Nova (1974–…): Season 48, Episode 21 - Universe Revealed: Big Bang - full transcript

New research and theories offer clues about the Big Bang and what may have existed before the universe's birth.

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We live in a tiny corner
of a vast universe.

A place filled
with an amazing array

of cosmic wonders.

There are blazars, quasars,
magnetars, pulsars.

Swirling gas clouds,

enormous black holes,

the collision
of colossal objects.

Yet, from the bounds

of our small, lonesome planet,

we have set out
to explore our universe,

searching for answers

to some of humanity's
biggest questions.

Why are we even here?

Or maybe I should say,
"How are we even here?"

We even dare to ask,

"How did it all begin?"


We can see the light
from the time

when the whole universe
was on fire.

And was there anything
before the Big Bang?

It wouldn't have been
like anything that

we can ever experience
or imagine.

But if we do find it,

then that means we can measure
the actual conditions

of the moment of creation.

nuts, right?


"The Big Bang."

Right now, on "NOVA."


♪ See me when I float
like a dove ♪

♪ The skies above are lined
with trees ♪

♪ I'm on my knees,
begging please ♪

♪ Come and take me away ♪


Each of us had a beginning,

the moment we entered
the universe

and took our place
on this planet.


But our planet
had a beginning, too.

As did our galaxy,
the Milky Way.

And billions of other galaxies.

Trillions of stars and planets

that make up our vast cosmos.

All of it must have started

even the universe itself.

Every human civilization has
some creation myth.


Why are we even here?

Or maybe I should say,
"How are we even here?"

How did the universe begin?

These questions, they're huge.


Questions that have remained

for much of human history.

Only in the last 70 years have
we ventured into space

in search of answers.

To find the origin of our
planet, our galaxy,

and ultimately, the universe.


For all the people back
on Earth,

the crew of Apollo 8 has
a message

that we would like to send
to you.

"In the beginning, God created
the heaven and the earth.

"And the earth was without form
and void.

"And darkness was upon
the face of the deep.

"And God said,

"'Let there be light.'

And there was light."

The pace of change of
technological advancement

has gone faster and faster
and faster.

The 20th century just took
things to the next level.


The Apollo missions were
our first step

beyond our home planet.

And in a way,
a step backwards in cosmic time.


It was during
the third moon landing

that clues to the origin

of not only the moon,
but the Earth, as well,

were discovered.


Nearly 100 pounds of
rock samples were collected

from across the
Fra Mauro landing site

and returned to Earth.


After decades of study,

scientists were able to date
these rocks

and rewind time
to a violent event

that forged not only our moon,

but Earth as we know it.


In a quiet corner of the
Milky Way,

a new star shines out

over a plain of debris.

Over millions of years,

rocks collide
and clump together,

building a system of planets.

Among them, the young Earth,

a hellish world.

Not yet the planet
we know today.

One more collision
will shape it.

A collision on a colossal scale.


There is another world born
nearby the fledgling Earth:


And the Apollo moon rocks

have helped us pinpoint
the moment

when these two young worlds met.

Theia, roughly the size of Mars,
collides with Earth,

shearing off enough material
to eventually form the moon.

And marking the final stage
of our planet's creation.

But understanding Earth's origin

is just the first step in our
scientific quest

to find the origin of the

We can start to understand

how everything in our universe

and maybe start to answer
that question

about, how did we get here?

Since the time of the
Apollo missions,

our exploration of the
solar system

has continued to deepen
our knowledge.

With each mission, we learn
more about how the planets

and the sun itself were formed

and evolved over billions
of years.


But the solar system,
the domain of the sun,

is only a small part

of a far larger region
of the universe:

our galaxy,

the Milky Way.


The Milky Way
is unimaginably vast.

So big that it would take us
tens of thousands of years

to travel to even
the nearest stars.

There's this great quote by
Arthur C. Clarke that goes,

"The only way to find the limits
of the possible

is to go beyond them
into the impossible."

We're all explorers,
and we're all curious.

And astronomy is, is sort of
the ultimate frontier, really.

A frontier that's being
constantly pushed

by new technology.

We have an amazing suite

of space-based observatories
at our disposal.

And one of these observatories
is shedding light

on the origin of planets
beyond our solar system,

taking us one step closer to the
beginning of the entire cosmos.

Kepler is a planet hunter.

Not able to physically venture
to the stars,

it stares at thousands of them
in a small patch of sky

for more than nine years.


Revealing something remarkable:

almost every star has at least
one planet in orbit.

Meaning there are even more
planets than stars

in our home galaxy,
and the variety

is breathtaking.

On the one hand, some things
look remarkably familiar.

And then other things that look
nothing at all

like what we've encountered
here close to home.

These planets outside of our
solar system,

they are zombie worlds.

And lava worlds.

Ice worlds.

Worlds where
it rains glass sideways.


And Kepler even finds one
planetary system

that takes us back towards
our galaxy's origin.


Kepler-444 is a system home
to five rocky worlds

117 light-years from Earth.


By analyzing the light from
this star,

the Kepler space telescope has
helped us

to estimate the system's age:

more than twice as old
as the sun.

So planets existed in our galaxy

long before the sun
and Earth were formed.

And the Milky Way must be more
than 11 billion years old.

The precise age of our galaxy
remains a mystery.

But luckily, we have a tool

to help us understand the
beginning of all galaxies.



Light is a very powerful tool

precisely because it doesn't
travel infinitely fast.

That means that if it has to
come to us

from somewhere very far away,
it needs some time.

Light travels at
186,000 miles a second,

slow on a cosmic scale.

It takes just over eight minutes
to reach us from the sun,

and more than four years
from our next nearest star.

When we look at objects that are

a million or a billion
light-years away,

then we're looking at them
as they were

a million or
a billion years ago.

Light to an astronomer

is like fossils to an

By studying ancient light,

we can look back towards
the origin of our galaxy,

and ultimately, the beginning
of the universe itself.


And there is one telescope,
more than any other,

that can help us step back
through cosmic history.

The Hubble Space Telescope
is the first great observatory.

And I say this with an absolute
straight face, totally serious:

it is one of the greatest
scientific missions

in all of human history.

In the early '90s, it set

to become the first major
optical telescope in space,

capable of seeing further out
into our universe

than ever before, and therefore,
further back in time.

I actually got to see

the telescope before it was
launched into space.

I was very lucky.

And to think that
that same object

that I was almost in the same
room with

would be hoisted into space

and would be orbiting our, our
little, lonesome planet,

I just find that extraordinary.

Go ahead, Charlie.

Okay, we have a go for release,

and we're gonna be
a minute late.

Okay, Charlie.


Houston, Discovery.

Residuals and ratios look good,

and we'd like to go to filter

We concur, Charlie.

Hubble gathers energy from
the sun

using two 25-foot solar panels

to power sensors
that analyze starlight.

All of this specialized

just gives us this immense
toolbox to be able to

find answers that I don't think

people ever really expected
we would find.


Orbiting 340 miles above
Earth's surface,

Hubble has a clear advantage
over ground-based telescopes.

The Earth's atmosphere kind of
blurs out lots of our images.

And so by putting the telescope
in space,

we get these precise,

images of our universe.


Hubble has revealed our
cosmic neighborhood

like we've never seen it before.

I was able to look
at those images.

And immediately, I got a very
strong sense

that this was exactly what
we needed.


Hubble has imaged great nebulae,
huge clouds of gas and dust...

Stars at the moment
of their birth.

You can think of them
as nurseries for stars.

They're the places where you
have a lot of baby stars

all hanging out together.

You see the Ring Nebula,

it just blows your mind away,

It's just, like, you think,

"Did someone draw a cartoon
into the lens?"

It's so amazing.

They're these stunning images,

and they really give us
a sense of

how stars form.


But Hubble was built to give us

a much larger view of the

and take us back in time.

Our understanding of the

is limited by how far out
we can see,

and that is the size
of the universe for us.

It's billions and billions
billions of light-years

in size... it's huge.

We're not a drop in the bucket.

We're not a drop in the ocean.

We are a single atom in a drop

in trillions
upon trillions of oceans.

Oceans filled
with countless faraway wonders

that Hubble shows us
as if they're close up,

taking us ever deeper
into the cosmos,

and further back in time.

our nearest large galaxy.

We see it as it was

two-and-a-half million years


And Hubble has seen further

imaging what looks like
a cosmic rose:

two colliding galaxies.

The larger galaxy, UGC 1810,

is about five times more massive
than its companion.

We see them as they were
300 million years ago.

But to wind back the clock to
the origin of all the galaxies,

Hubble needs to look farther
into space

than it ever has before.

One of the temptations
when you're an astronomer

is to only look at
the obvious things.

But that's just a tiny fraction
of everything in the universe.

Hubble's most surprising
discovery came

when it looked away from the

What we did is, we turned Hubble
toward a blank part of the sky,

and Hubble stared at it.


Peering into the darkness
for four months,

Hubble reveals the blackest
patch of space

is not quite so empty.


And what we ended up finding was

galaxies upon galaxies,

going back billions
and billions of years...

Much further back in time
than we would have guessed.

It glimpses primitive
and unusual galaxies,

unlike anything
in our current universe.


They are celestial fossils

that light the way to the
primordial past,

until eventually, right on the
limit of what it can see...

potentially one of the first
galaxies to form

in the universe.

So distant

that when we gaze upon it,

we are seeing 13.4 billion years
into the past.

So this awesome and oddly shaped
galaxy is called GN-z11.

It's the oldest and furthest
galaxy that Hubble can see.

It is so old and so far away
that by the time

the Earth started to form
4.6 billion years ago,

the light from it had
been traveling

for almost nine billion years.


So really,
this is light from right near

the beginning of our universe.

GN-z11 is one of the very
first galaxies,

forming at a time when the
universe itself

is still taking shape,

just a few hundred million years
after the Big Bang.

It's a strange galaxy
by today's standards.

Tiny in comparison to the
Milky Way.


But filled with enormous,
violent stars.

GN-z11 is this crazy galaxy,

because it's super-super-bright.

Like, we don't expect it
to exist in the early universe.


This huge kind of messy monster.

And the stars

are very young stars...
They've only just formed.

These stars probably aren't
the very first

to form in the universe.

But they're close.


What's most remarkable

is that not only can we see
this galaxy,

we're starting to build up
a picture

of what it may be like inside.

What is kind of exciting
prospect is that,

you could already have

if not planets, forming

around those first sets of

Delicate objects struggling
in the maelstrom

created by these
tempestuous stars.

These may be some of the first
planets in the universe.

Somewhere, there was
a first planet

that formed in the entire

We'll never know about it.

We'll never know when it formed

or where it formed
or what its fate was.

But it formed somewhere.


These are strange,
primordial worlds.

But their birth is a key part
of the universe's development.


The beginning of a relationship
between stars and planets.

A relationship that will,
billions of years later,

on one faraway world...

lead to life: you and me.

But long before,

before even the first stars
and galaxies existed,

the universe was
a very different,

very inhospitable place.

And so the story of the

very earliest days of the

are in many ways
a story of darkness.


This is a time astronomers call
the Cosmic Dark Ages.

We can't see galaxies and stars

because they have not yet
been born.

It's a period that optical
telescopes like Hubble

will simply never be able
to explore.

When we look into the Cosmic
Dark Ages,

we don't see light from any
stars at all.

Long before our planet existed,

before even the first stars,

just endless gloom.

With no starlight to follow,

it may seem as if our quest
to find

the beginning of the universe
has reached its end.

But perhaps counterintuitively,

the younger starlight we can see
offers clues

to help us understand
the origin of the universe.

But not just any starlight.

The light from one particular

type of star can tell us
how our universe grew to be

the way it is today.


These stars are called
white dwarfs.

They are the fading remains
of stars that long ago

burned with nuclear fusion.

So once a star like the sun
runs out of material to burn,

it will collapse in on itself
and expel material,

and what's left behind
is a white dwarf.


They are dense, planet-sized

usually composed of oxygen
and carbon.

Making white dwarves, in effect,
stellar diamonds.

So these white dwarfs,

these stellar corpses,

are incredibly exotic objects.

A teaspoon of this material
would weigh more than five tons.

It's one of the densest objects
in the universe.

It's just this very small,
very hot object

that's about the size
of the Earth

with about the mass of the sun.


How is it that these strange
stars can tell us anything

about a time before stars

and even give us clues about
the moment the universe began?

White dwarfs are critically

resisting the relentless
inward pull of gravity.

But only barely.

They're teetering on the edge
of destruction.

If their mass increases
above a critical limit,

then gravity takes over.



And in 2018, Hubble sees
what happens next.

The telescope focuses on
a galaxy far, far away...

NGC 2525...


Hunting for a distant
white dwarf at the end

of its extraordinary life.


For millions of years,
the white dwarf remains hidden,

locked in an orbit around
a much bigger star.

A red giant.


As they circle each other,
the white dwarf's gravity

pulls in gas and plasma
from the red giant.

The mass of the white dwarf


Until it approaches
a critical limit,

known as the Chandrasekhar

and surpasses it...


Triggering a colossal
thermonuclear reaction.

The white dwarf detonates

in what scientists call
a type la supernova.

This was an immensely energetic
event in the universe,

with the brightness
of five billion of our suns.

It was so luminous that Hubble
could take a time-lapse movie

of it as it evolved.


It's the brightness
of this event

that allowed it to be seen
by Hubble.

And why catching a type la
supernova in the act

is so exciting for scientists.

This bright light has quite
a story to tell.

Everything that's happened

to that light on the way
from its source to us,

everything it's encountered,
including time,

has affected
what we actually see.

The light from type la
supernovae give us

a tantalizing clue

to how our universe evolved.


And it's by charting
the evolution of the universe...

that we can build a road map
back to its beginning.

So, type la supernovae,

it's like the universe's
free gift to us.

Because they all explode
in the same way,

they reach pretty much
the same brightness.

So if you see one dimmer
than the other, it means

it's further away.

And that allows us to measure

to the galaxy that's hosting
this supernovae explosion.


We have seen type la supernovae
across the entire universe.

We can measure the distance
to their home galaxies.

And that can tell us how the
universe is changing over time.


So, when we look at
distant supernovae,

we see something really

Their light's not just dimmer,

it's redder.

And the further away they are,
the redder their light is.

But as the light travels from
this distant galaxy to us,

space itself is stretching, and
so the light gets stretched

along the way... it gets redder.

And this is called redshift.

We see the effect of redshift
in the light

from every distant galaxy.

And that means space
is stretching everywhere.

And that means something truly

It means our universe
is expanding.


By studying how galaxies
themselves are redshifted,

we have known for nearly
a century that the universe

is expanding.

But by using type la supernovae
to study it in detail,

we can accurately tell how fast
our universe is growing.

And what scientists find

is something completely

Astronomers working with the
Hubble Space Telescope

started to realize that the
universe is not just expanding,

but it's actually expanding
at an ever-increasing rate.

It's that accelerated
or speeding-up stretching

that really did catch
our community by surprise.

We know the universe
is expanding.

And thanks to Hubble, we have
evidence that this expansion

is accelerating over time.

So if you know the universe
is expanding,

you can just do
a thought experiment,

and turn time backward, and know
that the universe was smaller

in the past.

We can wind back the clock

through thousands of billions
of yesterdays.


Back to a time before our Earth
and sun.


To a time before
the first galaxies.

And finally, we can cross
the Cosmic Dark Ages

to pinpoint the moment
the universe began.


A moment we know happened
13.8 billion years ago.

The Big Bang.


The moment when our universe
burst into existence.

Yet, it wasn't anything
like an explosion.

This is the initial state
of the universe,

which was very hot
and very, very dense.


Everything, the whole universe,

was held together in a very tiny
region of space.


So everywhere in the universe

is almost like being
inside of a star.


All the matter that has ever
been produced

came from that moment in time.

These conditions
are unbelievably extreme,

and they no longer exist
in today's universe.


It almost seems miraculous,
if not ridiculous,

that we could study the origin
of the universe, right?

People say to me all the time,
"How could you know?

No one was there."

For decades, the Big Bang has
been science's best estimation

of how the universe began.


And in 2009,

a mission is launched to try
to get a better understanding

of this time in our universe.


The European Space Agency's
Planck telescope

is designed to look for the
remains of the Big Bang.

Not starlight this time,

but a different type of light:

the afterglow of the Big Bang,

the most ancient light
in the universe.

If we do find it,

then that means we can measure
the actual conditions

of the moment of creation.

nuts, right?


Planck will measure this
ancient light

with more precision
than ever before.

Sept, six, cinq,

quatre, trois,

deux, un, top.


The moment of the launch
is where everything is at risk.

And not just the launch,
there's a whole bunch of stages.

There was palpable excitement,

because we knew that this was
an amazing shot we had

at understanding
our universe better.



It's a two-month journey for
Planck to reach its destination.

Far beyond the orbit
of our moon.


Once in place,
Planck meticulously scans

the entire cosmos
over and over again.

Anything that's hot
tends to send out light.

So if the early universe
was really dense and hot,

there should be a load of light
left over from that time.

Using its five-foot mirror
and two detector arrays

to capture light in the form of

Planck builds a map
of the furthest reaches

of the universe,

looking back to a time long
before galaxies and stars.


After four years
of ceaseless scanning,

scientists are finally able
to glimpse a snapshot

of the aftermath of the Big Bang

in spectacular detail.


So this image that I'm
looking at here

is one of the most exciting
images in astronomy

and cosmology,
and it's an image of

the cosmic microwave background

So basically, the Big Bang

and this is the first light

that we see that came from that

that basically birthed
our universe.


Thanks to Planck, scientists now
have a detailed image

of the entire universe
in its infancy.

The best analogy of looking
at the first light

of the instrument,

I think, is like seeing
your child being born.

We can see the light from
the time when the whole universe

was on fire,

when the universe was not
empty space,

but a roiling, churning plasma.

We can look back to within
380,000 years after

the Big Bang.

Before that,
we can't see any light

because it was all absorbed
by the universe itself.


It may not be an image
of the Big Bang itself,

but the cosmic microwave
background is powerful evidence

that it did happen.

I couldn't wipe the smile
from my face for about a week.


Planck gives us details

of the earliest moments
of the universe.

And at first glance, all it sees
is an almost featureless glow.

So no galaxies, no stars,

just this glowing ball
of plasma.

And the radiation reflects
that, actually,

because when we first looked
at it,

this radiation was
incredibly smooth.

But Planck's highly sensitive
detectors can pick up

even the slightest variations,

variations we see as different
shades of blue, red, and yellow

in this iconic false color

Before, all we could see
is a uniform glow.

Now we can actually see
small patches on the sky,

differences in temperature,

which are really incredibly

The variations are less than
100,000th of a degree.

But they suggest that
the primordial fireball

was not perfectly uniform,

and these variations must have
come from somewhere,

pointing to a profound truth:

the Big Bang was not actually
the beginning.


The earliest moments of our
universe are very strange.

There is no matter.

All that exists is space-time
and energy.

An ocean of energy
almost uniform.

But not quite.

It wouldn't have been like
anything that

we can ever experience
or imagine.

It was a field of energy

that had tiny, tiny
quantum fluctuations

popping in and out of existence.

These fluctuations,
ripples in the ocean of energy,

hold the key to our universe

They are the origin
of everything.

If these fluctuations
didn't exist,

there wouldn't be a single star,

there wouldn't be a single bit
of cosmic dust

or anything like that.

And we certainly wouldn't
be here.


Imagine a speck
in that ocean of energy.

This speck is about to grow
so big it can accommodate

every star and galaxy
in our universe.

It just needs to grow fast.

That energy would drive

a remarkably rapid
stretching of space.

An exponentially rapid

So space would not just get
bigger, it would get bigger

faster, at a mind-boggling rate.

In the briefest of instants,

for less than a billion-billion-
billionth of a second,

the speck expanded much faster
than the speed of light,

a moment in time we call

So in this infinitesimally
small time,

our universe went from something
that's smaller than an atom...

to the size of a basketball.

That's an amazing amount
of stretching

in a very brief window.

We don't know why it started

and we don't know why it ended.

When that rapid expansion
slowed down,

something happened that dumped
a bunch of energy

into the universe,
created this fireball state.

Inflation creates the Big Bang.

But it was not,
as we commonly imagine,

some kind of explosion.

It was largely a transformation:

a transformation of energy
into matter.


And the rapid inflation left
its mark.

The tiny fluctuations
in the rippling ocean of energy

became imprinted into
our universe.

Those little quantum

they would have gotten stretched
as the universe itself stretched

so rapidly, so dramatically.

So a little wave of unevenness
that starts out during inflation

would get stretched
to astrophysical scales.


The fluctuations that existed
before the Big Bang

go on to create everything
we see in the sky today.


Gravity takes hold
of the tiny variations

that now crisscross
the young universe.

Creating great clumps of matter,

but also great voids.


Spinning a web-like pattern
that spans the universe.

The densest regions collapse...

to form the first stars.


And the first galaxies.

After nine billion years

of cosmic evolution,

a new star is forming
in the Milky Way:

our sun.


Eight planets emerge,

including our planet:


Here is a place where the
elements combine...

Hydrogen formed in the Big Bang,

carbon, oxygen, and others

forged in the hearts of stars...

To create life.




We are a speck of dust
on a speck of dust.

We're totally unimportant
to the universe

in any possible way
you can think of.

And yet we can see the beginning
of the universe.

I think it's very humbling
that us as humans,

we have come to understand
so much.


The universe has somehow
opened itself for us to study,

and maybe that's our only

I mean, maybe the universe
created us

so that we would understand it.


We are going to be
but a sentence in the

book of the universe.

And so I think it's incumbent
upon us to write

the best possible sentence
that we can.

I cannot wait for what is
to come.