Original subtitles

--Captions by VITAC-- www.vitac.com

CAPTIONS PAID FOR BY DISCOVERY COMMUNICATIONS

♪♪

[ 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 CREATION.

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.

AND ON MARCH 14, 2018,

STEPHEN HAWKING DIED IN CAMBRIDGE, ENGLAND.

THEY ARE UNDOUBTEDLY THE MOST RECOGNIZED SCIENTISTS

IN THE WORLD.

AND BETWEEN THEM, THEY HAVE TRANSFORMED OUR UNDERSTANDING

OF EVERYTHING.

♪♪

Gates: IF ALBERT EINSTEIN HAD NOT LIVED,

IT IS HARD TO IMAGINE

WHAT THE 20th CENTURY WOULD'VE BEEN LIKE.

Narrator: IN THE EARLY 1900s,

ALBERT EINSTEIN DEVELOPED AN IDEA SO REVOLUTIONARY

IT CHANGED THE COURSE OF HISTORY.

IT WAS CALLED RELATIVITY.

♪♪

Oluseyi: MANY OF EINSTEIN'S IDEAS ARE OUT THERE.

AT BEST, THEY'RE COUNTERINTUITIVE.

OTHERS ARE SIMPLY MIND-BENDING.

[ POP ]

Narrator: HIS GIANT LEAPS OF IMAGINATION

GAVE US A NEW UNDERSTANDING OF THE FABRIC OF REALITY...

♪♪

...AND REDEFINED OUR CONCEPTS OF TIME AND SPACE.

♪♪

AND, CRUCIALLY, HIS WORK 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.

♪♪

Levin: HAWKING IS INCREDIBLY INNOVATIVE,

ABLE TO MAKE DISCOVERIES THAT SEEMED TOTALLY COUNTERINTUITIVE

AND TOTALLY IMPOSSIBLE.

♪♪

Narrator: RIGHT UP TO HIS DEATH,

HE WAS REDEFINING OUR UNDERSTANDING OF THE UNIVERSE.

Strominger: HE SAID HE HADN'T BEEN THIS EXCITED IN 40 YEARS.

WHEN I MISS HIM THE MOST IS WHEN WE FIGURE SOMETHING OUT.

I'D LIKE TO TELL HIM.

♪♪

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.

♪♪

♪♪

[ 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.

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.

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.

HE JUST WAS ABLE TO LIVE WITHIN HIS MIND,

AND THAT, FOR ALL OF HUMANITY, WAS A GREAT BOON.

♪♪

Narrator: ON JANUARY 8, 1942,

STEPHEN HAWKING WAS BORN IN OXFORD, ENGLAND,

COINCIDENTALLY, ON THE 300th ANNIVERSARY

OF THE DEATH OF GALILEO.

UNLIKE EINSTEIN,

HE 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 AT UNIVERSITY, 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 1962, WHEN HE WAS JUST 20,

HAWKING'S HAPPY-GO-LUCKY LIFESTYLE

CAME TO A GRINDING HALT.

HE WAS DIAGNOSED WITH MOTOR NEURON DISEASE

AND GIVEN JUST TWO YEARS TO LIVE.

Hawking: 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.

♪♪

AND 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 OF THAT YEAR, 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 OUT THE DAYS AND YEARS,

THE ONE THING WE RELY ON TO BE CONSTANT AND UNCHANGING.

♪♪

EINSTEIN WAS GOING TO SHOW

HOW WE'D 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.

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.

♪♪

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.

♪♪

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'S 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, EXCEPT LIGHT.

BECAUSE, NO MATTER WHERE YOU ARE OR HOW FAST YOU'RE MOVING,

YOU WILL ALWAYS SEE LIGHT TRAVELING

AT EXACTLY THE SAME SPEED.

♪♪

AND EINSTEIN USE THIS FACT TO REDEFINE OUR NOTION OF TIME.

♪♪

WELL, 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: EINSTEIN KNEW THAT,

IF HE COULD UNDERSTAND THE PROPERTIES OF LIGHT,

THEN HE COULD UNDERSTAND THE WAY THE UNIVERSE REALLY WORKED.

AND HE DID IT 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.

♪♪

THE 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.

♪♪

IT WAS A STAGGERING CONCLUSION.

EINSTEIN'S CLAIM WAS THAT TIME DOES NOT RUN AT A FIXED RATE.

IT IS RELATIVE.

IT CAN SPEED UP AND SLOW DOWN, DEPENDING ON HOW YOU ARE MOVING.

♪♪

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 HIS THEORIES UP WITH MATHS.

♪♪

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 POINT --

AND, HERE, I ADDED TWELVE 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.

EXACTLY THE SAME WOULD APPLY TO US,

IF WE COULD TRAVEL FAST ENOUGH.

[ CAMERA SHUTTERS CLICKING ]

EINSTEIN EXPLAINED IT BY USING TWINS AS AN EXAMPLE.

HE REASONED THAT, IF ONE TWIN LEFT THE EARTH

IN A SPACESHIP TRAVELING AT VERY HIGH SPEED,

THEY WOULD EXPERIENCE TIME PASSING MORE SLOWLY

AND WOULD AGE MUCH LESS THAN THEIR 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 IDEA,

BUT WE'VE ACTUALLY DONE THIS EXPERIMENT FOR REAL.

NASA HAVE 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.

♪♪

IN 2015, SCOTT SPENT A YEAR

ON THE INTERNATIONAL SPACE STATION,

ORBITING AT OVER 25,000 KILOMETERS PER HOUR,

WHILE MARK STAYED ON THE PLANET BELOW.

WHEN HE RETURNED TO EARTH,

SCOTT WAS YOUNGER THAN HIS TWIN

BY A FULL FIVE MILLISECONDS.

Levin: 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: EINSTEIN'S THEORY OF SPECIAL RELATIVITY

COULD BE THE VITAL STEP THAT ALLOWS US

TO LEAVE THE EARTH AND EXPLORE THE COSMOS.

♪♪

BUT TO DO THAT, WE WOULD NEED TO DEVELOP

A WAY TO TRAVEL AT CLOSE TO THE SPEED OF LIGHT,

AND THAT IS A CONCEPT THAT WAS CLOSE

TO STEPHEN HAWKING'S HEART.

♪♪

♪♪

Hawking: 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,

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

INTO A REALITY.

♪♪

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.

John 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 IBUILT.

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 3.5 BY 3.5 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 1,000 TIMES FASTER

THAN ANYTHING WE HAVE BUILT BEFORE.

♪♪

[ SQUAWKING ]

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 TRAVEL 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: A FEW HOURS LATER, THE CLOUDS CLEARED

AND THE ROCKET TOOK TO THE SKIES.

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 JOURNEY THAT MAY, ONE DAY, ALLOW US

TO SEND HUMAN EXPLORERS INTO THE UNIVERSE,

A JOURNEY CHAMPIONED BY STEPHEN HAWKING

AND INSPIRED BY ALBERT EINSTEIN.

♪♪

♪♪

IN 1909,

EINSTEIN'S REPUTATION WAS GROWING

AND HE WAS MADE A PROFESSOR AT THE UNIVERSITY OF ZURICH.

♪♪

IT WAS HERE HE SET TO WORK ON THE NEXT STAGE OF HIS MISSION

TO REVOLUTIONIZE OUR UNDERSTANDING OF THE UNIVERSE.

♪♪

HE WAS GOING TO REWRITE THE LAWS OF GRAVITY

WITH HIS NEW THEORY OF GENERAL RELATIVITY.

♪♪

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 EINSTEIN REALIZED 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.

♪♪

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 IN THREE DIMENSIONS.

IT'S A WARPED FOUR-DIMENSIONAL FABRIC

THAT CREATES COMPLEX SHAPES

THAT ARE SEEMINGLY IMPOSSIBLE FOR HUMANS TO VISUALIZE.

♪♪

ONCE AGAIN, TO COMPLETE HIS THEORY,

EINSTEIN USED MATHS.

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 HIS PAPER 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 MAY HAVE BEEN LOST FOR DECADES,

IF IT HAD NOT BEEN FOR THE WORK

OF A PIONEERING ENGLISH ASTRONOMER --

ARTHUR EDDINGTON.

♪♪

IN 1919,

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 THEM.

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 A WORLDWIDE CELEBRITY,

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.

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 RAGING FOR DECADES.

IT HAD STARTED SOON AFTER EINSTEIN HAD GIVEN

HIS THEORY OF GENERAL 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.

[ WIND WHISTLING ]

♪♪

IT DIDN'T JUST TELL US ABOUT THE STRUCTURE OF THE UNIVERSE.

IT COULD ALSO TELL US ITS HISTORY.

♪♪

BY 1927, A CATHOLIC PRIEST AND MATHEMATICIAN

CALLED GEORGES LEMAîTRA

WANTED TO KNOW WHAT EINSTEIN'S EQUATIONS 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 MONOTONOUS 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...[ AIR HISSING ]

...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.

[ POPS ]

Narrator: BY DISCOVERING 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: THE BIG QUESTION OF THE 1920s

WAS, "WHICH UNIVERSE DID WE LIVE IN?"

LEMAîTRA'S EXPANDING UNIVERSE,

OR EINSTEIN'S STABLE ONE?

♪♪

Narrator: THE ANSWER CAME IN 1929

FROM WHAT WAS THEN THE LARGEST TELESCOPE IN THE WORLD,

ON MOUNT WILSON, NEAR LOS ANGELES.

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: STEPHEN HAWKING HAD BURST ONTO THE WORLD STAGE

WITH A PAPER GIVING THEORETICAL PROOF

THE UNIVERSE MUST HAVE BEGUN WITH THE BIG BANG.

♪♪

BUT HIS 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: BLACK HOLES HAD FIRST BEEN DESCRIBED

AS FAR BACK AS 1916.

♪♪

WHILE SERVING ON THE FRONT LINE IN THE FIRST WORLD WAR,

A GERMAN ARTILLERY OFFICER CALLED 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 JUST BEFORE THE SECOND WORLD WAR,

SCIENTISTS WORKED 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.

♪♪

MEDIUM-SIZED STARS WOULD COLLAPSE IN A MASSIVE EXPLOSION

CALLED A SUPERNOVA,

LEAVING BEHIND A SUPER-DENSE REMNANT.

THESE NEUTRON STARS HAVE THE SAME MASS AS OUR SUN,

BUT COMPRESSED INTO A BALL JUST 10 KILOMETERS 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: HERE, IN THE DEATH OF GIANT STARS,

WAS A MECHANISM THROUGH WHICH BLACK HOLES

COULD FORM.

IT SUGGESTED THERE SHOULD BE MILLIONS OF THEM OUT THERE,

YET NO ONE HAD EVER SEEN A BLACK HOLE

OR EVEN A NEUTRON STAR.

THEY WERE SO SMALL AND FAR AWAY,

THEY WOULD BE INVISIBLE TO CONVENTIONAL TELESCOPES,

BUT A NEW TECHNOLOGY WAS DEVELOPING.

♪♪

[ TRILLING ]

♪♪

THIS IS THE MULLARD RADIO ASTRONOMY OBSERVATORY.

IN THE EARLY '60s, RADIO TELESCOPES LIKE THESE

HAD STARTED TO REVEAL WHOLE NEW AREAS OF SPACE

WE COULDN'T SEE WITH VISIBLE LIGHT.

♪♪

AND IN 1965, A 24-YEAR-OLD GRADUATE STUDENT

CALLED JOCELYN BELL

STARTED BUILDING A NEW RADIO TELESCOPE

CALLED THE INTERPLANETARY SCINTILLATION ARRAY.

[ TRILLING ]

Bell: THERE WERE ABOUT HALF A DOZEN OF US

THAT SPENT TWO YEARS BUILDING IT.

A LARGE NUMBER OF WOODEN POSTS, OVER A THOUSAND.

[ TRILLING ]

PROBABLY ABOUT 150 MILES OF WIRE AND CABLE.

IT WAS VERY PHYSICAL WORK.

I COULD SWING A SLEDGEHAMMER BY THE END OF MY PhD.

♪♪

Narrator: THE DATA FROM THE TELESCOPE WERE FED INTO THIS HUT,

WHERE IT WAS PRINTED OUT ON LONG ROLLS OF PAPER --

OVER 200 FEET OF RECORDINGS EVERY DAY.

WHAT JOCELYN BELL FOUND ON THOSE ROLLS

CHANGED THE WAY WE UNDERSTOOD THE UNIVERSE FOREVER.

THIS IS A PIECE OF THE ORIGINAL CHART,

AND IT'S VIRTUALLY IMPOSSIBLE TO SEE WHAT'S GOING ON.

SO, THE FIRST THING WE DECIDED TO DO WAS TO SPREAD THIS OUT

BY BASICALLY RUNNING THE PAPER FASTER UNDER THE PEN.

FINALLY GOT THIS STRING OF PULSES --

PULSE, PULSE, PULSE, PULSE,

PULSE, PULSE, PULSE, PULSE, PULSE, PULSE.

Narrator: THE CHALLENGE THEN WAS TO FIGURE OUT

WHAT COULD POSSIBLY BE GENERATING

THESE MYSTERIOUS RADIO SIGNALS.

Bell: THE PULSES ARE SHORT AND QUITE STEEP,

SO THESE THINGS HAVE TO BE SMALL.

THE OTHER THING THAT WE VERY QUICKLY ESTABLISHED

WAS THAT THE PULSE PERIOD WAS VERY, VERY CONSTANT.

IT WASN'T GETTING TIRED,

WHICH MEANS IT'S GOT LARGE RESERVES OF ENERGY,

WHICH MEANS IT'S BIG.

SO IT'S SMALL, AND IT'S BIG.

[ LAUGHS ] SO...

YOU HAVE TO BE MORE PRECISE IN WHAT YOU'RE SAYING.

IT'S SMALL IN WIDTH.

IT'S BIG IN MASS.

SO HIGH DENSITY.

[ SHARP PULSATING ]

THAT'S THE FIRST PULSAR.

CP 1919.

SO THAT'S WHAT IT SOUNDS LIKE

IF YOU LISTEN TO THE RADIO SIGNAL.

[ PULSE CONTINUES ]

SO IT'S SPINNING.

[ PULSE CONTINUES ]

♪♪

Narrator: JOCELYN HAD DISCOVERED A NEW, EXOTIC CLASS OF STAR.

TINY, SUPER DENSE OBJECTS,

THEY EMIT NO VISIBLE LIGHT...

BUT ROTATE AT ENORMOUS SPEED,

SENDING OUT BEAMS OF RADIO WAVES AS THEY DO SO.

THEY WERE NAMED PULSARS.

[ PULSE CONTINUES ]

SO THAT'S THE WHOLE STAR SPINNING AT THAT RATE.

AND THERE ARE SOME THAT ARE EVEN FASTER.

[ PULSE CONTINUES ]

IF YOU LISTENED TO THE FASTEST ONE,

IT WOULD SOUND LIKE YOUR KITCHEN BLENDER

IT'S GOING 700 REVS PER SECOND.

[ PULSE CONTINUES ]

THEY'RE HARD TO BELIEVE.

[ RECORDING STOPS ]

♪♪

Narrator: BUT THE KEY REALIZATION

WAS THAT THE EXISTENCE OF PULSARS HAD BEEN PREDICTED.

[ PULSE CONTINUES ]

♪♪

THEY WERE NEUTRON STARS

THAT WERE FORMED FROM THE COLLAPSE OF DYING SUNS.

♪♪

IT WAS A MASSIVE DISCOVERY.

♪♪

THIS WAS INCREDIBLY EXCITING TO PEOPLE

BECAUSE THE EXISTENCE OF A NEUTRON STAR,

WHICH WAS A DEAD STAR,

AN INCREDIBLY DENSE STATE OF MATTER,

WAS A SUGGESTION THAT IF THEY'RE REAL,

IF YOU CAN SEE THEM, MAYBE BLACK HOLES ARE TOO.

BECAUSE BLACK HOLES ARE LIKE THE NEXT STEP

IN THE KIND OF ASTRONOMICAL GRAVEYARD.

♪♪

Narrator: FOR THE FIRST TIME, IT SEEMED THAT

BLACK HOLES MIGHT REALLY EXIST.

AND IT IGNITED THE INTEREST OF STEPHEN HAWKING

AND THE NEXT GENERATION OF PHYSICISTS.

IT WAS A GOLDEN AGE OF RELATIVITY

AS WE SORTED OUT, UNDER HAWKING'S LEADERSHIP,

THE THEORY OF BLACK HOLES.

♪♪

SO WE COME TO EINSTEIN'S MOST FAMOUS EQUATION --

E EQUALS MC SQUARED.

[ EXPLOSION ]

THAT'S THE POWER OF E EQUALS MC SQUARED.

AND HAWKING MADE THE STUNNING DISCOVERY

THAT BLACK HOLES COULD EVAPORATE.

THAT WAS AN IN-YOUR-FACE, SHOCKING IDEA.

♪♪

♪♪

♪♪

♪♪