>> Stephen: WELCOME BACK, EVERYBODY.
MY NEXT GUEST IS A PROFESSOR OF PHYSICS AND MATHEMATICS AT
COLUMBIA UNIVERSITY, A BESTSELLING AUTHOR, AND AN
ALL-AROUND SMARTY PANTS.
HE'S HERE TO TELL US ABOUT THE DISCOVERY OF GRAVITATIONAL WAVES
AND WHY IT'S A HUGE DEAL.
PLEASE WELCOME OUR FRIEND, BRIAN GREENE.
GOOD TO HAVE YOU HERE.
YOU'RE CODIRECTOR OF COLUMBIA'S INSTITUTE FOR STRINGS,
COSMOLOGY, AND ASTROPARTICLE PHYSICS.
>> YES.
>> Stephen: THAT'S A PRETTY GOOD PICKUP LINE.
SINCE LAST WE WERE TOGETHER, SCIENTISTS DETECTED
GRAVITATIONAL WAVES.
I UNDERSTAND THIS IS SOMETHING EINSTEIN PREDICTED.
>> YES.
>> Stephen: HOW LONG AGO?
>> 100 YEARS AGO THIS YEAR, IN 1916.
THIS IS A HUGE DISCOVERY, NOT ONLY CONFIRMING EINSTEIN'S IDEAS
BUT OPENING A WHOLE NEW WAY OF EXPLORING THE UNIVERSE.
>> Stephen: DOES HE SEEM EVEN SMARTER NOW THAN HE USED TO
SEEM?
>> HE'S, LIKE, SO UP THERE, THAT THERE IS NO GETTING SMARTER.
IT'S LIKE INFUNT, FURTHER NORTH THAN THE NORTH POLE.
>> Stephen: THE SCIENTISTS ARE STILL DOING HIS HOMEWORK FROM
100 YEARS AGO ( LAUGHTER ).
>> YEAH, HE HAS GIVEN US AN INCREDIBLY RICH LEGACY THAT WE
HAVE BEEN PURSUING, YEAH, FOR 100 YEARS.
EVERYTHING THAT I'VE DONE IN MY OWN CAREER REALLY HAS, IN SOME
SENSE, BEEN TRYING TO PUSH FORWARD ON THE PATH THAT HE
FIRST BLAZE GLD WHAT IS A GRAVITATIONAL WAVE, AND WHY DOES
IT CHANGE EVERYTHING?
>> SO AIR, GRAVITATIONAL WAVE IS ACTUALLY A RIPPLE IN THE FABRIC
OF SPACE.
WE KNOW YOU THROW A PEBBLE INTO A POND, THE WATER RIPPLES.
NOW, THIS IS A RIPPLE, BUT NOT WITH WATER.
IT'S IN SPACE ITSELF.
>> Stephen: YOU ARE BLOWING MY MIND AGAIN.
( LAUGHTER ) SO WHAT ARE WE LOOK AT HERE?
>> THIS IS EINSTEIN'S GENERAL RELATIVITY WHICH HE DISCOVERED
IN 1915, A YEAR EARLIER, AND THE KEY IDEA IS HE FOUND GRAVITY
COMES FROM THE WARPS AND CURVES IN THE SPACE.
THE SUN WARPS THE SPACE AND KEEPS THE EARTH IN ORBIT.
>> Stephen: LIKE A BOWLING BALL ON A TRAMPOLINE.
>> TRAMPOLINE, EXACTLY RIGHT.
WHAT HAPPENED IS, THIS IS 1915.
HE DISWNT JUST STOP.
HE KEEPS GOING, AND A YEAR LATER HE REALIZES IF SPACE IS LIKE A
TRAMPOLINE, THEN IMAGINE KIDS RUNNING AROUND ON A TRAMPOLINE.
THEY'RE GOING TO SEND RIPPLES ON THE SURFACE.
SO HE SAYS THE SAME SHOULD BE TRUE OF THE FABRIC OF SPACE.
IF YOU'VE QOT TWO RAPIDLY ORBITING STARS, NEUTRON STARS OR
BLACK HOLES, HIS MATH PREDICTS THAT THEY WILL GENERATE A STEADY
MARCH OF RIPPLES IN THE FABRIC OF SPACE.
THOSE ARE GRAVITATIONAL WAVES THAT HE PREDICTED
MATHEMATICALLY.
>> Stephen: AND NOW THEY HAVE BEEN DETECTED.
>> YES.
>> Stephen: WHAT HAPPENED THAT ALLOWED US TO DO THAT?
>> YEAH, SO HIS MATH ALSO SHOWS, AS WE GO ON FROM HERE TO THE
NEXT SEQUENCE, HIS MATH SHOWS AS A GRAVITATIONAL WAVE RIPPLES BY
ANYTHING, IT WILL STRETCH IT AND COMPRESS IT.
YOU SEE IT HAPPENING-- >> Stephen: LIKE THE EARTH.
>> LIKE THE EARTH RIGHT HERE.
>> Stephen: BECAUSE WE'RE A PART OF THE FABRIC OF SPACE TIME
YOU AND ME AND THE EARTH IS STRETCHING AND COMPRESSING,
ALONG WITH THE RIPPLING OF SPACE TIME.
>> THAT'S EXACTLY RIGHT.
THE ONE THING, IS THIS IS EXAGGERATE GLD I HOPE SO.
>> A LITTLE BIT.
>> Stephen: I HOPE SO, I HOPE SO.
>> THE RIPPLES WOULD ACTUALLY CAUSE THE EARTH TO STRETCH AND
COMPRESS BY LESS THAN AN ATOMIC DIAMETER.
>> Stephen: HOW DO YOU-- HOW DO YOU MEASURE THAT?
>> HOW DO YOU MEASURE THAT?
>> Stephen: YES.
THAT'S WHAT I SAID?
>> YEAH.
( LAUGHTER ).
>> YEAH, THAT'S WHAT PEOPLE-- THOUSANDS OF SCIENTISTS HAVE
BEEN WORKING ON FOR 40, 50 YEARS.
THIS AMAZING TEAM OF RESEARCHERS, LIGO, LASER
INTERFEROMETER GRAVITATIONAL WAVE OBSERVATORY, JUST TWO WEEKS
AGO THEY ANNOUNCED THE FIRST DETECTION OF THESE GRAVITATIONAL
WAVES USING A SPECTACULAR PIECE OF EQUIPMENT.
THERE ARE ACTUALLY TWO OF THEM, ONE IN LOUISIANA AND THE ENERGY
WASHINGTON STATE.
>> Stephen: AND I UNDERSTAND THIS INVOLVES LASERS.
>> LASERS.
IN FACT WE SLAILGT MODEL VERSION OF IT HERE IF YOU WANT TO CHECK
IT OUT.
IN THIS DEVICE HERE-- IN FACT IF WE BRING THE LIGHTS DOWN, IT
WILL BE EASIER TO SEE.
WE HAVE A LASER, RIGHT HERE, THAT'S SENDING OUT A BEAM THAT
THIS DEVICE HERE SPLITS INTO TWO.
AND YOU CAN SEE THEY GO THAT DIRECTION TOWARD THE RIGHT, OUR
RIGHT, AND THIS UPSTAGE OVER HERE.
>> Stephen: AT WHAT POINT DO I PUT ON THE PINK FLOYD?
>> LET'S DO IT NOW!
>> Stephen: ANOTHER ALL RIGHT.
>> SO IN THE REAL EXPERIMENT, IT HITS A MIRROR THAT'S TWO AND A
HALF MILES AWAY.
>> Stephen: LIKE A TWO-AND-A-HALF-MILE PIPE OR
SOMETHING?
>> A TWO-AND-A-HALF-MILE EVACUATED PIPE, EXACTLY.
WHEN THE LASER BOUNCES BACK IT RECOMBINES, LIKE COMMINGLES, AND
WHEN THEY COMMINGLE THEY CREATE A VERY INTERESTING PATTERN.
I DON'T KNOW IF YOU CAN SEE TRIGHT HERE.
>> Stephen: THERE IT IS.
THERE IS AN IDEA OF THE PATTERN.
>> YOU HAVE BRIGHT AREAS.
THAT'S WHERE THE TWO BEAMS ARE WORK TOGETHER.
THE DARK AREAS ARE WHERE THE BEAMS ARE CANCELLING EACH OTHER
OUT.
AND THAT INTERFERENCE PATTERN IS ABSOLUTELY KEY.
NOW, LET ME JUST SHOW YOU, SO IF YOU BLOCK ONE OF THESE BEAMS
RIGHT HERE, YOU SEE HOW THE INTERFERENCE PATTERN GOES AWAY.
THEY'RE NO LONGER COMMINGLING.
IF I RELEASE IT, NOW YOU SEE THAT THEY ARE WORKING TOGETHER
TO CREATE THAT PATTERN.
>> Stephen: ALL RIGHT.
>> BUT THE KEY THING IS THIS PATTERN IS HIGHLY DEPENDENT ON
THE DISTANCE THAT THE LASER BEAM TRAVELS.
SO IF A GRAVITATIONAL WAVE ROLLS BY AND STRETCHES ONE DISTANCE
RELATIVE TO ANOTHER -- >> EVEN JUST THE DISTANCE OF,
LIKE, THE-- NOT THE DIAMETER OF AN ATOM.
>> THAT'S RIGHT.
THAT'S WHY THIS IS SUCH AN AMAZING PIECE OF EQUIPMENT, THE
REAL ONE, OF COURSE, THAT'S OUT THERE.
THIS IS JUST A MOD GLEL ANY MOVEMENT IN THIS BEAM MAKES THAT
PATTERN CHANGE.
>> OBVIOUSLY WE CAN'T DO IT HERE WITH THE GRAVITATIONAL WAVES BUT
WE CAN TRY IT, IF YOU'RE UP TO TO, AN EXPERIMENT WITH SOUND
WAVES.
>> >> Stephen: JUST YELL AT IT?
>> WE'LL SEE IF IT SHIFTS.
>> Stephen: SCIENCE!
SCIENCE!
>> WELL DONE, WELL DONE.
( CHEERS AND APPLAUSE ).
>> Stephen: SO, WHAT CAN WE DO?
NOW THAT WE KNOW THE GRAVITATIONAL WAVES ARE BENDING
SPACE TIME LIKE THIS, HOW CAN IT LET US SEE THE UNIVERSE IN A
DIFFERENT WAY?
>> YOU KNOW LIGHT CAN BE BLOCKED, RIGHT?
IF I COVER MY FACE YOU DON'T SEE ME ANY LONGER.
>> Stephen: THAT'S VERY FRIGHTENING.
MEAS PLOOEZ DON'T DO THAT.
>> CAN'T BLOCK GRAVITY, WHICH MEANS GRAVITY CAN GO INTO PLACES
IN THE UNIVERSE THAT LIGHT CANNOT PENETRATE.
>> Stephen: WHAT!
>> YEAH.
HOW DO YOU BLOCK GRAVITY?
YOU ALWAYS FEELS THE EARTH'S GRAVITY NO MATTER WHERE YOU GO.
USING THE GRAVITATIONAL SUFFER FASES WE MAY BE ABLE TO STUDY
HOW BLACK HOLES COMBINE AND WE MAY BE ABLE TO STUDY THE BIG
BANG ITSELF.
>> Stephen: THE SAME WAY YOU CAN SET OFF A BOMB ON ONE SIDE
OF THE EARTH ARE YOU CAN EASE A SEISMOGRAPH TO ECHO MAP THE
INSIDE OF THE PLANET, CAN HELP US MAP THINGS WE CAN'T SEE?
>> THAT'S EXACTLY RIGHT.
THE DEVICE IS ONLY SENSITIVE TO WAVES THE GRAVITY.
IT'S SHIELDED FROM ORDINARY ENVIRONMENTAL INFLUENCES.
>> Stephen: WOW.
>> AND IN FACT, YOU CAN ACTUALLY IN IN SOME SENSE HEAR THE
GRAVITATIONAL WAVES.
THEY VIBRATE AT A FREQUENCY THAT IF YOU TURN IT INTO SOUND, THE
HUMAN AIR CAN HEAR.
>> Stephen: SO LITERALLY, THESE WAVES CAN BE TURNED INTO
SOUND.
>> THEY CAN.
AND THESE ARE THE MOST SPECTACULAR SOUNDS FROM THE
STANDPOINT OF THEY HERALD A REVOLUTION IN OUR UNDERSTAND, OF
THE UNIVERSE.
>> Stephen: ANOTHER SO I UNDERSTAND YOU BROUGHT ONE OF
THESE SOUNDS WITH YOU.
>> YEAH, YEAH, I DID.
>> Stephen:S AND THIS THE SOUND OF WHAT?
WHAT ARE WE LISTENING TO?
>> THIS IS THE SOUND OF TWO BLACK HOLES COLLIDING.
>> Stephen: THIS IS ACTUALLY A COMPUTER RENDERING OF
GRAVITATIONAL WAVES INTO SOUNDS.
>> THIS IS A SIM LAIRKZ BUT THE DATA AGREES WITH THE
SIMULATION.
>> >> Stephen: THIS IS WHAT IT
WOULD SOUND LIKE.
>> THIS IS WHAT IT WOULD SOUND LIKE.
>> Stephen: DRUM ROLL PLEASE.
( LAUGHTER ) >> Stephen: IS GOD BUGS BUNNY?
WHAT IS THAT?
>> BIG THINGS COME IN LITTLE PACKAGES.
THOSE SOUNDS ARE REALLY US THINGS ABOUT THE UNIVERSE THAT
WE HAVE NO OTHER WAY OF DISCERNING.
THOSE KINDS OF SOUNDS ARE THE FUTURE OF STUDYING THE COSMOS.
>> Stephen: WELL, THANK YOU FOR BRINGING US THE FUTURE
TONIGHT.
BRIAN GREENE, WHAT A PLEASURE.
( CHEERS AND APPLAUSE ) GRAVITY WAVES.
BRIAN GREENE.
SCIENCE!