Original subtitles

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.