IS THERE MEANING
IN THE UNIVERSE? PURPOSE IN LIFE? I CARE ABOUT
MEANING AND PURPOSE. SO I OFTEN EXPLORE ORIGINS. DID THE UNIVERSE BEGIN? IF SO, HOW SO? CAN SCIENCE
EXPLAIN IT ALL NATURALLY? OR IS SOMETHING
SUPERNATURAL REQUIRED? ANOTHER WAY TO ADDRESS
MEANING AND PURPOSE IS BY EXPLORING DESTINIES. WILL THE UNIVERSE END? IF SO, HOW SO? IF NOT, WHY NOT? I YEARN TO KNOW WHETHER THE
UNIVERSE WILL END IRRESPECTIVE OF MEANING AND PURPOSE. THE SHEER MAJESTY OF HUMAN
THOUGHT VENTURING TRILLIONS OF YEARS INTO THE FUTURE! WILL THE UNIVERSE EVER END? I'M ROBERT LAWRENCE KUHN AND
CLOSER TO TRUTH IS MY JOURNEY TO FIND OUT. WHAT WOULD IT MEAN FOR
THE UNIVERSE TO "END"? DISTURBANCE? DISRUPTION? DISINTEGRATION? DISAPPEARANCE? AND WHAT ACTUALLY WOULD "END"? HOW COULD ALL THAT EXISTS -
A VAST UNIVERSE OF 100 BILLION GALAXIES, MANY WITH HUNDREDS OF
BILLIONS OF STARS AND PLANETS - JUST CEASE TO EXIST? I BEGIN WITH A THEORETICAL
PHYSICIST WHO USES FUNDAMENTAL LAWS TO EXPLAIN
HOW THE COSMOS WORKS. FROM SUB-ATOMIC PARTICLES
TO THE GRAND STRUCTURE OF THE UNIVERSE. MICHIO KAKU. MICHIO, WHAT CAN WE SAY TODAY
ABOUT WHAT THE FAR FUTURE OF OUR WHOLE UNIVERSE REALLY WILL BE? PHILOSOPHERS AND POETS HAVE
ASKED THE QUESTION, WILL THE WORLD END IN FIRE OR ICE? WE CAN NOW GIVE AN ANSWER. THE UNIVERSE, WE
THINK, WILL DIE IN ICE. OUR EARTH WILL
PROBABLY DIE IN FIRE. PROBABLY BE EATEN UP
BY THE SUN AS IT DIES. OUR MILKY WAY GALAXY WILL
PROBABLY DIE IN FIRE AS IT COLLIDES WITH ANDROMEDA, A
NEARBY GALAXY, AND GETS EATEN ALIVE BY OUR CLOSEST
GALACTIC NEIGHBOR. THE LATEST EVIDENCE SHOWS THAT
THE UNIVERSE IS NOT SLOWING DOWN BUT IT'S SPEEDING UP OUT
OF CONTROL, AND THAT WE WILL PROBABLY ALL DIE IN ICE,
TRILLIONS UPON TRILLIONS OF YEARS FROM NOW. AND WHAT HAPPENS TO THE
PARTICLES IN OUR UNIVERSE, AS THE UNIVERSE ACCELERATION
SPEEDS UP AND GETS FASTER AND FASTER? ALL THE PARTICLES JUST
GET MORE AND MORE DISPERSED FROM EACH OTHER. THAT'S RIGHT. AND THE NIGHT SKY WILL BE
UNRECOGNIZABLE IN THE FUTURE. THE GALAXIES WILL BE SO FAR AWAY
THAT LIGHT CANNOT EVEN REACH US ANYMORE, AND IT'S GOING TO BE
QUITE DARK AT NIGHT, AS THE SUNS BLINK OUT IN OUTER SPACE. THE UNIVERSE SEEMS TO
EVOLVE IN FIVE BASIC STAGES. THE FIRST STAGE WAS THE FIERY
BIG BANG AND THE CREATION OF THE EARLY STARS. WE'RE IN THE SECOND STAGE,
A VERY EARLY STAGE, THE STAGE OF STAR FORMATION. BUT ON THE LARGE SCALE OF
THINGS, LIFE AND STAR FORMATION IS JUST THE VERY
FIRST TWO STAGES. THEN WE GO INTO A MUCH
LARGER STAGE, WHERE THE STARS BEGIN TO DIE. RED DWARF STARS BEGIN
TO DOMINATE THE UNIVERSE, THEN BLACK HOLES. ALL OF A SUDDEN ALL THE
STARS ARE GONE IN THE FUTURE, THEY'RE NOTHING BUT
DEAD NEUTRON STARS. WE HAVE BLACK HOLES THAT ARE
DYING EMBERS OF THESE GIGANTIC OBJECTS THAT ONCE
FLARED UP IN THE UNIVERSE. EVEN BEYOND THAT,
ATOMS THEMSELVES BEGIN TO DISINTEGRATE. THE PROTON, WHICH IS THE
BEDROCK OF OUR EXISTENCE - EVERYTHING WE SEE AND
TOUCH IS MADE OUT OF PROTONS - THEY BEGIN TO DISINTEGRATE. AND IN THE FAR FUTURE,
EVERYTHING BECOMES A GAS, A GAS OF ELECTRONS, A GAS OF
NEUTRINOS, AND TEMPERATURES ARE SO LOW THAT NO MACHINE CAN
POSSIBLY CREATE ANY MOTION IN THIS DISTANT FUTURE. IN OTHER WORDS, THE LAWS OF
PHYSICS ARE A DEATH WARRANT TO ALL INTELLIGENT LIFE. SO WHAT DOES THAT MEAN? HOW DO WE REFLECT UPON THAT? EVERYTHING SEEMS SO NORMAL. WELL, THE JOB OF US PHYSICISTS
IS TO CALCULATE THE ENGINE DRIVING THIS RUN-AWAY
EXPANSION OF THE UNIVERSE. IT SEEMS TO BE SOMETHING CALLED
THE COSMOLOGICAL CONSTANT. THE DARK ENERGY,
THE ENERGY OF NOTHING. NOTHING, BELIEVE IT OR NOT,
THE VACUUM OF OUTER SPACE, IS A STOREHOUSE OF ENERGY THAT'S
PUSHING THE GALAXIES APART. WE HAVE LOOKED FOR THE ENGINE
DRIVING THIS EXPANSION, AND SOME PEOPLE HAVE LOOKED FOR
ALTERNATIVE COSMOLOGIES. THERE IS A THEORY CALLED THE BIG
SPLAT THEORY, WHERE OUR UNIVERSE IS A MEMBRANE, THIS GIGANTIC
BEACH BALL, WHICH COLLIDES WITH ANOTHER BEACH BALL AND THE
COLLISION COULD BE PERIODIC, AND EACH COLLISION
CREATES A BIG BANG OF SORTS. EVERY TRILLION YEARS OR SO. RIGHT. SO, IN THAT UNIVERSE, PERHAPS
WE CAN START ALL OVER AGAIN, BUT IT DOES MEAN THERE'S GOING
TO BE A FIERY BIG CRUNCH WHERE EVERYTHING WE SEE
AROUND US WILL BE IN FLAMES. SO WE HAVE A CHOICE. EITHER BEING BURNT ALIVE IN FIRE
OR FROZEN IN ICE, BUT EITHER ONE SEEMS TO BE A LOGICAL
CONCLUSION OF THE EQUATIONS. IT SEEMS TO BE UNAVOIDABLE. THAT'S IT? THAT'S THE STORY? THE WHOLE STORY? FIRE OR ICE? AND WE GET THE ICE? "UNAVOIDABLE" SAYS
MICHIO, ACCORDING TO THE LAWS OF PHYSICS. BUT WHY SO CERTAIN? AFTER ONLY A FEW HUNDRED
YEARS OF MODERN SCIENCE? AND BARELY A CENTURY
OF SCIENTIFIC COSMOLOGY? I'D WANT THERE TO BE MORE. THE STORY'S TOO SHORT. THE VISION TOO SIMPLE. WHAT'S THE RATIONALE
BEHIND THE FIRE AND THE ICE? WHY THE FIRE? WHY THE ICE? I GO TO MIT TO VISIT A
COSMOLOGIST WHO EXPLORES FRONTIERS OF
KNOWLEDGE, MAX TEGMARK. FIRE OR ICE, MAX? BIG CRUNCH OR BIG CHILL? WHEN I WAS FIRST TAUGHT
THIS STUFF IN GRADUATE SCHOOL, THAT THERE WERE TWO FUTURES. EITHER THERE WAS THE BIG
CHILL, THINGS EXPAND FOREVER, OR THERE'S THE BIG CRUNCH. AND TO FIGURE IT OUT, ALL YOU
NEEDED TO DO WAS MEASURE HOW MUCH STUFF THERE WAS AND SEE IF
ITS GRAVITATIONAL PULL WOULD BE STRONG ENOUGH TO
REVERSE THE EXPANSION. RIGHT. SUDDENLY, DARK ENERGY
BURST ON THE SCENE - RIGHT? IT STARTED TO BEGIN TO LOOK LIKE
THERE WAS NOT ENOUGH STUFF TO REVERSE THE EXPANSION AND WE
WERE GOING FOR THE BIG CHILL. NOW IT TURNED OUT THAT THAT
DIDN'T MATTER ANY MORE, BECAUSE DARK ENERGY NOW MAKES UP
THREE-QUARTERS OF THE UNIVERSE, AND IT REFUSES TO DILUTE. IT'S THIS REALLY WEIRD STUFF
THAT HAS THE PROPERTY THAT IF YOU PUT IT INTO TWICE
THE VOLUME, THE DENSITY IS STILL THE SAME! SO THERE'S NOW TWICE
AS MUCH MASS THERE. SO IT SEEMS TO BE ENERGY,
LITERALLY, OF EMPTY OF SPACE. EXACTLY. AND THE FACT THAT IT DOESN'T
DILUTE, WHILE ALL THE OTHER STUFF DILUTES, MEANS
EVENTUALLY IT TAKES OVER. AND THE WHOLE FUTURE OF
THE UNIVERSE DEPENDS ON WHAT THIS STUFF IS. IF THE STUFF STAYS CONSTANT,
LIKE EINSTEIN'S COSMOLOGICAL CONSTANT IDEA, THEN THE
FUTURE IS THE BIG CHILL. EXPANSION FOREVER. ON THE OTHER HAND, IF THIS
STUFF ACTUALLY DOES DILUTE A LITTLE BIT, AND EVENTUALLY
GOES NEGATIVE, YOU ACTUALLY GET A BIG CRUNCH! SO THE BIG CRUNCH
IS BACK IN THE CARDS. AND THE THIRD POSSIBILITY IS
THAT IT ACTUALLY ANTI-DILUTES - YOU GET AN EVEN HIGHER DENSITY
OF THIS STUFF WHEN IT STRETCHES OUT, IN WHICH CASE YOU GET A BIG
RIP, WHERE A FINITE TIME FROM NOW THE DENSITY OF THIS STUFF
ACTUALLY BECOMES INFINITE, THE UNIVERSE EXPANDS SO FAST
THAT IT EVEN RIPS APART THE SOLAR SYSTEM AND THEN RIPS APART
THE PLANET, THEN RIPS APART THE ATOMS WE'RE MADE OF. SO NOW, IT'S THE BIG CHILL, THE
BIG CRUNCH, OR BIG RIP, AND IT ALL COMES DOWN TO UNDERSTANDING
WHAT THE DARK ENERGY IS. FIRST SOME PEOPLE THOUGHT IT
WAS A FLUKE, MAYBE THE SUPERNOVA PEOPLE HAD GOTTEN IT WRONG. BUT THE AMAZING THING IS NOW WE
HAVE A COMPLETELY INDEPENDENT WAY OF MEASURING
THIS STUFF, ALSO. WHAT WE CAN DO IS FIRST WE
CAN USE EINSTEIN'S THEORY OF GRAVITY, WHICH TELLS US THAT IF
SPACE IS NOT AS FLAT, SO THAT REALLY BIG TRIANGLES, HOWEVER
ANGLED, ADD UP TO 180 DEGREES. THEN WE KNOW EXACTLY HOW
MUCH STUFF THERE MUST BE. WE KNOW THE TOTAL MATTER BUDGET. THEN WE CAN GO OUT AND LOOK AT
THE GALAXIES AND SEE HOW MUCH STUFF IS THERE REALLY, AND
WE GET ONLY 25% OF THAT. SO THERE'S GOT TO BE 75% OF THIS
OTHER STUFF, WHICH IS EXACTLY THE SAME NUMBER THAT THE
SUPERNOVA MEASUREMENTS GET. HOW DID YOU
CALCULATE THAT AGAIN? YOU USED THE GEOMETRY OF SPACE. THAT'S RIGHT, AND THAT'S ONE OF
THE MOST PROFOUND THINGS ABOUT EINSTEIN'S THEORY OF GENERAL
RELATIVITY, THAT THERE'S A RELATION BETWEEN HOW MUCH
STUFF THERE IS IN SPACE AND THE GEOMETRIC SHAPE OF
SPACE, HOW CURVED IT IS. SO WE MEASURE THE CURVATURE,
WE KNOW HOW MUCH STUFF. SO THE MILLION DOLLAR QUESTION
NOW IS TO SEE IS IT CONSTANT. BECAUSE IF IS, IT'S THE
BIG CHILL WE'RE IN FOR. IF IT'S NOT CONSTANT, IT'S
THE BIG CRUNCH OR THE BIG RIP. SO THIS IS VERY EXCITING,
BECAUSE CLEARLY WE WANT TO KNOW THE FUTURE OF OUR UNIVERSE. AT THE SAME TIME, THOUGH, WE
MUSTN'T GET HUBRIS AND SAY THAT'S THE FUTURE OF THE
UNIVERSE, WITH A CAPITAL 'T', BECAUSE THAT'S THE FUTURE
OF OUR PART OF SPACE HERE. IF INFLATION REALLY HAPPENED
AND THERE ARE OTHER REGIONS LIKE THIS AS WELL,
THEN THAT'S JUST - - LOTS OF BALLOONS
ALL AROUND THE ROOM. YEAH, AND THAT'S JUST GOING
TO BE THE FUTURE OF THIS PATCH. AND THERE MAY WELL BE OTHER
PATCHES WHERE THIS DARK ENERGY HAS A DIFFERENT VALUE WHICH
WILL HAVE A DIFFERENT FUTURE. SO, I THINK THAT'S PROBABLY THE
CASE, BECAUSE THAT'S THE ONLY EXPLANATION WE HAVE FOR WHY
DARK ENERGY DENSITY HAS SUCH A BIZARRE VALUE. THE VALUE IS 10 TO THE POWER
-123, SO IT'S ONE DIVIDED BY ONE WITH 123 ZEROES. AND THE ONLY EXPLANATION I FIND
THE LEAST BIT COMPELLING FOR THIS IS THAT THIS IS SOME KIND
OF STUFF WHICH HAS A DIFFERENT DENSITY IN DIFFERENT PARTS OF
SPACE AND THEN IT'S NO SURPRISE THAT WE HAPPEN TO LIVE IN A
PLACE WHERE THAT VALUE ALLOWS THE FORMATION OF GALAXIES. BECAUSE IF THAT WERE
VERY DIFFERENT, THERE WOULD BE NO GALAXIES. IF THAT WERE JUST A
LITTLE BIT DIFFERENT. IF IT WERE JUST TEN TIMES
BIGGER, YOU WOULDN'T MAKE ANY GALAXIES HERE, BECAUSE THE
ANTI-GRAVITY FORCE WOULD TAKE OVER BEFORE THE GRAVITY
HAD TIME TO PULL THE MATTER TOGETHER IN GALAXIES. IT'S EXACTLY RIGHT. WELL, THAT IS A
UNBELIEVABLE NUMBER. AND TO BE SO CLOSE TO ZERO BUT
YET NOT ZERO, IS ASTONISHING. AND THE WHOLE FUTURE
IS DETERMINED BY IT! EXACTLY. SO CLEARLY THAT'S A NUMBER
WE WOULD LIKE TO UNDERSTAND. SO FAR DARK ENERGY IS JUST A
CODE WORD FOR OUR IGNORANCE. DARK ENERGY DETERMINES
THE FATE OF THE UNIVERSE. IF MORE OF IT - ALL DIE BY ICE,
EXPANDING INTO OBLIVION. IF LESS OF IT - ALL DIE BY FIRE,
CRUSHED BY IMMENSE GRAVITY. NICE TERM, "DARK" ENERGY. AS IF PHYSICISTS
UNDERSTOOD THIS STUFF. FROM WHERE DID DARK ENERGY COME? I FOLLOW THE TRAIL. I GO TO LAWRENCE BERKELEY
NATIONAL LABORATORY. I VISIT THE SCIENTIST WHOSE
WORK REVEALED DARK ENERGY - SAUL PERLMUTTER. SAUL DISCOVERED THAT THE
EXPANSION OF THE UNIVERSE IS NOT SLOWING DOWN - BUT SPEEDING UP! IT WAS ONE OF THE MOST
SHOCKING DISCOVERIES IN THE HISTORY OF SCIENCE. SAUL, THEORETICAL PHYSICISTS
HAVE TAKEN THE WORK THAT YOU'VE DONE SHOWING THAT THE UNIVERSE
EXPANSION IS NOW ACCELERATING AND NOW PREDICT A
PRETTY DISMAL FUTURE. HAVING LIVED WITH THE DATA,
HOW CAN YOU HELP US REALLY UNDERSTAND WHAT THE FAR FUTURE,
THE FAR, FAR FUTURE WILL BE? WHAT WE'VE SEEN IS OF COURSE
A SURPRISING CHANGE FROM THE EARLIEST UNIVERSE, WHEN WE THINK
THE UNIVERSE WAS SLOWING DOWN, TO WHAT APPARENTLY SEEMS TO
BE THE LAST HALF OF THE LIFE OF THE UNIVERSE, IN WHICH
IT'S BEEN SPEEDING UP. AND SINCE WE DON'T UNDERSTAND
EXACTLY WHY THAT SPEED UP IS HAPPENING, IT'S A LITTLE BIT
DIFFICULT TO EXTRAPOLATE WITH CONFIDENCE AS TO WHAT WILL
HAPPEN IN THE LONG FAR FUTURE. EVERYBODY KNOWS THE
UNIVERSE IS EXPANDING. WE THOUGHT THE EXPANSION
WOULD SLOW DUE TO GRAVITY. HOW HAS THIS EXPANSION TRACKED? SO, IT LOOKS AS IF THE
UNIVERSE USED TO SLOW DOWN... WHEN FOR EXAMPLE? WE THINK FURTHER BACK THAN
ABOUT 7 BILLION YEARS AGO. SO ABOUT HALF OF THE
TIME BACK IN HISTORY, IT WAS ACTUALLY SLOWING DOWN. AND WE THINK IT'S BECAUSE
BACK THEN THE UNIVERSE WAS MORE DENSE, SO BASICALLY YOU KNOW,
ALL THE MATTER WAS CLOSER TO ALL THE OTHER MATTER AND GRAVITY
WAS STRONGER, THEREFORE. SAME AMOUNT OF MATTER IN
A SMALLER AMOUNT OF SPACE. EXACTLY, AND AS THE UNIVERSE
EXPANDED THOUGH, YOU KNOW, ALL THE STUFF NEAR US
BECAME MORE AND MORE DILUTE. DISTANCES BETWEEN ALL THE
PARTICLES IN THE UNIVERSE BECAME FURTHER AND FURTHER IN THE
OBJECT OF THE UNIVERSE AND SO GRAVITY BECOMES WEAKER AND WE
THINK THAT WHAT'S HAPPENING IS THAT YOU'RE BEGINNING TO SEE
UNDERNEATH IT, THERE WAS ALWAYS THIS DARK ENERGY TRYING TO
PRESS, TRYING TO EXPAND SPACE AND IT WASN'T WINNING
BECAUSE GRAVITY WAS SO POWERFUL. BUT ONCE GRAVITY BECOMES
WEAK ENOUGH, IT TAKES OVER. BECAUSE THIS DARK ENERGY
IS IN EVERY BIT OF SPACE. EXACTLY, WE THINK IT
PERVADES ALL OF EMPTY SPACE... IN THE SAME AMOUNT, SO THE MORE
SPACE YOU HAVE THE MORE ABSOLUTE AMOUNT OF THIS DARK
ENERGY YOU HAVE... EXACTLY, AT THAT POINT,
FROM THEN ON, THE UNIVERSE WILL EXPAND FASTER AND FASTER
AND OF COURSE THEN THE THING JUST BUILDS ON ITSELF BECAUSE
NOW THE MORE YOU EXPAND, THE MORE OF THE DARK ENERGY
YOU HAVE RELATIVE TO THE MASS, AND SO THE MORE IT
WANTS TO EXPAND FASTER. IN FACT, SINCE WE DON'T
KNOW WHAT CAUSES THE CURRENT ACCELERATION, I MEAN YOU COULD
IMAGINE IT WILL TURN OUT TO BE A SERIES OF DIFFERENT NEW DARK
ENERGIES COMING INTO PLAY. SOME MAY WANT YOU TO SPEED
UP, SOME MIGHT WANT YOU TO SLOW DOWN, AND THAT'S THE REASON WHY
YOU MIGHT NOT WANT TO MAKE A DEFINITIVE PREDICTION TODAY AS
TO WHAT THE FATE THE UNIVERSE WILL BE AT THE END OF TIME. CAUSE WE NOW KNOW, WHICH WE
DIDN'T EVEN KNOW JUST A FEW YEARS BACK, THAT YOU CAN
HAVE NEW THINGS HAPPENING. AND SO, IF THERE'S A NEW THING
THAT HAPPENED SEVEN BILLION YEARS AGO, HOW DO WE KNOW THAT
THERE WON'T BE ANOTHER NEW THING THAT OCCURS IN ANOTHER
SEVEN BILLION YEARS? SO, THE OPEN UNIVERSE
IS STILL AN OPEN QUESTION? IN MY MIND AND I THINK THAT
MOST PEOPLE WOULD SAY THAT WE CAN'T KNOW YET. IS DARK ENERGY THE MASTER
OF THE FATE OF THE UNIVERSE? WILL DARK ENERGY CONTINUE
TO INCREASE AND POWER AN EVER-QUICKENING EXPANSION
INTO NOTHINGNESS - ICE. OR SOMEHOW REVERSE, CHANGING THE
FUTURE INTO A BIG CRUNCH - FIRE. EITHER WAY, NOT SO NICE. BUT MOST COSMOLOGISTS
NOW BELIEVE THAT THERE ARE MANY UNIVERSES. A MULTIVERSE - AN
INFINITY OF UNIVERSES. IF SO, THEN EVEN IF DARK ENERGY
DECIMATES "OUR UNIVERSE," IT WOULD NOT TAKE
DOWN THE WHOLE OF REALITY. BUT WHY POSTULATE
OTHER UNIVERSES WHICH WE CANNOT EVER SEE? I GO BACK TO MIT TO MEET A
PIONEER OF MULTIPLE UNIVERSES - THE DISCOVERER OF
COSMIC INFLATION - ALAN GUTH. ALAN, FROM YOUR PERSPECTIVE,
PARTICULARLY IN THE CONTEXT OF INFLATION THEORY WHICH YOU
CREATED, HOW DO YOU SEE THE FAR, FAR FUTURE OF THE UNIVERSE? INFLATION IN ITS SIMPLEST FORM
PRODUCES NOT JUST THE SINGLE UNIVERSE, BUT IN FACT AN
INFINITE NUMBER OF UNIVERSES. INFLATION IS A TWIST ON THE
BIG BANG THEORY IN WHICH ONE PROPOSES THAT IN THE EARLY
HISTORY OF OUR UNIVERSE, THERE WAS A PERIOD OF
EXPONENTIAL EXPANSION THAT WAS DRIVEN BECAUSE THE UNIVERSE
AT THE TIME, WE BELIEVE, WAS FILLED WITH PECULIAR KIND OF
MATERIAL THAT LITERALLY TURNS GRAVITY ON ITS HEAD AND PRODUCES
A GRAVITATIONAL REPULSION INSTEAD OF THE USUAL
GRAVITATIONAL ATTRACTION THAT WE'RE ACCUSTOMED TO. THIS INFLATION WOULD END BECAUSE
THIS REPULSIVE GRAVITY MATERIAL IS FUNDAMENTALLY UNSTABLE,
SO IT DECAYS LIKE A RADIOACTIVE SUBSTANCE DECAYS. BUT IT DOESN'T ALL END THERE. WHILE IT'S DECAYING,
IT'S ALSO CONTINUING TO EXPONENTIALLY EXPAND. BECAUSE OF THE EXPONENTIAL
EXPANSION THAT CONTINUES ALL THIS TIME, THE HALF THAT DID NOT
DECAY WOULD AT THE END OF THIS PERIOD, HAVE A VOLUME WHICH
IS IN FACT MUCH LARGER THAN EVERYTHING THAT
YOU STARTED WITH. SO AT EACH STAGE, EVEN WHILE
THIS REPULSIVE GRAVITY MATERIAL IS DECAYING, THE VOLUME OF IT
JUST KEEPS GETTING LARGER AND LARGER AND IN FACT AT
AN INCREDIBLY RAPID RATE. AND ONCE THIS PROCESS
STARTS, IT CANNOT BE STOPPED? AS FAR AS WE CAN TELL,
IT CANNOT BE STOPPED. SO THEN MAYBE THE QUESTION WE
HAVE TO ASK, BIFURCATES INTO TWO RADICALLY DIFFERENT QUESTIONS. ONE IS WHAT IS THE
FAR FUTURE OF OUR PIECE? WHICH I THINK YOU CALL A POCKET
UNIVERSE, IT'S A VERY BIG POCKET, BUT IT'S
A POCKET UNIVERSE. AND THEN WHAT IS THE FAR
FUTURE OF ALL THAT EXISTS, THAT INFLATION IS CREATING
ALL THESE MULTIPLE UNIVERSES? THAT'S RIGHT. IS THAT FAIR TO DO? THAT'S FAIR TO DO. SO AS FAR AS THE MULTI-VERSE IS
CONCERNED, AS FAR AS EVERYTHING THAT EXISTS IS CONCERNED, THIS
PICTURE OF ETERNAL INFLATION SAYS THAT IT WILL GO ON FOREVER
AND FOREVER THERE WILL BE REGIONS THAT WILL BE INFLATING. THOSE REGIONS
WILL DECAY IN PLACES. EACH TIME A DECAY OCCURS, IT
WILL PRODUCE A POCKET UNIVERSE. AND THIS WILL GO ON LITERALLY
FOREVER PRODUCING AN INFINITE NUMBER OF POCKET UNIVERSES. AND SO, IN SOME WAYS IT'S
A ROSY PICTURE BECAUSE IT GOES ON FOREVER. THE STORY FOR OUR
POCKET IS MUCH LESS ROSY. OUR POCKET RIGHT
NOW IS UNDERGOING ACCELERATED EXPANSION. AND IF THAT CONTINUES THEN IT
WILL EXPONENTIALLY EXPAND INTO THE INFINITE FUTURE. AS THAT HAPPENS, ALL OF THE
MATTER IN THE UNIVERSE WILL DILUTE DUE TO THIS
ENORMOUS EXPANSION. AND IT DOES MEAN THAT
ULTIMATELY LIFE WOULD DIE OUT IN OUR POCKET UNIVERSE. SO, EVEN IF OUR LITTLE POCKET
DISAPPEARS, THAT THE PLENTITUDE OF ALL REALITY IS
LITERALLY INFINITE. THAT'S RIGHT, THAT'S RIGHT. THERE WOULD BE THINGS GOING ON
IN OUR UNIVERSE OR AT LEAST OUR MULTI-VERSE LITERALLY
FOREVER IN A VOLUME WHICH IS ESSENTIALLY INFINITE. AN UNFATHOMABLE MULTITUDE OF
POCKET UNIVERSES - EACH "POCKET" VASTLY LARGER THAN ALL
THAT WE SEE IN OUR UNIVERSE. SO THAT EVEN IF THE FUTURE
OF OUR UNIVERSE IS DECAY INTO EMPTINESS, THERE WOULD BE
INFINITE NEW POSSIBILITIES IN AN UNENDING COSMOS. THE PLENTITUDE OF ALL REALITY IS
SO OVERWHELMING - I AM DRAINED. IT IS JUST TOO MUCH. BUT I REMAIN RESTLESS. ALWAYS, THE FAR FAR FUTURE
OF THE UNIVERSE - AND ITS APPARENTLY CERTAIN
END - KEEPS NAGGING ME. WHILE ATTENDING A COSMOLOGY
CONFERENCE ON A SHIP, I MEET A COSMOLOGIST FROM TUFTS WHO
FOCUSES ON ETERNAL INFLATION - KEN OLUM. KEN DID HIS PHD UNDER ALAN GUTH,
AND SUDDENLY, I WAS BACK IN THE 'END GAME'. KEN, HOW MANY DIFFERENT
WAYS CAN THE UNIVERSE END? I'M SURE THERE ARE MANY WAYS IN
WHICH THE UNIVERSE COULD END. THE SIMPLEST WAY, THE WAY THAT'S
GOING TO HAPPEN IF THERE'S NOTHING GOING ON THAT WE DON'T
KNOW ABOUT - IS THAT EVERYTHING WILL GET VERY DARK AND COLD. EVENTUALLY ALL THE STARS WILL
USE UP THEIR FUEL AND BURN OUT. EVENTUALLY ALL THE BLACK
HOLES WILL EVAPORATE AND PROTONS WILL DECAY. NOTHING OF ANY
STRUCTURE WILL BE LEFT. THERE WON'T BE ANY POSSIBILITY
FOR LIFE ANY MORE BECAUSE THERE WON'T BE ANY ENERGY, ANY FREE
ENERGY FOR PEOPLE TO LIVE ON AND THERE WON'T BE REALLY
ANY CHANCE FOR ANYTHING INTERESTING TO HAPPEN. SO ANOTHER POSSIBILITY IS THAT
THE UNIVERSE WILL REALLY COME TO AN END IN SOME WAY, A SHARP END. WHAT WE THINK OF AS THE VACUUM
EMPTY SPACE MIGHT NOT BE THE LOWEST ENERGY STATE. IT MIGHT BE POSSIBLE FOR IT
TO DECAY INTO SOMETHING ELSE. SOME DIFFERENT KIND OF STUFF
WHICH WOULD BE VERY UNLIKE WHAT WE HAVE. AFTER THAT DECAY THE UNIVERSE
WOULD THEN COLLAPSE AND IN ANY CASE ONCE THE UNIVERSE IN
WHICH WE LIVE HAD DECAYED INTO SOMETHING ELSE, THE
LAWS OF PHYSICS WOULD BE COMPLETELY DIFFERENT. SO SUDDENLY WE WOULD
NOT BE HERE ANY MORE. THE USUAL WAY THAT THIS
MIGHT HAPPEN IS THROUGH THE NUCLEATION OF A BUBBLE. SO IF YOU IMAGINE THAT SOMEWHERE
OUT IN SPACE SOMEHOW A LITTLE BUBBLE FORMS OF SOMETHING
WHICH IS DIFFERENT AND HAS A LOWER ENERGY, THIS
BUBBLE MIGHT EXPAND. IT WOULD EXPAND AT
ESSENTIALLY THE SPEED OF LIGHT. WHEN THIS BUBBLE PASSED OVER
US WE WOULD CEASE TO EXIST. SO, THERE'S ANOTHER. AND EVENTUALLY THAT WOULD JUST
GO THROUGH THE WHOLE UNIVERSE. EVENTUALLY THE UNIVERSE WOULD
BE COVERED BY BUBBLES LIKE THIS. NOTHING WOULD BE LEFT EXCEPT
THIS OTHER WHATEVER IT WAS. NOW, IS THERE A
FINITE POSSIBILITY OF SUCH A BUBBLE OCCURING? IF THERE IS, THEN AT SOME
POINT IT HAS TO HAPPEN. WELL, THERE ARE TWO PIECES
TO THE QUESTION OF A FINITE POSSIBILITY OF A
BUBBLE OCCURRING. ONE IS DOES THE RIGHT THEORY OF
COSMOLOGY, THE RIGHT FUNDAMENTAL THEORY OF PHYSICS REALLY,
ALLOW THE VACUUM TO DECAY INTO SOMETHING ELSE? AND THE ANSWER TO
THAT IS NOBODY KNOWS. IF IT DID ALLOW IT,
THEN IT WOULD COME WITH SOME FINITE PROBABILITY. THEREFORE EVENTUALLY THIS WOULD
HAPPEN, SO THE UNIVERSE WOULD NOT GO ON FOREVER. EXCEPT THAT IF THE UNIVERSE
IS EXPANDING EXPONENTIALLY, THE GROWTH IN THE VOLUME DUE TO
THE EXPANSION COULD BE BIGGER FOREVER THAN THE LOSS OF THE
VOLUME DUE TO THE FORMATION OF THE BUBBLE OF SOMETHING ELSE. SO THERE WILL BE BUBBLES AND
BUBBLES AND BUBBLES AND IN THE SPACE BETWEEN THE BUBBLES
EVERYTHING WILL KEEP EXPANDING. INSIDE THE BUBBLE
PROBABLY COLLAPSES. BUT IN BETWEEN THE BUBBLES
EVERYTHING EXPANDS AND SO MAYBE HALF THE UNIVERSE IS TAKEN UP
BY THESE GROWING BUBBLES BUT THE HALF WHICH IS LEFT
EXPANDS BY TEN TIMES. SO THERE'S MORE SPACE
NOW THAN THERE WAS BEFORE. SO THE UNIVERSE COULD GO ON THAT
WAY EVEN THOUGH ANY GIVEN POINT YOU WOULD EXPECT EVENTUALLY TO
BE SWALLOWED UP BY A BUBBLE AND COME TO AN END. THE TOTAL AMOUNT OF LEFT
OVER SPACE WHICH IS STILL JUST EXPANDING AND GETTING
COLDER WOULD STILL GROW FOREVER. OF MORE INTEREST TO ME AT LEAST
IS THE POSSIBILITY THAT NEW UNIVERSES LIKE OURS
COULD FORM AS BUBBLES. AND THEN THIS WOULDN'T ALLOW
US TO CONTINUE ON FOREVER BUT INSIDE THAT
BUBBLE IT WOULD GROW. IT WOULD BECOME A WHOLE NEW
INFINITE UNIVERSE OF ITS OWN AND THAT UNIVERSE WOULD BE FULL OF
PEOPLE AND EVERYTHING ELSE THAT COULD HAPPEN IN A UNIVERSE
BECAUSE IT WOULD BE INFINITELY BIG, SO PEOPLE LIKE US WOULD
COME INTO EXISTENCE AGAIN. WOULD THERE BE ANY POSSIBILITY
OF THE ENTIRETY OF THE UNIVERSE, WE'RE USING IT LOOSELY BUT NOT
JUST THE ONE WE'RE SEATED IN BUT THE ENTIRE MULTI-VERSE, ALL
THE UNIVERSES, COMING TO AN END. IS THAT EVEN POSSIBLE? WELL THE GENERAL IDEA OF THE
WAY THAT MULTI-VERSES WORK ALL POSSIBLE THINGS ARE HAPPENING
SO COLLAPSING UNIVERSES THAT DO COME TO AN END ARE BEING
PRODUCED AND EXPANDING UNIVERSES THAT DON'T COME TO AN
END ARE BEING PRODUCED. BUT OF COURSE THE WHOLE
THING COULD BE IN A SIMULATION. THE ENTIRE MULTI VERSE COULD
BE SIMULATED AND AFTER A WHILE IT'S THE END. WELL, YEAH, BUT IN THAT CASE YOU
HAVE SOMETHING ELSE DOING THE SIMULATION AND SO THAT EXISTS. RIGHT, SO, OF COURSE WE KNOW
NOTHING ABOUT WHAT KIND OF INTELLIGENT ENTITY IT WOULD BE
THAT'S BUILT THESE BIG COMPUTERS THAT DO THE SIMULATION. THERE COULD ALSO BE
ALL KIND OF THINGS. WE DON'T KNOW AND WE NEVER CAN
KNOW FOR CERTAIN IF THE LAWS OF PHYSICS THAT WE HAVE OUR
UNDERSTANDING OF THE UNIVERSE IS THE FINAL UNDERSTANDING. THERE COULD BE MORE TO IT. THE UNIVERSE COULD REQUIRE SOME
SORT OF STUFF TO EXIST AND AFTER A WHILE THE STUFF COULD RUN OUT. OR THERE COULD BE LAWS OF
PHYSICS THAT WE DON'T KNOW ANYTHING ABOUT NOW THAT COME
INTO PLAY ONLY AFTER A LONG PERIOD OF TIME. SO THE QUESTION WILL THE
UNIVERSE EVER COME TO AN END? I DON'T THINK COULD EVER BE
REALLY DEFINITIVELY ANSWERED. THE END OF OUR UNIVERSE -
ICE OR FIRE - SEEMS INEVITABLE. BUT WHO CARES WHAT HAPPENS IN
BILLIONS OR TRILLIONS OF YEARS? EVEN SUCH A DIRE FUTURE SEEMS
IRRELEVANT TO OUR MORTAL HUMAN LIVES - WHERE LIVING TO 100
IS A CAUSE FOR CELEBRATION. I DISAGREE. I FEEL DEEPLY AND DAILY THAT
MEANING AND PURPOSE - IF ANY OF IT IS REAL - MUST RELATE TO
REALITY - WHICH INCLUDES IF, HOW AND WHY THE
UNIVERSE WILL END. BUT WISHING FOR
MEANING AND PURPOSE MUST NOT DRIVE COSMOLOGY. COSMOLOGY IS A YOUNG SCIENCE - BUT ITS REVELATIONS
ARE REMARKABLE. EVEN IF ALL THINGS WILL
ULTIMATELY END, NEW THINGS WILL ALWAYS BEGIN. AND I AM TAKEN BY "THE
PLENTITUDE OF ALL REALITY." DESTINIES, I BELIEVE, PROVIDE
PARALLEL MEANING WITH ORIGINS BECAUSE IF ORIGINS
CAN BE PROMISES, DESTINIES CAN BE FULFILLMENTS. BUT FOR ME, SIMPLY WONDERING
WHETHER THE UNIVERSE WILL END IS ITSELF MEANING - IF NOT PURPOSE. TAKING US CLOSER TO TRUTH. FOR COMPLETE INTERVIEWS
AND FOR FURHTER INFORMATION, PLEASE VISIT
WWW.CLOSERTOTRUTH.COM.
