Ancient Aliens s21e01 Episode Script

1
A lost city.
Hidden in the Andes.
Mysterious metal spheres of
extraterrestrial origin.
And a sunken city that was said to be the
home of the Gods.
Over the years, ancient Aliens has
investigated some of the most astonishing
breakthroughs in archaeology,
astronomy and physics
that challenge traditional
beliefs about human history.
Now, we're counting down the 10 most
extraordinary discoveries we've examined.
Discoveries that just might present
undeniable proof of our extraterrestrial past.
For ancient astronaut theorists like me,
there is nothing more exciting than when a
new discovery is made
that points to evidence of
extraterrestrial visitations
in the distant past.
And while it's not easy to narrow it down
to just 10, our list covers discoveries in
everything from
science to archaeology to
astronomy, like the first
entry in our countdown.
It is a mysterious object that flew
through our solar system.
And what makes it truly
extraordinary is that some scientists
believe it might have been
an extraterrestrial craft.
At number 10 on our countdown of the top
10 extraordinary discoveries, Oumuamua.
The Hawaiian island of Maui, October 19,
Astronomers at the Haleakala
Observatory detect a mysterious
object traveling at high speed
through our solar system.
The object has a strange
oblong shape and is on a trajectory
that is unlike anything that
has ever been seen before.
I was in charge of coordinating the
observing to characterize the object.
There were four images
taken that showed an
object moving rapidly
with respect to the stars.
At that point, they
started to compute an orbit
to try and understand
what this object was.
Once more data came
in, it was very clear that
this object was from
outside the solar system.
This was really exciting.
By calculating the object's speed and
trajectory, astronomers determined that it
originated in another
star system, making it
the first interstellar
object ever discovered.
They named the object Oumuamua,
meaning Voyager from the distant past,
reaching out to us.
And incredibly, some
astronomers suggested it
might be some type of
extraterrestrial technology.
Oumuamua doesn't look like a typical
asteroid.
It's elongated.
It's not round or chunky like you would
think an asteroid is.
And there were a lot of astronomers and
scientists who studied Oumuamua,
and it looks like it could
possibly have been a probe
from some other civilization
outside our solar system.
What I think is interesting is that
Oumuamua is cigar-shaped, because there
are stories and eyewitness reports of
cigar-shaped UFOs.
So is it possible that there is some type
of a connection?
Is it possible that some asteroids are
actually extraterrestrial spacecraft?
While it might sound like science fiction,
in 2023, a team of scientists launched an
expedition to find fragments of a
meteorite on the ocean floor, one that
they believed contains evidence of Alien
technology.
At number nine on our countdown,
the Belau Spheres.
The Bismarck Sea, June 2023, 100 miles
north of Papua New Guinea.
Harvard astrophysicist Dr. Avi Loeb and a
team of scientists are attempting to
retrieve the remnants of
an exploded meteor from the
bottom of the Pacific Ocean
using a large magnetic sled.
Two weeks into the project, the sled pulls
up something unexpected.
Loeb did find a number of
beads, little spherules, not
much bigger than a BB, that
they were able to dredge up.
Upon first glance, they look kind of
exotic.
They have little swirls in them.
They're almost perfectly round.
For Dr. Loeb, the discovery of these
mysterious spheres is particularly
exciting because he believes that the
exploded object they came from is unlike
any other meteor that's ever landed on
Earth.
He first learned about this meteor in
2019, and based on its speed and
trajectory, he was able to surmise that it
was interstellar.
I came across a meteor
catalogue that the government
compiled using its
missile warning system.
The meteor discovered in 2014 was actually
from outside the solar system.
The meteor burned up 18.7 kilometers above
the ocean surface, and it released a few
percent of the energy of the Hiroshima
bomb when it exploded.
The government released the light curve of
the fireball of the explosion,
and from that we infer that
the object must have been made
of some alloy that is much
tougher than iron meteorites.
And that raises the possibility that it
may have been a spacecraft.
A spacecraft?
Could it be that the object
that exploded over the ocean
north of Papua New Guinea
was an extraterrestrial craft?
Dr. Loeb believes the
small metallic spheres his
team discovered could
confirm his radical theory.
Initial testing of the spherules showed
that they had an unusually high
concentration of beryllium,
lanthanum, and uranium,
making a never-before-seen
compound known as bilao.
That bilao composition does not exist in
any known mineral or rock that we know of,
and so this does
speak to his hypothesis
that they're manufactured
extraterrestrially.
Dr. Avi Loeb proposes that these spherules
may be part of some type of E.T.
technology.
Could that really be a remnant of a far,
far distant extraterrestrial civilization?
Dr. Avi Loeb's suggestion that the objects
discovered in the Pacific Ocean may have
come from an extraterrestrial spacecraft
is a thrilling prospect.
But there is another scientist who made a
similar intriguing discovery, not in the
ocean, but in Earth's upper atmosphere, and
he's convinced that it is of Alien origin.
Number eight on our countdown,
the titanium microsphere.
The University of Sheffield, England,
Andrew, on you.
Countdown, please.
Astrobiologist Dr. Milton Wainwright and
his research team released a hydrogen
balloon that travels 25 miles up into
Earth's stratosphere.
Once the balloon reaches
its target altitude, a capture
mechanism collects samples
of whatever material is around it.
Then the balloon bursts and the capture
mechanism descends by parachute back to
Earth so that its contents can be
analyzed.
One of these balloons
was hit at an incredible
rate by something that
left behind a small crater.
And when they actually dug into this crater
to see what it was, it was a tiny sphere.
And when they actually examined what the
sphere was made of, it was found to be of
titanium and vanadium,
and these are elements that
shouldn't be there naturally
out in the lower atmosphere.
The microscopic sphere
is just 200 microns in
diameter, roughly the
thickness of a human hair.
There's no Earth material
associated with them, and they're
too large to be carried
from Earth to these altitudes.
They must be incoming from space.
Where are they coming from?
We just don't know.
This tiny sphere, when they studied it
under an electron microscope, saw that it
was actually a shell that had
now broken, and coming out of it
was this strange ooze that
they felt was biological in nature.
A biological substance that originated not
on Earth, but from somewhere in space?
Is it possible that this
discovery is evidence of
a living organism from a
world other than our own?
The characteristics of these organisms is
very interesting.
They're made of carbon and oxygen,
so we know they're life forms.
They don't contain silicon, so they're
elements of cosmic dust.
They're very unusual.
When I see the shapes
of these things, I'm amazed
because I've never seen
anything like them on Earth.
There's no textbook version of the
pictures we've been seeing.
Although it is still unknown just
where these spheres come from,
Dr. Wainwright believes they are being
used to introduce new life forms on Earth.
With Dr. Wainwright's small metal sphere,
you have to wonder is this protein ooze
that's inside it something to jumpstart
life on the planet?
Without a doubt, one of my favorite places
to explore is Egypt.
And what I find truly exciting
is when technology reveals
new secrets about its ancient
monuments and temples.
Like an extraordinary discovery that was
made in 2017 when researchers located a
hidden chamber inside
the Great Pyramid that's
big enough to fit
the Statue of Liberty.
At number seven on our countdown of the
top ten extraordinary discoveries,
the Great Pyramid Void.
Egypt.
Just west of Cairo
stands the most mysterious
and sophisticated wonder
of the ancient world.
The Great Pyramid.
Built from more than two
million limestone blocks, this
massive structure is
engineered to near perfection.
Despite being studied for
hundreds of years, much
about the Great Pyramid
remains shrouded in mystery.
And in November 2017,
media outlets around
the world announced
an incredible discovery.
Archaeologists detected a chamber near the
pyramid's north face that is approximately
one hundred feet long and more than six
feet tall.
The discovery of that void is
sensational because it opens
up the whole discussion to more
questions and to new answers.
In April 2018, Giorgio Tsoukalos entered
the Great Pyramid along with Egyptologist
Ramy Romany and Dr. Giulio Magli,
a professor of archaeoastronomy
from the Polytechnic
University in Milan, Italy.
So this is it, the Grand Gallery.
They are inside the
Grand Gallery, which is
directly beneath the
newly discovered void.
From here to the ceiling is about ten
meters high and it goes about fifty meters
in, which is a hundred and fifty feet
deep.
I mean, that just gives you an idea of how
huge this place is.
And it's perfect.
So you think the void is right on top of
our heads here?
I think it covers the Grand Gallery.
In your opinion, what do you think is
inside that void that was just discovered?
Okay, there is one possibility.
The pyramid texts mention the destiny of
the pharaoh.
The pharaoh will sit on an iron throne
among the stars.
Can you elaborate on that iron throne?
Yes, of course.
There was no melted iron in Egypt.
Melted iron in Egypt
will come at the end of
the Bronze Age, so
about 1200 years later.
But they were using the
small part of iron, which
is coming on the Earth due
to meteoritic phenomena.
Precious objects of iron, meteoritic iron,
were made for the pharaohs.
And so maybe also this throne.
A throne containing pieces of metal found
in a meteorite?
Could such an object really
be embedded inside a secret
chamber located within
the Great Pyramid of Giza?
According to ancient Egyptian writings
called the Pyramid Texts, the God Osiris
and his wife Isis came to Earth from stars
in the constellation of Orion.
And it is from these two Gods that all
human life originates.
According to the story, Osiris had an iron
throne that possessed awesome powers.
Throughout ancient Egypt and the temples,
we see depictions of the Gods,
extraterrestrial beings, on their thrones.
These thrones are feathered because they
are ascension vehicles.
They are vehicles that take them to the
stars and back.
What could be inside that void?
There are many theories out there.
To this day, we don't know what's inside.
And that's the most exciting part for
Egyptologists.
Every day I'm looking
forward to find what's
inside that new void
that has been discovered.
Just what is inside the Great Pyramid's
void remains to be seen.
But if it's anything like the amazing
discovery that's next on our list,
it may leave us with more questions than
answers.
I'm talking about the giant stone boxes
that weigh nearly a hundred tons,
whose purpose is still unknown.
At number six on our countdown of the top
ten extraordinary discoveries,
the Serapeum of Saqqara.
Saqqara, Egypt, 1850.
Here, twenty miles south of the Giza
pyramids, French archaeologist Auguste
Mariette is surveying
the area when he notices
a stone object protruding
from the ground.
Upon closer inspection, it appears to be
the head of a Sphinx.
He started to clear the
area, and so his team dug
down and revealed Sphinx
after Sphinx after Sphinx.
He soon lines up over a hundred sphinxes,
follows the pathway, and is led to an
underground tunnel,
an entrance that's blocked.
He dynamites the entrance.
He is now in a seven
hundred foot long tunnel
that's been carved
out of the limestone.
Inside the ancient structure,
Mariette discovered inscriptions
that identify the underground
complex as the Serapeum.
And within its chambers, he found gigantic
stone boxes.
Inside that Serapeum are
twenty-four niches that contain some
of the biggest stone sarcophagi
ever discovered in Egypt.
The boxes themselves range in weight from
seventy to seventy-five tons, and the lids
alone weigh between twenty and twenty-five
tons.
What compelled the ancient Egyptians to
place twenty-four enormous and precisely
crafted stone boxes deep beneath the
Earth?
Archaeologists suggest they were built to
be the burial place of sacred Apis bulls.
The Apis bull is related to the Egyptian
God Pata, who was a major creator God.
He was the God of Memphis, the capital
city.
He was the God of all craftsmen.
The Apis bull was one of the most sacred
animals in all of ancient Egypt.
But when Auguste Mariette opened the
sarcophagus, they were empty.
There was nothing in there.
The absence of the Apis bulls has led
ancient astronaut theorists to suggest the
boxes might have served a more profound
purpose, as a type of an advanced,
even extraterrestrial, technology.
One of the ideas, too,
of the sarcophagi is
that they're super
high-tech storage devices.
You know, they're
hermetically sealed, they're, you
know, in spaces that
would be difficult to get to.
Perhaps something dangerous and technical
was kept in these boxes.
We're coming up on the halfway point in
our countdown of the top ten extraordinary
discoveries, and this next one truly blows
my mind.
In 2003, archaeologists
began to excavate an ancient
lost city, hidden deep in
the jungles of Guatemala.
In total, they found over a hundred
thousand structures that remarkably
revealed a profound connection to the
stars.
At number five, the lost city of El
Mirador.
The El Mirador Basin, northern Guatemala,
Archaeologist Dr. Richard Hansen begins an
aerial survey of the dense jungle using a
sophisticated remote sensing method called
Lidar.
The results reveal an extraordinary
Metropolis that had been lost to history.
What's amazing is we've found what seems
to be an entire civilization that the
Mayans had built a long time ago we never
knew were there.
There are pyramids there that rival the
pyramids in Egypt.
Now, archaeologists realize that this area
was at one time densely populated.
There were hundreds of thousands if not
even millions of people living there.
And they built huge pyramid cities.
At the center of the
ancient Metropolis are two
gigantic pyramids now known
as El Tigre and La Danta.
La Danta, the bigger
of the two, is larger in
volume than the Great
Pyramid of Giza in Egypt.
The Danta is not just a pyramid,
it's a pyramid with pyramids on top of it.
This is a massive structure
that's rivaling or even
bigger than any other
known Maya temple complex.
For ancient astronaut
theorists, perhaps the
greatest discovery is
in the layout of the site.
Some archaeologists have suggested that El
Mirador is aligned with the Pleiades and
that pyramids and other structures there
are actually recreating the Pleiades star
system on the grounds in the El Mirador
base.
The Maya themselves associate the
celestial beings that had contact with
their own ancestors with the Pleiades
constellation.
What we have discovered right there is a
lost chapter of history human history that
could be a direct connection to the
ancient astronaut theory.
Our next extraordinary discovery was made
in a remote area of Peru and this one
really took archaeologists by
surprise because here they found
a massive complex that is
older than the pyramids of Egypt.
At number four on our countdown,
Caral.
Peru, 1994.
While conducting research at the base of
the Andes Mountains, Peruvian
archaeologist Dr. Ruth Shady
Solis notices several hills in
the landscape that do not appear
to have been formed naturally.
People had known it
was there but most people
had assumed that these
great mounds were natural.
But Ruth Shady decided to excavate and
turned out she'd actually hit the jackpot
because she'd found one of the most
important sites in South America.
Dr. Shady and her team
discovered the ruins of an
extraordinary lost city that
has come to be known as Keral.
When you visit Keral you find a huge
archaeological complex.
There's a large sunken amphitheater to the
south, there's a major pyramid to the
north, and then there are more minor
pyramids that surround central areas.
There are also other buildings, residential
buildings, so it's a really huge complex.
But the most extraordinary discovery was
still to come.
Towards the bottom of the great mound they
found remains of what seemed to be Reed
bags or baskets in which
the Earth and stones would
have been carried to
make this enormous mound.
And of course you can date reeds by the
radiocarbon method and to everyone's
surprise the answer came far earlier than
anybody had expected.
This site went back at least to 2600 BC or
earlier.
So that was putting it back 4,600 or more
years which made it one of the oldest
sites as far as civilization in the
Americas.
Keral could be the mother culture of the
whole of South America.
The dating of Keral has
really put into question
the origins of
civilization on the planet.
At the time the greater pyramid of Keral
was created.
Ziggurats were being
built in Mesopotamia
and the steppe pyramids
were rising in Egypt.
This was the beginning of a world wide
Pyramid Age.
You have pyramids all
over the world start to spring
up and you have to
wonder how did this happen?
Did they all have the same
teacher that was assisting them
or instructing them on how to
build these massive structures.
Scientific breakthroughs and
archaeological finds are always compelling.
But for Ancient Astronaut Theorists like me,
what's really exciting is when a story
once thought to be fiction is
proven to be based on historical fact.
Like the discovery of a
sunken city that according
to ancient Hindu texts
was the home of the Gods.
Number three on our countdown of the
top ten extraordinary discoveries, Dwarka.
Northwest India, April 1983.
Marine archaeologist Dr. S.R.
Rao begins a seven year
underwater exploration
just off the coast of the
modern city of Dwarka.
And what he discovers is stunning.
Submerged twenty feet beneath the surface
of the ocean, he finds sandstone walls,
cobblestone streets, and further evidence
of a prosperous ancient city.
At Dwarka what has been found so far under
the ocean is incredibly tantalizing.
For instance there is
this huge wall estimated
about five hundred
and eighty meters long.
Pottery has been found.
Stone anchors have been found so this
seems to be a maritime city.
The remains that have been discovered
beneath the waters have been radiocarbon
dated to at least nine thousand five
hundred years.
So this was many thousands of years older
than that of Sumeria, Egypt, and China.
So what exactly was going on in India at
this time?
Are these ruins evidence of a city that is
over nine thousand years old?
And if so, who built it?
Dr. S.R.
Rao and other researchers
believe that the ruins belonged
to a legendary ancient city
that was also called Dwarka.
According to the sacred
Hindu text, the Mahabharata,
ancient Dwarka was once the
home of the God, Lord Krishna.
In the Mahabharata, Dwarka is described as
Krishna's kingdom.
There are magnificent
palaces all having wonderful
windows, wonderful
balconies in high rise buildings.
So it is beautifully described in the
Mahabharata as being a very important city.
The Mahabharata tells that the land came
up out of the sea, the ocean released this
land, was a special place of great magic
and beauty.
According to the story, Dwarka was
destroyed after another Hindu God,
Lord Salva, attacked it from a flying
chariot.
He had a celestial chariot, which is
almost like a plane that he could fly.
And this plane was like a stealth fighter
plane.
So he came to Dwarka and then he started
bombarding the city.
Krishna is killed.
And the city, this magnificent city built
on land that came out of the sea,
sank back into the ocean again.
It only existed during the time that
Krishna lived there.
For centuries, the story of ancient Dwarka
was believed to be merely a legend.
But is it possible that these
underwater ruins are evidence
that the ancient Hindu texts
are based in actual history?
If so, it wouldn't be
the first time that a
supposedly mythological
site was found to be real.
In the 1870s, archaeologists discovered
the ruins of Troy, a legendary city from
Greek mythology that was assumed to be
completely fictitious.
For hundreds of years,
people thought that the story
of the Trojan War, the
Trojan Horse, is all myth.
But then, archaeologists found the ruins
of Troy.
And we know there was the Trojan War,
just like the way the ancients called it.
Now we know that Troy did exist.
And similarly, Dwarka in the Mahabharata,
it was not just a mythical city.
Once upon a time, it really did exist.
But if the underwater ruins of Dwarka
really are the place described in the
Mahabharata, might the story of its demise
also be true?
Was it destroyed in an aerial assault
waged by an otherworldly visitor?
This would indicate to us that the legends
are really correct about this place,
that this was a real event, one that
perhaps included extraterrestrials.
Every so often, a discovery
is made that sounds like it's
been ripped straight from
the pages of a fantasy novel.
And that's exactly what happened when a
family renovating their home in central
Turkey stumbled upon the entrance to an
entirely hidden world.
At number two on our countdown of the top
ten extraordinary discoveries,
the underground cities of Turkey.
Nevsehir Province, Turkey.
Here, in 1963, a simple
home renovation in the town
of Derinkuyu led to an
extraordinary discovery.
A cave wall was opened, revealing a
passageway to an elaborate underground city.
Derinkuyu is this massive underground
tunnel system going down three levels,
with many streets, with
many shafts and corridors and
rooms and caverns that can
hold massive amounts of people.
Archaeologists were astounded
by this massive underground
city that extends as much
as 280 feet beneath the Earth.
And they got an even bigger surprise more
than 50 years later, in 2014, when another
even larger underground city was discovered
beneath the nearby town of Nevsehir.
It is absolutely stupendous.
It covers about 5 million square feet.
It goes down over 370 feet into the
ground.
And it's estimated that this could have
held 20,000 people or more.
Archaeologists got inside and there were
churches, there were vessels and jars,
there were wineries,
there was living quarters,
there were places where
they made linseed oil.
Further exploration revealed that the two
underground cities were actually connected.
I was many times in
the underground cities in
Turkey, and this is a
fantastic experience.
These are linked together.
There are 7 kilometers long underground
tunnels connecting the two cities.
According to many
archaeologists, these cities
were most likely
constructed around 800 B.C.
to provide shelter from an invading army.
But some researchers suggest they could be
much older.
One Turkish archaeologist by the name of
Omar Demir, who was actually the creator
of the Dankeu, found evidence of Stone Age
talks going back to the Paleolithic era.
This is at the time of the last Ice Age.
This tells us that these underground cities
are perhaps 11, 12, 13,000 years old.
If the underground cities of Turkey really
are as much as 13,000 years old,
just who could have built them?
And why?
Ancient Astronaut Theorists suggest
that these sprawling underground cities
may be shelters that are
described in the sacred writings of
Zoroastrianism, one of
the world's oldest religions.
In a text called the Vendhi Dad,
a young ruler named Yima is instructed to
build an underground sanctuary by the God
Ahura Mazda.
Ahura Mazda told the great early king Yima
that there would be a terrible disaster.
A winter would come such as has never been
known.
It would be so cold that at midday it
would be dark like night.
Ahura Mazda instructs Yima to build a
vara.
This is a huge structure, two miles long,
two miles wide, an underground hall of
sorts where things can be protected from
the terrible winter.
In the vara, Yima was to hide a remnant of
the people and then extensive seed bank,
also a pair of each of the animal species.
Ahura Mazda was known to have descended
from the sky.
In a vehicle with fixed wings,
it looks like some type of flying device.
That would suggest that he was in fact an
extraterrestrial.
As far as ancient astronaut theorists are
concerned, the story of Yima is an account
of an Alien intervention in the distant
past.
And they suggest it is very possible that
the shelters Yima was said to have built
are, in fact, the underground cities that
have been found in Turkey.
The vara is supposed to be a huge
enclosure that not only houses a large
number of people, but it's to have big
streets that go through it.
It's divided into certain areas.
The vara could be the underground cities
in Turkey.
We've reached the top spot on our
countdown, and this next extraordinary
discovery completely upended our
understanding of human civilization.
It's an astonishing Megalithic complex of
massive stone pillars and mysterious
carvings that predates
the world's earliest
known civilization by
more than 5,000 years.
At number one, Göbekli Tepe.
Sanliurfa, Turkey, October 1994.
While plowing his
field, a shepherd spots a
strangely shaped stone
protruding from the ground.
After brushing away the dirt, he realizes
the stone may be part of an ancient ruin.
He reports his find to the
local museum, and is visited
by Klaus Schmidt from the
German Archaeological Institute.
It wasn't until German archaeologist Klaus
Schmidt visited the site and began digging
that they realized what was really at the
site.
What he discovered was mind-blowing.
After discovering the first
T-shaped pillar buried at
the site, he soon found more
of these massive structures.
The site becomes known as Göbekli Tepe,
meaning Potbelly Hill.
The site of Göbekli Tepe is a series of
circular enclosures, but then in the
center of each enclosure
you have two particularly big
T-shaped pillars of limestone
sort of facing each other.
Many of these pillars have remarkable
carvings on them, wonderful carvings and
bas -reliefs of animals, birds,
insects, all kinds of things.
So to fashion those and
carve them and set them up
in these structures was
just absolutely amazing.
Many of these were carved into human form.
They would have arms on the side of them,
they would have hands that come round to
the front, they would have garments that
drop down the front.
Twenty different enclosures were built and
each one seemingly at the end of its
useful life was completely covered over
with rubble and soil before the next.
Enclosure was built.
Intrigued by his discovery,
Klaus Schmidt had the
sediment layers of the
site radiocarbon dated.
The results were astonishing.
It is the first archaeological
site in the world that proves
its age dating as far back as
12,000 years, around 10,000 BC.
The discovery and the official acceptance
of Göbekli Tepe's dating has changed the
history of archaeology.
All of this suggests a understanding of
technology, of masonry, of art,
of carving at the end of the last ice age.
We realize that there is some great
culture and possibly even a high
civilization that existed here as much as
11,000 years ago.
Archaeologists believe the Sumerians were
the world's first civilization,
emerging around 5,000 BC.
But the discovery of Göbekli Tepe put that
into serious question.
And some researchers
have noticed a curious
connection between the
Sumerians and Göbekli Tepe.
At Göbekli Tepe, there's
a carving of these three
handbags that appear
above this bird-like creature.
And what's fascinating about this is that
you can find carvings of similar handbags
about 400 miles to the south where the
ancient Sumerians lived.
And there, the handbags are held by these
winged figures called Anunnaki.
The Anunnaki, as told in the Sumerian
stories, had these advanced powers,
they had connection with abbans,
they're extraterrestrial beings,
and it makes you wonder
if Göbekli Tepe was in
fact a place of connection
with these beings.
It's exciting to think that
Göbekli Tepe might hold clues
to extraterrestrial contact
that occurred 12,000 years ago.
And as far as I'm concerned, with every
extraordinary discovery, from lost
civilizations hidden from sight,
to ancient structures and artwork that
suggests contact with otherworldly beings,
to objects from space that defy
explanation, we get one
step closer to understanding
the truth about humankind's
extraterrestrial past.