Original subtitles

NARRATOR: Unexplained transmissions

from the farthest reaches of the cosmos,

mysterious objects entering our solar system,

and mounting evidence we are not alone.

For nearly two decades,

Ancient Aliens has traveled the globe

exploring towering megalithic structures,

mysterious artifacts,

and stories of otherworldly beings,

in a quest for evidence that might reveal the truth

of our extraterrestrial origins.

Astronomers have been searching the universe for decades,

and personally, I think there's a really good chance

that soon we'll discover an inhabited planet.

NARRATOR: Now we take a look back

through the Ancient Aliens archives

to the show's very origins,

to examine the evidence that we are not alone.

We have never been alone.

♪ ♪

Since the beginning of humankind,

people have been wondering:

Is there other intelligent life in the cosmos?

And, of course, to people like the three of us, the answer is

a resounding yes.

And what's even more exciting is that

we now live in a time where we might find

- undeniable proof. - WILLIAM HENRY: Absolutely.

I mean, the James Webb telescope

can survey practically the entire universe,

and astronomers have detected these mysterious

interstellar objects

that are moving in ways they're not supposed to.

Yeah, right. And scientists

have been actively searching for extraterrestrial life

since the 1960s.

And we talked about this way back in season one

of Ancient Aliens in an episode called

"The Return."

NARRATOR: Throughout human history,

man has gazed up at the stars in awe and with wonder.

Our ancient ancestors charted their movements,

identified constellations,

and marked time by creating celestial-based calendars.

The stars also became the source of countless myths and legends.

Many of these describe visitors coming down to Earth

from somewhere out there.

Others speak of entire civilizations

existing out in the cosmos.

MICHAEL CREMO: The ancient Sanskrit writings of India

tell us, for example, there are

400,000 humanlike species

scattered throughout the cosmos

in different planets, different solar systems,

even different dimensions.

NARRATOR: But where are these alien beings?

Did they come to Earth in the past,

as the ancient astronaut theory suggests, and then leave?

If so, will they ever come back?

Today, scientists around the world

have stopped waiting around and are taking steps

to find intelligent extraterrestrial life.

Will technology finally be able to prove

what our ancient ancestors believed thousands of years ago?

In 1960, astronomer and physicist Frank Drake

set up an unusual telescope in the hills of West Virginia.

The strange device was made from

surplus World War II radar equipment.

But rather than containing a traditional optical lens,

it housed a directional radio antenna.

PAUL DAVIES: A few simple calculations showed

that radio telescopes have the power

to transmit and receive

across literally interstellar distances.

We're talking many light-years.

So, Frank Drake, uh, turned a radio telescope

on a couple of nearby stars

and tuned in to see if he could pick up

a message from the aliens.

So, this was a sort of crazy thing to do.

NARRATOR: Drake failed to pick up any sounds that day,

but the science of radio astronomy was born.

If we couldn't see aliens in space,

maybe we could hear them.

MICHAEL DENNIN: The things we focused on in the past

for searching for extraterrestrial life

is really passively trying to discover signals

on the basis that if they were

technologically advanced, they would have

some form of electricity like we do,

and all electricity generates radiation,

and it sends out the signals, and hopefully we detect it.

NARRATOR: In 1961, Frank Drake and a group of astronomers,

physicists and biologists

formed a privately-funded organization called SETI,

the Search for Extraterrestrial Intelligence.

Their goal was to focus massive radio telescopes

towards space and listen.

Drake estimated the probability

that intelligent life existed out in the universe

in a formula that became known as the Drake equation.

SARA SEAGER: The Drake equation is like a bridge between

scientists and nonscientists

because it explains what you would want to know

to give a number about how common alien life could be.

JENNIFER HELDMANN: There are multiple, uh, factors within the Drake equation,

like the fraction of stars that could have planets

and the fraction of those planets that could be habitable

and the fraction of those that might have liquid water

and how many could have evolved intelligent life.

And then one important factor

is the lifetime of those civilizations,

and that is a big unknown.

Uh, we only know of one. That's ourselves.

And, uh, how long are we gonna be around?

That's to be determined.

NARRATOR: Using his equation, Drake estimated

that over 100 million advanced civilizations

could exist in just the Milky Way galaxy.

BILL BIRNES: SETI presupposes

that if you've got an alien civilization

capable of traveling,

that's developed electronics, they have a fingerprint.

That fingerprint is a repetitive signal.

A repetitive signal will tell them

that it's not just noise, junk frequencies out there,

but a real attempt at communicating,

maybe not with us but with each other.

NARRATOR: But what if SETI intercepts

a transmission from another world?

What would happen next?

According to SETI's post-detection protocols,

once an extraterrestrial radio signal is confirmed,

news of the event should be kept secret

until the authorities have been notified.

The government will then decide

whether or not to try and make contact.

DAVIES: I think all bets are off, because

here is this message, it could contain

enormously important information that would

transform our society and maybe destabilize it.

What is it gonna mean for the future of our civilization?

These are momentous questions.

NARRATOR: Today, SETI continues to scan the vicinities

of nearby stars for artificially-produced signals

using several of the world's largest telescopes.

In the next several years,

when it becomes fully operational,

SETI's new Allen Telescope Array

will allow for the reconnaissance

of up to a million stars.

SEAGER: SETI has to search a huge, huge area.

They'll tell you that, now,

they have searched the equivalent of like

a glass of water compared to the entire ocean on Earth.

They have a long way to go.

NARRATOR: While SETI listens passively to signals from outer space,

NASA has attempted to contact alien life directly

through messages sent aboard its space probes.

DENNIN: It's a long shot,

but there's no reason in my mind

not to expect that life evolved elsewhere.

What's harder to predict or try and understand is:

How likely is it

that it happened close enough that there'd be someone

we could actually communicate with?

NARRATOR: In 1972, NASA agreed to attach small plaques

onto the outside of its twin Pioneer space probes,

the first human-built objects

destined to leave our solar system.

NASA contacted Cornell University professor

Dr. Carl Sagan to craft the message.

DENNIN: Carl Sagan was one of the most active astronomers

in the search for life outside our planet.

He was a very prominent scientist,

he was an excellent astronomer,

and he really did a lot to help us understand how we might

contact other life or detect life elsewhere in the universe.

NARRATOR: Sagan, along with SETI founder Frank Drake,

designed a gold-anodized aluminum plaque

measuring roughly six-by-nine inches

that contained a collection of symbolic images

representing humans and Earth.

ALBERT HARRISON: The man and a woman were nude.

And the gentleman was holding

one arm up like this, in what was intended to be

a sign of, uh, a sign of greeting.

NARRATOR: A schematic design of the solar system was also shown,

with the planned trajectory

of the Pioneer spacecraft marked on it,

and a diagram of 14 pulsar stars around the sun

made a chart that might help someone

work out where the craft originated.

DENNIN: We tried to give them an idea of where we're located,

and that's an interesting problem is to figure out

how you would tell someone where you're located

in space, 'cause you don't know where they're gonna find it.

And it was all in a very stylistic design,

but in an attempt to hopefully communicate

at least some of these ideas.

NARRATOR: Five years later, in 1977,

Dr. Sagan got a second chance

at designing an interstellar message

when NASA agreed to attach another one

to the Voyager space probes.

This time, Sagan created a record album

made of gold-plated copper,

along with a series of basic instructions

in how to make it work.

Sagan estimated that the metallic disc

could survive in space for at least a billion years.

DENNIN: At this point, we obviously haven't

learned anything yet about extraterrestrial life

'cause we haven't been contacted back.

Um, but I think, for our own purposes,

any time you try and go and figure out

how you want to communicate something,

it pushes your boundaries

and understanding of communication itself.

SEAGER: We all want to find aliens.

Whether it's the planetary scientists

looking for signs of life on another distant planet,

whether it's the ancient alien proponents,

who want to find signs of life of aliens

who visited in the past,

and whether it's people today

who want to have experiences with UFOs

and aliens that have visited them recently.

All of us are trying to do the same thing.

NARRATOR: While the search

for extraterrestrial beings continues,

a new space-based telescope

is hunting for planets that may contain life.

Are there other Earths out there?

And if so, how will we find them?

NARRATOR: On March 6th, 2009,

NASA launched a Delta II rocket into space.

On board was a new telescope

named in honor of German astronomer Johann Kepler.

The space-based telescope was designed specifically

to discover the existence of earthlike planets

located outside our own solar system.

The Kepler search is focused on a specific section

of the Milky Way known as Orion's Spur.

Kepler's job is to answer the question:

How common are other Earths?

And to do this, Kepler's looking at one part of the sky

for three and a half years.

Imagine, like, keeping your eyes open

and staring at just one part of the sky.

HELDMANN: And what they're doing is they're looking at stars,

and then, as a planet goes around that star,

when the planet gets in front of the star,

the starlight dims just a little bit from our vantage point,

because it's being blocked by the planet.

And so, you look for that dimming of those stars,

and then that's how you're able to detect these planets.

NARRATOR: So far, the Kepler telescope has confirmed the existence

of five planets outside our own solar system.

NASA officials expect to find several hundred more

exoplanets like these before their mission is completed.

Once a planet has been located,

scientists must then determine if it might contain water.

HELDMANN: We know from Earth

that all life on Earth requires liquid water.

So that is the approach that we've been taking

for looking for life elsewhere in the universe:

follow the water.

And so that is the step one.

DAVIES: On Earth, wherever we find liquid water, we find life.

And it's true.

Life on Earth can exist under

an extraordinary range of conditions.

There are extreme organisms

that live in the scalding effluent

coming out of the Earth's crust, deep beneath the ocean.

There are other remarkable organisms

living in the waste pools of nuclear reactors

and extreme radiation environments and so on.

But the one thing that seems to be

absolutely necessary for life as we know it is liquid water.

NARRATOR: To determine if a planet

contains water and possibly life,

scientists use special telescopes

to analyze its atmosphere.

SEAGER: We look at the light coming from the planet,

and we split that light up, like a rainbow.

Now, if you look at a rainbow in the sky

and you look really, really carefully,

you will see some dark lines.

You'll see some colors missing from the rainbow.

And those colors are missing

because of absorption by gases in Earth's atmosphere.

So, effectively, we're getting a rainbow

from another planet and we're looking for dark lines

that tell us what kind of gases are in the atmosphere.

NARRATOR: To better understand how life affects its atmosphere,

NASA scientists study microbial mats

at California's Moss Landing Wildlife Area.

BRAD BEBOUT: Microbial mats are important to NASA

for a-a whole bunch of reasons.

The organisms that are in microbial mats

have been on Earth just about longer

than any other kind of organism.

They make a number of things

which we call biomarkers, which are important

in our search for life on other planets.

So, there are textural biomarkers,

so when you pull up a piece of microbial mat

and look at the surface, what does that look like?

One of the things that we're doing with these microbial mats

is we're measuring the fluxes of methane.

Methane is a gas that's produced by certain kinds of organisms

that use the organic matter that's in these mats.

And when that methane goes into our atmosphere,

it can be detected by other missions

such as terrestrial planet finders,

is one of NASA's concept missions for looking for gases

that are produced by life on exoplanets.

DENNIN: We can look for the signature of oxygen

or water on a planet, and at least

that would give us an idea of life-forms like ourselves,

ones that are carbon-based and use oxygen

and carbon dioxide cycles.

Our atmosphere is not stable without living organisms.

It would've evaporated away by now.

And so, if you're looking out in space and you detect,

around a star, a signature of the chemicals

that we know exist for life,

that's very strong evidence that life is there.

That doesn't help you know if it's intelligent life,

but it does give you an evidence for life.

NARRATOR: With a universe literally full of possibilities,

planet hunters focus their search on an area

they call a Goldilocks zone.

SEAGER: The Goldilocks zone for planets

is the place where a planet is not too hot, not too cold,

but just the right temperature for life.

Right now,

we know of no planets like Earth in a Goldilocks zone.

One planet comes close. It's called Gliese 581D.

But we're not entirely sure if that planet is really

in the Goldilocks zone or not.

DAVIES: In recent years, it's been recognized

that there's more than one Goldilocks zone.

For example, there could be life, uh, inside

icy planetesimals, these, like, small planets or large moons.

The moon of Jupiter, Europa, is a very good example.

Europa is liquid beneath an ice cap.

It's liquid underneath because of

tidal heating and friction going on inside the planet.

So it could be that there is life,

uh, microbial probably only,

deep down under the ice on Europa.

HELDMANN: It's a very challenging question,

if there's life elsewhere in our solar system.

You have so many components that have to come together.

We have to have an understanding of the science.

We have to ask the right questions.

I wish I had a tricorder that I could just go

and, like, point and it would say "life"

or "no life," right? But we don't have that,

so we have to be smart and we have to be clever,

and we have to develop instruments that can

actually address the questions we're trying to answer.

SEAGER: It's inevitable.

There are so many planets out there, it's inevitable

that we'll find one in the Goldilocks zone any day.

NARRATOR: But while the Kepler telescope

has only just begun scanning the horizon,

NASA is already planning the next step

in its search for extraterrestrial life.

People always ask me, "Do you expect

to find an Earth in your lifetime?"

And I say, "Yes, absolutely."

DAVIES: When I was a student, there was almost

nobody prepared to argue that way.

The feeling back in the '60s and '70s was

that even if there were other earthlike planets,

life is such an improbable freak event

that it would never, ever happen anywhere else.

Now the prevailing view is,

yes, the universe is teeming with life.

Everybody wants to meet an alien,

but we have to start small.

We have to learn how to walk before we can run.

GEORGE NOORY: The fascinating thing for me

is that we're only four and a half billion years old

in a universe that's close to 14 billion years old.

What would happen with some of these earthlike planets

that had a five- or ten-billion-year

head start on us?

Gosh, you can only imagine.

NARRATOR: As we advance our technology

in the search for extraterrestrial life,

could we be getting closer

to finding definitive proof that we are not alone?

As far as ancient astronaut theorists are concerned,

we may have already detected

concrete evidence of an alien intelligence

in the form of strange signals coming from space.

You really have to respect mainstream scientists

who choose to be part of a group called

the Search for Extraterrestrial Intelligence.

DAVID CHILDRESS: Yeah, and when it comes

to looking for advanced alien civilizations in the cosmos,

they've been leading the charge for over half a century.

Oh, absolutely. And in 2016,

I visited one of their largest observatories

in Northern California,

where they have dozens of satellite dishes

capturing radio waves from outer space.

And what's so exciting is that, over the years,

SETI has detected some really unusual signals.

NARRATOR: Delaware, Ohio.

August 15, 1977.

At Ohio State University's Big Ear radio telescope,

astronomer Jerry R. Ehman conducts research

for SETI, the Search for Extraterrestrial Intelligence.

While reviewing recorded data,

he detects a highly unusual signal

originating from the constellation Sagittarius.

They're looking for this bandwidth of 1,420 megahertz.

And specifically, they believe that this bandwidth

corresponds to water

and that intelligent civilizations might encode

the electromagnetic frequency of water with a detectable signal.

So there's Jerry Ehman, on the Big Ear telescope,

doing his SETI work, and a 72-second burst comes in

on the 1,420-megahertz signal.

72 seconds of very bizarre static

that does not look natural.

It looks artificial.

It looks like something

that was intelligently built and sent.

So, he writes, "Wow!" next to this part of the readout,

and it is now known as the "Wow! signal."

And still, to this day, the Wow! signal has never

been properly explained, nor has it been deciphered.

NARRATOR: While there are various theories

as to what may have caused the now famous Wow! signal,

from terrestrial radio broadcasts to comet trails,

SETI has not ruled out the possibility

that it may represent modern man's

first radio contact with extraterrestrials,

and they have plans to reexamine the area

where it originated in the near future.

To get a firsthand look into this continued search

for extraterrestrial life, in March of 2016,

researcher and publisher Giorgio Tsoukalos

traveled to the Allen Telescope Array

in Hat Creek, California, where he met

with the director for SETI research, Seth Shostak.

This is truly amazing.

What can you tell me about this place?

Well, this place is, uh, an observatory,

but it's a radio observatory, so these things around us,

these 42 antennas, they pick up radio waves.

And we're trying to pick up very special sort of radio waves,

namely some that would tell us somebody's out there.

By having lots of these dishes here,

we can look at more of the sky at once.

We can look at multiple star systems at once.

Why radio waves?

What's so significant about radio waves?

SETH SHOSTAK: Radio waves go at the speed of light,

and they also, by the way, go through all the gas

and dust that's between the stars.

So, you know, if you want to communicate

from one part of the galaxy to another,

radio waves are a great way to do it.

So, the way this works is actually kind of simple.

I mean, the cosmic radio static,

it comes in from the sky and it bounces off

that big reflector there, that first one, okay?

- That's-that's a mirror for radio waves. - Mm-hmm.

And that redirects into this secondary reflector

on the end, on the nose there,

and then they're directed to the receiver,

and that's inside.

That information goes through

a fiber optic over to the control room.

So, this is where the data coming through

the fiber optics kind of ends up

after it's been processed in a display like this.

And what are we looking at right here?

So, we're looking, in this case, at three star systems

at once, okay? So that speeds up the search.

It also allows us to determine whether we're really

seeing E.T. or just interference.

The data from one of these star systems

is being displayed over on this part of the screen here.

This is called a waterfall plot.

And that-- Can you see? Can you see that line

- of brighter dots there? - This right here, yes. Mm-hmm.

SHOSTAK: Yeah, that's, uh, slightly more static at that frequency,

slowly going down the dial.

That's the kind of thing we're looking for.

So then, if this here were an actual E.T. signal,

how would it differentiate itself?

Uh, would it be a bit thicker, a bit more pronounced,

a bit longer, or... what are you looking for?

It could be all of those things.

So, what you do is, when you find

a signal like this, you make a test.

You'll just move the antennas a little bit

and see if the signal goes away.

And then point it back at the star

and see if it comes back.

You say, "Well, that's looking promising."

You do that again, go off, go on, go off, go on.

If you do that five or ten times, you start to get excited.

I hope that that day will come very soon.

SHOSTAK: The Wow! signal continues to intrigue people.

So we are going to use the Allen Telescope Array

to reobserve the Wow! signal,

look in the same spot on the sky,

look over a wider range of frequencies,

and-and if there's something up there

and it's still broadcasting, of course, we would find it.

NARRATOR: While SETI has yet to find

an explanation for the Wow! signal,

NASA's Kepler telescope team has continued to search

for signs of alien life in other solar systems,

despite the U.S. government's open denial

of extraterrestrial contact.

In September 2015, after more than five years of research,

members of the Kepler team revealed

some incredible findings

coming from the star KIC 8462852,

also known as "Tabby's star,"

named for the astronomer who discovered it.

WILCOCK: What we see from Tabby's star

is changes in light output

that are not attributable to comets, to planets,

to asteroids or to other fragments

that would orbit the star.

We're seeing quasiperiodic dimmings of the light

that can be as much as a 21% reduction

in the luminosity that's coming out of the star.

Now, we have the scientists who are publishing papers

in which they propose that one of the explanations

for what they're seeing

is a massive extraterrestrial construct

akin to something known as a "Dyson sphere."

MIKE BARA: The Dyson sphere

is actually a gigantic structure built around a star,

which harnesses the energy of the star, and could, in fact,

be used to travel

from one place to another within the galaxy.

This story is a total game changer,

because it suggests that a Type II civilization,

a civilization that can harness the power of an entire star,

actually does exist,

and we can see it with our telescopes.

NARRATOR: Is it possible that astronomers hunting for habitable planets

may have accidentally discovered

the first extrasolar civilization?

If so, why do government officials

remain reluctant to fully acknowledge

what the findings might suggest?

According to ancient astronaut theorists,

NASA's real fear isn't aliens.

It's how the public might react.

And for further proof,

they point to the agency's response

to possible signs of life on Mars.

You can't talk about the search for intelligent life

in the cosmos without discussing our exploration of Mars.

It is the most earthlike

of all the planets in our solar system.

GIORGIO TSOUKALOS: Right, and what's incredible

is that we've been photographing Mars

since 1965, which is before the Moon missions.

Yeah, and we even have evidence that NASA

may have found microbial life-forms

on Mars back in the 1970s.

We covered this in a 2014 episode called

"Aliens and the Red Planet."

NARRATOR: Cape Canaveral, Florida.

August 20, 1975.

LAUNCH DIRECTOR: Ignition. We have liftoff.

NARRATOR: The United States launches

a Titan rocket carrying the Viking spacecraft.

Viking is embarking on a 420-million-mile journey

to one of the most prominent sights in the night sky:

Mars.

If all goes well, in 11 months, the unmanned probe

will touch down on the Martian surface

and search for evidence of life.

Mainstream scientists say Mars is most likely a dead planet

because of its incredible temperature swings

and high levels of solar radiation.

So why is NASA spending a billion dollars to explore it?

JONATHAN YOUNG: The night sky is an astounding thing.

To the naked eye, the Red Planet could be seen

with its special colors.

After all, it's the biggest thing

you see up there past the Moon.

So it's been a special object of fascination

and reverence because

religious systems often were associated with the planets

and the stars, the sky in general.

Speculations about what's there.

Is intelligent life there? Are the gods there?

Th-That's gone on for a long time.

BOB FRISBEE: Our dream for life on Mars probably goes back

even to the ancient times, when we were just doing

naked eye observation.

It's the planet that really stands out,

that we now know is

very close to Earth, in terms of physical conditions.

Even though Venus is much more like Earth

in size and gravity,

it's a hellhole in the solar system.

But Mars, Mars is out there within our grasp.

NARRATOR: Among the first to record this fiery red ball

in the night sky were ancient Egyptian astronomers.

In 1534 BC,

they placed Mars on humanity's first chart

of the known cosmos, the Senenmut star map.

Two and a half centuries later,

the Egyptians painted the planet Mars

on the ceiling of the tomb of Seti I.

But while the Egyptians honored Mars,

many other ancient cultures feared it

because they associated the Red Planet

with death, destruction and war.

According to some anthropologists,

this is because the planet glows red

like the color of blood spilled on the battlefield.

From India to Rome, all of the ancient societies

had a reverence for Mars,

a great closeness to Mars.

Very important in their pantheon,

very important in the imagination of the people

that some kind of connection

with that red planet be maintained.

NARRATOR: But while many ancient societies felt a bond with Mars,

most did not identify it as a planet like Earth.

The ancients thought planets

were as uninhabitable as the Sun.

ROBERT BAUVAL: They saw them as

wandering stars. In fact, the word "planet"

means, in Greek, "wandering star," "planeta."

You have the fixed stars, the constellations,

but then you have these-these stars wandering about.

They seem to follow the Sun because

they appear to move against the background

of the fixed stars the same way the Sun does.

NARRATOR: It wasn't until the 17th and 18th centuries,

when astronomers finally had telescopes

powerful enough to make out features on the surface of Mars,

that we started to imagine life on the Red Planet

as a real possibility.

SHOSTAK: By the 1860s, an Italian astronomer

by the name of Angelo Secchi

thought he saw straight lines crisscrossing the surface

of our little ruddy buddy up there, Mars.

And he called them "canali."

The idea was picked up by an American astronomer

by the name of Percival Lowell.

And Percival Lowell built his own observatory

down in Flagstaff, Arizona.

He spent a lot of time looking through a telescope at Mars,

and he wrote books about this.

He was articulate, he was clever,

and he convinced a lot of the public,

and some of the scientific establishment,

that there really was a civilization on Mars

busy digging up their planet

because they needed to irrigate their crops.

NARRATOR: But why has Mars

fascinated humankind throughout history?

Is it simply due to the planet's proximity to Earth

and its striking red color in the night sky?

Or is it possible, as ancient astronaut theorists contend,

that Mars really was, at one time,

inhabited by intelligent life?

The Cydonia region of Mars.

July 20, 1976.

An alien spacecraft sent from Earth touches down

on the Red Planet.

After a ten-month journey,

Viking I has reached its destination.

- (people cheering) - NARRATOR: To NASA scientists,

it's a momentous event.

For the first time in its history,

the United States has a probe on another planet.

Viking was the first spacecraft to actually attempt

a soft landing on Mars,

and give us an actual feel,

a taste for what the conditions were on the surface.

We looked out at those pictures of the surface,

and they looked so much like the Pacific deserts here,

like Death Valley.

We all half expected to see a miner

and his burro come walking up over the nearest rise.

NARRATOR: Scientists knew that finding definitive

signs of life on Mars was a long shot.

But when the Viking lander performed four tests

on the Martian soil, looking for microbial life,

it returned surprising and controversial results.

Dr. Gil Levin designed

one of the tests that the Viking probe performed.

LEVIN: Microorganisms breathe, just like you or I

or anything else.

And then they give off carbon dioxide.

So we got a tiny sample, a thimbleful,

of the soil, put into a little container.

It was monitored for seven days continuously

to see if there are any bubbles forming in the tube.

Surprisingly, the tests

came up positive for life

by the criteria that had been approved by NASA.

NARRATOR: However, the result of another important test,

one looking for organic matter on the Martian surface,

was negative.

But Dr. Levin says the other test wasn't nearly

as sensitive as his experiment.

It needed three million bacteria in a thimbleful of Martian soil

to find signs of life,

while Dr. Levin's test only required 30 bacteria.

So, there was a vast discrepancy

in the sensitivity of the two experiments.

And I immediately said, "Well, you know,

"they both could be right.

"We detected life, but maybe there aren't

"enough bacteria per unit of soil

for the organic analysis instrument to find."

But NASA was very cautious, and they opted to say,

"no organic matter."

There goes the ball game. No life.

NARRATOR: Dr. Levin has fought NASA for almost 40 years

on whether the Viking probe found evidence of life on Mars.

If he was right about the results of his test,

this would be the first proof accepted by mainstream science

that life exists outside our planet.

But ancient astronaut theorists

say an even more profound discovery regarding

the Red Planet has been uncovered right here on Earth.

NARRATOR: Washington, D.C.

August 7th, 1996.

On the south lawn of the White House,

30 years after NASA announced the Viking mission

had not found evidence of life on Mars,

President Bill Clinton held an historic press conference

to announce some momentous news.

Microbial life may exist on the Red Planet after all.

Scientists had found what they believed

to be fossilized remains on a Martian meteorite

that crashed to Earth 12,000 years ago.

(explosion booming)

It must be confirmed by other scientists,

but clearly,

the fact that something of this magnitude is being explored

is another vindication

of America's space program and our continuing support for it,

even in these tough financial times.

FRISBEE: There was enormous excitement over this discovery.

Based on the chemical composition of the meteorite,

we could tell that it was from Mars.

Inside the rock, researchers found different chemicals,

and in particular, different physical shapes of objects

that looked extremely similar to microorganisms here on Earth.

NARRATOR: Soon after the president's press conference,

scientists began to backpedal

on whether the meteorite actually showed signs of life.

They said the original team of experts may have been wrong.

The image certainly looks like some kind of a microorganism.

But the opponents said the microorganism remains

are too small to have DNA to be inside it.

And therefore, it can't be a fossil.

Since then, microorganisms have been found that small

which have DNA in them.

But it has not been resolved.

NARRATOR: But given the controversy surrounding the possibility

that life may have been discovered on Mars,

starting with the Viking mission of the 1970s

and continuing to the present day...

LAUNCH DIRECTOR: Liftoff.

NARRATOR: ...some scientists say NASA

almost seems to be avoiding the issue.

The space agency has never retried Gil Levin's test

for signs of life on the Red Planet.

It is very puzzling as to why NASA has refused

to send life detection experiments back to Mars.

My experiment discovered

the most remarkable thing yet known about Mars:

that there's something highly reactive in the soil,

chemical or biological.

But we really should find out what it is.

It is startling that NASA has made no attempt

to determine that issue.

I truly think NASA knows there is life on Mars.

But for some reason unbeknownst to me,

it does not want that information out.

NARRATOR: Has NASA found definitive signs of life on Mars

that they're intentionally keeping from the public?

And if so, have they found evidence

that an advanced civilization once lived on the Red Planet?

Some ancient astronaut theorists believe they have

and, as evidence, point to a report

commissioned by NASA in 1960...

...that offers advice for how to reveal the news

if the American space program

should ever find proof of extraterrestrial life.

BARA: The so-called Brookings Report essentially said

that in your travels throughout the solar system,

there is a distinct possibility

that you will discover artifacts,

that you will actually discover evidence

of an ancient alien presence on Venus, on the Moon or on Mars.

And the implications of such an announcement, if it were made,

would be potentially devastating to the human race.

It could be catastrophic.

In fact, it used the word "disintegrate."

BAUVAL: I would imagine that it would be something

that would be kept secret for a while.

I don't think it's a bunch of men

sitting in a room and smoking cigarettes

and saying, "We're gonna keep this secret."

But it is a responsibility,

and I think that they would certainly be very, very careful

as to how to let out this knowledge.

NARRATOR: Is it possible that not just microbial life

but also intelligent beings

once called the Red Planet their home?

And if so, what would that mean

for the existence of life elsewhere in the cosmos?

If life used to exist on Mars,

particularly if it formed independently of Earth life...

...life in the universe is all over the place.

That means that of the billions of planets discovered now...

...similar to Earth, through our universe,

many of them would have life on them.

And if there is life different from life on Earth

that has evolved, there would be every reason to suspect

such evolution would have gone on, on countless other Earths

and that there would be intelligent life

out there as well.

♪ ♪

We want there to be life on Mars.

We want there to be life somewhere beyond here.

We want that transcendent connection to the heavens.

We don't want it to be invaders,

but we don't want to be alone in the universe.

NARRATOR: If signs of microbial life have been found on Mars,

is it really far-fetched to consider the possibility

of advanced life elsewhere in the cosmos?

According to ancient astronaut theorists,

evidence might be closer to home than we realize.

And they suggest further clues could be uncovered

by examining leaked transmissions

sent by NASA astronauts.

The discoveries we are making on Mars are incredible,

but we find equally intriguing discoveries

in our own Earth's orbit.

We have countless photos and videos

from NASA missions showing unidentified flying objects

that look like spacecraft.

Yeah, and astronauts have claimed

that they have seen things that they couldn't explain,

and this goes all the way back to the Apollo 11 Moon mission.

- Right. - Yeah, and it's not just

American astronauts, it's Russian cosmonauts, too.

So, when you have photos and videos,

multiple eyewitness accounts, you have to wonder:

Is there an alien presence right above our planet?

NARRATOR: NASA Ames Research Center.

Moffett Field, California.

On December 5th, 2011,

astronomers working with the Kepler Space Telescope

announced the discovery of a planet

they called Kepler-22b, orbiting within

what's known as the habitable zone of a distant star.

Today's discovery is a tantalizing indication

that, with time, Kepler may find true Earth analogs.

SHOSTAK: Kepler-22b is about 600 light-years away from Earth,

so that's a long way.

But it is, in fact, in an orbit

that means that the daytime temperatures on that planet

might be comparable to a summer in San Francisco.

So that's the first time we found a planet

that might have liquid oceans,

maybe a thick atmosphere, maybe even life.

What we'd ultimately like to do, first, is just...

just understand how other planetary systems are made up.

But then we really would like to find earthlike planets.

Planets in the habitable zone of sunlike stars.

NARRATOR: But is it possible that NASA scientists

have been searching for life they already know exists?

Some believe previous voyages into space

have uncovered evidence of an extraterrestrial presence.

CONTROL: Houston, Discovery. How do you read? Over.

ASTRONAUT: Discovery, Houston. Read you loud and clear.

LAUNCH DIRECTOR: Go for main engines start.

Main engines up and burning.

Three, two, one, zero and liftoff.

CONTROL: Roger roll, Discovery.

NARRATOR: On September 12th, 1991,

the Space Shuttle Discovery, STS-48,

flew nearly 350 miles above the surface of the Earth.

Its crew, led by Captain John Creighton,

performed several missions, including the deployment

of an Upper Atmosphere Research Satellite.

CONTROL: He is a go for free drift.

ASTRONAUT: Okay, we're in free drift.

NARRATOR: But while the astronauts occupied themselves

with various tasks,

a video camera at the rear cargo bay door...

...captured footage that NASA claims no longer exists.

But a number of amateurs

that were monitoring the transmission

produced what they allege is genuine footage from STS-48.

The video shows what appears to be

a series of unidentified glowing objects and flashing lights...

...that change direction and accelerate rapidly.

Apparently, the space shuttle was surrounded by some kind of,

uh, UFO, a flying saucer type of craft.

Some kind of a shield, at one point,

was supposedly put around the shuttle briefly.

And then the UFO and everything disappeared.

One of the astronauts openly states over an open channel,

"Hey, we're being tracked by an alien spacecraft."

And then all of a sudden, all the transmission just ceases.

And I think what happened was is that he must have realized

he was on the public channel, not the private channel,

and he probably very, very quickly

switched over to the private channel

to describe what it was he was seeing.

STORY MUSGRAVE: I knew everyone, and I heard stories from everyone.

Nobody brought me any evidence.

So, one side of the coin, it's everywhere out there.

Has it been here? I have no evidence.

NARRATOR: NASA officials claim the video images

show ice particles glinting in the sun.

But is it possible

that video transmissions from the space shuttle

captured more than what NASA officials want to admit?

Occasionally, uh, astronauts,

shuttle astronauts will report that they've seen

things or experienced things in space that they can't explain

and that might be due to an alien presence.

Ever since humankind launched itself into space,

there have been reports where astronauts describe something

that they saw while being up in the spaceship.

And we have to remind ourselves that those stories

are reported by astronauts

and not by insane people.

NARRATOR: In 1996,

video captured aboard the Space Shuttle Columbia, STS-80...

...reportedly shows a number of fast-moving objects

just outside the craft.

These unidentified objects appear as bright streaks.

Analysis of their speeds and directions

have prompted some researchers to dismiss the claims

that the objects were shuttle debris or meteors.

BARA: There's space shuttle video of two very specific missions,

STS-48 and STS-80, which clearly show

what appear to be powered vehicles

operating in low Earth orbit, defying all the laws of physics

and clearly performing the way UFOs

or extraterrestrial spacecraft are supposedly able to perform.

NARRATOR: But American astronauts are not the only space travelers

reporting otherworldly encounters.

In 1985, Soviet cosmonauts aboard the Salyut 7

reported seeing seven celestial beings orbiting Earth.

CHILDRESS: Six cosmonauts

claimed that, as they looked out of the window

of the space station, they saw what they described

as winged angels surrounding their ship,

and that these were luminous beings

looking like people but also having, uh,

bizarrely, wings on them... and they're in space.

So you have to wonder: Uh, what's going on here?

And were these angels some kind of extraterrestrials

in special space suits or with fields around them

and they were investigating the Soviet, uh, space station?

And then suddenly, bang, they just vanished.

NARRATOR: If reports from trained scientists are true,

is this proof that extraterrestrial intelligence

has been trying to contact us?

SEAN-DAVID MORTON: Gordy Cooper approached the United Nations

about them actually setting up, uh, a-a bureau

at the United Nations for extraterrestrial contact.

EDGAR MITCHELL: This is not unknown knowledge.

There are people that know, and there seems to be

perhaps several different species of aliens visiting here.

And it looks like, likely they have been

for a long, long time.

NARRATOR: Might NASA really be withholding classified information

regarding the existence of extraterrestrial beings?

Could that explain why particular video

and communication feeds from space missions

have been withheld from the public?

And if the unexplained phenomena

astronauts have encountered in orbit

point to an alien intelligence, is it a new presence

or one that has been observing us

from the very beginning?

There have been a lot of strange things observed

above our planet,

but perhaps the most compelling of all

is the object they call "the Black Knight satellite."

Yeah, it's fascinating, because whatever this thing is,

there have been reports about it for over 50 years.

TSOUKALOS: Yeah, and, you know, there's a possibility

that we have a reference of this satellite

in an ancient text that's almost 2,000 years old.

We covered this in a 2016 episode called

"The Mysterious Nine."

NARRATOR: December 1998.

During the assembly of the International Space Station,

U.S. astronauts spot a large unidentified item

orbiting the Earth.

They take photographs of the mysterious object

and post them on the NASA website.

WILCOCK: When you actually look

at the photographs of the object,

it very obviously looks artificial.

This is not a meteor.

This is not a chunk of rock.

This is something that has a dark, streamlined,

technological appearance,

almost like some of the stealth aircraft that we've built,

with a kind of bent nose in the front, sort of like a hawk.

NARRATOR: Curiously, NASA officials quickly remove the photos

and claim the object was space debris.

Most likely, a thermal blanket

inadvertently released from the space station.

But some independent researchers are not convinced

and suggest that it might be the latest evidence

of the Black Knight satellite

that first made headlines three years before

the first man-made satellite was launched into orbit.

In 1954,

both the San Francisco Examiner and the Aviation Week journal

published articles detailing what appeared to be

artificial satellites orbiting the Earth.

It really shocked a lot of people,

because although the concept of satellites were known,

nobody on the planet was flying a satellite.

The story really takes off

with a man named Major Donald Keyhoe.

He was formerly with the U.S. military

and wrote a number of books on UFOs.

One of the things that Keyhoe wrote about

was how, supposedly, a number of military insiders

had told him that the U.S. military

was tracking one or two unknown satellites

of extraordinary size in Earth orbit.

Nobody knew what they were.

This was long before Sputnik,

the first satellite launched by the Russians,

and it gave rise to the idea that it was extraterrestrial.

NARRATOR: The United States Department of Defense

was said to have recruited the assistance

of astronomer Clyde W. Tombaugh in 1953

to identify this strange object.

However, his conclusions were never made public.

Based on its appearance on radar in the 1960s,

scientists estimated that the mystery satellite

weighed over ten tons.

It was not only several times larger than anything

worldwide space programs were capable of launching

but it also seemed to be traveling

in an artificial orbit,

circling the Earth from pole to pole.

The Black Knight is said to be in a polar orbit,

which was what you would do if you wanted to cover

the entire planet Earth as it rotated underneath you.

Weather satellites, spy satellites

are commonly put into this polar orbit

in order to cover the entire surface of the Earth.

This implies that it is an unnatural object.

What's particularly intriguing about this satellite

is it's not one of ours.

In other words, the theory is that this is

an extraterrestrial satellite

that has perhaps been monitoring planet Earth

for thousands of years.

In the 1930s, ham radio operators claimed

they were picking up radio signals from outer space.

And Nikola Tesla himself

claimed that he was picking up radio signals from Mars.

So, you have to wonder: Were ham radio operators

and even Nikola Tesla somehow picking up signals

from this extraterrestrial ship orbiting our planet?

WILCOCK: A ham radio operator was able to decipher this signal

and create a matrix grid of individual dots

that were either white or black.

When he looked at this grid, he concluded that it was a map

of the Epsilon Boötis constellation,

positioned where it would have been 13,000 years ago.

NARRATOR: Might this mysterious object

actually have traveled to Earth 13,000 years ago?

And if so, was it put into orbit by extraterrestrials

in order to observe Earth?

Ancient astronaut theorists say yes

and suggest that descriptions of an extraterrestrial satellite

can even be found thousands of years ago,

in the Hebrew text known as the Apocalypse of Baruch.

The Apocalypse of Baruch

is one of the best ancient astronaut stories in existence

because it describes an eyewitness account

of a satellite orbiting the Earth.

Baruch describes how he sees a magnificent bird

that watched the happenings on the planet.

And from time to time, this bird would extend its wings

to glean or to gather the power of the Sun,

And after flying around, that bird will be so exhausted,

it would retract its wings.

If we look at today's satellites in space, it's the same story.

We have solar cells on wings that can extend

and then they can retract at will.

So, what if Baruch witnessed something similar?

Baruch himself said that this is the "guardian of the earth."

NARRATOR: Might the mythological bird

described in the Apocalypse of Baruch

have actually been an observational satellite?

Could this be proof that extraterrestrials

have been keeping watch over our planet

for thousands of years,

as some ancient astronaut theorists suggest?

And if intelligent life-forms exist beyond Earth,

why haven't they made themselves known?

Perhaps additional clues can be uncovered

by exploring why and how

they may be deliberately avoiding detection.

You know, every year, we learn that there are more and more

habitable planets out there.

And it really makes you think that there must be dozens,

even hundreds of intelligent species out there.

Yeah, and scientists are now on board with the probability

of other life in the universe.

And you know, it's interesting, it's been suggested

that one of the reasons why we haven't

detected extraterrestrials

is because more advanced races

are seeking to evade detection by us.

Right. This is the so-called zoo hypothesis.

And believe it or not, it was proposed

by an astrophysicist from MIT.

NARRATOR: If extraterrestrial beings do exist in the universe,

where are they?

That was the question posed by Enrico Fermi,

one of the leading scientists of the 20th century.

(explosive booming)

DAVIES: Shortly after the Second World War,

the famous physicist Enrico Fermi,

who was taking part in the Manhattan Project

to build the atomic bomb,

was talking at Los Alamos with some friends

about the reports, uh, of flying saucers,

and Fermi, uh, suddenly said, uh,

in relation to extraterrestrial intelligent beings,

"Where are they?"

And he was simply making the point

that if there was a civilization somewhere in the galaxy,

uh, that had arisen, uh, say, a hundred million years ago,

then they had plenty of time

to have spread across the galaxy.

BALL: Fermi said,

"Gee, if there's all of these civilizations out there

on all of these planets out there, where is everybody?"

NARRATOR: The Fermi paradox, as it became known,

was an attempt to explain the lack of evidence of aliens

despite the mathematical probability of their existence.

But in the 1960s, MIT astrophysicist John Ball

rebutted Fermi's hypothesis

with a controversial one of his own:

the zoo hypothesis.

The zoo hypothesis says that, uh,

we are in a zoo or a wilderness area

that they have essentially left alone

and are going to leave alone

to allow us to develop in our own way and our own rate.

MICHAEL CROWE: Extraterrestrials have detected us on Earth

but have chosen not to come here, not to invade,

but rather to observe us

as we observe animals in the zoo.

They've thought, "We'll do a study of those Earthlings

and see what sort of people they are."

Now, why would they do this? Well, if, on the one hand,

we have nothing they want-- that's surely true--

and on the other hand, we aren't able to interfere

with whatever they're doing-- that's also surely true.

They're out there doing their own thing,

and they're not paying any attention to us,

and we're not clever enough

to eavesdrop on whatever they're doing.

That's the predicament we're in.

We have something that is looking down and monitoring us.

We are on the petri dish, and we can't get out far enough

to see what's behind those eyes behind that microscope?

NARRATOR: If aliens are watching us right now, where are they?

Some believe they are sitting out in space

in what are called Lagrange points,

named after mathematician and astronomer Joseph Lagrange,

who discovered them in 1772.

There are five of these points between the Sun,

the Earth and our Moon.

SEAGER: Lagrange points are points between two bodies

where the forces balance equally.

Think of, like, a seesaw when you have

one really heavy person and one really light person.

There's a kind of balance point in there,

and that's what a Lagrange point is.

DAVIES: Lagrange points is where we send some of our own satellites.

And that's a point in space

where you can just sort of sit there inert,

for millions of years if you had to,

without having to worry about in-course corrections.

If you go anywhere else in the solar system,

uh, then in order to keep pace with Earth as it orbits the Sun,

you've got to continually, uh, change your-your position.

SEAGER: So, people have talked about Lagrange points

as a place where a spacecraft might hide out.

Because you don't have to do a lot to stay in that spot.

It's sort of equally balanced and you just get carried along.

TSOUKALOS: If an extraterrestrial race

would've ever visited our solar system,

they could've placed a probe in those specific points

in order to observe us,

to record us, what have you.

So, I mean, this is not something,

uh, that the ancient astronaut theory has proposed.

This is, you know, university professors,

astrophysicists, who have proposed this.

NARRATOR: Some argue that another reason

alien beings have yet to reveal themselves

is because they don't yet consider us worthy.

This forms the basis of John Ball's jungle hypothesis.

BALL: The jungle hypothesis just means that,

if you have animals, such as ants,

that live in the jungle,

no matter how many of them you have, their chances

of ever having seen a human being are very slim.

Not because we're hiding or anything

but we just don't have a reason to go into the jungle

and step on anthills.

So, the idea is that we are probably related

to advanced extraterrestrial intelligence

similar to an anthill might be related to humans,

and the fact that we've never seen

any extraterrestrial intelligence

is just, we don't have anything they want.

HOWE: We could actually shake hands with something

that might have been coming and going on this planet,

for literally thousands, perhaps millions of years,

and has kept a distance during the last age of man,

for reasons unknown,

and maybe is waiting for us all to finally grow up.

CROWE: One thing that can be said

with a great deal of confidence

is that if the contact is initiated by them,

they are going to be not only superior to us

but greatly superior to us.

They won't be just beginners like we are.

They will be far more advanced than we are.

NARRATOR: Both the jungle and zoo hypotheses

propose that alien beings are watching us

but are, for the time being, keeping their distance.

But what if they're not?

What if, just as our search takes us deeper into the cosmos,

interstellar visitors are quietly making their way

into our solar system?

Astronomers have been searching the universe for decades,

and personally, I think there's a really good chance

that soon we'll discover

an inhabited planet,

because of all the new discoveries

we're making in outer space.

Like interstellar objects.

For years, we were told it was impossible

for an asteroid from another part of our universe

to enter our solar system,

but now astronomers have detected three

of these interstellar travelers,

beginning with 'Oumuamua in 2017.

Yeah, and scientists say that 'Oumuamua

is coming from the Pleiades star cluster.

And there are so many ancient stories

of beings from the Pleiades coming to Earth

that we dedicated an entire episode to this

in 2020 called "They Came from the Pleiades."

NARRATOR: Maui, Hawaii.

October 19th, 2017.

Scientists at the University of Hawai'i Haleakala Observatory

detect a strange object

traveling through our solar system.

They initially catalog it as an asteroid,

but after further examination,

researchers observe that the object accelerated

as it approached the Sun,

acting more like a comet

but without any other comet-like characteristics.

The find forces astronomers to reclassify it

as something entirely new: an interstellar object.

KAREN MEECH: We'd never seen anything like this

in the solar system before.

We get an estimate of its size

at about 800 meters, or half a kilometer in length.

Roughly a cigar-like shape.

It was moving very fast,

a little more than 195,000 miles per hour.

You get a chill sometimes

when you understand something is very important

or is really exciting,

and that's what I felt with this object.

NARRATOR: Our Milky Way galaxy

is estimated to consist of 100,000 million stars,

each indicating the presence of a solar system.

Because the distances between them are so vast,

astronomers believed it was impossible

for an object from another solar system

to reach our own, until now.

It just came from outside our solar system,

meaning it wasn't material from our star being created.

It's from a different star system, somewhere else.

That's historic, that we've actually seen it.

We now know objects can travel from one star system to another.

NARRATOR: Researchers dubbed the interstellar visitor

"'Oumuamua," a Hawaiian term

meaning "a messenger from afar arriving first."

Is it possible that the interstellar visitor

was, in fact, a messenger?

One sent on a mission to our solar system?

MICHAEL SALLA: Different scientists have analyzed the data

and deduced that it's something very different

to an asteroid or a comet.

So, the scientific data does point to it actually being

some artificial creation.

We've had open speculation about, uh,

how this thing might be an interstellar spacecraft,

a talk from-from a Harvard professor.

NARRATOR: The chair of Harvard's Astronomy Department,

Dr. Avi Loeb, noted that the object

seemed to follow the propulsion patterns

of a new technology that is currently being tested

for future space missions

known as "solar sail propulsion."

Large reflective sails capture sunlight

to propel a craft through the vacuum of space.

You can design, essentially, photon sails.

So, the idea has been to make a-a material

that reflects photons, which is light, very efficiently.

You deploy this, and you basically

accelerate under starlight.

And then you just cruise.

NARRATOR: Was similar alien technology

used to propel 'Oumuamua?

BRUCE FENTON: It makes you wonder:

You know, was that a targeted mission,

some sort of probe that has been sent in to look for life?

TRAVIS TAYLOR: Before man actually went

to the Moon and walked on it, we sent a lot of probes

around the Moon to look at it.

And it's quite likely

that some version of NASA from some other star system

could send a probe here to Earth.

NARRATOR: The trajectory of the interstellar object

took it past the Sun, where it made a turn

and then ran parallel to Earth's orbit.

It traveled between our planet and Mars

before it began its journey out of our solar system.

When 'Oumuamua arrived, nobody knew where it came from.

Then, in 2018,

an astronomer at the University of Hertfordshire

retraced its movements and discovered

that it came from the Pleiades.

We have to ask: Is it possible that it was actually sent

from the Pleiades?

NARRATOR: For ancient astronaut theorists, the revelation

that 'Oumuamua traveled to our solar system

from the area of the Pleiades star cluster

is highly intriguing.

The Pleiades figures into the creation stories

of many ancient cultures from all around the world,

where it was taught that divine beings

came from these stars to seed life on Earth.

If we look at the mythologies

of the Pleiades around the world,

there's some indication that this star cluster

is, in some way, related to a visitation in ancient times.

NARRATOR: Located over 400 light-years from Earth,

near the constellation of Taurus,

the Pleiades is commonly recognized

as seven bright stars

but actually consists of thousands.

SHOSTAK: The Pleiades. Everybody's heard of the Pleiades.

They're also known as the Seven Sisters,

'cause if you have really good eyesight,

you can see seven stars in a very compact configuration

in the winter sky.

And, in fact, there are a lot more stars than seven.

There are actually 3,000 stars in the Pleiades.

MICHIO KAKU: So, the Pleiades is a star cluster.

They're not separated by huge distances,

but they occur in a small area.

That's different from a constellation,

where the stars could be moving in all sorts of directions

and are separated by huge distances.

NARRATOR: The importance of this massive star cluster to ancient peoples

is revealed not only by their creation stories

but also in how they oriented their most important structures.

FENTON: All around the world,

we find ancient structures

that have alignments that infer a relationship to the Pleiades.

Now, these can be found in places like Chaco Canyon,

in Mesoamerica, in various parts of the world.

It's clear that the ancient people

wanted to incorporate the rising of the Pleiades in some way,

uh, with the building of these megastructures.

NARRATOR: Additionally, ancient artwork and artifacts

pay homage to these same stars,

with one depiction dating back an incredible 18,000 years.

KAKU: Perhaps the earliest reference

to the Pleiades is in the Lascaux caves in France.

But these go back thousands of years into antiquity,

even before the written language.

The Pleiades constellation shows up in various artifacts,

one of them even being a Sumerian tablet relief

that shows what appears to be some type of a god

coming out of the Pleiades constellation.

An interesting artifact coming out of the 1600s

is the Nebra sky disc, depicting the constellation of Pleiades.

TSOUKALOS: Worldwide, we find hundreds of references

having to do with the Pleiades.

Not just on one continent, not just in one culture,

but in multiple continents, in multiple cultures worldwide.

That, to me, indicates

that something happened here on Earth

having to do with someone visiting from the Pleiades.

ANDREW COLLINS: The seven stars making up the star cluster of the Pleiades

are very often represented as human figures.

Uh, in Greek mythology,

they are seven sisters.

And in India, they are associated with the seven rishi.

These are wise benefactors to humanity

from some kind of astronomical place in the sky.

We have to wonder: Why are the Pleiades

being so specifically picked out of the night sky?

Is it possible that the Pleiades

are the place where our sky gods have come from?

NARRATOR: With thousands of stars in the Pleiades,

could it be a place that contains an earthlike planet,

one that could have been the home planet

for our extraterrestrial ancestors?

The Kepler space telescope

has found evidence of planets in the Pleiades.

So, Kepler works by finding dips of light

as a planet passes in front of the star

that it's orbiting relative to the Earth.

Astronomers were able to see that there is some dimming

of stars in the Pleiades,

which is likely caused by planets.

NARRATOR: Are we entering a new era of alien visitation?

One where we will see the return of the Pleiadians

and other extraterrestrial races?

Perhaps further evidence can be found

by examining a second interstellar object

that recently entered our solar system.

NARRATOR: Crimea. August 30th, 2019.

At the MARGO observatory,

amateur astronomer Gennadiy Borisov

detects a strange object traveling through the sky.

It is dubbed the Borisov Comet

and becomes the second interstellar object

ever discovered in our solar system...

...nearly two years after 'Oumuamua

traveled from the Pleiades star cluster.

AMY SHIRA TEITEL: The Borisov Comet is the second known object

we found that has interstellar origins.

It was traveling way too fast

to have come from our own outer solar system,

which means it has to have come from another solar system.

Whether we're just getting better

at detecting these objects

or whether we're seeing this new kind of thing

swinging by our Sun, it's a really exciting time

to be looking for things

that are coming from outside our solar system.

HENRY: This is kind of alarming to some astronomers

because we wonder: Are these cosmic messengers

coming here bringing us warnings?

Are they signaling something?

Is this just the start of more interstellar objects

entering into our solar system?

And if so, how many more of these objects

are we going to start seeing?

MEECH: In 2017, a paper was published

trying to estimate the number of interstellar objects

that we might have.

One estimate suggests

that at any one moment, we might have

one 'Oumuamua-like object

inside the orbit of Earth at any time.

It shows us new possibilities of what's out there.

We've had a piece of something

from another solar system delivered to us.

I think this is inching us closer

to the discovery of life elsewhere.

My personal belief is there is life out there.

NARRATOR: Now, after the historic discovery

of two interstellar objects

that were delivered to our solar system,

could a new age be upon us?

One that will soon see the arrival

of intelligent beings from another world?

HENRY: If 'Oumuamua is an interstellar probe,

we know now that it comes from the Pleiades.

Is the Borisov object also

some form of intelligently directed interstellar object?

And are there other species out there that are

also sending probes that we soon will discover?

TSOUKALOS: In the earliest of oral traditions

and the earliest of texts,

everybody is waiting for someone to return.

I hope that we will make official contact

within our lifetime, meaning in the next 50 or so years.

I've always said that the big secret will be,

when the hatch opens and they walk down the ramp,

that we'll look at each other in the mirror,

'cause they will look like you and me.

NARRATOR: Throughout human history,

we have looked to the stars to guide our ships,

to align our most sacred monuments,

and to search for our place in the universe.

But could we have a far more profound connection

with these distant suns?

And if so, are we on the verge

of recovering this lost knowledge?

Perhaps now that we are able to detect

the visitors coming to our solar system

from the far reaches of space,

we will soon discover the undeniable proof

that we are not alone,

we have never been alone.

I'm just blown away

by the profound new evidence from the Webb telescope,

from SETI, interstellar objects.

We're right on the cusp of something truly amazing.

Yeah, I mean, we've had so many interesting discoveries

over the last, say, 20 years that it's amazing.

I mean, scientists are really proving

that there's life out there in the universe.

TSOUKALOS: Right, and when you consider that

universities like Harvard are joining the discussion,

that is something that 30, 40 years ago

would've been, you know, wishful thinking,

but now it is happening.

You know, it's baked inside of us,

into our DNA, that we are not alone,

and, hey, we are from out there.

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