Through the Wormhole (2010–2017): Season 1, Episode 4 - What Happened Before the Beginning? - full transcript
Following a review of the discovery and evidence for the Big Bang this program examines the progress of scientists trying to determine what went on before the Big Bang that could have caused it.
FREEMAN:
The Big Bang.
A torrent of energy
that propeIIed our universe
from nothing into everything,
creating both space and time.
It's the best theory yet
of what happened
at the beginning of time.
But a new generation
of scientists
is daring to contempIate what
was once thought impossibIe.
Are we wrong about the Big Bang?
And might we soon discover what
happened before the beginning?
Space, time, Iife itseIf.
The secrets of the cosmos
Iie through the wormhoIe.
How did the universe begin?
We've aII heard of the Big Bang,
but how do we reaIIy know
that's the way it was?
I mean, after aII, nobody
was around to see it happen.
And if that question seems
hard to answer, try this one.
What happened
before the universe began?
[ BeII cIanging ]
I first encountered
this eternaI question
at the Methodist church.
Sweet chariot
Coming for to carry me home
FREEMAN:
In the book of Genesis,
God said, ''Let there be Iight,''
and there was Iight.
God then created the heavens
and the earth.
But if everything began
at this moment,
how was God around to create it?
CouId there ever have been
a time before time?
[ Crickets chirping ]
It's a question
that has intrigued scientists
and phiIosophers
and the rest of us
for more than 5,000 years.
But in the 1 920s,
a scientific discovery
shone some new Iight
on the beginning of time
and what might have come before,
thanks to this man --
Edwin HubbIe.
Atop Mount WiIson
in Southern CaIifornia,
HubbIe aimed a powerfuI
new weapon at the heavens --
the mighty
Hooker 1 01 -inch teIescope.
As he Iooked through it,
he became the first man
to appreciate
the true scaIe of the universe.
HubbIe saw that smaII patches
of bIurry sky
were not gas cIusters,
but, in fact, other gaIaxies.
The universe was fiIIed
with not thousands,
but hundreds of biIIions
of them.
RemarkabIe as this discovery
was, HubbIe's observations
wouId Iead to an even more
profound concIusion --
The universe is expanding,
every singIe gaIaxy drifting
farther and farther apart.
Run this picture back in time,
and aII the math points
to a singIe moment
of an infiniteIy smaII,
infiniteIy dense beginning
to our universe.
Scientists have a name for this
initiaI state -- a singuIarity.
Before this Big Bang,
there is nowhere and no-when.
There is IiteraIIy nothing
before this beginning.
Run the cIock forward
from that singuIarity,
and the starting gun
is the Big Bang. . .
. . .a coIossaI expIosion
of energy and matter
that gave birth to everything
we see in the sky today.
It aIso created space and time.
As aII the radiation and matter
shoots out
in different directions,
the universe
eventuaIIy starts to cooI.
Gravity causes matter
to cIump together,
and stars are born. . .
and then expIode.
Later, swirIing disks
of dust and rocks
gather around newer stars.
EventuaIIy, severaI biIIion
years after the Big Bang,
we get a pIanet Iike Earth.
This mind-twisting story
has become the new dogma.
But however robust,
the Big Bang
is stiII just a theory.
Princeton professor of physics
Dr. David SpergeI
has spent much of his career
trying to understand if and how
this catacIysmic event happened.
PeopIe sometimes caII him
''Mr. Universe.''
For SpergeI, the Big Bang
is stiII the most compIete
and scientificaIIy sound modeI
of the earIy universe.
Everything around us
came from the hot Big Bang.
The universe started out --
Big Bang theory --
very, very hot, very dense.
That hot radiation cooIed.
From that emerged matter,
radiation,
everything that makes up
the worId around us.
And here we are at BeII Labs
at Crawford HiII,
the pIace where
the hot Big Bang theory
reaIIy aII started,
in some ways.
Arno Penzias and Robert WiIson
are a pair of radio astronomers
who worked here
at BeII Laboratories.
What they were doing is they
were studying the microwave sky
as BeII Labs was expIoring
the idea of using it
for microwave communication.
FREEMAN:
It was 1 964.
At this point,
the two men were not trying to
soIve any big cosmic questions.
They were just trying
to get the darn thing to work.
[ Hissing ]
For starters, a mysterious hiss
was interfering
with their radio signaI.
DR. SPERGEL:
Penzias and WiIson
were reaIIy good
radio astronomers,
so they buiIt
a reaIIy nice teIescope.
And they designed it so there
shouIdn't be any background,
yet it was there.
FREEMAN:
This background hiss they heard
was coming from every corner
of the sky.
WiIson and Penzias
tried everything,
even sweeping the dirt
and Ieaves out of the antenna,
but stiII there was noise.
They tried cooIing the receivers
with Iiquid heIium.
StiII there was noise.
They even removed
a famiIy of nesting pigeons
and their associated droppings.
And stiII the noise
wouId not go away.
Sometimes science consists
of cIeaning up a Iot of stuff
and seeing what's Ieft behind.
Having eIiminated
anything they can think of,
they reaIized there had to be
something eIse there.
PENZIAS:
The onIy possibiIity was
that it was coming from
somepIace outside our gaIaxy.
And that seemed Iike
such a far-out idea.
We just didn't know
what to do with that resuIt.
FREEMAN: ConsuIting with a team
of Princeton physicists,
WiIson and Penzias reaIized
that the onIy reason
something couId come
from every part of the sky
is if it were actuaIIy a faint
echo of a huge cosmic event.
We had reaIIy measured
the background temperature,
the remnant noise from
the creation of the universe.
FREEMAN: After 40 years
of specuIation and caIcuIation
by some of the most famous
scientists in the worId,
the two radio engineers
had stumbIed upon a faint cry
from our own cosmic birth.
[ Hissing continues ]
The cause of the hiss had to be
the Ieftover heat
from the Big Bang.
A picture of the beginning
of time and space
was starting to emerge.
DR. SPERGEL: This baIIoon
is our whoIe universe.
As I expand the universe. . .
. . . notice how
aII the things on the baIIoon
move apart from each other.
We're not in the center
of the universe.
It's the whoIe universe that's
expanding -- expanding in time.
Same is true with the radiation.
It's not that the microwave
radiation is coming towards us
and we're in the center
of the Big Bang.
The whoIe baIIoon is fiIIed with
radiation from the Big Bang.
As the baIIoon expands,
the radiation gets coIder.
Bigger the baIIoon,
coIder the universe is.
We can now run the universe
back in time.
The universe is contracting,
getting hotter, getting hotter,
getting hotter, hotter stiII.
We're now back at the moment
of initiaI singuIarity.
We're at the moment
in which the Big Bang started.
Everything -- aII of space --
is contracted right here.
This is when the hot radiation
was generated.
It's not generated in one spot.
It's generated everywhere.
The Big Bang happened everywhere
on the surface of the baIIoon.
FREEMAN:
The accidentaI discovery
of cosmic microwave
background radiation
earned the two radio engineers
the NobeI Prize for physics.
It aIso gave scientists
the first good estimate
of when the Big Bang happened.
Between 1 2 biIIion
and 1 4 biIIion years ago.
Our understanding
of the universe
wouId never be the same.
But for David SpergeI,
Iistening to the echo
of the Big Bang
from a hiII in New Jersey
was not good enough.
He wanted to time-traveI
back to that first moment
when Iight fiIIed the universe
and see it.
What he needed was a rocket.
MAN: We have ignition.
Looking good.
Lift-offl
FREEMAN: A rocket
which wouId take a picture
of the earIiest moment
of the universe.
lt's working its way
through the lift-off. . .
FREEMAN: 2001 .
With the Iaunch of the WiIkinson
Microwave Anisotropy Probe,
or WMAP,
scientists were attempting to
see as far back as they couId,
to the beginning of our worId.
SpergeI's dream
was taking fIight.
DR. SPERGEL: When we Iook
at the microwave background,
we're Iooking out in space,
back in time.
We're Iooking back
to when the universe
was onIy 300,000 years oId.
That's the moment at which
the universe became coId enough
that eIectrons and protons
combined to make hydrogen.
Hydrogen's transparent
to microwave Iight,
so Iight couId then traveI
freeIy from then to now.
FREEMAN: Two years Iater,
the resuIts are in.
First resuIts from
NASA's WiIkinson Microwave. . .
FREEMAN: The WMAP deIivers
on its promise --
a crystaI-cIear baby picture
of the universe
just 380,000 years
after its birth.
These pictures are worth
more than a thousand words.
This is a picture
of me as a baby.
Notice the high forehead,
the ears, the nose.
CIassic smiIe.
WeII, I'm certainIy oIder
and hopefuIIy wiser
than I was in this picture.
The basic DNA is the same.
We try to do the same thing
in cosmoIogy.
We take the universe's
baby picture,
and we see what it Iooked Iike
when it was a few days oId.
We can then use that picture
to Iook at how we got
from the baby picture
to the universe we see today.
But perhaps even more exciting,
we can take the picture
and go further back in time
and Iearn about
the universe's beginnings,
Iearn about
where the baby came from,
equivaIentIy what happened
in the first moments
of the Big Bang.
The detaiIs of our birth
are actuaIIy imprinted
in this picture.
FREEMAN:
But what happened
between that moment
of singuIarity
and the WMAP image
380,000 years Iater?
For Dr. AIan Guth,
a physicist from M IT,
this missing moment in our
universe's timeIine was the key
to everything that came before
and after the Big Bang.
DR. GUTH:
The universe that we see
is, in fact,
unbeIievabIy uniform,
and that's hard to understand,
because conventionaI expIosions
don't behave that way.
FREEMAN: But other scientists
have different ideas
about what might have happened
at that moment of singuIarity.
DR. BOJOWALD:
The physicaI Iaws break down.
The mathematicaI equations
just don't make sense anymore.
FREEMAN:
The beginning of time
is about to get
a whoIe Iot stranger.
40 years
after two radio astronomers
first heard a faint whisper
from our own cosmic birth,
David SpergeI now has his
baby picture of the universe.
Despite the vibrant coIors
visibIe in the WMAP image,
it onIy describes a miniscuIe
variation in temperature
across the universe.
DR. SPERGEL:
When we Iook at the WMAP map,
what we're seeing
are tiny variations
in the temperature of the
universe from pIace to pIace,
variations that are
one part in 1 0,000,
one part in 1 00,000.
So, I think of the universe we
Iook at with the WMAP sateIIite
as not being chaotic,
but being very ordered,
homogeneous, and smooth.
FREEMAN:
But if time and space started
in a catacIysmic expIosion
of energy,
wouIdn't the universe be uneven
and messy in aII directions?
Not exactIy.
I can't start this
with ''not exactIy,'' can I?
[ Laughs ]
FREEMAN:
For Dr. AIan Guth,
what happened
during this earIy moment in time
was an intriguing mystery
that had to be soIved.
Figuring this out
became his Iife's work.
There had been in cosmoIogy
a serious probIem
in understanding
the uniformity of the universe.
It has the same intensity
in every direction that we Iook
to one part in 1 00,000.
And that means that the Big Bang
was unbeIievabIy uniform.
And that's hard to understand,
because conventionaI expIosions
just don't behave that way.
We've set up a baIIoon
that's gonna be dropped
from a very high height
up there on a crane.
The baIIoon is fiIIed
with paint,
and we'II get to see
what kind of a spIat
a typicaI expIosion makes.
So, this is what a typicaI
expIosion might Iook Iike,
and as you can see,
it's anything but uniform.
There are spots here
and spots there
and white spots in between.
The earIy universe was nothing
Iike what's on the canvas here.
FREEMAN:
AIan needed something
that wouId immediateIy
smooth out
aII the hot, dense pIasma that
had just come into existence.
I came across
this idea of infIation,
the idea that gravity can,
under some circumstances,
act repuIsiveIy and produce
a gigantic acceIeration
in the expansion
of the universe,
and that this
couId have happened
in the very earIy universe.
The key idea behind infIation
is the possibiIity
that at Ieast a smaII patch
of the earIy universe
contained this pecuIiar kind
of repuIsive-gravity materiaI.
And aII you need
is a tiny patch of that,
and the Big Bang starts to do
this repuIsive-gravity effect.
FREEMAN:
Cosmic infIation takes pIace
right after a pop
from nothing into something.
About one triIIion,
triIIion, triIIionth
of a second afterwards,
a force fieId takes
aII the highIy compressed space
created in that first
singuIar moment,
which is stiII
aImost infiniteIy smaII. . .
and drives it out.
A tiny fraction of a second
Iater,
the universe had doubIed in size
1 00,000 times.
A different kind of painting
iIIustrates this idea.
DR. GUTH: We're going to paint
in time-Iapse photography
a growing sphere.
Instead of getting
the ''spIot'' that we had
when we just dropped
the baIIoon,
here we shouId see a very smooth
growth of an earIy universe.
FREEMAN: With this smooth
and orderIy expansion,
our universe was formed.
DR. GUTH: This idea of infIation
has now essentiaIIy become
the standard version
of cosmoIogy,
and it makes
a number of predictions
which have been confirmed,
so it agrees very weII
with what we see.
FREEMAN:
With the addition of infIation,
the Big Bang theory became
a cohesive three-act pIay.
Act one. . .
a singuIarity
pops into existence
out of nowhere and no-when,
containing in one singIe dot
aII the energy that wiII ever be
in our universe.
Act two --
infIation suddenIy takes hoId,
an unimaginabIy rapid
expansion of space
smoothIy spreading out
that energy,
bringing order to the universe.
It's now a massive soup
of evenIy expanding pIasma.
Act three -- the universe cooIs.
Matter starts to cIump together
under the force of gravity,
eventuaIIy forming
stars, gaIaxies, and pIanets.
For most cosmoIogists,
this three-act pIay
is the best expIanation
for what happened at
the beginning of the universe.
But not for everybody.
Interpreting this as a beginning
is indeed just a crutch.
It's not derived
from any theory.
It's just a pIace where
the theory itseIf breaks down.
FREEMAN: Dr. Martin BojowaId
is a professor of physics
at the Institute for Gravitation
and the Cosmos at Penn State.
He is a rising star in
a new generation of cosmoIogists
which is chaIIenging
some Iong-heId beIiefs
about the universe.
InfIation may have fixed
act two,
but Martin thinks
the pIay stiII starts
with a very unIikeIy act one.
The sudden and singuIar pop
from nothing
into the entire universe.
A singuIarity just means
we don't understand the theory
weII enough.
FREEMAN: AIan Guth used
the theory of infIation
to dig down to a triIIion,
triIIion, triIIionth of a second
after the beginning.
Martin went
a miIIion times cIoser.
In BojowaId's theory,
time is not free-fIowing,
but made up of discrete,
measurabIe chunks.
These chunks of time
are caIIed space-time atoms.
It's a very different way
of thinking about what happened
before the beginning.
[ CIock ticking ]
DR. BOJOWALD:
Here we have a beautifuI
oId grandfather cIock.
As we can see,
there's a penduIum.
It's swinging
in a continuous way,
thereby teIIing the cIock
how time is proceeding.
They're not discrete marks,
but rather a continuous motion
of the penduIum.
This is the cIassicaI picture
of time measured continuousIy.
Now, in quantized time,
it's a whoIe different story.
For quantized time,
we have a picture
as given by the second hand
of the cIock here.
It's not continuous.
It's not the penduIum swing,
which we couId stop
at any time, at any position.
Here, the different positions
are given
by certain discrete sets between
one tick and the next one.
It's a finite amount of time
which cannot be
further subdivided.
FREEMAN: In BojowaId's version
of the earIy universe,
you never get to nothing.
The second hand
on the quantized cIock
marks not just
the beginning of one moment,
but the end of another.
The tick that signaIed dawn
in our universe
marks one second past midnight
in the Iast.
[ CIock ticking ]
DR. BOJOWALD: So,
we have this baIIoon universe.
If we imagine what it couId have
been before the Big Bang,
it was coIIapsing,
so the voIume was shrinking.
Now, if we foIIow
the usuaI evoIution,
according to generaI reIativity,
that wouId have been ending
in a singuIarity.
The whoIe baIIoon
wouId just compIeteIy defIate.
But with the atomic nature
of space and time,
the attractive behavior
of gravity changes.
It becomes repuIsive
at these high densities.
The coIIapse stops.
Then the forces turn around,
so there's a repuIsive force
which makes the universe
re-expand.
At some point --
we're not sure yet --
but it might recoIIapse
at some time in the future,
so aII the air
might go out again.
The voIume wouId decrease,
the density wouId increase,
and then probabIy approach
another Big Bang.
FREEMAN: The universe
expands and contracts,
but it never actuaIIy begins.
There couId have been a series
of universes before this one
and more to come after this one.
BojowaId is working through
the probIems and conundrums
that aII
radicaI new theories face.
His theory is by no means
compIete, and it may never be.
DR. BOJOWALD: We are stiII
working on the equations.
We don't have
the compIete answer yet,
but it seems to be
the best theory yet
to address these issues.
[ BeII toIIs, cIock ticking ]
FREEMAN:
But in 2001 ,
two of the Ieading cosmoIogists
in the worId
pubIished a paper suggesting
an even more radicaI approach
to what happened
at the beginning.
For these two scientists,
there was another answer
so strange and unexpected
that it had never
been considered.
There are bangs and bangs
and bangs forever.
FREEMAN: Our universe
may not be the onIy one,
but one of hundreds, thousands,
maybe an infinite number.
It's an inspiring
and daunting suggestion --
the universe is an endIess cycIe
prompted by an endIess series
of bangs, forever.
When you Iook out into space,
gaze at a distant star,
you aIso Iook back in time.
Light from distant gaIaxies
can take biIIions of years
to reach us.
Now we know there's a Iimit
to how far back we can see,
an edge to the visibIe universe.
The Iight
from that cosmic backdrop
has taken 1 3.7 biIIion years
to make it to Earth.
What Iies beyond that curtain?
According to
Professor Martin BojowaId,
time becomes
squeezed and distorted
as it nears a singuIarity
and then bounces back out
into another expansion.
But perhaps there's
an aItogether different way
to Iook at what happened
before the beginning.
South African scientist
Dr. NeiI Turok
is now daring to go
further into the past
than aImost anyone eIse.
Africa!
Africa!
His radicaI view of the cosmos
was infIuenced
by his parents' struggIes
during apartheid.
DR. TUROK: My father and mother
were poIiticaI activists
against
the South African government.
They went to jaiI
for their opinions.
But uItimateIy,
democracy came to South Africa,
and they were both eIected
members of ParIiament --
the onIy husband-and-wife
members of ParIiament
apart from NeIson
and Winnie MandeIa.
They served
as a modeI of persistence.
Just because at the moment
your ideas are not fashionabIe
or agreed upon,
if you beIieve what you're doing
is right, persist.
FREEMAN: From the moment
he entered the fieId
of theoreticaI physics,
the South African scientist
was Iooking for new answers
to age-oId probIems.
DR. TUROK: There is
a conventionaI wisdom
in the fieId, and peopIe are
very sIow to adopt new ideas.
And, frankIy,
many peopIe have buiIt
their careers on the status quo,
and they don't want a new idea
coming aIong
and rocking the boat.
FREEMAN:
For NeiI, the WMAP announcement
brought up famiIiar feeIings
about seeing the universe
through
a sIightIy different Iens
than some of his coIIeagues.
DR. TUROK:
In the WMAP press announcement,
of course
the scientists invoIved
Iinked it expIicitIy
to infIation
and said, ''This dramaticaIIy
confirms infIation.''
And this made me squirm.
[ Laughs ]
My point of view
was that the information
contained in the WMAP data
was, in itseIf, not sufficient
to prove or refute infIation.
FREEMAN:
He wasn't aIone.
Across the AtIantic, another
intrepid scientist Iabored
to uncover the truth behind what
happened before the beginning.
PauI Steinhardt
is the AIbert Einstein
professor of physics
at Princeton University.
As a young man,
PauI was inspired to study
science by the moon Iandings.
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.
[ AppIause ]
FREEMAN: In 1 999,
the two men combined forces
to see if they couId answer
some of their probIems
with the infIationary modeI of
what happened at the beginning.
InfIation had
some extraordinary successes,
so it's tough competition
to compete with infIation.
So I wiII not teII you aII
the ideas that were attempted
and dumped in the wastebasket.
We have simiIar objectives,
which is to shake the fieId up
once in a whiIe
and come up with something boId
and originaI and different
and to improve
on the status quo.
DR. STEINHARDT: I organized
a conference with NeiI Turok.
We had a common interest
in string theory,
which were just coming out
at that time,
whether they might stimuIate
some new ideas in cosmoIogy.
FREEMAN: String theory was
deveIoped in the Iast 35 years
as an attempt to devise
a singIe theory
expIaining everything
in the universe.
In it, everything is made
of minute, vibrating strings.
But for the mathematics
of string theory to work,
there have to be
more than the three dimensions
of space that we see.
Rather, there are 1 0 dimensions
pIus time.
Space-time is a fIexibIe
substance, Iike a membrane,
and it can stretch and shrink.
So, we knew
these things couId move,
but nobody had reaIIy studied
the dynamics of that process.
So we brought in experts,
Iike Burt Ovrut,
who is one of the most
proficient deveIopers
of particIe-physics modeIs
based on string theory.
DR. STEINHARDT: And he gave
a beautifuI series of Iectures
in which he described to us
this idea
of our three-dimensionaI worId
being embedded in a brane worId
separated by a smaII gap
from another brane worId
aIong
an extra spatiaI dimension.
DR. TUROK: And as we sat there,
we both had the same thoughts. . .
DR. STEINHARDT:
Which is, if you imagine
that this is reaIIy
the structure of the universe,
there's a new
possibIe interpretation
for what is the Big Bang.
What have we
not been facing up to, you know?
What is
the eIephant in the room?
And the number-one question
was the singuIarity.
We both sort of approached Burt
from both ends.
And cornered Burt
after his Iecture.
Each of us finished
the sentence of the other.
And said, ''You know, weII,
what about
if these things coIIide?
What wouId happen then?''
''And is it possibIe
the Big Bang is not a beginning,
but is a coIIision?''
And his response was, ''Maybe.''
FREEMAN:
The meeting soon broke up,
but the three men
had aII been invited
to attend the same pIay
in London that evening.
DR. STEINHARDT:
We met at the train pIatform,
and then we began to reaIIy
imagine this idea in more detaiI
about what it wouId mean if the
Big Bang were not a beginning,
but the Big Bang
were a coIIision.
DR. TUROK: And then
we had a train ride to London,
where we just brainstormed
about this
in a very Ioose and unstructured
and unmathematicaI way.
DR. STEINHARDT: We asked
ourseIves the question,
''CouId we invent something
which was different
than the infIationary picture,
that was different
than the standard picture?''
DR. TUROK: We had
some rough ideas how to do it,
but it wasn't at aII obvious.
DR. STEINHARDT:
Time was fIying past us
as the train was moving aIong.
It's one of those rare occasions
when you're having
a conversation
and you feeI Iike a reaIIy
exciting idea is emerging --
sort of that sixth sense
that something important
is happening.
Coming up with this rough idea
for how things might work
is, of course, exciting.
But in having an idea Iike that
and then deciding
to reaIIy pursue it,
you are condemning yourseIf
to years of misery,
because you now have to
fIesh this out.
FREEMAN: And to soIve
this mystery, NeiI and PauI
wouId turn to one of
the toughest mentaI chaIIenges
of the human mind --
the incredibIy strange worId
of 1 1 -dimensionaI space.
And universes
paraIIeI to our own.
AIbert Einstein
was a formidabIe thinker.
His theories of reIativity
were groundbreaking deveIopments
that triggered
a century of cosmic insights.
But even more fundamentaI
was his reaIization that time
and space are intertwined.
The three dimensions of space
are reaIIy part
of a four-dimensionaI fabric
caIIed space-time.
But now there's a new movement
in theoreticaI physics.
It's caIIed string theory.
And out of string theory
comes M-theory.
In M-theory, there are not four,
but an astounding
1 1 dimensions --
1 0 dimensions of space
pIus one of time.
What is M-theory?
Okay.
So, M-theory is an attempt to --
Let me start again.
Three-dimensionaI infinite
worIds stretching off --
Let me start again.
Why wouId one
even think about --
I mean, how does one
make that not sound crazy
in two sentences?
[ Laughs ]
So, M-theory is a. . .
promising, unified theory
of aII the fundamentaI forces
and constituents
that we observe in nature.
In a sense,
you couId describe it
as the cuImination
of aII the deveIopments
in theoreticaI physics
over the 20th century.
In order
to make this theory work,
one needs to have more than the
usuaI three spatiaI dimensions,
so a key idea behind M-theory
is that there are more than
the three dimensions of space
that we experience.
There are hidden dimensions.
In fact, there are seven more.
And the reason
we're not aware of them
is that they are so, so tiny
that in order to see them,
you'd need an enormousIy
powerfuI microscope
far more powerfuI
than any we have.
Our three-dimensionaI worId
Iives in a surface
embedded in a space
with an extra spatiaI dimension
that separates it
from another such surface.
FREEMAN:
One possibiIity
that springs
from these extra dimensions
is that this other
three-dimensionaI worId
couId be just a fraction
of a centimeter from ours
and yet hidden from our view.
DR. STEINHARDT: These surfaces
are caIIed branes,
standing for ''membrane,''
which is to remind us
that these surfaces are eIastic.
They can stretch,
they can wiggIe, they can warp.
They can move
aIong this extra dimension.
AII of the particIes
we're made of
are actuaIIy
curIed-up IittIe branes.
And aII the dimensions of space
we traveI in
are comprised
of branes themseIves.
And so
everything in the universe
is composed
of these geometricaI objects.
I don't know
if I can repeat that again.
[ Laughs ]
FREEMAN: Caution.
You have entered a pIace
caIIed ''brane worId.''
DR. STEINHARDT: We're stuck
Iike fIies on fIy paper
on our brane worId.
We simpIy can't reach out
into the extra dimension --
even 1 0 to the minus-30
centimeters --
to touch the other brane worId.
FREEMAN: It was
through this worId of branes
that PauI and NeiI
stumbIed onto a potentiaIIy
radicaI new theory
of what happened
before the beginning.
So, here
I have a piece of materiaI,
and it Iooks Iike
a two-dimensionaI object
because one of the dimensions
goes up
and one goes side to side.
But if we Iook a IittIe bit
cIoser at this object,
and Iook at it from the side,
you'II see that actuaIIy
there are two
pieces of materiaI,
separated by a tiny gap.
And you couId think of this gap
as being
the fourth dimension of space.
And the coIIision of these two
three-dimensionaI worIds --
the one we Iive in
and another one --
wouId have been the Big Bang.
It wouId be a coIIision instead
of a springing from nothingness.
So, if the branes existed
before and after,
that means
space and time existed before.
They couId have heIped set up
the conditions we observe
in the universe today.
They coIIide,
and they move apart again.
The Big Bang
is not the beginning.
That means we have more time
to soIve
aII the cosmoIogicaI probIems
that infIation was designed
to soIve.
So, we began to imagine,
''CouId we repIace that idea
with something that occurred
before the bang?''
And as we were going
aIong the train ride,
we began to imagine
Iots of possibiIities,
so that by the end, it seemed
Iike a very exciting aIternative
to the standard
Big Bang infIationary picture.
FREEMAN:
For the next 1 8 months,
the three men and another
physicist, Justin Khoury,
worked feverishIy
to cIarify and justify
their initiaI spark
of creativity.
DR. STEINHARDT: Now we had to
make the mathematics work,
and this invoIved
deveIoping a Iot of new physics
to expIain the motion of branes
moving aIong extra dimensions
under the infIuence of a force
which is trying
to draw them together.
This mathematics
didn't exist before.
FREEMAN: A new theory of the
universe starts to come aIive.
DR. TUROK:
The picture we had in mind
was two three-dimensionaI worIds
stretching off to infinity
but separated from each other
by a tiny gap --
a fourth dimension of space.
The two three-dimensionaI worIds
are actuaIIy puIIed together
by a very, very weak force.
The force
has to be very, very weak.
Otherwise the bang wouId occur
too quickIy.
DR. STEINHARDT: We know that
the cycIes can't be too short,
because the universe has aIready
gone 1 4 biIIion years
since the Iast bang.
A triIIion years is probabIy
a good, you know, typicaI vaIue
for what we expect
the Iength of a cycIe to be.
DR. TUROK:
As the branes approach,
the force
gets stronger and stronger.
And when they coIIide,
kinetic energy of the branes
is then converted
into the hot radiation
that fiIIs
both three-dimensionaI worIds
and Iooks Iike the Big Bang.
DR. STEINHARDT: So that when
the branes move apart again,
they're now fiIIed
with the matter and radiation
that was created
at the coIIision.
This then causes the branes to
begin to expand again and cooI,
creating a new period
of expansion, cooIing,
creation of new atoms,
moIecuIes, stars, and gaIaxies.
We now had an expIanation
for the Big Bang.
This is normaIIy referred to
as cosmic singuIarity --
some sort of breakdown
in the Iaws of physics,
which in the standard Big Bang
theory, you simpIy ignore.
But in this picture,
you are actuaIIy providing
an expIanation for it.
It was, in fact, the coIIision
between these two brane worIds.
It was a theory of
what was the cosmic singuIarity.
FREEMAN: It was a radicaI
and eIegant soIution
to one of the great
cosmic mysteries of aII time.
According to NeiI and PauI
and their coIIeagues
Burt and Justin,
there was aIways
a time before time.
After aImost two years of work,
it was time
to present this new theory
to their feIIow scientists.
At a conference in FinIand,
the two physicists
Iaid out their theory.
The reception was icy.
The criticism was that we were
simpIy assuming or asserting
the branes wouId be fIat
and paraIIeI to begin with
without showing
why that shouId be the case.
We'd been so excited
about this idea,
and yet everyone eIse
was just pooh-poohing it.
To be fair, I mean, the session
did not go weII for us.
The next morning,
we were both rather depressed,
so we began to traveI
aIong the river near Rovaniemi
and have this discussion about,
''What couId we repIace
this idea with?''
So, we began to think
about something
that wasn't yet incIuded
in the theory,
which was
the idea of dark energy.
FREEMAN:
Dark energy is a recent
and totaIIy surprising
astronomicaI discovery --
a mysterious force
that's causing the universe
to expand even faster.
EventuaIIy, the dark energy
wiII expand the universe so much
that it wiII be nothing
but coId and empty space.
In the Ianguage of M-theory,
that transIates to a fIat brane.
The dark-energy phase stretches
out the three-dimensionaI worIds
and makes them very fIat and
very empty and very paraIIeI.
Of course, that immediateIy
cIicked with another idea.
WeII, we're using something now,
but we're using it
before the bang.
WeII, maybe
the source of dark energy then
was actuaIIy
the same as the one now
and the universe
is cycIic somehow.
DR. TUROK:
So you couId have a bang
foIIowed by
a normaI period of the universe,
Iike we Iive in today,
foIIowed by a second bang
in our future,
foIIowed by another bang,
and so on.
There are bangs
and bangs and bangs forever.
FREEMAN:
Their theory was now compIete.
Two branes come together,
inject one another with energy.
Then dark energy
takes a triIIion years or so
to spread that energy out.
The branes fIatten
and then come together again.
This cycIe happens endIessIy.
NeiI Turok and PauI Steinhardt
had come up with
a remarkabIe aIternative theory
to the Big Bang
and cracked the door onto what
happened before the beginning.
As different as the modeIs are,
they produce
the same exact variations
in the background radiation.
The same WMAP image
fits both ideas.
It's certainIy the case that
when WMAP made its announcement,
the way most peopIe interpreted
that announcement was,
it's beautifuIIy consistent
with the Big Bang
infIationary picture.
To us, it meant
that the cycIic modeI
was in the game
as much as infIation was.
FREEMAN:
But which theory is right?
The answer to one of the biggest
cosmic mysteries of aII --
was there a time
before our time? --
couId be circIing the earth
a miIIion miIes over our heads.
Professor Martin BojowaId's
bouncing universe
is stiII a work in progress,
but for proponents
of the cycIic and
the Big Bang infIation modeI,
the answer to how and when
the universe started
may be moving toward us
across time and space
Iike tiny rippIes
in the cosmic ocean.
GravitationaI waves.
DR. TUROK: GravitationaI wave is
pretty much Iike a sound wave.
[ Horn bIares ]
We're used to a sound wave
traveIing from me to you
as I speak,
as a compression and expansion
of the air between us.
And so the moIecuIes get more
denseIy packed and further apart
as the wave moves
from me to you.
FREEMAN:
But gravitationaI waves rippIe
not air moIecuIes,
but space itseIf,
which means
that they can stretch out
or compress a beam of Iight
and cause a shift in its coIor.
DR. TUROK:
So, if space is expanded,
we'II see the radiation shifted
to red frequencies,
Ionger waveIengths.
But if it's coming towards us,
we'II see
it's sIightIy bIuer than
it wouId otherwise have been.
And so by carefuIIy anaIyzing
the pattern of radiation
on the sky,
we can, in fact, infer
if there are gravitationaI waves
traveIing through
our part of the universe.
FREEMAN:
And rocket technoIogy
wiII get the scientists
far enough up into space
to espy
these gravitationaI waves.
DR. SPERGEL:
The PIanck sateIIite
is the successor to WMAP.
It wiII be measuring the sky
with about twice the resoIution
and about
1 0 times the sensitivity.
The PIanck sateIIite is reaIIy
the first device we have
which seems to have
a strong capabiIity
of maybe finding
these gravity waves.
And if we're Iucky,
that'II teII us what happened
during the first moments
of the Big Bang,
or maybe even before.
FREEMAN: For proponents
of the Big Bang infIation modeI,
finding significant
gravitationaI waves
wouId be the finaI step
in proving
that there was a giant expansion
of whooshing energy
from a pIace
of nowhere and no-when.
But PauI Steinhardt
and NeiI Turok
are aIso Iooking forward
to the PIanck sateIIite resuIts.
In their cycIic modeI of
the beginning of the universe,
two branes coming together
wouId be
a much Iess intense coIIision,
and the chances are
that gravitationaI waves
wouId be aImost nonexistent.
If we observe
these gravitationaI waves
in the PIanck sateIIite,
that wiII support
the infIationary theory
and ruIe out the cycIic picture.
And converseIy,
if we don't see them,
that wouId strongIy support
the cycIic picture.
FREEMAN:
But no matter which description
of the beginning of the universe
appears to be more accurate,
the true winner wiII be our own
scientific understanding.
Yeah, to me,
it's man against nature.
We're trying to figure out
nature's secrets.
If we're Iucky,
we'II be surprised.
FREEMAN: These tiny,
aImost undetectabIe waves
wiII have a tsunami-Iike effect
on the future direction
of cosmoIogy.
Instead of appearing
from nowhere and no-when
and rising
from stardust to humankind,
we may have to consider
the mind-boggIing premise
that we are just
the Iatest version
of an endIess series
of universes.
We stiII might not know what
happened before the beginning.
But we wouId know
that something did.
The finaI answer
may be cIose at hand.
The Big Bang.
A torrent of energy
that propeIIed our universe
from nothing into everything,
creating both space and time.
It's the best theory yet
of what happened
at the beginning of time.
But a new generation
of scientists
is daring to contempIate what
was once thought impossibIe.
Are we wrong about the Big Bang?
And might we soon discover what
happened before the beginning?
Space, time, Iife itseIf.
The secrets of the cosmos
Iie through the wormhoIe.
How did the universe begin?
We've aII heard of the Big Bang,
but how do we reaIIy know
that's the way it was?
I mean, after aII, nobody
was around to see it happen.
And if that question seems
hard to answer, try this one.
What happened
before the universe began?
[ BeII cIanging ]
I first encountered
this eternaI question
at the Methodist church.
Sweet chariot
Coming for to carry me home
FREEMAN:
In the book of Genesis,
God said, ''Let there be Iight,''
and there was Iight.
God then created the heavens
and the earth.
But if everything began
at this moment,
how was God around to create it?
CouId there ever have been
a time before time?
[ Crickets chirping ]
It's a question
that has intrigued scientists
and phiIosophers
and the rest of us
for more than 5,000 years.
But in the 1 920s,
a scientific discovery
shone some new Iight
on the beginning of time
and what might have come before,
thanks to this man --
Edwin HubbIe.
Atop Mount WiIson
in Southern CaIifornia,
HubbIe aimed a powerfuI
new weapon at the heavens --
the mighty
Hooker 1 01 -inch teIescope.
As he Iooked through it,
he became the first man
to appreciate
the true scaIe of the universe.
HubbIe saw that smaII patches
of bIurry sky
were not gas cIusters,
but, in fact, other gaIaxies.
The universe was fiIIed
with not thousands,
but hundreds of biIIions
of them.
RemarkabIe as this discovery
was, HubbIe's observations
wouId Iead to an even more
profound concIusion --
The universe is expanding,
every singIe gaIaxy drifting
farther and farther apart.
Run this picture back in time,
and aII the math points
to a singIe moment
of an infiniteIy smaII,
infiniteIy dense beginning
to our universe.
Scientists have a name for this
initiaI state -- a singuIarity.
Before this Big Bang,
there is nowhere and no-when.
There is IiteraIIy nothing
before this beginning.
Run the cIock forward
from that singuIarity,
and the starting gun
is the Big Bang. . .
. . .a coIossaI expIosion
of energy and matter
that gave birth to everything
we see in the sky today.
It aIso created space and time.
As aII the radiation and matter
shoots out
in different directions,
the universe
eventuaIIy starts to cooI.
Gravity causes matter
to cIump together,
and stars are born. . .
and then expIode.
Later, swirIing disks
of dust and rocks
gather around newer stars.
EventuaIIy, severaI biIIion
years after the Big Bang,
we get a pIanet Iike Earth.
This mind-twisting story
has become the new dogma.
But however robust,
the Big Bang
is stiII just a theory.
Princeton professor of physics
Dr. David SpergeI
has spent much of his career
trying to understand if and how
this catacIysmic event happened.
PeopIe sometimes caII him
''Mr. Universe.''
For SpergeI, the Big Bang
is stiII the most compIete
and scientificaIIy sound modeI
of the earIy universe.
Everything around us
came from the hot Big Bang.
The universe started out --
Big Bang theory --
very, very hot, very dense.
That hot radiation cooIed.
From that emerged matter,
radiation,
everything that makes up
the worId around us.
And here we are at BeII Labs
at Crawford HiII,
the pIace where
the hot Big Bang theory
reaIIy aII started,
in some ways.
Arno Penzias and Robert WiIson
are a pair of radio astronomers
who worked here
at BeII Laboratories.
What they were doing is they
were studying the microwave sky
as BeII Labs was expIoring
the idea of using it
for microwave communication.
FREEMAN:
It was 1 964.
At this point,
the two men were not trying to
soIve any big cosmic questions.
They were just trying
to get the darn thing to work.
[ Hissing ]
For starters, a mysterious hiss
was interfering
with their radio signaI.
DR. SPERGEL:
Penzias and WiIson
were reaIIy good
radio astronomers,
so they buiIt
a reaIIy nice teIescope.
And they designed it so there
shouIdn't be any background,
yet it was there.
FREEMAN:
This background hiss they heard
was coming from every corner
of the sky.
WiIson and Penzias
tried everything,
even sweeping the dirt
and Ieaves out of the antenna,
but stiII there was noise.
They tried cooIing the receivers
with Iiquid heIium.
StiII there was noise.
They even removed
a famiIy of nesting pigeons
and their associated droppings.
And stiII the noise
wouId not go away.
Sometimes science consists
of cIeaning up a Iot of stuff
and seeing what's Ieft behind.
Having eIiminated
anything they can think of,
they reaIized there had to be
something eIse there.
PENZIAS:
The onIy possibiIity was
that it was coming from
somepIace outside our gaIaxy.
And that seemed Iike
such a far-out idea.
We just didn't know
what to do with that resuIt.
FREEMAN: ConsuIting with a team
of Princeton physicists,
WiIson and Penzias reaIized
that the onIy reason
something couId come
from every part of the sky
is if it were actuaIIy a faint
echo of a huge cosmic event.
We had reaIIy measured
the background temperature,
the remnant noise from
the creation of the universe.
FREEMAN: After 40 years
of specuIation and caIcuIation
by some of the most famous
scientists in the worId,
the two radio engineers
had stumbIed upon a faint cry
from our own cosmic birth.
[ Hissing continues ]
The cause of the hiss had to be
the Ieftover heat
from the Big Bang.
A picture of the beginning
of time and space
was starting to emerge.
DR. SPERGEL: This baIIoon
is our whoIe universe.
As I expand the universe. . .
. . . notice how
aII the things on the baIIoon
move apart from each other.
We're not in the center
of the universe.
It's the whoIe universe that's
expanding -- expanding in time.
Same is true with the radiation.
It's not that the microwave
radiation is coming towards us
and we're in the center
of the Big Bang.
The whoIe baIIoon is fiIIed with
radiation from the Big Bang.
As the baIIoon expands,
the radiation gets coIder.
Bigger the baIIoon,
coIder the universe is.
We can now run the universe
back in time.
The universe is contracting,
getting hotter, getting hotter,
getting hotter, hotter stiII.
We're now back at the moment
of initiaI singuIarity.
We're at the moment
in which the Big Bang started.
Everything -- aII of space --
is contracted right here.
This is when the hot radiation
was generated.
It's not generated in one spot.
It's generated everywhere.
The Big Bang happened everywhere
on the surface of the baIIoon.
FREEMAN:
The accidentaI discovery
of cosmic microwave
background radiation
earned the two radio engineers
the NobeI Prize for physics.
It aIso gave scientists
the first good estimate
of when the Big Bang happened.
Between 1 2 biIIion
and 1 4 biIIion years ago.
Our understanding
of the universe
wouId never be the same.
But for David SpergeI,
Iistening to the echo
of the Big Bang
from a hiII in New Jersey
was not good enough.
He wanted to time-traveI
back to that first moment
when Iight fiIIed the universe
and see it.
What he needed was a rocket.
MAN: We have ignition.
Looking good.
Lift-offl
FREEMAN: A rocket
which wouId take a picture
of the earIiest moment
of the universe.
lt's working its way
through the lift-off. . .
FREEMAN: 2001 .
With the Iaunch of the WiIkinson
Microwave Anisotropy Probe,
or WMAP,
scientists were attempting to
see as far back as they couId,
to the beginning of our worId.
SpergeI's dream
was taking fIight.
DR. SPERGEL: When we Iook
at the microwave background,
we're Iooking out in space,
back in time.
We're Iooking back
to when the universe
was onIy 300,000 years oId.
That's the moment at which
the universe became coId enough
that eIectrons and protons
combined to make hydrogen.
Hydrogen's transparent
to microwave Iight,
so Iight couId then traveI
freeIy from then to now.
FREEMAN: Two years Iater,
the resuIts are in.
First resuIts from
NASA's WiIkinson Microwave. . .
FREEMAN: The WMAP deIivers
on its promise --
a crystaI-cIear baby picture
of the universe
just 380,000 years
after its birth.
These pictures are worth
more than a thousand words.
This is a picture
of me as a baby.
Notice the high forehead,
the ears, the nose.
CIassic smiIe.
WeII, I'm certainIy oIder
and hopefuIIy wiser
than I was in this picture.
The basic DNA is the same.
We try to do the same thing
in cosmoIogy.
We take the universe's
baby picture,
and we see what it Iooked Iike
when it was a few days oId.
We can then use that picture
to Iook at how we got
from the baby picture
to the universe we see today.
But perhaps even more exciting,
we can take the picture
and go further back in time
and Iearn about
the universe's beginnings,
Iearn about
where the baby came from,
equivaIentIy what happened
in the first moments
of the Big Bang.
The detaiIs of our birth
are actuaIIy imprinted
in this picture.
FREEMAN:
But what happened
between that moment
of singuIarity
and the WMAP image
380,000 years Iater?
For Dr. AIan Guth,
a physicist from M IT,
this missing moment in our
universe's timeIine was the key
to everything that came before
and after the Big Bang.
DR. GUTH:
The universe that we see
is, in fact,
unbeIievabIy uniform,
and that's hard to understand,
because conventionaI expIosions
don't behave that way.
FREEMAN: But other scientists
have different ideas
about what might have happened
at that moment of singuIarity.
DR. BOJOWALD:
The physicaI Iaws break down.
The mathematicaI equations
just don't make sense anymore.
FREEMAN:
The beginning of time
is about to get
a whoIe Iot stranger.
40 years
after two radio astronomers
first heard a faint whisper
from our own cosmic birth,
David SpergeI now has his
baby picture of the universe.
Despite the vibrant coIors
visibIe in the WMAP image,
it onIy describes a miniscuIe
variation in temperature
across the universe.
DR. SPERGEL:
When we Iook at the WMAP map,
what we're seeing
are tiny variations
in the temperature of the
universe from pIace to pIace,
variations that are
one part in 1 0,000,
one part in 1 00,000.
So, I think of the universe we
Iook at with the WMAP sateIIite
as not being chaotic,
but being very ordered,
homogeneous, and smooth.
FREEMAN:
But if time and space started
in a catacIysmic expIosion
of energy,
wouIdn't the universe be uneven
and messy in aII directions?
Not exactIy.
I can't start this
with ''not exactIy,'' can I?
[ Laughs ]
FREEMAN:
For Dr. AIan Guth,
what happened
during this earIy moment in time
was an intriguing mystery
that had to be soIved.
Figuring this out
became his Iife's work.
There had been in cosmoIogy
a serious probIem
in understanding
the uniformity of the universe.
It has the same intensity
in every direction that we Iook
to one part in 1 00,000.
And that means that the Big Bang
was unbeIievabIy uniform.
And that's hard to understand,
because conventionaI expIosions
just don't behave that way.
We've set up a baIIoon
that's gonna be dropped
from a very high height
up there on a crane.
The baIIoon is fiIIed
with paint,
and we'II get to see
what kind of a spIat
a typicaI expIosion makes.
So, this is what a typicaI
expIosion might Iook Iike,
and as you can see,
it's anything but uniform.
There are spots here
and spots there
and white spots in between.
The earIy universe was nothing
Iike what's on the canvas here.
FREEMAN:
AIan needed something
that wouId immediateIy
smooth out
aII the hot, dense pIasma that
had just come into existence.
I came across
this idea of infIation,
the idea that gravity can,
under some circumstances,
act repuIsiveIy and produce
a gigantic acceIeration
in the expansion
of the universe,
and that this
couId have happened
in the very earIy universe.
The key idea behind infIation
is the possibiIity
that at Ieast a smaII patch
of the earIy universe
contained this pecuIiar kind
of repuIsive-gravity materiaI.
And aII you need
is a tiny patch of that,
and the Big Bang starts to do
this repuIsive-gravity effect.
FREEMAN:
Cosmic infIation takes pIace
right after a pop
from nothing into something.
About one triIIion,
triIIion, triIIionth
of a second afterwards,
a force fieId takes
aII the highIy compressed space
created in that first
singuIar moment,
which is stiII
aImost infiniteIy smaII. . .
and drives it out.
A tiny fraction of a second
Iater,
the universe had doubIed in size
1 00,000 times.
A different kind of painting
iIIustrates this idea.
DR. GUTH: We're going to paint
in time-Iapse photography
a growing sphere.
Instead of getting
the ''spIot'' that we had
when we just dropped
the baIIoon,
here we shouId see a very smooth
growth of an earIy universe.
FREEMAN: With this smooth
and orderIy expansion,
our universe was formed.
DR. GUTH: This idea of infIation
has now essentiaIIy become
the standard version
of cosmoIogy,
and it makes
a number of predictions
which have been confirmed,
so it agrees very weII
with what we see.
FREEMAN:
With the addition of infIation,
the Big Bang theory became
a cohesive three-act pIay.
Act one. . .
a singuIarity
pops into existence
out of nowhere and no-when,
containing in one singIe dot
aII the energy that wiII ever be
in our universe.
Act two --
infIation suddenIy takes hoId,
an unimaginabIy rapid
expansion of space
smoothIy spreading out
that energy,
bringing order to the universe.
It's now a massive soup
of evenIy expanding pIasma.
Act three -- the universe cooIs.
Matter starts to cIump together
under the force of gravity,
eventuaIIy forming
stars, gaIaxies, and pIanets.
For most cosmoIogists,
this three-act pIay
is the best expIanation
for what happened at
the beginning of the universe.
But not for everybody.
Interpreting this as a beginning
is indeed just a crutch.
It's not derived
from any theory.
It's just a pIace where
the theory itseIf breaks down.
FREEMAN: Dr. Martin BojowaId
is a professor of physics
at the Institute for Gravitation
and the Cosmos at Penn State.
He is a rising star in
a new generation of cosmoIogists
which is chaIIenging
some Iong-heId beIiefs
about the universe.
InfIation may have fixed
act two,
but Martin thinks
the pIay stiII starts
with a very unIikeIy act one.
The sudden and singuIar pop
from nothing
into the entire universe.
A singuIarity just means
we don't understand the theory
weII enough.
FREEMAN: AIan Guth used
the theory of infIation
to dig down to a triIIion,
triIIion, triIIionth of a second
after the beginning.
Martin went
a miIIion times cIoser.
In BojowaId's theory,
time is not free-fIowing,
but made up of discrete,
measurabIe chunks.
These chunks of time
are caIIed space-time atoms.
It's a very different way
of thinking about what happened
before the beginning.
[ CIock ticking ]
DR. BOJOWALD:
Here we have a beautifuI
oId grandfather cIock.
As we can see,
there's a penduIum.
It's swinging
in a continuous way,
thereby teIIing the cIock
how time is proceeding.
They're not discrete marks,
but rather a continuous motion
of the penduIum.
This is the cIassicaI picture
of time measured continuousIy.
Now, in quantized time,
it's a whoIe different story.
For quantized time,
we have a picture
as given by the second hand
of the cIock here.
It's not continuous.
It's not the penduIum swing,
which we couId stop
at any time, at any position.
Here, the different positions
are given
by certain discrete sets between
one tick and the next one.
It's a finite amount of time
which cannot be
further subdivided.
FREEMAN: In BojowaId's version
of the earIy universe,
you never get to nothing.
The second hand
on the quantized cIock
marks not just
the beginning of one moment,
but the end of another.
The tick that signaIed dawn
in our universe
marks one second past midnight
in the Iast.
[ CIock ticking ]
DR. BOJOWALD: So,
we have this baIIoon universe.
If we imagine what it couId have
been before the Big Bang,
it was coIIapsing,
so the voIume was shrinking.
Now, if we foIIow
the usuaI evoIution,
according to generaI reIativity,
that wouId have been ending
in a singuIarity.
The whoIe baIIoon
wouId just compIeteIy defIate.
But with the atomic nature
of space and time,
the attractive behavior
of gravity changes.
It becomes repuIsive
at these high densities.
The coIIapse stops.
Then the forces turn around,
so there's a repuIsive force
which makes the universe
re-expand.
At some point --
we're not sure yet --
but it might recoIIapse
at some time in the future,
so aII the air
might go out again.
The voIume wouId decrease,
the density wouId increase,
and then probabIy approach
another Big Bang.
FREEMAN: The universe
expands and contracts,
but it never actuaIIy begins.
There couId have been a series
of universes before this one
and more to come after this one.
BojowaId is working through
the probIems and conundrums
that aII
radicaI new theories face.
His theory is by no means
compIete, and it may never be.
DR. BOJOWALD: We are stiII
working on the equations.
We don't have
the compIete answer yet,
but it seems to be
the best theory yet
to address these issues.
[ BeII toIIs, cIock ticking ]
FREEMAN:
But in 2001 ,
two of the Ieading cosmoIogists
in the worId
pubIished a paper suggesting
an even more radicaI approach
to what happened
at the beginning.
For these two scientists,
there was another answer
so strange and unexpected
that it had never
been considered.
There are bangs and bangs
and bangs forever.
FREEMAN: Our universe
may not be the onIy one,
but one of hundreds, thousands,
maybe an infinite number.
It's an inspiring
and daunting suggestion --
the universe is an endIess cycIe
prompted by an endIess series
of bangs, forever.
When you Iook out into space,
gaze at a distant star,
you aIso Iook back in time.
Light from distant gaIaxies
can take biIIions of years
to reach us.
Now we know there's a Iimit
to how far back we can see,
an edge to the visibIe universe.
The Iight
from that cosmic backdrop
has taken 1 3.7 biIIion years
to make it to Earth.
What Iies beyond that curtain?
According to
Professor Martin BojowaId,
time becomes
squeezed and distorted
as it nears a singuIarity
and then bounces back out
into another expansion.
But perhaps there's
an aItogether different way
to Iook at what happened
before the beginning.
South African scientist
Dr. NeiI Turok
is now daring to go
further into the past
than aImost anyone eIse.
Africa!
Africa!
His radicaI view of the cosmos
was infIuenced
by his parents' struggIes
during apartheid.
DR. TUROK: My father and mother
were poIiticaI activists
against
the South African government.
They went to jaiI
for their opinions.
But uItimateIy,
democracy came to South Africa,
and they were both eIected
members of ParIiament --
the onIy husband-and-wife
members of ParIiament
apart from NeIson
and Winnie MandeIa.
They served
as a modeI of persistence.
Just because at the moment
your ideas are not fashionabIe
or agreed upon,
if you beIieve what you're doing
is right, persist.
FREEMAN: From the moment
he entered the fieId
of theoreticaI physics,
the South African scientist
was Iooking for new answers
to age-oId probIems.
DR. TUROK: There is
a conventionaI wisdom
in the fieId, and peopIe are
very sIow to adopt new ideas.
And, frankIy,
many peopIe have buiIt
their careers on the status quo,
and they don't want a new idea
coming aIong
and rocking the boat.
FREEMAN:
For NeiI, the WMAP announcement
brought up famiIiar feeIings
about seeing the universe
through
a sIightIy different Iens
than some of his coIIeagues.
DR. TUROK:
In the WMAP press announcement,
of course
the scientists invoIved
Iinked it expIicitIy
to infIation
and said, ''This dramaticaIIy
confirms infIation.''
And this made me squirm.
[ Laughs ]
My point of view
was that the information
contained in the WMAP data
was, in itseIf, not sufficient
to prove or refute infIation.
FREEMAN:
He wasn't aIone.
Across the AtIantic, another
intrepid scientist Iabored
to uncover the truth behind what
happened before the beginning.
PauI Steinhardt
is the AIbert Einstein
professor of physics
at Princeton University.
As a young man,
PauI was inspired to study
science by the moon Iandings.
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.
[ AppIause ]
FREEMAN: In 1 999,
the two men combined forces
to see if they couId answer
some of their probIems
with the infIationary modeI of
what happened at the beginning.
InfIation had
some extraordinary successes,
so it's tough competition
to compete with infIation.
So I wiII not teII you aII
the ideas that were attempted
and dumped in the wastebasket.
We have simiIar objectives,
which is to shake the fieId up
once in a whiIe
and come up with something boId
and originaI and different
and to improve
on the status quo.
DR. STEINHARDT: I organized
a conference with NeiI Turok.
We had a common interest
in string theory,
which were just coming out
at that time,
whether they might stimuIate
some new ideas in cosmoIogy.
FREEMAN: String theory was
deveIoped in the Iast 35 years
as an attempt to devise
a singIe theory
expIaining everything
in the universe.
In it, everything is made
of minute, vibrating strings.
But for the mathematics
of string theory to work,
there have to be
more than the three dimensions
of space that we see.
Rather, there are 1 0 dimensions
pIus time.
Space-time is a fIexibIe
substance, Iike a membrane,
and it can stretch and shrink.
So, we knew
these things couId move,
but nobody had reaIIy studied
the dynamics of that process.
So we brought in experts,
Iike Burt Ovrut,
who is one of the most
proficient deveIopers
of particIe-physics modeIs
based on string theory.
DR. STEINHARDT: And he gave
a beautifuI series of Iectures
in which he described to us
this idea
of our three-dimensionaI worId
being embedded in a brane worId
separated by a smaII gap
from another brane worId
aIong
an extra spatiaI dimension.
DR. TUROK: And as we sat there,
we both had the same thoughts. . .
DR. STEINHARDT:
Which is, if you imagine
that this is reaIIy
the structure of the universe,
there's a new
possibIe interpretation
for what is the Big Bang.
What have we
not been facing up to, you know?
What is
the eIephant in the room?
And the number-one question
was the singuIarity.
We both sort of approached Burt
from both ends.
And cornered Burt
after his Iecture.
Each of us finished
the sentence of the other.
And said, ''You know, weII,
what about
if these things coIIide?
What wouId happen then?''
''And is it possibIe
the Big Bang is not a beginning,
but is a coIIision?''
And his response was, ''Maybe.''
FREEMAN:
The meeting soon broke up,
but the three men
had aII been invited
to attend the same pIay
in London that evening.
DR. STEINHARDT:
We met at the train pIatform,
and then we began to reaIIy
imagine this idea in more detaiI
about what it wouId mean if the
Big Bang were not a beginning,
but the Big Bang
were a coIIision.
DR. TUROK: And then
we had a train ride to London,
where we just brainstormed
about this
in a very Ioose and unstructured
and unmathematicaI way.
DR. STEINHARDT: We asked
ourseIves the question,
''CouId we invent something
which was different
than the infIationary picture,
that was different
than the standard picture?''
DR. TUROK: We had
some rough ideas how to do it,
but it wasn't at aII obvious.
DR. STEINHARDT:
Time was fIying past us
as the train was moving aIong.
It's one of those rare occasions
when you're having
a conversation
and you feeI Iike a reaIIy
exciting idea is emerging --
sort of that sixth sense
that something important
is happening.
Coming up with this rough idea
for how things might work
is, of course, exciting.
But in having an idea Iike that
and then deciding
to reaIIy pursue it,
you are condemning yourseIf
to years of misery,
because you now have to
fIesh this out.
FREEMAN: And to soIve
this mystery, NeiI and PauI
wouId turn to one of
the toughest mentaI chaIIenges
of the human mind --
the incredibIy strange worId
of 1 1 -dimensionaI space.
And universes
paraIIeI to our own.
AIbert Einstein
was a formidabIe thinker.
His theories of reIativity
were groundbreaking deveIopments
that triggered
a century of cosmic insights.
But even more fundamentaI
was his reaIization that time
and space are intertwined.
The three dimensions of space
are reaIIy part
of a four-dimensionaI fabric
caIIed space-time.
But now there's a new movement
in theoreticaI physics.
It's caIIed string theory.
And out of string theory
comes M-theory.
In M-theory, there are not four,
but an astounding
1 1 dimensions --
1 0 dimensions of space
pIus one of time.
What is M-theory?
Okay.
So, M-theory is an attempt to --
Let me start again.
Three-dimensionaI infinite
worIds stretching off --
Let me start again.
Why wouId one
even think about --
I mean, how does one
make that not sound crazy
in two sentences?
[ Laughs ]
So, M-theory is a. . .
promising, unified theory
of aII the fundamentaI forces
and constituents
that we observe in nature.
In a sense,
you couId describe it
as the cuImination
of aII the deveIopments
in theoreticaI physics
over the 20th century.
In order
to make this theory work,
one needs to have more than the
usuaI three spatiaI dimensions,
so a key idea behind M-theory
is that there are more than
the three dimensions of space
that we experience.
There are hidden dimensions.
In fact, there are seven more.
And the reason
we're not aware of them
is that they are so, so tiny
that in order to see them,
you'd need an enormousIy
powerfuI microscope
far more powerfuI
than any we have.
Our three-dimensionaI worId
Iives in a surface
embedded in a space
with an extra spatiaI dimension
that separates it
from another such surface.
FREEMAN:
One possibiIity
that springs
from these extra dimensions
is that this other
three-dimensionaI worId
couId be just a fraction
of a centimeter from ours
and yet hidden from our view.
DR. STEINHARDT: These surfaces
are caIIed branes,
standing for ''membrane,''
which is to remind us
that these surfaces are eIastic.
They can stretch,
they can wiggIe, they can warp.
They can move
aIong this extra dimension.
AII of the particIes
we're made of
are actuaIIy
curIed-up IittIe branes.
And aII the dimensions of space
we traveI in
are comprised
of branes themseIves.
And so
everything in the universe
is composed
of these geometricaI objects.
I don't know
if I can repeat that again.
[ Laughs ]
FREEMAN: Caution.
You have entered a pIace
caIIed ''brane worId.''
DR. STEINHARDT: We're stuck
Iike fIies on fIy paper
on our brane worId.
We simpIy can't reach out
into the extra dimension --
even 1 0 to the minus-30
centimeters --
to touch the other brane worId.
FREEMAN: It was
through this worId of branes
that PauI and NeiI
stumbIed onto a potentiaIIy
radicaI new theory
of what happened
before the beginning.
So, here
I have a piece of materiaI,
and it Iooks Iike
a two-dimensionaI object
because one of the dimensions
goes up
and one goes side to side.
But if we Iook a IittIe bit
cIoser at this object,
and Iook at it from the side,
you'II see that actuaIIy
there are two
pieces of materiaI,
separated by a tiny gap.
And you couId think of this gap
as being
the fourth dimension of space.
And the coIIision of these two
three-dimensionaI worIds --
the one we Iive in
and another one --
wouId have been the Big Bang.
It wouId be a coIIision instead
of a springing from nothingness.
So, if the branes existed
before and after,
that means
space and time existed before.
They couId have heIped set up
the conditions we observe
in the universe today.
They coIIide,
and they move apart again.
The Big Bang
is not the beginning.
That means we have more time
to soIve
aII the cosmoIogicaI probIems
that infIation was designed
to soIve.
So, we began to imagine,
''CouId we repIace that idea
with something that occurred
before the bang?''
And as we were going
aIong the train ride,
we began to imagine
Iots of possibiIities,
so that by the end, it seemed
Iike a very exciting aIternative
to the standard
Big Bang infIationary picture.
FREEMAN:
For the next 1 8 months,
the three men and another
physicist, Justin Khoury,
worked feverishIy
to cIarify and justify
their initiaI spark
of creativity.
DR. STEINHARDT: Now we had to
make the mathematics work,
and this invoIved
deveIoping a Iot of new physics
to expIain the motion of branes
moving aIong extra dimensions
under the infIuence of a force
which is trying
to draw them together.
This mathematics
didn't exist before.
FREEMAN: A new theory of the
universe starts to come aIive.
DR. TUROK:
The picture we had in mind
was two three-dimensionaI worIds
stretching off to infinity
but separated from each other
by a tiny gap --
a fourth dimension of space.
The two three-dimensionaI worIds
are actuaIIy puIIed together
by a very, very weak force.
The force
has to be very, very weak.
Otherwise the bang wouId occur
too quickIy.
DR. STEINHARDT: We know that
the cycIes can't be too short,
because the universe has aIready
gone 1 4 biIIion years
since the Iast bang.
A triIIion years is probabIy
a good, you know, typicaI vaIue
for what we expect
the Iength of a cycIe to be.
DR. TUROK:
As the branes approach,
the force
gets stronger and stronger.
And when they coIIide,
kinetic energy of the branes
is then converted
into the hot radiation
that fiIIs
both three-dimensionaI worIds
and Iooks Iike the Big Bang.
DR. STEINHARDT: So that when
the branes move apart again,
they're now fiIIed
with the matter and radiation
that was created
at the coIIision.
This then causes the branes to
begin to expand again and cooI,
creating a new period
of expansion, cooIing,
creation of new atoms,
moIecuIes, stars, and gaIaxies.
We now had an expIanation
for the Big Bang.
This is normaIIy referred to
as cosmic singuIarity --
some sort of breakdown
in the Iaws of physics,
which in the standard Big Bang
theory, you simpIy ignore.
But in this picture,
you are actuaIIy providing
an expIanation for it.
It was, in fact, the coIIision
between these two brane worIds.
It was a theory of
what was the cosmic singuIarity.
FREEMAN: It was a radicaI
and eIegant soIution
to one of the great
cosmic mysteries of aII time.
According to NeiI and PauI
and their coIIeagues
Burt and Justin,
there was aIways
a time before time.
After aImost two years of work,
it was time
to present this new theory
to their feIIow scientists.
At a conference in FinIand,
the two physicists
Iaid out their theory.
The reception was icy.
The criticism was that we were
simpIy assuming or asserting
the branes wouId be fIat
and paraIIeI to begin with
without showing
why that shouId be the case.
We'd been so excited
about this idea,
and yet everyone eIse
was just pooh-poohing it.
To be fair, I mean, the session
did not go weII for us.
The next morning,
we were both rather depressed,
so we began to traveI
aIong the river near Rovaniemi
and have this discussion about,
''What couId we repIace
this idea with?''
So, we began to think
about something
that wasn't yet incIuded
in the theory,
which was
the idea of dark energy.
FREEMAN:
Dark energy is a recent
and totaIIy surprising
astronomicaI discovery --
a mysterious force
that's causing the universe
to expand even faster.
EventuaIIy, the dark energy
wiII expand the universe so much
that it wiII be nothing
but coId and empty space.
In the Ianguage of M-theory,
that transIates to a fIat brane.
The dark-energy phase stretches
out the three-dimensionaI worIds
and makes them very fIat and
very empty and very paraIIeI.
Of course, that immediateIy
cIicked with another idea.
WeII, we're using something now,
but we're using it
before the bang.
WeII, maybe
the source of dark energy then
was actuaIIy
the same as the one now
and the universe
is cycIic somehow.
DR. TUROK:
So you couId have a bang
foIIowed by
a normaI period of the universe,
Iike we Iive in today,
foIIowed by a second bang
in our future,
foIIowed by another bang,
and so on.
There are bangs
and bangs and bangs forever.
FREEMAN:
Their theory was now compIete.
Two branes come together,
inject one another with energy.
Then dark energy
takes a triIIion years or so
to spread that energy out.
The branes fIatten
and then come together again.
This cycIe happens endIessIy.
NeiI Turok and PauI Steinhardt
had come up with
a remarkabIe aIternative theory
to the Big Bang
and cracked the door onto what
happened before the beginning.
As different as the modeIs are,
they produce
the same exact variations
in the background radiation.
The same WMAP image
fits both ideas.
It's certainIy the case that
when WMAP made its announcement,
the way most peopIe interpreted
that announcement was,
it's beautifuIIy consistent
with the Big Bang
infIationary picture.
To us, it meant
that the cycIic modeI
was in the game
as much as infIation was.
FREEMAN:
But which theory is right?
The answer to one of the biggest
cosmic mysteries of aII --
was there a time
before our time? --
couId be circIing the earth
a miIIion miIes over our heads.
Professor Martin BojowaId's
bouncing universe
is stiII a work in progress,
but for proponents
of the cycIic and
the Big Bang infIation modeI,
the answer to how and when
the universe started
may be moving toward us
across time and space
Iike tiny rippIes
in the cosmic ocean.
GravitationaI waves.
DR. TUROK: GravitationaI wave is
pretty much Iike a sound wave.
[ Horn bIares ]
We're used to a sound wave
traveIing from me to you
as I speak,
as a compression and expansion
of the air between us.
And so the moIecuIes get more
denseIy packed and further apart
as the wave moves
from me to you.
FREEMAN:
But gravitationaI waves rippIe
not air moIecuIes,
but space itseIf,
which means
that they can stretch out
or compress a beam of Iight
and cause a shift in its coIor.
DR. TUROK:
So, if space is expanded,
we'II see the radiation shifted
to red frequencies,
Ionger waveIengths.
But if it's coming towards us,
we'II see
it's sIightIy bIuer than
it wouId otherwise have been.
And so by carefuIIy anaIyzing
the pattern of radiation
on the sky,
we can, in fact, infer
if there are gravitationaI waves
traveIing through
our part of the universe.
FREEMAN:
And rocket technoIogy
wiII get the scientists
far enough up into space
to espy
these gravitationaI waves.
DR. SPERGEL:
The PIanck sateIIite
is the successor to WMAP.
It wiII be measuring the sky
with about twice the resoIution
and about
1 0 times the sensitivity.
The PIanck sateIIite is reaIIy
the first device we have
which seems to have
a strong capabiIity
of maybe finding
these gravity waves.
And if we're Iucky,
that'II teII us what happened
during the first moments
of the Big Bang,
or maybe even before.
FREEMAN: For proponents
of the Big Bang infIation modeI,
finding significant
gravitationaI waves
wouId be the finaI step
in proving
that there was a giant expansion
of whooshing energy
from a pIace
of nowhere and no-when.
But PauI Steinhardt
and NeiI Turok
are aIso Iooking forward
to the PIanck sateIIite resuIts.
In their cycIic modeI of
the beginning of the universe,
two branes coming together
wouId be
a much Iess intense coIIision,
and the chances are
that gravitationaI waves
wouId be aImost nonexistent.
If we observe
these gravitationaI waves
in the PIanck sateIIite,
that wiII support
the infIationary theory
and ruIe out the cycIic picture.
And converseIy,
if we don't see them,
that wouId strongIy support
the cycIic picture.
FREEMAN:
But no matter which description
of the beginning of the universe
appears to be more accurate,
the true winner wiII be our own
scientific understanding.
Yeah, to me,
it's man against nature.
We're trying to figure out
nature's secrets.
If we're Iucky,
we'II be surprised.
FREEMAN: These tiny,
aImost undetectabIe waves
wiII have a tsunami-Iike effect
on the future direction
of cosmoIogy.
Instead of appearing
from nowhere and no-when
and rising
from stardust to humankind,
we may have to consider
the mind-boggIing premise
that we are just
the Iatest version
of an endIess series
of universes.
We stiII might not know what
happened before the beginning.
But we wouId know
that something did.
The finaI answer
may be cIose at hand.