED
IF TWO BLACK HOLES COLLIDED.
YOU BEGAN WITH TWO MASSIVE STARS.
THIS ONE COLLAPSED, FORMED A BLACK HOLE,
AND THEN, LATER, THAT ONE COLLAPSED,
FORMED A BLACK HOLE.
AND THEN CREATE A BINARY GOING AROUND EACH OTHER.
THAT BINARY EMITS GRAVITATIONAL WAVES,
SPIRALS TOGETHER CLOSER AND CLOSER.
AND THE BLACK HOLES COLLIDE.
BUT WE'VE NEVER SEEN PAIRS OF BLACK HOLES.
WE COULDN'T SEE PAIRS OF BLACK HOLES,
BECAUSE BLACK HOLES DON'T EMIT ANY ELECTROMAGNETIC WAVES.
AS THEY GO AROUND EACH OTHER,
THEY ONLY PRODUCE GRAVITATIONAL WAVES.
SO THE ONLY WAY WE WOULD EVER SEE THEM WAS WITH OUR DETECTORS.
♪
Narrator: TO ATTEMPT TO DETECT THE GRAVITATIONAL SIGNALS
FROM COLLIDING BLACK HOLES,
KIP THORNE AND RAI WEISS EMBARKED
ON ONE OF THE MOST EXPENSIVE SCIENTIFIC VENTURES
EVER ATTEMPTED.
AFTER YEARS OF PLANNING,
CONSTRUCTION STARTED IN LIVINGSTON, LOUISIANA, IN 1994.
THE LASERS WOULD BE FIRED ALONG THESE ARMS,
EACH 2 1/2 MILES LONG,
BEFORE REFLECTING OFF THE MIRRORS
AND RETURNING TO SENSORS SO FINELY TUNED,
THEY COULD, IN THEORY, DETECT A SHORTENING OF THE ARMS
CAUSED BY GRAVITATIONAL WAVES OF JUST
A MILLION-MILLION-MILLIONTH OF A FOOT.
3,000 MILES AWAY, IN HANFORD, WASHINGTON,
AN IDENTICAL FACILITY WAS ALSO BUILT.
FOR ANY DETECTION TO BE CONFIRMED,
IT WOULD HAVE TO BE PICKED UP BY BOTH DETECTORS AT THE SAME TIME.
THE INSTRUMENTS WERE ACTIVATED IN 2002.
FOR EIGHT YEARS, THEY LISTENED TO THE UNIVERSE.
BY 2010, THEY HAD HEARD ABSOLUTELY NOTHING.
♪
FOR THE LIGO TEAM, THE PRESSURE WAS MOUNTING.
Thorne: WE HAD CONVINCED THE NSF AND CONGRESS
THAT THEY SHOULD SPEND $1 BILLION ON THIS,
AND WE HAD NOTHING TO SHOW FOR IT.
Narrator: DOUBLING DOWN,
THEY SUSPENDED THE PROJECT FOR FIVE YEARS
TO INSTALL AN EVEN MORE PRECISE SET OF DETECTORS.
IT WAS A FRIGHTENINGLY HIGH-STAKES GAMBLE.
♪
Narrator: IN SEPTEMBER 2015,
ALMOST EXACTLY 100 YEARS AFTER EINSTEIN PUBLISHED
HIS THEORY OF GENERAL RELATIVITY,
RAI WEISS' GRAVITATIONAL-WAVE DETECTORS WERE REACTIVATED.
JUST TWO DAYS LATER, BOTH SITES RECORDED AN UNUSUAL SIGNAL.
LADIES AND GENTLEMEN,
WE HAVE DETECTED GRAVITATIONAL WAVES.
WE DID IT.
[ CHEERS AND APPLAUSE ]
Narrator: AFTER WORKING ON THE PROBLEM FOR ALMOST 50 YEARS,
IT WAS A MASSIVE VINDICATION FOR RAI AND HIS FRIEND KIP
AND EINSTEIN'S THEORIES.
I WANT TO FIRST REMIND YOU OF EINSTEIN'S 1915 BIG DISCOVERY
WAS REALLY THE FORMULATION OF THESE FIELD EQUATIONS.
HE APPLIED THESE FIELD EQUATIONS
TO THE IDEA OF GRAVITATIONAL WAVES.
♪
Weiss: ALMOST THE FIRST DAY OF THE REAL RUN,
WE SAW WHAT IS IN FRONT OF YOU ON THE SCREEN HERE.
AND LET ME PLAY IT FOR YOU.
THAT ISN'T MUCH. IT'S A LITTLE BLIP.
THAT'S ALL YOU HEARD.
BUT LET ME CHANGE -- AND THIS IS THE TRICK.
WE MADE IT SO THAT YOU COULD HEAR IT BETTER
BY CHANGING THE FREQUENCY OF EVERYTHING.
[ BLIPS ]
AND THAT CHIRP IS THE CHARACTERISTIC
OF THIS PARTICULAR SOURCE.
AND THAT WAS SOMETHING WHICH WAS QUITE ASTOUNDING TO US.
[ BLIPS ]
♪
Narrator: LONG, LONG AGO, IN A GALAXY FAR, FAR AWAY,
A PAIR OF BLACK HOLES,
EACH AROUND 30 TIMES MORE MASSIVE THAN THE SUN,
CIRCLED EACH OTHER, MOVING FASTER AND CLOSER.
Thorne: THE POINT WHEN WE FIRST SEE THE GRAVITATIONAL WAVES,
THEY'RE MAYBE 1,000 KILOMETERS APART,
EACH ONE ROUGHLY 100 KILOMETERS IN SIZE.
AND THEY'RE GOING AROUND AND AROUND,
CREATING STRONGER AND STRONGER WARPING OF SPACE AND TIME.
AS THEY NEAR EACH OTHER,
THEY WARP SPACE AND TIME IN A WILD WAY,
VERY MUCH LIKE A STORM AT SEA.
Narrator: AND THEN THE BLACK HOLES COALESCE.
♪
IN THAT INSTANT, THREE TIMES THE MASS OF THE SUN
IS CONVERTED INTO PURE ENERGY.
BUT NONE OF THAT ENERGY IS EMITTED AS LIGHT.
IT IS ALL RELEASED AS GRAVITATIONAL WAVES.
Thorne: THERE WAS A HUGE AMOUNT OF ENERGY.
TURNS OUT TO BE 50 TIMES HIGHER THAN THE TOTAL POWER OUTPUT
OF ALL THE STARS IN THE UNIVERSE PUT TOGETHER.
BY FAR THE LARGEST EXPLOSION, IN TERMS OF POWER OUTPUT,
EXCEPT THE BIG BANG,
THAT WE EVER HAD ANY EVIDENCE OF.
♪
Narrator: AS THEY TRAVEL THROUGH SPACE AT THE SPEED OF LIGHT,
THE WAVES DISSIPATE, GETTING SMALLER AND SMALLER,
UNTIL, 1.3 BILLION YEARS LATER,
THEY PASS THROUGH RAI'S DETECTORS.
[ BLIPS ]
Weiss: I WISH I COULD HAVE TOLD EINSTEIN DIRECTLY
THAT WE HAD SEEN A BLACK HOLE DOING THIS.
THAT WOULD HAVE BEEN JUST A WONDERFUL EXPERIENCE,
TO SEE THE EXPRESSION ON HIS FACE
AFTER THAT WE'D TOLD HIM THAT.
[ BLIPS ]
Narrator: THE DISCOVERY OF GRAVITATIONAL WAVES
IS YET ANOTHER TRIUMPH OF EINSTEIN'S THEORY OF RELATIVITY,
A THEORY THAT HAS BEEN REPEATEDLY TESTED
AND PROVED TO BE CORRECT.
♪
STEPHEN HAWKING HAD LIVED LONG ENOUGH
TO CELEBRATE THIS LAST RESOUNDING VINDICATION
OF EINSTEIN.
AND HAWKING HAD ONE LAST GREAT STROKE OF GENIUS OF HIS OWN.
♪
Narrator: STEPHEN HAWKING HAD BEEN WORKING ON BLACK HOLES
FOR A DECADE WHEN HE HAD AN INSIGHT
THAT WOULD COMPLETELY REWRITE THE BLACK HOLE PLAYBOOK.
Hawking: UP TO 1974, EVERYONE, INCLUDING ME,
THOUGHT THAT NOTHING COULD GET OUT OF A BLACK HOLE.
THEN I DISCOVERED THAT THE UNCERTAINTY PRINCIPLE
OF QUANTUM MECHANICS ALLOWED PARTICLES TO LEAK OUT.
BY ADDING QUANTUM MECHANICS,
HAWKING MADE THE STUNNING DISCOVERY
THAT, ACTUALLY, BLACK HOLES COULD EVAPORATE.
BLACK HOLES ARE NOT WHAT YOU THOUGHT THEY WERE.
BLACK HOLES CAN ACTUALLY RADIATE.
YEAH, THAT WAS AN IN-YOUR-FACE,
SHOCKING IDEA THAT HE PUT FORWARD.
Hawking: QUANTUM MECHANICS IMPLIES THAT THE WHOLE OF SPACE
IS FILLED WITH PAIRS OF VIRTUAL PARTICLES
AND ANTIPARTICLES
THAT ARE CONSTANTLY MATERIALIZING IN PAIRS
AND ANNIHILATING EACH OTHER.
NOW, IN THE PRESENCE OF A BLACK HOLE,
ONE MEMBER OF A PAIR OF VIRTUAL PARTICLES
MAY FALL INTO THE HOLE,
LEAVING THE OTHER MEMBER WITHOUT A PARTNER.
AS PARTICLES ESCAPE FROM A BLACK HOLE,
THE HOLE WILL LOSE MASS AND SHRINK.
EVENTUALLY, THE BLACK HOLE WILL LOSE ALL ITS MASS AND DISAPPEAR.
♪
Narrator: THE DISCOVERY THAT BLACK HOLES EMITTED PARTICLES
WAS SOON NAMED HAWKING RADIATION.
IT SHOWED THAT BLACK HOLES WERE EVEN STRANGER
THAN WE HAD IMAGINED.
Levin: HOW CAN A BLACK HOLE EVAPORATE?
IT SEEMED SO PECULIAR AND VERY COUNTERINTUITIVE,
BUT IT MADE SENSE.
THE CALCULATIONS WERE CHECKED OVER AND OVER AGAIN,
AND IT MADE SENSE.
THIS IS COMPLETELY COUNTER TO EVERYTHING
WE THOUGHT THAT WE UNDERSTOOD ABOUT BLACK HOLES
IN THE YEAR 1970.
♪
Narrator: IF THAT IS TRUE,
IT MEANS THAT, GIVEN ENOUGH TIME,
ALL BLACK HOLES WILL EVAPORATE.
AND THAT PROSPECT HAS TROUBLING IMPLICATIONS
FOR THE REST OF PHYSICS.
[ FIRE CRACKLING ]
♪
Oluseyi: A CENTRAL PRINCIPLE OF ALL PHYSICS --
IN FACT, IT'S WRITTEN INTO THE LAWS OF QUANTUM THEORY --
IS THAT INFORMATION CANNOT BE DESTROYED.
CONSIDER THIS NEWSPAPER.
IT HAS INFORMATION ON EVERY PAGE.
AND IF I WERE TO THROW IT ON THIS FIRE,
IT'S QUICKLY CONSUMED BY THE FLAMES.
AND IT LOOKS LIKE THE INFORMATION IS DESTROYED.
BUT IF I WERE ABLE TO TAKE ALL THE ASHES,
COLLECT ALL THE SMOKE AND ALL THE HEAT,
AND ANALYZE AND RECONSTRUCT THE PATHS OF ALL THE PARTICLES,
THEN I SHOULD BE ABLE TO RECONSTRUCT
WHAT'S ON EVERY PAGE.
AND THIS IS BECAUSE THE LAWS OF PHYSICS ALLOW US
TO TELL THE ENTIRE FUTURE
AND THE ENTIRE PAST OF ANY SYSTEM.
NO ONE'S SAYING IT'S EASY, BUT IT IS POSSIBLE,
AS LONG AS YOU HAVE ALL THE INFORMATION.
WE CALL THIS DETERMINISM.
Narrator: SCIENTISTS BELIEVE
THAT THE PRINCIPLE OF DETERMINISM
APPLIES TO ALL SYSTEMS,
NO MATTER HOW BIG OR HOW COMPLEX.
IT SHOULD EVEN APPLY TO THE ENTIRE UNIVERSE.
SO, IF I WERE TO SOMEHOW KNOW THE POSITION AND STATE
OF EVERY PARTICLE IN THE UNIVERSE,
I COULD APPLY THE LAWS OF PHYSICS
AND KNOW THE ENTIRE FUTURE OF THE UNIVERSE
AND THE ENTIRE PAST OF THE UNIVERSE.
BUT THERE IS A CATCH, BECAUSE IF,
AS HAWKING PREDICTED, BLACK HOLES COULD EVAPORATE
IN SUCH A WAY THAT THEY LEAVE BEHIND
NO TRACE OF THE MATERIAL THAT WAS INSIDE,
THEN INFORMATION COULD BE LOST.
AND EVEN IF ONLY A SMALL AMOUNT OF INFORMATION IS LOST,
THEN EVERYTHING IS LOST.
YOU CAN'T RECONSTRUCT THE PAST
AND YOU CAN'T PREDICT THE FUTURE.
IT SEEMS TRIVIAL,
BUT, ACTUALLY, IT WAS A MASSIVE PROBLEM
THAT SHOOK THE VERY FOUNDATIONS OF PHYSICS.
AND THIS BECAME KNOWN AS THE INFORMATION PARADOX.
♪
Hawking: IF DETERMINISM,
THE PREDICTABILITY OF THE UNIVERSE,
BREAKS DOWN WITH BLACK HOLES,
IT COULD BREAK DOWN IN OTHER SITUATIONS.
EVEN WORSE, IF DETERMINISM BREAKS DOWN,
WE CAN'T BE SURE OF OUR PAST HISTORY EITHER.
THE HISTORY BOOKS AND OUR MEMORIES
COULD JUST BE ILLUSIONS.
IT IS THE PAST THAT TELLS US WHO WE ARE.
WITHOUT IT, WE LOSE OUR IDENTITY.
♪
Narrator: THE INFORMATION PARADOX
HAS TROUBLED PHYSICISTS FOR DECADES.
IF HAWKING WAS RIGHT
AND BLACK HOLES DID DESTROY THE INFORMATION THEY CONTAIN,
THEN THEY WOULD ALSO DESTROY ALMOST EVERYTHING
WE KNOW ABOUT MODERN PHYSICS.
IT CREATED THIS BIG RIFT BETWEEN THOSE
WHO WERE ADHERENTS TO QUANTUM THINKING
AND THOSE WHO WERE ADHERENTS TO RELATIVITY.
THE QUANTUM PEOPLE SAYING, "THE INFORMATION MUST GET OUT.
WE DON'T KNOW HOW, WE DON'T SEE HOW, BUT IT MUST."
AND THE RELATIVISTS SAYING, "YOU KNOW,
MAYBE THE INFORMATION'S JUST LOST."
I'M INCLINED TO SUSPECT THAT INFORMATION
IS TRULY LOST DOWN BLACK HOLES,
BUT MINE IS THE MINORITY POINT OF VIEW.
WHO CARES IF BLACK HOLES EVAPORATE
AND SWALLOW LITTLE BITS OF INFORMATION AS THEY GO?
BUT IN THE 40-PLUS YEARS SINCE THEN,
IT'S KIND OF BEEN LIKE A SNOWBALL,
THE IMPORTANCE OF THIS PROBLEM,
AND HAS GROWN AND GROWN.
Narrator: HAWKING WAS ABOUT TO FIND A WAY OUT
OF THE INFORMATION BLACK HOLE HE HIMSELF HAD CREATED.
♪
Narrator: THE INFORMATION PARADOX WAS A PROBLEM
THAT STEPHEN HAWKING WORKED ON FOR OVER FOUR DECADES.
AND, IN 2015, HE CAME UP WITH A MAJOR BREAKTHROUGH.
Hawking: MANY SCIENTISTS FELT THAT INFORMATION
SHOULD NOT BE LOST,
BUT NO ONE COULD SUGGEST A MECHANISM
BY WHICH IT COULD BE PRESERVED.
THE ARGUMENTS WENT ON FOR YEARS.
FINALLY, I FOUND WHAT I THINK IS THE ANSWER.
I REALIZED THAT A BLACK HOLE CAN STORE THE INFORMATION
IN WHAT IS CALLED
SUPERTRANSLATIONS OF THE HORIZON.
Narrator: HAWKING'S NEW IDEA
WAS THAT AS OBJECTS FALL INTO A BLACK HOLE,
THEY DISTURB THE EVENT HORIZON,
LEAVING BEHIND A PATTERN OF TURBULENCE,
WHICH COULD PRESERVE THE INFORMATION
ABOUT EVERYTHING THAT HAS FALLEN INSIDE.
Hawking: I AM NOW WORKING WITH MY COLLEAGUES,
MALCOLM PERRY AT CAMBRIDGE
AND ANDREW STROMINGER AT HARVARD,
ON WHETHER THIS CAN RESOLVE THE PARADOX.
Perry: IF INFORMATION IS STUCK ON THE HORIZON,
IT HAS NOT FALLEN INTO THE BLACK HOLE.
AND YOU CAN'T DIRECTLY OBSERVE IT FROM THE OUTSIDE,
BUT WHAT WILL HAPPEN IS IT WILL INFLUENCE
THE HAWKING RADIATION THAT COMES OUT OF THE BLACK HOLE,
AND THAT MAY BE ENOUGH TO HELP YOU RESOLVE
THE INFORMATION PARADOX.
♪
Strominger: WHEN WE FIRST CAME UPON IT,
WE WERE UP UNTIL LATE AT NIGHT.
HE SAID HE HADN'T BEEN THIS EXCITED IN 40 YEARS.
AND HE STARTED WORKING ON IT BASICALLY FULL TIME.
Narrator: TOGETHER, THE SCIENTISTS WROTE THREE PAPERS ON THE SUBJECT...
EDGING CLOSER TO A SOLUTION TO THE INFORMATION PARADOX.
♪
IT WAS HAWKING'S LAST GREAT IDEA.
♪
SADLY, THIS IS THE LAST PAPER THAT STEPHEN WROTE.
HE WAS FULL ENGAGED WITH IT RIGHT TILL THE VERY END.
♪
Narrator: HAWKING DIED IN MARCH 2018 AT THE AGE OF 76,
OVER HALF A CENTURY AFTER
HE HAD BEEN GIVEN JUST TWO YEARS TO LIVE.
♪
Strominger: HE WAS KIND OF MAGICAL TO BE AROUND.
WHEN I MISS HIM THE MOST IS, WHEN WE FIGURE SOMETHING OUT,
I'D LIKE TO TELL HIM.
♪
Narrator: SUCH WAS HIS CONTRIBUTION TO SCIENCE.
HIS ASHES WERE INTERRED IN WESTMINSTER ABBEY,
ALONGSIDE SIR ISAAC NEWTON AND CHARLES DARWIN.
Thorne: STEPHEN WAS ONE OF THE GREAT MINDS OF THE 20th CENTURY,
IN TERMS OF HIS IMPACT ON OUR UNDERSTANDING
OF THE LAWS THAT GOVERN THE UNIVERSE.
I MISS STEPHEN GREATLY.
IT WAS A TREMENDOUS LOSS FOR ME, PERSONALLY.
♪
Narrator: HIS GRAVESTONE IS ETCHED
WITH THE EQUATION DESCRIBING HAWKING RADIATION.
STEPHEN HAWKING'S LEGACY WILL CLEARLY BE A VITAL PART
IN THE UNFOLDING STORY OF PUTTING GRAVITY
AND QUANTUM MECHANICS TOGETHER.
AND AS WE GO FORWARD, EVERYTHING THAT WE DO,
IN SOME SENSE, WILL GO RIGHT BACK TO STEPHEN HAWKING.
Narrator: AND FROM HAWKING, ALL ROADS LEAD BACK
TO THAT OTHER GREAT MASTER OF THE UNIVERSE,
ALBERT EINSTEIN.
EINSTEIN DIED IN 1955.
AND IN JUST HALF A CENTURY,
HE HAD REIMAGINED THE ENTIRE UNIVERSE.
Greene: WELL, ALBERT EINSTEIN ENTERS THE WORLD WHEN IT'S ONE WAY,
AND BY THE TIME HE LEAVES THE WORLD,
IT'S COMPLETELY DIFFERENT.
WE NOW LIVE IN A WORLD
WHERE WE UNDERSTAND THE UNIVERSE HAD A BEGINNING.
WE CAN TELL HOW LONG AGO IT WAS.
THOSE ARE STUNNING ACHIEVEMENTS AND STUNNING SHIFTS,
BOTH IN OUR SCIENTIFIC AND OUR CULTURAL PERSPECTIVE.
Green: HE WAS A FIGURE THAT IS RARE,
YOU KNOW, ONCE IN A 100 YEARS,
MAYBE ONCE IN 500 YEARS.
♪
[ CLOCK TICKING ]
Narrator: TIME -- WE THINK OF IT AS REGULAR AS CLOCKWORK...
TICKING OUT THE STEADY PROGRESS OF THE UNIVERSE.
BUT TIME IS NOT CONSTANT.
AND THAT HOLDS THE KEY TO THE SECRETS OF THE COSMOS.
AND THE TWO PEOPLE WHO HELPED US UNLOCK THOSE MYSTERIES
ARE JOINED BY A COSMIC COINCIDENCE OF TIMING.
♪
ON MARCH 14, 1879,
ALBERT EINSTEIN WAS BORN IN ULM, GERMANY.
Kaiser: EINSTEIN GAVE TO US ALL A SET OF TOOLS
THAT LITERALLY HELP US ORGANIZE THE WORLD AROUND US TO THIS DAY.
Narrator: AND ON MARCH 14, 2018,
STEPHEN HAWKING DIED IN CAMBRIDGE, ENGLAND.
Perry: I THINK STEPHEN SHOULD BE REMEMBERED
AS ONE OF THE MOST REMARKABLE PEOPLE OF THE 21st CENTURY.
HE IS SOMEONE WHO, 1,000 YEARS FROM NOW,
WILL BE REMEMBERED.
HIS NAME WILL BE KNOWN.
THAT'S NOT TRUE FOR MOST OF US.
Narrator: BETWEEN THEM, THEY HAVE TRANSFORMED
OUR UNDERSTANDING OF THE ENTIRE UNIVERSE.
AS A WORKING PHYSICIST, I LOOK AT THESE TWO GIANTS
AND I HAVE NOTHING BUT GRATITUDE
THAT THEY REVEALED THE WORLD TO BE SO MUCH MORE
THAN IT WOULD HAVE BEEN.
AND WITHOUT THEM,
WHO KNOWS IF WE WOULD HAVE GOTTEN TO THIS WONDROUS STAGE
IN OUR UNDERSTANDING.
Hawking: I HAVE A REAL FEELING OF ACHIEVEMENT
THAT I HAVE MADE A MODEST BUT SIGNIFICANT CONTRIBUTION
TO HUMAN KNOWLEDGE
DESPITE MY CONDITION.