All language subtitles for Ancient Aliens S10E06 The Other Earth

NARRATOR: Billions of
Earth-like planets...

MICHAEL DENNIN: Why would
there be this vast universe

and just us?

NARRATOR: ...each capable
of sustaining life.

DAVID CHILDRESS: In many ways,
it's like finding

the Garden of Eden.

NARRATOR: ...and each
with possible evidence

that we are not alone.

GIORGIO TSOUKALOS:
We have this imprint

within all of us,
that our origin is out there.

That life as we know it,
on planet Earth...

originated elsewhere.

NARRATOR:
Since the dawn of civilization,

mankind has credited

its origins to gods

and other visitors
from the stars.

What if it were true?

Did extraterrestrial beings

really help
to shape our history?

And, if so, might this
explain our search...

for another Earth?

NARRATOR: July 23, 2015.

After more than six years

of observing
over 150,000 star systems

within the Milky Way galaxy,

NASA scientists,
using the Kepler Telescope,

discover what they believe to be
an Earth-like planet,

located 1,400 light years away.

Kepler-452B...

Or Earth 2.0,
as it has become known...

Is 60% larger than Earth.

The exo-planet
orbits a star slightly larger

and brighter than our sun

and falls within that star's
"Goldilocks zone"...

making it a leading candidate

to prove life exists
on a planet other than our own.

Some planets are too close
to their stars,

so they're too hot.

Some of them are too far away,

so they're too cold.

Recently, they found one

which they've actually
called the Goldilocks planet.

As you can probably
surmise from that,

that means that it's
almost just right.

What that means
is that there's a potential

that it might be
teeming with life.

PAUL DAVIES: The problem
looking for Earth-like planets

beyond the solar system
is they're hard to spot.

There may be billions
within our galaxy alone

that satisfy
roughly the conditions

of being Earth-like.

They have to have a magnetic
field and a few other conditions

that will be congenial for life,

but the liquid water, as well,

I think everybody agrees,
is key.

The Kepler discovery made
people sit up and take notice,

'cause it would possibly have
the all-important liquid water

that is the key
to looking for life

as we know it
beyond the solar system.

NARRATOR: Of the 100 billion
stars that make up

the Milky Way galaxy,
astronomers now estimate

that one in five
has an Earth-sized planet

with the potential for life.

And NASA scientists predict
that we are likely to find

signs of alien life
by the year 2025,

bringing us ever closer to
answering the age-old question:

"Are we really alone
in the universe?"

DENNIN:
Humans are really excited

about life on other planets.

There's a lot
of empty space out there,

and it would be a big waste,
if there wasn't more life.

Why would there be
this vast universe

and just us?

Forever people have wondered,
"Are we alone?

"Is there life out there?

Are there other
intelligent beings?"

And that's why
we're so insistent upon

searching for another Earth.

I think there's
that need to realize

that we're not alone
in the universe.

We want answers.

We're going out into space
because we want to find out

are there other beings
out there like us?

NARRATOR:
Since the Ancient Babylonians

first documented
observations of Venus,

humans have speculated
that inhabited worlds

may exist beyond Earth.

And from the time
of the ancient Greeks,

philosophers and scholars

have theorized
on the probability

of the existence
of otherworldly civilizations

other than our own.

In 1961,
radio astronomer Frank Drake

was the first to publicly
propose a mathematical argument

for the likelihood
of the existence

of intelligent
extraterrestrial life

in the galaxy.

DENNIN: Frank Drake
developed an equation

that took the probability
of different things happening:

Having the right type of sun,
having the right type of planet,

how many planets
and stars there were

and made an estimate
of how likely life would be.

JOHN BRANDENBURG: The Drake
equation would seem to logically

predict tens of thousands

of civilizations out there,

that we ought to be able
to hear on radio traffic.

NARRATOR: But if there is
such a high probability

for the existence
of intelligent life-forms

elsewhere in the universe,
why haven't we encountered them?

SEAGER: If there are so many
other planets out there,

and if the chance for

intelligent life
out there is high,

why hasn't anyone visited us?

BRANDENBURG:
The human race should be typical

of what intelligent life is like
in the rest of the cosmos.

Plus the cosmos is much older
than the human race.

We tend to expand into all
possible living spaces.

Intelligent life in the rest
of the universe

should probably
act like that, too.

People like us
should be filling the cosmos.

Everywhere we point
a radio telescope

we should be picking up noise.

Instead, there's nothing.

NARRATOR: While radio telescopes
have yet to pick up

a transmission from
other intelligent beings

in the universe, ancient
astronaut theorists propose

that contact has, in fact,

already taken place.
And evidence of this

can be found
throughout the world.

The question "where are they?"
should be answered with:

"Look at the ancient
astronaut theory,"

because we are suggesting

that there is evidence

that goes back
thousands of years

by the stories
that we have of gods...

Lowercase "G"...
Descending from the sky.

It doesn't matter
on what continent.

Every single continent
was visited.

CHILDRESS: I would say that

the evidence is there

and it's all around us,
whether it's in

megalithic sites that are

aligned to constellations,

such as the Great Serpent Mound
in Ohio.

Even the pyramids at Giza.

And even stories of beings
coming down in spaceships,

interacting with people.

Evidence is overwhelming

that there are extraterrestrials
all over the universe,

and that they're coming here.

NARRATOR: According to ancient
astronaut theorists,

one of the earliest and most
compelling pieces of evidence

to support the notion that
extraterrestrials have, in fact,

visited Earth, can be found

with an ancient Sumerian
cylindrical seal

known as VA243.

Author Zecharia Sitchin
was the first to suggest

that on this seal,

which is estimated to be
at least 4,500 years old,

is a depiction
of our solar system.

JASON MARTELL: You can see
in the seal that there's

a whole complete model
of the solar system

accurately being displayed
with the sun in the center.

Now, till the time
of Copernicus and Galileo,

no one knew that we actually
orbited the sun,

so the only explanation is
someone who had this knowledge

gave it to humanity,

and that there has been
extraterrestrial presence

in interaction with people
in the past.

And we see this
across the globe.

NARRATOR: Throughout the world,

ancient cultures
have told stories of gods

descended from
specific star systems.

The Maya associated their gods

with the Pleiades star cluster,

as did the Native Americans,
hundreds of miles away.

The Dogon tribe
and the ancient Egyptians

believed their gods
came from the star Sirius.

ERICH VON DANIKEN: In old Egypt,

we have, for example, Osiris,

who comes from Orion.

Osiris was married to Isis.

Isis comes from
the star of Sirius.

These extraterrestrials,
the so-called gods,

they pointed up to the sky and
said, "Look, this is our home."

NARRATOR: Is it possible that
there are intelligent beings

inhabiting other planets
within our solar system,

as ancient astronaut
theorists contend?

If so, could they have
once sought out Earth

as we now seek
other habitable planets?

Perhaps further evidence
will be revealed

with our plans to colonize Mars.

NARRATOR: Spring 2013.

The Mars One project
solicits candidates

for their proposed settlement
on Mars.

Over 200,000 people apply

for the chance
to be the first humans

to colonize the Red Planet.

Only 24 will be selected.

None are expected to return.

BRANDENBURG:
The Mars One mission

is a very ambitious mission.

They've canvassed the whole
world's aerospace contractors

and tried to make heavy use
of the experience

on the space station, where
they've made living modules.

Those same modules
can be brought to Mars

and support human life.

NARRATOR: Scientists
are testing working models

of living quarters for Mars,

such as NASA's
Deep Space Habitat.

Engineers designed these pods

to be constructed remotely,
before humans arrive.

Once built, the habitats
will supply oxygen and water

and minimize the harmful effects

of atmospheric radiation
to humans.

Yet even these engineering feats

won't allow humans
to live on Mars

for extended periods of time.

DENNIN:
We have tried experiments

with actually making
a survivable environment

in a pod,

and it seems to be
very, very hard to do

for a very long scale.

If we want
long-term habitation on Mars

and colonization of Mars,

personally,
I vote for terraforming.

NARRATOR:
Terraforming is the process

of turning an environment
unsuitable for human habitation

into one
that mankind can live in.

Scientists are currently
researching the various ways

we might someday terraform
an entire planet.

DENNIN: When you think
about terraforming Mars,

the key, really, is getting
a dense atmosphere

that forms protection
from the radiation from the sun,

makes the temperature
really high enough,

and gets things going
with plant life and oxygen.

So one question is, where do you
get that denser atmosphere?

Couple of options:

There is various amounts
of gases

trapped in the polar caps,

so you can imagine melting
those, releasing the gas.

DAVIES:
Terraforming another planet

is a very, very long-term
prospect.

Now, if we were going
to terraform Mars

to make it more Earth-like, we
can think of ways of doing that.

We can seed it with microbes

that might produce
a thicker atmosphere.

You can dramatically modify
conditions on a planet

by suitable intervention,

and Mars would seem to be
a good one to do it for.

Mars was
once much more Earth-like.

Perhaps we could bring it back,

make it more Earth-like again.

BRANDENBURG:
Earth's early atmosphere

and Mars' present atmosphere,

in composition,
are very similar.

Earth had a lot of water vapor,

nitrogen, and carbon dioxide.

That's what Mars' atmosphere
consists of.

NARRATOR: Ancient astronaut
theorists propose

that if humans are planning
to one day give Mars

a breathable atmosphere,

extraterrestrials may have done
the same thing with Earth,

millions of years ago.

There's a distinct possibility

that the Earth
could've been terraformed.

When you look at the development
of Earth, what you see is that,

at every stage, the planet got
exactly what it seemed to need

to develop into this beautiful
blue world that we live on.

When we needed oxygen,
there was bacteria introduced

into the ecosystem

that actually sucked up
carbon dioxide

and methane gas
and-and pumped out oxygen.

We're looking at what Mars is,

and we're thinking of trying
to build an atmosphere

and everything else.

And the first question
you'd have to ask yourself is:

Did extraterrestrials come here
and do the same thing?

NARRATOR:
But how did our planet,

that was once devoid of oxygen,

turn into the lush green world
we know today?

Scientists have struggled
for years

to discover
just how Earth became habitable.

There's always been a-a problem
about life on Earth.

Did it actually
start here on Earth,

or come here
from somewhere else?

There's no known transition
from non-life to life

that we can all agree on.

Seeing as we don't know how life
began, it's up for grabs.

But we know, on Earth,
it was microbes

that made the oxygen atmosphere.

NARRATOR:
Although scientists agree

that Earth's
oxygenated atmosphere

most likely can be attributed
to the presence of microbes,

many theories exist

as to where exactly
these organisms came from.

One intriguing speculation

that has caught the attention
of ancient astronaut theorists

involves grooved metal balls
called Klerksdorp spheres.

These mysterious round objects

were found scattered in
mineral deposits in South Africa

that date back 3 billion years.

There are people that argue
that these spheres are natural,

but there's really
no natural objects

that bear any resemblance
to them at all.

And the fact that they're buried
in rock that is so old indicates

that somebody sort of scattered
them throughout the planet.

They appear to be
metallic, constructed spheres

in which you could have placed
bacterial life

that would definitely
have been able to then spill out

into the ecosystem,
multiply, divide,

and change the environment,

exactly as we're proposing to do
on the planet Mars.

We might say that this is just

a natural occurring thing
on Earth,

but this may be evidence
that Earth was seeded

by some kind of bacteria
or microbes brought here

and what we have today
has been purposely created

by beings with tremendous powers
and knowledge.

NARRATOR:
Did extraterrestrial beings

introduce organisms to Earth

that started life,

just as humans
may someday do to Mars?

If so,
could our ancestral origin

actually come from
another planet in the galaxy?

The answer may be right
in front of us,

lying within the physiology

of our own bodies.

NARRATOR: Tell al-Uhaymir, Iraq.

Here, in what was once the
ancient Sumerian city of Kish,

archaeologists unearthed

the world's
oldest written document.

The Kish tablet

dates to 3,500 BC,

and is believed to pre-date
both the Sumerian cuneiform

and Egyptian
hieroglyphic writing

by nearly a hundred years.

Developing the ability
to express thoughts

through written language
is one of the first ways

in which man separated itself

from the rest
of the animal kingdom.

In the 5,000 years since,

humans have harnessed
electricity,

split the atom,

developed computers,

and placed a man on the Moon.

No other species on Earth

can claim such unique
achievements

in such a short span of time.

In comparison to other animals,

our evolution is pretty brief.

Um, it's-it's been
a fairly short time,

only a couple of million
years, probably,

since the first hominids.

WARD: One of the great
scientific questions

is why is it our species

uniquely arose into this

truly advanced
technological intelligence

that we have.

Clearly, there's nothing else on
planet Earth that is like us.

There are many intelligences,
but nothing

is wielding technology
to the extent that we do.

DAVIES: If we just had to sort
of go back to the jungle,

the proverbial jungle,
and just survive,

most of us wouldn't really
live for very long.

Human beings,
apart from their intelligence,

uh, really are not
very well-suited

to occupying a wide range
of environments.

(crying)

NARRATOR: In addition to our
incredible intelligence,

biologists have also
noted contrasts

between human physiology
and other animals.

FISHER:
Compared to other animals,

I think we're a little odd.

A baby horse is born,
for instance, it's able

to walk around and do its own
thing, like, immediately.

The same is certainly not true
of a... of a human infant.

We are pretty helpless.

We're born before we're quite
neurologically cooked.

There are many vulnerabilities
which go alongside

our much-vaunted intelligence.

We became bipeds and that
freed up our forelimbs

to be able to manipulate
objects, make tools and so on.

But it comes at a price,

because we've got
these back problems.

WILLIAM LEONARD:
Lower back pain is something

that is virtually unknown
in other primate species,

whereas it's something
that is very common

in contemporary humans.

NARRATOR: In 2013,
ecologist Dr. Ellis Silver

set forth in his book
Humans Are Not From Earth

a possible theory
to explain why humans

seem so evolutionarily
unsuited to the planet.

BARA: Dr. Ellis Silver

developed an idea that perhaps
the human race

did not actually naturally
evolve here on the Earth,

but somewhere else.

DAVID WILCOCK:
Silver's book raises a lot

of very provocative
and intriguing questions.

For example, why is it that

we get cataracts from the sun?

Why is it that the sun
seems to hurt us

if we go out for too long?

So Dr. Silver suggests that we
might've come from a planet

with different solar exposure.

We also have 223 genes

that appear in human DNA

that do not appear
in any other species on Earth,

suggesting, again,

that there's something
unusual about us.

BARA: They've discovered
that astronauts,

when they're in space,

their circadian rhythms actually
change from 24 hours...

Like we have
when we're here on Earth...

To 24.9 hours, which is
the exact circadian rhythm

or the exact length
of a Martian day,

not an Earth day.

NOORY: The patterns
of who we are as human beings

doesn't fit into
some of the other creatures

that are on this planet.

Dr. Silver, his theory was

that we were either brought here
or seeded here,

but clearly
of an extraterrestrial origin.

CHILDRESS: We are, in a sense,

transplanted here

from some other solar system.

And Neanderthals
were already here

and we are a cross-bred...

part-alien race

that's part Neanderthal
and part extraterrestrial.

NARRATOR:
Might Dr. Silver's observations

of human physiology be proof

that we are a hybrid species,

one whose origin
comes from a celestial place?

Ancient astronaut
theorists say yes,

and claim further evidence
can be found

in the narratives
of numerous religions.

Brigham Young, one of
the most important leaders

of the Mormon religion,

proposed that the biblical Adam

was not created on Earth,

but was born to parents
on another world

and then was
brought to our planet.

In the Zohar,

the primary text
of Jewish mysticism,

a similar story is told.

TZADOK:
Adam actually had parents.

A mother and a father.

And that God took Adam

from whatever place
that he came from...

We don't understand
what that is,

another dimension,
another world, we don't know.

We are half physical

and we are half
something much greater.

Celestial,
extraterrestrial, divine.

TSOUKALOS: According
to the ancient astronaut theory,

we were created
in the image of the gods

and those stories are reflected

in all of our ancient legends.

For example, the Native American
culture clearly states

that our entire planet
was seeded.

LOGAN HAWKES:
In the ancient American world,

part of their
core belief system is that

they may not
have originated on Earth.

We know that the Hopi,
for example,

believed that they were
brought to the Earth

by star people
from the Orion system.

NARRATOR: Is it really possible

that our origins
are not entirely

from this planet?

And if so, does this explain

why we are drawn to the search
for an other Earth?

Perhaps the answers lie

in ancient tales
told across the world

of a paradise lost forever.

NARRATOR: In October of 2018,

the James Webb Space Telescope...

The most powerful telescope
ever built...

Will take its place
in the cosmos,

nearly one million miles
from Earth.

It is just the latest tool

in our endless pursuit
of locating

another habitable planet.

Since Galileo Galilei

first aimed a telescope
skyward in 1609,

billions of dollars
and countless resources

have been spent
on humanity's search

for an other Earth.

It is more than a search

for intelligent life
in the universe.

The quest to explore
the universe

is nothing less than
our longing for transcendence.

It is a search for meaning.

It is a search for what
is beyond our understanding.

WILCOCK:
Could there also be a yearning

and a longing
for some other planet

that we came from?

And so when we look up
at the stars, there's this

genetic beckoning that we feel

to want to explore,

to want to find out
what happened to us.

How did we end up here?

NARRATOR: Is it possible

that our attempt to locate
life on other planets

is, in fact, a quest to locate

our extraterrestrial origins,

as ancient astronaut
theorists propose?

If so,
is this drive deeply ingrained

in our genetic memory?

CHILDRESS:
In many ways, it's like

finding the Garden of Eden,
where we came from.

And perhaps the Garden of Eden
was on another planet,

and this is part of our own DNA,

to find out where we came from.

NARRATOR:
The tale of a lost paradise

is among the most enduring myths
in the world.

Celtic legends speak of
the mysterious Island of Avalon

that required supernatural
transport to visit.

The Buddhist
and Hindu traditions tell

of the forbidden land
of Shambhala.

And in the Taoist tradition,

they refer
to various celestial paradises

where the immortals reside.

In the Taoist tradition,
there's a belief

that, um, immortals who ascend

to these paradises
and to heavens,

they can actually be demoted

for bad behavior or misconduct,
and banished.

And when they are banished,
they are banished,

typically, back to Earth.

NARRATOR:
Might the cross-cultural stories

of a utopian world be not
mythology, but actual history?

Could these stories be evidence

that life came to Earth
from another planet?

Ancient astronaut theorists
say yes,

and suggest that further proof
may be found

in the historical records of
a tiny farming town in England.

Woolpit Village.

The 12th century AD.

Two small children
mysteriously appear

near the opening of a cave...

A boy and a girl speaking in a
language that is indecipherable.

But even more odd...
Their skin is green.

SABINA MAGLIOCCO:
The farmers in the area

who were harvesting vegetables
came upon these two children.

Their skin was green,

and their clothing was said
to be made of a strange fabric.

It was a fabric unfamiliar

to the people
who were describing them.

KATHLEEN McGOWAN COPPENS:
The children are immediately

whisked off
and put into isolation

from the rest of the village
for several days,

because no one is sure
if they're actually human.

MAGLIOCCO: The children said
that they came

from the land of Saint Martin,

a land that was, in many ways,
much like Earth.

They described
the place that they came from

as not being as bright
as our land is.

There was no bright sun,
there was no dark night,

but it was a sort of twilit land

with the sky the color
of early evening.

NARRATOR: Prominent 12th century
historian William of Newburgh

included a detailed account
of the Green Children

in his major work,
History of English Affairs.

He noted
that they eventually acclimated

to their new environment.

YOUNG:
The children gradually became

part of the community.

The boy, the younger
of the two children, died,

but the girl survived, and
there are some serious tracking

of her descendants, indicating

that she is a real person
in history.

NARRATOR: Many theories
have been proposed

as to where exactly
these children came from.

McGOWAN: The most popular
theory seems to be

that they came
from another planet,

a planet with a different type
of orbit,

a planet that was not exposed
to the sun.

NARRATOR:
Does the well-documented account

of the Green Children of Woolpit
give credence

to the existence
of another inhabited world

separate from our own?

Some ancient astronaut
theorists suggest

that another Earth may exist,
not in space,

but deep within the Earth,

right under our feet.

NARRATOR: June 13, 2014.

Scientists researching
the Earth's mantle

announce that they have found
what they believe

to be a vast body of water,
three times the volume

of all of our oceans combined,

contained within a mineral layer

400 miles inside the Earth.

The discovery
shakes the foundation

of what scientists and scholars
thought they knew

about the ground under our feet.

We have just scratched
the surface of the Earth.

We drilled down,
like, eight miles,

and we had to stop
because it got too hot.

Out of 4,000 miles...

Basically to
the core of the Earth...

We went down eight.

That's nothing.

AGNEW: We have more than 70

active space programs right now.

We can tell you more
about the surface of the Moon

than we can the surface
underneath our own oceans.

NARRATOR:
Our scientific understanding

of the internal structure
of the Earth

is primarily based
on observations of seismic waves

generated during earthquakes

and knowledge
of Earth's gravitation field.

Since we have not actually
drilled down far enough

to confirm these findings,

could it be that we may be wrong

about the composition
of our own Earth?

Some ancient astronaut theorists
say yes,

and suggest that according
to our earliest mythologies,

an other Earth might not
be found in the heavens,

but deep within our own planet.

AGNEW: One of the most
consistent themes that we find

in ancient cultures,
when we travel around the world,

is the idea that there is
another world,

another Earth,
inside of the planet.

One of those is
the Maya tradition.

They have a holy book
called the Popol Vuh.

Inside this book,
it talks about two twin boys

that came up out of the Earth,

and were actually
the first humans on the planet.

And to this day,
they still believe

that life force comes
from inside the planet,

not from outside, in heaven.

The Mayans have this,

the Tibetans have this,

the Hopi Indians have this.

CHILDRESS:
Within Buddhism, there's stories

of a place called Agarta,
or Agarte,

which is an inner world.

And it's inhabited,
too, by people,

and that they are
an advanced race.

And even that they have trains
and vehicles

that are moving
through this inner Earth.

TZADOK: The most ancient
teachings share with us

the shocking revelation

that the Garden of Eden
was on no place

on the face of the Earth,

but rather, the Earth is hollow,

and that the Garden of Eden

is an entire domain
in inner Earth.

So, are these stories literal?

There are those
who believe that they are.

NARRATOR: Is it possible

that an other Earth
can be located

within the confines
of our own planet?

Historically, underground realms
were not relegated

to mere mythology.

Well-respected scientists

and mathematicians
have long speculated

about a theory that became known
as Hollow Earth.

DENNIN:
The scientist Edmond Halley

is most famous
for Halley's Comet.

He was also very interested
in the Earth,

and one of the challenges is,
was trying to figure out

what was the real structure
of the inside of the Earth.

He had a fascinating theory
of not just a hollow Earth,

but a Earth with multiple layers

and many different atmospheres

with many different layers
of land and earth,

circling and being concentric
as you went towards the center.

NARRATOR: 75 years later,

18th century mathematician
Leonhard Euler

put forth his own
Hollow Earth theory,

with no concentric shells

and a sun at the center,
spanning 600 miles.

AGNEW: Euler was
a gifted mathematician.

He developed this idea

that the planet, Earth,
is not only hollow

but the poles
are actually thinned.

And there are actually entrances
into the inner core

at the North and South Poles
of the Earth.

He imagined that there were
advanced civilizations

living inside the planet.

NARRATOR: Ideas of
an occupied Hollow Earth

would be revisited
nearly two centuries later,

in 1947, when famous polar
explorer Admiral Richard Byrd

flew reconnaissance missions
over the North Pole.

Byrd allegedly reported
in his private journal,

about a mysterious land
beyond the North Pole,

which he called the
Center of the Great Unknown.

AGNEW: Admiral Richard Byrd
was able to fly

to the North Pole and back,

and recorded flying
over lush green areas

where none should have been.

And then, three years later,
he flew over the South Pole.

BARA: It's rumored that
when Admiral Byrd's task force

actually got to Antarctica,

that one of the first things
they discovered

was an entrance
into a Hollow Earth civilization

that was populated
by very, very advanced beings.

Admiral Byrd made
a lot of unusual statements,

including talking about

what he called
a new kind of craft

that could fly
from pole to pole.

This was reported in newspapers
in Chile and Argentina

and ultimately
in English papers, too.

And when Byrd got back
to the United States,

he was brought back
to Washington,

where he was questioned very
heavily about his statements.

And allegedly he was told
to stop talking about this.

NARRATOR: Is it possible

that entrances to another world

can be found
at the Earth's poles?

And if so,

did Admiral Byrd actually pass
through one of them?

According to some
ancient astronaut theorists,

such gateways do exist,

but rather than leading
to inner Earth,

they may be portals
to another dimension.

NARRATOR:
Lively, Ontario, Canada.

Just over one mile deep
underground

is one of the most isolated
physics labs in the world,

SNOLAB.

The facility was built deep
within the Earth

in order to block out
cosmic radiation.

This could allow scientists
to possibly

catch a glimpse of an element
that they are confident

exists throughout the cosmos,

but have been unable to detect.

Physicists claim
that everything we can observe

accounts for less than
five percent of the universe.

What constitutes the rest
is completely unknown,

but is thought to include
a mysterious substance

called dark matter.

We know that most of the matter
in the universe

is not made of atoms
or atomic nuclei.

'S something else entirely.

There's a long list
of what dark matter might be,

and some things
we know about already,

black holes, for example,

that's making up part
of the mass of the universe.

If you look out
in the solar system,

you can see the orbits
of various galaxies, universes,

solar systems, planets,
all of these,

and you can map their orbits,
and you realize

that there's missing matter that
you can't see through light.

This is
what we call dark matter.

NARRATOR:
The existence of dark matter

was not scientifically accepted
until the 1980s.

Since that time,

many scientific speculations
have been made

as to its true nature.

Theories range
from it being the glue

that holds together
the visible universe

to a shadow galaxy
that contains within it

a parallel universe.

One theory is, is that, uh,
the dark matter particles

are particles that are not
really part of this universe.

These hidden dimensions
somehow allows

this dark matter to exist.

It's like a secret room.

You own a big mansion
and it turns out

there's a secret room in it and
you just don't know where it is.

WILCOCK: Scientists are saying
these higher dimensions

may, in fact,
coexist with our own

and could, in fact, represent
habitable layers of reality

that are hidden from us...

A world that is outside of
our physical ability to measure

but that has people
living in it.

And those people
could be coming and going

to our reality all the time.

NARRATOR:
Could an extraterrestrial world

actually be located
in a parallel universe,

hidden within dark matter?

If so, might our
current scientific exploration

of dark matter
lead us to discover

that we are not alone
in the cosmos?

But whether an other Earth
exists in another dimension...

under our feet...

or in a distant galaxy...

What would its discovery mean
for the future of humanity?

YOUNG: If we were to discover
the other Earth,

the place we have sought,
the missing world,

it would be profoundly humbling.

So this would be quite
a paradigm shift.

History would change
in a very major way.

WILLIAM HENRY: If we were
to find another planet

with life on it, it would affirm

what spiritual and sacred
traditions have been saying:

That we are, in fact, part
of a larger family

of, perhaps,
other civilizations.

TSOUKALOS:
We have this cosmic origin.

We have this imprint
within all of us

that our origin is out there.

If we discover intelligent life,

the question we then have
to ask,

are those the same people
that visited us in the past?

NARRATOR: Is mankind
on the brink of uncovering

definitive evidence
that we are not alone?

Will we learn that
there is other intelligent life

in the universe,

perhaps far older
and more advanced than humans?

And might
such a discovery force us

to redefine everything we know
about ourselves?

Perhaps, one day soon,

we will find
that there is an other Earth

and not just one, but thousands.

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