All language subtitles for How.the.Universe.Works.S07E06.Did.the.Big.Bang.Really.Happen.1080p.WEB.x264-CAFFEiNE

Narrator: The big bang,
the story of everything --

time, the universe, us.

The big bang, one,
has a cool name,

and two, it's the history
of our universe.

This is it. It's all of us.

It's all things.

Narrator:
That's the traditional view,

but is it right?

More and more scientists
aren't sure.

In the old, outdated
big bang theory,

our universe just popped
into existence from nothing.

We talk about it as
the beginning of the universe,

but what it really is
is the end of our understanding.

Narrator: Astronomers are
ripping up the old rules,

but that creates new problems.

How can we possibly say
that universe expanded

faster than the speed of light?

Narrator: But are they asking
questions with no answers?

What was the origin?

Is there even a sense to asking,
"was there a time before time?"

We don't know.
We got nothing, folks.

Well, we got some things,
but it's tough.

It's tough.

It doesn't tell us
what happened, really,

at the beginning.

This is still
an absolute puzzle.

Narrator:
So just how did it all start?

The big bang theory
is a good story, but is it true?

�

-- captions by vitac --
www.vitac.com

captions paid for by
discovery communications

�

to begin at the beginning --

no space, no time,

everything in the known universe

compressed into a dot smaller
than an atom.

Suddenly, out of this,
the universe expands.

Stars and galaxies form,

creating
the cosmos we see today.

The story of our universe starts
with a big bang, or does it?

So the big bang
is the observed truth,

but there are details that
haven't been quite worked out.

There are a lot of things
that may have happened.

It's just one explanation.

�

tremblay: Science isn't about
being right all the time.

It's about being wrong,

and we could absolutely be wrong
about a major component

in our understanding
of the universe.

Narrator:
We're putting one of science's

greatest stories to the test.

The big bang sure sounds
like an explosion, but was it?

An explosion is a sudden release
of energy from one point

usually generating light,

heat, pressure,

and a bang.

But did the big bang
even explode?

When you hear the term bang,
you think of a noise,

but you have to realize
that it's sound waves

propagating through air.

So after the big bang,
there's no air.

There was no air.

There's no way to hear anything,
so in that sense, it was silent.

Narrator:
So the big bang didn't bang,

but to make the universe,

it must've pushed out stuff,

lots of stuff.

Every explosion
has an ignition point.

What about the big bang?

So if you were to only think of
the big bang as an explosion,

you would very rightly ask,

"well, where's the center
of that explosion?

Where is the center
of the universe?"

Narrator:
There was no central point.

There's nowhere in the sky
you can point and say,

"that's where the big bang was."

The big bang is everything.

The big bang happened here,
where I'm sitting.

The big bang happened
on the other side of the planet.

The big bang happened
in the Andromeda galaxy.

The big bang occurred throughout

the universe simultaneously.

Narrator: During an explosion,

debris fires out
from the center.

This debris spreads out
unevenly,

with different-sized pieces

landing at different distances
from the blast center,

but did the big bang
shoot material out

in this explosive manner?

For clues, we need to search
the night sky.

One of the things that's really
very striking about the universe

when you simply
take a telescope

and start looking in different
directions is that it,

roughly speaking, looks the same
in all directions.

Narrator: Although the universe
is peppered with individual

galaxies and galaxy clusters,

the big picture is what
astronomers call homogeneous.

When we say the universe
is homogeneous,

it means it's almost exactly
the same on very large scales

with very, very
little differences.

It's perfectly smooth.

Narrator: If we believe
the classic big bang story,

the same amount of material
was shot out

over the same distance
in all directions.

Our smooth,
homogeneous universe

doesn't appear to be the result
of what we know as an explosion.

It wasn't big,
and it wasn't a bang.

The big bang was not
an explosion like a grenade

or a bomb or dynamite

where there is material rushing
out from a common center.

It's not like there's a ring
of galaxies

that came out
from some explosion.

Narrator:
A firecracker explosion is

triggered by a fuse,

so what set off the big bang?

What I would say is there's
no such thing as,

"what triggered the big bang?"

You know, we tend to think when
something happens,

when there's an effect,
there was a cause, right?

There was something that made
it happen,

but here, we're talking
about the whole universe.

There's nothing outside
the universe

to bring it into existence.

Narrator:
The science is clear.

The universe did not start
with an explosion,

but if there was no bang,

then how did everything start
so small and get so big?

The young universe,
we do understand,

and that old contemporary
universe, we also understand.

We've stitched together
this story

where we don't fully understand

the first few paragraphs
of the story,

but we know
the rest of the book.

Narrator: How can we get to
the bottom of the big bang story

when we can't even read
the first page of the book?

The only hope we have
is to search back in time,

line by line.

One of the amazing things about
being a cosmologist

is that telescopes
are time machines.

It takes a while for light
to get here,

so if we look
farther out into space,

we're really looking back into
the history of the universe,

and that's amazing.

Narrator: The first clues to
unraveling the big bang mystery

came with the introduction
of advanced telescopes

in the 1920s.

�

Edwin hubble
was studying the light

coming from distant galaxies,

and what he realized was
the more distant the galaxy was,

the more reddened
the light was.

Why should that be?

Well, it turns out that
light reddens

if a galaxy
is moving away from us.

It's called the red shift.

So what he discovered was pretty
much every galaxy in the sky

was moving directly away
from the milky way.

Narrator: This was truly one of
science's landmark moments.

Hubble had proved one of
the basic principles

of the big bang story --

our universe
is continuously expanding.

There was only one conclusion
to draw.

If you extrapolate that back
in time,

it looks like everything
was coming

from one point at one time.

That's the big bang.

Narrator: Hubble's discovery
grabbed the headlines,

but the idea
of an expanding universe

had been proposed
two years earlier

by a Belgian priest
and physicist.

The real idea of the big bang
comes from georges lema�tre.

He realized that if you
ran time backwards,

back to the beginning of time,

maybe everything coalesced
into a single atom,

the primeval atom.

Narrator: Lema�tre believed
the infant universe

was extremely small and dense,

squeezed into a single point --

the primeval atom.

Later, scientists would define
this point

as an infinite entity
called a singularity,

but there's a problem.

The singularity and the laws
of physics don't mix.

It may be one infinitely
small point,

but it causes some
impossibly big problems.

�

narrator: The big bang --
for almost a century,

it's been science's leading
account of how everything began.

�

but there was no explosion,

no bang, and it wasn't big.

In fact, the father of
the big bang, georges lema�tre,

claimed everything originated
from one tiny point

he called the primeval atom.

I think one of the hardest
things to grasp

about the idea of the big bang
is that everything you see,

everything you've ever known,
everybody, every house,

every tree, every planet,
every moon, every star,

every galaxy in the entire
universe at some point,

13.8 billion years ago,

was compressed down
into a tiny little dot.

Narrator: In fact, far smaller
than a tiny dot,

infinitely small,
a point called a singularity,

and this singularity has been
causing astronomers headaches

for decades.

It's all because of one word --
infinite.

As soon as you start getting
the word infinity,

things are infinitely larger,
infinitely small.

In physics, it means that
you don't understand everything.

Narrator: Einstein's general
relativity predicts

the theoretical existence
of singularities,

but in practice,
a singularity

is where our current laws
of physics break down.

We do not understand
singularities.

These are some of
the theoretical questions

that are real conundrums,

and people are trying
to figure out what to do.

The universe is telling us
something is going on here

that we don't understand
quite yet with our math.

Our mathematics are incomplete.

This is a sign that
general relativity

is not up to the task
of describing the earliest,

earliest moments
of the universe.

Narrator: General relativity
predicts singularities,

but in reality, it doesn't work

when things are really tiny.

Einstein's picture
of general relativity

is incredibly successful

at describing the motion
of planets around the sun,

the bending of light
around massive objects,

the growth and expansion
of the universe itself,

but it breaks down
when gravity gets too strong

and gets too small.

Oluseyi: General relativity
may not be the best tool

for understanding
the origin of the universe.

Say, for example,

you want to weigh
some spices in your kitchen.

You can use a kitchen scale.

That works really fine,
but now say, on the other hand,

you wish to weigh your truck.

That's just not
the right tool for it.

Narrator: So forget relativity.

Maybe another fundamental branch
of theoretical physics

can help out --
quantum mechanics.

This deals with the small,
the very small,

but what about
the infinitely small?

Can quantum mechanics prove
the existence of a singularity?

General relativity seems to say
that singularities exist.

They're a very
straightforward prediction

of general relativity.

That doesn't fit well with
what quantum mechanics says.

Quantum mechanics tends
to fuzz things out.

It doesn't really like
singularities.

Narrator: In some theories of
quantum mechanics,

the science of the small,

there's a limit
to how small you can go.

For example, I'm not gonna be
able to fold this paper

more than seven times.

One, two, three, four,

I'm feeling good.

Five, oh, man, six,
can I do it?

Can I do it?
Can I break the laws of physics?

No, I can't.

There's a limit.
I just can't go past it.

Narrator: You can't keep
folding paper or space

into smaller
and smaller fragments,

and according to most laws
of quantum mechanics,

you can't have anything
infinitely small

and infinitely dense.

Singularities
seem to be doomed.

So is the big bang story wrong,

or are we just too dumb
to work it out?

Our laws of physics are
our best attempts

to model with mathematics

all of our observations
of the universe.

The universe doesn't care
what we think.

The universe doesn't care
how we understand it.

This is just our attempts

to explain the behavior
that we see,

and the earliest moments
of the big bang

is a big example of where
our understanding falls short.

�

narrator: Maybe the answer lies
in a combination

of general relativity
and quantum mechanics.

All right, guys. Go ahead.

Narrator:
But they won't play ball.

One, two, three. Deuce!

-Who's house?
-Our house.

-Who's house?
-Our house.

-One, two, three.
-Go usc!

-Whoo!
-Whoo!

Sutter: Imagine the rules of
quantum mechanics

are like the rules
that lacrosse players

might use to play their game,

and the rules
of general relativity

are the rules
that baseball players

would use to play their game.

If you're just watching
a baseball game

then they're just following
the rules of baseball

or general relativity.

If you're just watching
a lacrosse game,

you're watching the rules
of lacrosse play out,

you're watching the rules
of quantum mechanics.

But if you take one team
from lacrosse

and one team from baseball

and put them together
and ask them to start playing,

they don't even know how
to interact with each other.

It's fundamentally different
rules that simply don't connect.

Each of these pillars
of modern science,

quantum mechanics
and general relativity,

are wonderful
in their domain,

but when we try to marry them,
which is what we need to do

to describe the earliest moments
of the universe,

it all goes haywire.

Narrator:
Perhaps both teams playing with

a unified set of rules

will shed some light
on the big bang.

Merging together quantum
mechanics and general relativity

is the gold standard.

It's what every theoretical
physicist

would really love
to do in the modern age.

We haven't done it yet.

We have ideas, so when I say,
"we haven't done it yet,"

we don't agree on
what the right idea is.

What will ultimately reconcile
quantum mechanics with gravity?

Is there even a reconciliation
between them?

What do we need?

Do we need more surprising,
more powerful observations,

new data that
we weren't expecting,

another genius or 1,000 geniuses
to come along

and find the route through
the mathematics to marry it?

It's probably all of the above.

Narrator: So a major premise of

the big bang story
remains unproven,

but what about
monsignor lema�tre's

other assertions?

Was the infant universe,
the primeval atom,

intensely hot,

and if so,
just how hot was it?

�

�

narrator:
The story of the big bang

is based on the discovery

that the universe
is continuously expanding,

and if we go back in time,

this leads to one
inescapable conclusion.

�

so if you run
the clock backwards

and let the universe
get younger,

it'll get smaller
and smaller and smaller,

and then everything is basically
compressed into one point.

Narrator:
The big bang story claims

this point
was infinitely small,

but scientists have not been
able to prove

the existence
of such singularities.

In our universe,
we see all galaxies

receding from all
other galaxies on average.

Imagine if you were looking
at trains leaving a station.

If you ran the clock backwards,

the trains would converge
to the same station.

Now, did these trains come
from the same station?

Probably.

Did they come from the exact
same platform?

Probably not.

You can't fit all the trains
onto the same platform.

Narrator: But while physicists
can't prove everything came

from an infinitely small
and dense singularity,

they're convinced
the observable universe

did expand
from one small point,

and this point was incredibly
dense and incredibly hot.

Imagine that you
and a bunch of friends

are in a very large room,

and you're all hanging out,
and it all seems normal,

but now you're
all cramped together

in a very small elevator,

and it starts to feel
much warmer

because you're interchanging
all of this heat.

It's sort of like that
in the early universe.

Everything is smashed together.

Everything is very hot.

Narrator: It makes sense
theoretically that this period

was intensely hot,
but how do you prove it?

How do you take the temperature
of the early universe,

which began
13.8 billion years ago?

You can't, but you can take
the temperature

of the coldest part
of the universe now.

So if you go away
from all the stars

and get away
from all the galaxies,

you might think space was
infinitely cold, absolute zero,

but it turns out it's not.

Narrator:
Empty space has a temperature

of roughly 455 degrees
fahrenheit below zero,

5 degrees
higher than absolute zero.

Where did these mysterious
extra 5 degrees come from?

Big bang believers
thought they had the answer.

They claimed this faint
trace of heat

was left over from
the incredibly hot

infant universe.

Getting the proof took decades,

but it came in 1964
by pure accident.

Penzias and Wilson were
bell labs engineers,

and they were given
an assignment

to measure certain
radio signals

for the idea of sending
wireless signals via telephones,

so rural areas
could have telephone.

Narrator:
They used a radio antenna

shaped like a giant horn.

The problem was, no matter where
they pointed this horn,

they kept hearing
kind of a static,

just a radio noise
coming from every direction.

Sutter: And they thought, "okay.
Maybe it's a satellite,"

but it didn't match up
with any satellite positions.

There's a nearby army base,

and they called up
the army base and said,

"hey. Are you broadcasting
at this frequency?"

And they said, "no. We're not."

Thought, "maybe
it's pigeon poop."

Well, you know,
there are these pigeons

nesting inside the antenna,

and their droppings are creating
this noise in your telescope.

So they actually went inside
and scraped out

all these pigeon droppings,

but no matter what they did,
the noise remained.

They tried everything they could
to remove this background noise,

and they finally realized
it was coming from the sky.

It was real.

Narrator: What they were hearing
was not radio waves

but a different form
of radiation --

microwaves, a heat signature
left over from the big bang.

�

they had discovered
the cosmic microwave background,

a ghostly snapshot
of the early universe.

Different colors highlight
subtle variations

in temperature.

The cooler blue areas
will develop

to form stars and galaxies.

The warmer orange areas
will eventually make up

the vastness
of intergalactic space.

Sutter:
The cosmic microwave background

is a literal baby picture
of our universe.

It's the equivalent of
a picture of you

when you were seven seconds old.

Narrator: We can date the cosmic
microwave background

to 380,000 years
after the big bang.

The temperature here
is estimated

to be 5,000 degrees fahrenheit,

but how hot was the big bang?

As we run the clock backwards,
the universe gets smaller,

and the temperature increases.

We know what the temperature
of the cosmic

microwave background was,
but prior to that time,

we know the universe was getting
smaller and smaller and smaller,

and therefore it had to get
hotter and hotter and hotter.

Narrator:
But can we find out how hot?

In the early universe,
it was much smaller, denser,

and hotter than it is today,
and in fact,

it was so hot it could
fuse hydrogen into helium.

25% of the mass
in the early universe

is fused into helium in this
timescale of just a few minutes,

so it's trillions
and trillions of times

more than the amount of fusion
that's going on in the sun.

�

narrator: Extremely high
temperatures are required

to fuse hydrogen into helium.

Scientists estimate fusion
started 100 seconds

after the big bang,

when temperatures reached
1 billion degrees fahrenheit.

During the very first fractions

of the very first second
of the big bang,

some estimate the temperature
could have reached

250 million trillion
trillion degrees fahrenheit,

but what sparked
this massive release of energy

here at the birth
of the big bang?

The initial moments
of our universe

are a source of frustration

because it'd be really nice
to know that,

but also a source
of curiosity.

This is the frontiers
of physics.

This is where we're really
pushing things

to try to understand

the fundamental aspects
of reality.

Narrator: But even if we could
back up the big bang story

by proving the way everything
came from a tiny hot point,

there's still another problem.

Where did everything that made
up that tiny point come from?

You can't get something
from nothing, right?

We all know that,
except it looks like

we got everything from nothing.

The entire universe seems
to have appeared out of nowhere.

How can that work?

�

narrator: The big bang --

no space,
total darkness, nothing.

�

suddenly, the universe
sparks into life.

Really?

Surely, everyone knows you can't
get something from nothing.

�

it's really the ultimate
question.

How did the universe
come into being?

And the thing is we don't want
just everything to come nothing.

It seems like a trick,
but here we are.

We exist, so something
must've happened,

and we just don't understand
the physics of it yet.

This is one of the big
open questions in cosmology,

the origin of the universe,

and I think that people
have variously said stuff like,

"oh, the universe
has come from nothing."

Like, ta-da!

Now there's a universe,
but remember, we don't have data

about the earliest moments
of the universe.

We don't know
what was going on.

Narrator:
We're struggling in the dark.

To get insight into what may
have happened

before the big bang,

that period of apparent
nothingness,

physicists look to empty space,

but does empty really mean

there's absolutely
nothing there?

It's not that there's something
coming from nothing

because that old-fashioned idea
of nothing just doesn't apply

to what we think of
as empty space.

Narrator: It turns out empty
space is far from empty.

The vacuum of space is really
a writhing sea awash

with charged quantum particles
and electromagnetic fields.

The vacuum of space itself
can be a very dynamic thing.

Matter can spontaneously
appear out of the vacuum

and then
spontaneously annihilate.

The vacuum is full of particles
and antiparticles

that are whizzing
into existence

and then disappearing,
colliding with each other.

Narrator: Space is full of
virtual particles

popping in
and out of existence.

And there's no question
that they're real.

Their effects are
absolutely visible.

We can see them.

Narrator: In extreme physics,
things can get strange.

Maybe nothing is something
after all.

If empty space
contains particles

that apparently
come from nothing,

could some sort
of similar process

have triggered the big bang?

The quantum vacuum itself

can randomly, spontaneously,

without any input just --

have a lot of energy,
perhaps enough energy

to spark something
that we would call a big bang.

�

narrator: There are many
speculative theories

about the origin
of the universe,

but is its sudden appearance
out of nothingness

the only trick it pulled off?

It also made matter from energy.

The universe is full of
galaxies, stars, planets,

and comets.

Where did they all come from?

According to the big bang
narrative -- from one tiny dot.

When the universe began,

there was actually no room
for matter at all.

The temperature was so high.

The spaces were so compressed
that matter couldn't exist.

Narrator:
So how did the universe manage

to become full of matter?

In the primeval atom,
there was no room for matter,

but it was crammed
full of energy,

and as Einstein tells us,

all we need
to create matter is energy.

According to e equals
mc squared,

energy and matter
are interchangeable.

Einstein taught us with
special relativity

that energy and matter
are two sides of the same coin.

You can convert matter
into energy by,

say, blowing something up.

Narrator:
The most fearsome example

of converting matter into energy

was the atomic bomb,
developed in the 1940s.

�

but with the big bang,
this process was reversed.

Energy created matter,

matter that expanded
out and out

to fill a whole universe,

and in cosmic terms,

the universe where matter would
develop grew remarkably fast.

Right after the universe
was born,

it had an unbelievable
growth spurt,

basically going from being
a toddler

to a teenager
in the single tick of a clock.

Narrator: How could the universe
get so big so quickly?

If we believe
the big bang story,

it appears to have broken

one of the most
fundamental laws of physics.

Did the early universe
really grow faster

than the speed of light?

�

�

narrator:
In the classic big bang story,

the observable universe expands

from a ball of energy
smaller than an atom.

Today,
the universe is estimated

to be 93 billion light years
in diameter.

Think about the vast universe
that we see all around us today,

and it was once a tiny,
tiny little volume,

unimaginably dense.

The universe must've gone
through a colossal growth spurt.

�

narrator:
With a steady rate of expansion,

there simply hasn't been enough
time for the universe

to grow to its current size.

Regions of the universe that
were close neighbors in the past

are now so far apart
that their separation can't be

explained by normal expansion.

And the huge size of the cosmos

is not the only strange thing
we've discovered.

The universe is what astronomers
call flat.

Sutter: Our universe is lumpy
and bumpy at small scales.

There's galaxies.
There's black holes.

There's people.

There's all sorts of junk,
but at large scales,

global scales,

truly universal scales,
our universe is flat.

�

narrator:
Could this universal flatness

and the super rapid growth

somehow be connected?

�

we know that the big bang
wasn't an explosion,

or matter in the universe
would be unevenly distributed.

�

yet something pushed everything

outwards and fast, but what?

�

in 1980, Alan guth,
a young Stanford cosmologist,

came up with a potential answer.

His theory of inflation says
the observable universe

expanded from being smaller
than an atom

to the size of a basketball
almost instantaneously.

In this tiny fraction
of a second

at the beginning
of the universe,

like a millionth of a second
but a millionth of that,

a millionth of that
and a millionth of that,

the universe expanded by --

take the size of the universe
at that time

and multiply it by a one with,
say, roughly 50 zeros behind it.

Inflation drove the accelerated
expansion of the universe,

made it get really,
really big really, really fast,

and then it stopped.

Narrator:
Inflation seems to solve

two big bang headaches --

how the universe got so huge
so quickly

and why it's so flat.

Because it inflated
everywhere at once,

all the energy in the universe
which would turn into matter

was pushed out evenly at
the same time and same pace.

Sutter: And the first stars
grow together

to become the first galaxies.

Even here, us,
in the solar system, we're born.

We're seeded in the event
of inflation.

�

narrator: Parts of the universe
that are now separated

by 93 billion light years

once had the same
cosmic zip code.

To have expanded so quickly,
inflation must have broken

one of the fundamental rules
of physics.

We all know that one rule
the universe sticks to

all the time
is that nothing can travel

faster than the speed of light.

So how can we possibly say that
the universe expanded

faster than the speed of light?

Narrator:
But inflation says the universe

expands into nothingness.

There was no outside
of the universe.

The universe was everything.

So space itself was inflating,

and space can move as fast
as it wants.

You can't go faster
than the speed of light

through space,

but space itself is allowed
to stretch and expand

as fast as it wants,

and that's what our universe
is doing.

The idea of inflation smooths
out the universe

in kind of a peculiar way.

You can kind of think of it
as having a sheet

with a lot of wrinkles in it,

and if you take that sheet
and snap it really hard,

those wrinkles
very suddenly flatten out.

The theory of inflation is one
of the craziest-sounding ideas

in the history of science,

so crazy
that it might just be right.

Narrator: Inflation helps us to
understand the inexplicable,

but there's a problem.

We don't know what triggered
or powered inflation.

The inflationary universe idea
imagines

that the universe was suffused

with some kind of ultradense
energy at early times,

something that pushed
the universe apart.

What caused there to be
that hot expanding stuff?

We have to be humble
and acknowledge

that we don't know for sure.

Narrator:
But whatever started it,

inflation
was over in a split second.

Sutter:
It didn't last very long,

and this is difficult
to understand.

How did inflation stop?

We don't know.
We got nothing, folks.

Well, we got some things,
but it's tough.

It's tough.

Narrator: But has the process of
inflation really stopped?

One radical theory proposes
if the force called inflation

kick-started
the expansion of one universe,

then why not another
and another and another?

�

is inflation creating
a whole series of new universes?

Is there a multiverse?

�

narrator: If we believe
the big bang story,

a dot smaller than an atom
expanded to make a universe

93 billion light years across.

A theory called cosmic inflation

claims to explain
this stupendous growth.

�

but inflation may create
more questions than answers.

�

inflation gave us more than
we had bargained for.

We tried to come up
with a mechanism

that would just create
our universe and stop

and then quickly realized that,

actually, just like most
car factories

don't produce one car
and then stop

but produce many cars, inflation
tends to produce one universe

then another and a vast number
of them, a multiverse.

Narrator: It's a process called
eternal inflation.

It proposes that while inflation
ended in our universe

and led to formation of stars
and galaxies,

we're just one small part
of a vast continuously

inflating multiverse.

Imagine a series of bubbles
next to each other.

Those are the different
universes,

and so our bubble is expanding,

and we're bumping into
our neighboring universe,

and we're going
to expand into it

if the multiverse theory
is correct.

Narrator:
A big bubbling multiverse

sounds like science fiction,

but there is prospective
evidence to back up the theory.

Scientists have spotted
an unusual Mark

on the cosmic
microwave background,

that snapshot
of the infant universe.

There's a spot in
the Southern hemisphere

that's not necessarily
the coldest spot

or the biggest spot,

but it's the coldest
biggest spot,

and it's strange.

We don't know how
to fully explain it.

Narrator: One unproven but
intriguing theory

is that this area
is a kind of cosmic dent,

surface dent from an impact
with another universe.

I work in the building
with the people

that discovered
this giant cold area,

and they were pointing it out
and saying,

"well, that doesn't
make any sense.

"Why would the microwave
background be like that?

"Hey, maybe that's evidence
of another universe

interacting with our own."

That's something that,
when you go to lunch,

makes you pause.

Narrator:
If you buy into the idea

of a crowded multiverse,

cosmic bangs and scrapes
are not only perfectly possible,

they're probable.

There may be many universes
outside expanding

under the force
of inflation right now.

One analogy is

think about a superhero
that just can't be killed.

They keep regenerating.

Narrator: If the multiverse
narrative is correct,

it places a giant question Mark
over the story of the big bang.

The possibility of
a multiverse suggests

not just one
but a whole series of big bangs.

�

but not all physicists
buy into this thesis.

The community is divided
on the idea of the multiverse,

predictably, because there are
some of us who believe

that this sort of leap
of imagination is justified,

and there are others,
sort of hardliners,

who think that, until we have
empirical evidence,

this is not a scientific idea.

Narrator:
Others welcome the fact that,

when it comes to
explaining everything,

we're not simply stuck with
the good old big bang narrative.

I would've felt kind of
claustrophobic

if it turned out
that all that existed was earth,

and I was happy
that we discovered

that it was part
of something bigger,

the solar system, the galaxy,

a cluster of galaxies
or universe,

so I'd feel even better
if there's still more space out

there and parallel universes,

the more the merrier.

Narrator:
While it's an appealing notion,

without empirical evidence,

it's a theory requiring
a leap of faith.

�

there's no reason to think
that the tiny, little creatures

that we are actually perceive
the vast true nature of reality.

This is still
an absolute puzzle.

We have ideas. I have ideas.

Other people have
proposed models, right?

But we have no data, really,
that helps us

distinguish between these ideas,
and to be honest,

the ideas themselves
aren't fully fleshed out.

Narrator: Support for
the classic big bang model

seems to be
increasingly shaky.

The latest thinking proposes
not one,

but a whole series
of big bangs.

�

as scientists continue to
rewrite the traditional story,

more and more questions
are being asked,

but for now,
many remain unanswered.

What was the origin?

Is there even a sense to asking,
"was there a time before time?"

And I think the answer is yes.

You know, our science and our
math, they're just incomplete.

Some day, we may have
the mathematics

to describe the earliest
moments of the universe.

Some day, we may be able
to make predictions

that we can connect
to observations.

Just because that day
isn't today

doesn't mean that
that day will never come.

We've learned an enormous amount
in the last 100 years,

but now we're left with some
pretty serious puzzles

that are gonna be
really tough to solve,

so I'm waiting
for the next Einstein.

�