NARRATOR: NASA's mission is to explore the unknown.
Man: There's more that we don't know than we do know.
That's just the nature of the universe.
NARRATOR: In the search for answers,
it launches its scientists into space,
its craft beyond the limits of the solar system.
Williams: Taking risks is part of making discoveries.
Space exploration is like lighting a match,
and we don't know what lurks in the shadows.
There could be anything out there.
NARRATOR: Mysterious tracks,
hunted astronauts,
fountains of life on Saturn's moon,
and possible evidence of an alien invasion...
NASA's missions have uncovered disturbing anomalies...
Man: Okay, we're seeing three or four objects.
Man #2: Yeah, there are three objects.
...that continue to perplex our finest scientific minds.
These are "NASA's Unexplained Files".
NASAs.Unexplained.Files.S01E04.Black.Knight.Rises.1080p.WEB.x264-CRiMSON English HI/SDH CC Converted SRT Subtitles - UF (v1.04) ... Captions by VITAC... www.vitac.com
captions paid for by Discovery communications
a mysterious object floats above our atmosphere.
It looks like a klingon bird-of-prey.
NARRATOR: Some say it's a stealth craft
from a secret defense project...
Oberg: The black knight goes back
to the early years of the space age and even before.
NARRATOR: Or something even more sinister.
Friedman: There's a black world out there...
lots of things we can't explain.
That's the way life is.
[ indistinct radio chatter ]
NARRATOR: December 1998...
six NASA astronauts
are about to open a new chapter in space exploration.
Their mission...
to assemble the international space station,
the first permanently manned satellite
to orbit the Earth.
Jerry Ross is the spacewalk mission specialist.
When you're starting to lay the cornerstones
of something as important as the international space station,
you're pumping
and you want to get on with the program.
Man: But the other one has a dash-one,
and you've hit the nail on the head.
NARRATOR: Seven days into the mission,
Ross and fellow astronaut Jim Newman
are installing thermal protection
on the new space station
when someone spots something unexpected.
A crew member said, "what's that?"
and I'm starting to look around, trying to understand...
"what's that? What are they talking about?"
NARRATOR: The crew immediately follow
NASA's UFO-sighting protocol.
The first thing we try to do is to take pictures of what we see
so that we have photographic evidence.
[ camera shutter clicks ]
NARRATOR: Back on Earth,
the photographs create an instant sensation
in the UFO community.
They see a link to a mysterious object from the 1950s
known as the black knight.
Some people thought it was extraterrestrial in origin,
others that it came from closer to home.
The black knight goes back
to the early years of the space age and even before.
People were beginning to watch the skies,
looking for satellites... secret ones.
NARRATOR: These so-called "dark satellites"
were unexplained blips that mysteriously appeared on radar.
And sometimes ominous black shapes
were spotted hovering in the sky.
At the time,
the Russians accused the U.S. of space espionage,
while the U.S. suspected the same.
The black knight is just one of many things
that we don't have explanations for.
Certainly, people don't understand
that just because it's ours
doesn't mean we tell everybody about it.
Man: Do it. I'll guarantee you.
NARRATOR: But Jerry Ross doesn't buy the dark satellite theory.
He believes there's a simpler explanation.
Ross: Jim was supposed to put a thermal blanket
on the outside of the station to protect it from heat losses.
Man: We'll start at the base and then work our way up.
Ross: I was ahead on my task,
so Jim offered to give me the thermal blanket
and let me attach it,
when someone said, "what's that floating away?"
I looked, and I saw this blanket.
I looked at the tether of where it was supposed to be,
and it wasn't there.
In this case, it's a story of an oops...
dropping a piece of equipment.
It wasn't alien. It was a mistake.
It was a really bad feeling.
NARRATOR: The blanket looks black
because its reflective surface is facing away from the Earth,
out towards the darkness of space.
But not every sighting of the black knight
can be so easily explained.
There were reports in the '50s
of strange things in orbit around the Earth.
We don't know what they were.
They weren't ours, as far as we know.
We don't think they were Russia's, either.
What does that leave?
Who knows?
NARRATOR: Conventional scientific wisdom suggests
that any alien intruder
would have to travel light-years to reach us...
But one NASA craft
has discovered potential signs of extraterrestrial life
right next door.
[ morse code beeping ]
a NASA probe detects a mysterious energy source
on one of Saturn's dead moons,
and the search for life takes an unexpected leap forward.
Enceladus is now my number-one choice
for where we might find life.
We thought Enceladus was dead. It blew our minds.
When we see a puzzle like this, we want to figure it out.
d'Antonio: It's spectacular...
nothing like it in our solar system
that we've seen so far.
NARRATOR: NASA's Cassini probe transmits mission data
across a billion miles of space.
[ morse code beeping ]
when it passes 700 miles above Saturn's moon Enceladus,
project investigator Michele Dougherty
can't believe what she sees.
Dougherty: I look at the data.
I see these large changes, and I think, "This is weird.
"I don't understand what's going on at all.
What could it be telling us?"
I take a deep breath, and I phone the Cassini project.
And I say,
"we think we're seeing an atmosphere at Enceladus.
Enceladus is alive."
NARRATOR: Putting her reputation on the line,
Dougherty persuades NASA to interrupt its mission,
turn the probe around,
and take an even closer look at Enceladus.
[ morse code beeping ]
what happens if we don't see anything?
No one's ever gonna believe anything I say again.
NARRATOR: Skimming Saturn's rings,
Cassini takes a closer look at Enceladus.
The images it sends back are astonishing.
Enormous plumes of liquid water
spew out of a moon that should be dead.
The plumes that we're seeing at Enceladus are huge...
...Half the size of the moon itself.
It validates the decision that we made to go close
and really give us a new discovery
that no one actually thought was ever gonna be there.
So, it's really cool.
NARRATOR: The sensational discovery
hits the world's headlines,
but planetary scientists are baffled
by the giant liquid plumes.
Dr. Brines: It should be completely frozen,
but yet we have liquid water,
32 degrees fahrenheit and warmer,
coming out of this thing, spewing into space.
NARRATOR: Something or someone is heating up a moon
that should have frozen to death millions of years ago.
We expect that the surface of Enceladus
has a little bit of heat on it
because of the solar radiation coming in,
but you could power 20 coal power stations
with the heat that we find.
And that's a real surprise.
What is powering Enceladus?
NARRATOR: One theory is
that the mysterious energy emanates
from Saturn's extreme gravitational force.
d'Antonio: Enceladus isn't like our moon.
It has a rocky core,
but it actually has a water ocean
beneath a mantle of thick ice.
As Enceladus orbits Saturn,
Saturn's massive gravity squishes it,
putting a lot of energy
into that little, tiny, 300-mile-diameter ball.
And so, that's helping to push that ice water
out of these fissures at high velocity.
NARRATOR: Cassini flies through a plume
spewing from the icy moon's geyser.
What it discovers
turns Enceladus from a barren, freezing wasteland
into a promising place for extraterrestrial life.
d'Antonio: The interesting thing is, coming out with those geysers
we're also seeing hydrocarbons...
building blocks of life.
Enceladus is now my number-one choice
for where we might find life.
Dr. Reid: If you find liquid water,
you can start to talk about the possibilities
for perhaps finding some kind of alien life
beneath the surface of Enceladus.
I think if somebody had suggested that
before the mission went there,
they would have been carted off into a small room.
Dr. McKay: The next step is directly search for life.
We want to go back to the plume
with more sophisticated instruments,
and I think even grab a sample and bring it back to Earth.
NARRATOR: Up next...
Sun damage on a cosmic scale...
There is a hole... nothing there.
NARRATOR: ...And something out there
may be watching us.
Why wouldn't an alien culture use spy satellites?
We're completely at the mercy of our sun.
We can't control it, we barely understand it,
and all life depends on it.
NARRATOR: But has our sun turned to the dark side?
What the heck is going on there?
NARRATOR: A giant chunk of the sun is missing.
There is a hole... nothing there.
It's as if aliens had scooped the surface.
NARRATOR: July 2013,
Goddard Space Center...
the headquarters of NASA's SOHO Solar observatory.
Its mission...
to keep an eye on our fiery star.
The SOHO project is an early-warning system
about new phenomena
which could have an impact here on Earth.
NARRATOR: Scientists monitoring the satellite feeds
see something extraordinary...
a gigantic shadow creeping across the sun...
...a 500,000-mile-wide hole.
As NASA struggles to assess the threat,
the dramatic images fuel a storm of speculation.
Friedman: This was weird.
We don't know whether that was artificially induced on the sun.
It's as if aliens had scooped the surface.
NARRATOR: Whatever the cause,
the results could be catastrophic for us.
A dip of even 7% in the sun's output
could cast the Earth into another ice age.
On NASA's satellite feeds,
the strange black void is unmistakable.
But outside,
the summer sun seems to shine as brightly as ever
while the hole remains invisible to the naked eye.
So, here we are on Earth, living our normal lives,
and there's a disaster movie going on on the sun.
NARRATOR: In an effort to explain the hole,
scientists turn to a satellite
that captures pictures of super-hot gases
in the sun's atmosphere.
Its high-tech cameras see things that humans can't
things visible only in the ultraviolet spectrum.
Suddenly, the hole looks different.
Dr. Raferty: What appears to be an area of dark, empty space,
in actual fact,
it's filled with gases that are much colder
than those that we can see in the area around it.
NARRATOR: The giant shadow
is really a cold patch in the sun's atmosphere.
When we're talking a cold patch, we're not talking alaska.
It's still a million degrees.
NARRATOR: Solar scientists
call these cooler areas coronal holes.
Coronal holes are places where material can escape
and get out into the interplanetary medium.
NARRATOR: To the horror of scientists,
this coronal hole...
...could be in a perfect position
to blast the Earth with solar particles.
Dr. Brin: This giant coronal hole
is spewing charged particles across space,
and when the Earth happens to be in the way,
you can get a solar storm.
Friedman: A solar storm can knock out satellites.
Electronics won't function properly.
And we have occasionally had that happen.
That's real. It's not an imaginary concern.
If we are hit, it's really a big deal.
NARRATOR: Traveling at 1.5 million miles an hour,
the deadly sunbeam will take 58 hours to reach the Earth.
When it hits,
the first sign should be a spectacular light show
at the Aurora Borealis
as the planet's magnetosphere fights to protect us
by absorbing the energy of the bombarding particles.
July 20, 2013,
Two and a half days after scientists first spotted the hole,
the northern sky erupts with flashing colors.
Could this be the opening act in a global meltdown?
The awesome display lasts for two days...
...then dims.
To the scientists' relief,
the storm was nothing more than a beautiful light show.
It dealt Earth a glancing blow.
Next time, we might not be so lucky.
The sun can have quite a temper
and can turn into a real potential foe.
Friedman: Strange as it may seem,
there's a lot we don't know
about that big orange ball up there.
NARRATOR: Humanity's knowledge of physics
comforts us when facing the unknown.
But in deep space,
something appears to be playing by a different set of rules.
Capps: We're constantly discovering things
that don't fit any of the theories,
and then we come up with new theories.
What's going on? We don't know.
NARRATOR: A bright object enters Earth's orbit.
Holy cow!
This is the most odd thing we've ever seen.
NARRATOR: Official explanations don't add up.
Then experts begin to think the unthinkable...
Could this be an extraterrestrial probe
within our solar system?
NARRATOR: Could we be looking at something
that's also looking back at us?
We on the edge
of mass destruction
NARRATOR: El Centro, California.
Amateur astronomer Bill Yeung
is one of a select group of stargazers
with a very important task.
Bill Yeung is an Arizona-based astronomer
who's taken it as his mission
to watch out for near-Earth objects
that could pose a danger to us.
NARRATOR: In September 2002,
Yeung spots a bright object in orbit around the Earth,
which sets off alarms.
This object became very apparent as something unusual,
primarily because of its motion.
It was moving very fast and moving in a velocity
that's very much like the velocity of the Earth.
It's too big to be a spanner dropped by an astronaut.
It's too big to be a satellite. So, what is it?
NARRATOR: The mysterious object is more than 60 feet across
and orbiting close to the Earth.
Yeung immediately reports the sighting to the authorities.
The first thought is, "this is an asteroid."
NARRATOR: NASA takes the threat of an asteroid impact
very seriously.
Friedman: Asteroids are kind of important
because they might occasionally
beat the heck out of the surface of the planet.
Binzel: Asteroids are traveling at about 30 miles per second.
That's an incredible velocity.
And when you have an object that has mass,
that's a lot of kinetic energy.
It's probably what did in the dinosaurs.
[ roaring ]
NARRATOR: But asteroid J002E3
isn't behaving like an asteroid at all.
Most asteroids trace a regular orbit around the sun
within the belt between Mars and Jupiter,
but this mysterious object doesn't do that.
Pope: This thing goes around the Earth,
then it shoots off.
It goes several times around the sun.
It comes back.
NARRATOR: Concerned, NASA's Jet Propulsion Laboratory
joins other scientists in the investigation.
Binzel: The first question we asked...
is it real as a natural object,
or is it something different,
something that we didn't understand?
NARRATOR: They direct the infrared telescope in Hawaii
towards the object for a closer look.
As the first set of data came through the pipeline,
we took one look at it...
And I was like, "holy cow!"
this is the most odd thing we've ever seen.
And we pulled up the spectrum, and it was full of paint.
NARRATOR: The exotic anomaly has a coating
with the same chemical signature as industrial paint.
Binzel: This object was no natural asteroid.
It was unlike anything we'd every seen before.
It's paint. This can't be an asteroid.
NARRATOR: No known natural object is covered in paint,
but when NASA checks if any man-made satellites
are stationed in that area of space,
they draw a blank, raising an alarming possibility.
When you think about it, we use spy satellites,
and here's this object orbiting the Earth.
Why wouldn't an alien culture use spy satellites?
[ beeping ]
NARRATOR: NASA's Jim Oberg doesn't buy that theory.
He supports further investigation
of the paint evidence.
The paint is the clue. The paint is the proof.
NARRATOR: Detailed analysis of the data
reveals the entire surface of this 60-foot object
is covered in titanium dioxide,
a compound that makes paint white...
...The color of NASA hardware.
Man: 3...2...1...0.
All engines running.
NARRATOR: But if this is a part of a rocket,
it's in a very strange place.
The question is, how did it get there?
NARRATOR: NASA connects the dots
and comes up with a plausible explanation.
Based on the orbit
and based on the fact this object is covered in paint,
we are able to calculate backward
and determine that this object...
...Is the third stage of the Saturn V rocket
that carried astronauts Conrad, Bean, and Gordon to the moon
on Apollo 12.
NARRATOR: Astronaut Alan Bean remembers what it was like
to ride on that Saturn V.
I've been a lot of vehicles on Earth,
in airplanes and all that.
I felt nothing that had the vibration and shaking
that the Saturn V had.
There's 7.5 million pounds of thrust going on down there,
and when it's going,
that's the biggest, most powerful engine
ever built on Earth.
NARRATOR: NASA concludes
that the old rocket booster jettisoned en route to the moon
somehow found its way back into Earth's orbit.
They just float away, but you don't worry about it.
NARRATOR: NASA closes the case.
But for some, the theory seems too convenient.
The fact is, we don't know what this thing is.
To this day, it remains a mystery.
NARRATOR: Coming up next.
Did joyriding aliens tear up the red planet?
Looks like someone did wheelies on Mars.
NARRATOR: An unmanned probe
beams back some of the very first images of Mars...
We had to be there. We had to go there.
NARRATOR: But unexpected tracks raise fears
that we may not be the first explorers.
Could they be animals or vehicles perhaps
or some other phenomenon?
Friedman: It wouldn't surprise me at all
if there were tracks from previous visitors on Mars.
NARRATOR: November 1971...
after its 5 and a half month voyage to Mars,
unmanned probe Mariner 9 is heading straight into a storm.
There were no surface features. It was just blank.
[ thunder crashes ]
NARRATOR: The planet-wide dust storm rages for two months
before Mariner 9 begins beaming back images
of the martian surface to Earth.
Schultz: As the dust cleared,
it was kind of like this big reveal.
Here was this planet emerging from below
with complexities and features that we just had hints at.
NARRATOR: Among the first crystal-clear images
of giant volcanoes and sprawling canyons,
the probe picks up something else.
[ indistinct conversations ]
Dr. Treiman: Many of the images showed dark tracks,
many, many tracks... parallel,
some of them with loops and wiggles in them.
And there was a question... what are these tracks?
These tracks are very bizarre
because they go up and over relief,
depending on where you are.
They're strange, but they're actually big.
Maybe you think it's an animal or a vehicle.
Is that what caused the tracks?
Schultz: It just doesn't look right.
It looks like someone did wheelies on Mars.
NARRATOR: Viking 1 is still five years away
from touching down on the martian surface.
Whatever left these mysterious tracks
didn't come from Earth.
Martian tracks are another area that we need to investigate,
but it's not easy to do.
You got to be up close and personal,
so to speak, with them to find out more about them.
NARRATOR: Searching for explanations,
geologists look at other features of Mars' surface,
but the weird tracks' appearance generates the most buzz.
One of the important clues to the origin of the tracks
was that they just start and stop.
Some of them just start out of nowhere.
Others end in a circle or a curlicue.
NARRATOR: The circular ending to some of the tracks
suggests something extraordinary.
One possibility for these tracks is dust devils.
NARRATOR: Dust devils are small, swirling columns
formed by rising hot air.
On Earth, they can form in desert landscapes.
Orbiters take pictures of the areas where the tracks form,
searching for similar phenomena on the martian surface.
The images that come back
send shockwaves through the scientific community...
impossibly high dust devils.
Schultz: Some of these dust devils
got up to altitudes of, say, three miles.
They're enormous.
Some of them get as high as mount Everest,
and so they develop this instability
and they just keep on moving.
Dr. Treiman: There are actually movies taken
by the Mars exploration rovers
of dust devils going by,
and you can see in successive frames
the column of dust moving across the field of view.
NARRATOR: For now, scientists acknowledge
that the dust-devil explanation remains just a theory.
Schultz: Well, we have good hypotheses,
good theories on how these features are formed,
but a lot of this
is based on what we understand for the Earth.
But we don't know for sure.
We've only been to couple of places,
so Mars is just one mysterious place after another.
NARRATOR: In the quest to unravel the mysteries of the universe
the only tools we can trust are the laws of physics.
But when a scientist gazes into the abyss of deep space...
Taking risks is part of making discovery.
NARRATOR: He detects thousands of objects
traveling at impossible speeds.
Something out there is defying
the fundamental laws of the universe.
December 1995...
[ beep ]
...The Hubble telescope.
Professor Bob Williams points
the most expensive telescope ever made
at a completely empty patch of sky
just to see what's out there.
There were no bright stars.
There were no known radio sources, x-ray sources,
and just tried to pick out a random area of the sky
that we knew nothing about.
NARRATOR: The first Hubble images
were completely ordinary.
They appeared to show galaxies.
Williams: It wasn't until we added them all up
that it was apparent
that there were 2,500 galaxies,
most of them really faint.
NARRATOR: And those galaxies were moving very fast.
They seem to going away from us faster than the speed of light.
NARRATOR: But nothing travels faster than light.
You just can't send physical objects or even information
faster than the speed of light.
The speed of light is the ultimate speed limit.
NARRATOR: Everything in nature is based on this simple fact.
If something violates this constant speed...
...The laws of physics break down.
Something was somehow violating
one of the universe's most fundamental laws.
Capps: You have to be open to the possibility
that the theories we know, physics,
we might be missing something.
Was Einstein right, or is he maybe slightly wrong?
Or is there some way to beat Einstein by warping space?
NARRATOR: What if the objects Bob Williams saw
weren't galaxies at all?
What if they were artifacts
hurtling through interstellar space?
If a craft could distort space using a warp drive,
it could traverse the cosmos in hours
rather than billions of years.
It would shrink the space in front of the spacecraft
and dilate it behind,
so it would look like
the spacecraft would ride a wave towards the destination star
faster than light.
NARRATOR: The signature of such a warp drive
could look very similar to the light given off by a galaxy
that appears to be moving faster than the speed of light,
but warp technology
is well beyond humanity's current capabilities.
Shostak: There have been probably plenty of other civilizations
who've already figured that out,
and there could be, you know, all sorts of,
I don't know, interstellar commerce going on
with civilizations who know about this.
NARRATOR: But the idea of warp drives
is too incredible to Bob Williams.
Williams: One could say about the faint objects,
"what you actually see there
are witches riding around on broomsticks."
I can't disprove that.
So, fine.
You choose not to believe that they're galaxies?
Great. What is your evidence?
NARRATOR: If these really are galaxies,
the explanation for their extraordinary speed
could be even weirder than a warp drive.
Space is bendy.
Einstein showed with general relativity
that space has a fabric...
it will stretch, it will warp,
it will deform, it will compress.
NARRATOR: According to Einstein's theory,
anything observed from a moving object
appears to be traveling faster than it actually is...
Like when the train you're on pulls out of a station
and the platform seems to be moving
instead of the train.
On top of that, space-time itself is expanding.
So, as the trains speed away from one another,
the very track they are on is stretching between them.
The points will move away
without having to really travel anywhere.
So, it would look like
the distance is increasing at a very high rate.
And there is absolutely no limit
on how fast you can stretch space-time.
NARRATOR: If this is true,
then these galaxies only appear to defy the laws of physics
because the space between them is expanding.
But that only partially explains
the incredible speed of some of these galaxies.
We're constantly studying things that make no sense,
that don't fit any of the rules we have,
don't fit any of the theories,
and then we come up with new theories.
NARRATOR: Coming up...
Stalking the shuttle...
Normally, an object wouldn't change direction
unless it was under intelligent control.
NARRATOR: ...and a radical new theory
that is truly out of this world.
The universe could be full of the seeds of life.
NARRATOR: In Earth orbit,
Space Shuttle Discovery's onboard cameras
capture something extraordinary.
They'd never seen anything like this before.
Friedman: Debris behaving in a peculiar way like this
doesn't make any sense.
It can't be natural. It must be artificial.
NARRATOR: Two and a half years
after the Columbia shuttle disintegrates on re-entry,
NASA sends Space Shuttle Discovery into orbit.
The plan is to dock with the international space station
and resupply the two people on board,
but the mission's prime focus is safety.
One of the things that we're gonna break out right away
is gonna be the cameras.
NARRATOR: Within minutes, NASA finds unnerving evidence
of damage to the shuttle's thermal shielding.
For Discovery's seven crew, this is a nightmare scenario.
NASA's experts realize
that a small section of the heat shield
became deformed during launch.
If something isn't done,
it could catastrophically endanger the shuttle's re-entry.
Man: Go for the depressurization of the air lock.
Robinson: Copy that, Houston.
NARRATOR: For the first time ever,
astronauts attempt to repair the underbelly of the shuttle.
With his feet clamped to the space station's grapple arm,
mission specialist Steve Robinson risks his life
to ensure that his crew will get home safely.
Veteran astronaut Leroy Chiao
knows exactly how the spacewalker feels.
You're kind of in this battle mode, if you will.
You have a very heightened sense of awareness.
If you somehow become disconnected from the station,
well, you're just gonna float away,
and it's pretty much over for you.
Here we go.
The stakes have never been higher,
but Steve Robinson keeps his cool.
Discovery, Houston. Everyone is extremely happy.
You're go to wrap it up,
and we'll prep for the next step.
Okay. Will do that.
NARRATOR: Robinson's repair appears to be a success,
but as the shuttle prepares for re-entry,
one of its cameras capture
a strange object sweeping the area,
and the world begins to wonder if the astronauts are safe.
Dr. Birnes: What they saw
has been described as "the boomerang"...
an object heading in one direction
and changing direction and heading away.
NARRATOR: The boomerang's course change looks so deliberate
some observers speculate the shuttle is being stalked.
Pope: What's going on here?
Normally, an object wouldn't change direction
unless it was under intelligent control.
NARRATOR: Although NASA hasn't released
a separate scientific investigation concludes
the boomerang is space debris
whose trajectory is influenced by drag from Earth's atmosphere.
But not everyone agrees.
Debris behaving in a peculiar way like this
doesn't make any sense.
And yet, when you stop to think about it,
if this is an intelligently controlled vehicle,
that's a very big story indeed.
NARRATOR: Such a big story that the boomerang footage
becomes a social-media phenomenon.
Over 100,000 people
watch its disturbing switchback through space.
If the boomerang ever comes back,
the world will be waiting.
Pop culture depicts E.T. with a spaceship,
but some scientists believe
we should be looking closer to home for alien life.
Life here began out there.
NARRATOR: Are we the aliens?
NARRATOR: We have always looked to the skies to find aliens,
searching the cosmos for the telltale signs of life,
but now a radical new idea
is infecting the scientific community.
Our original conception of life is
that it must have started here on Earth,
but we don't know that that's the case.
NARRATOR: What if we're not Earth life at all?
What if we're invaders from another world?
What if we are the aliens?
Earth 3.8 billion years ago,
a raging, molten inferno
under constant meteorite bombardment.
No place for life.
But what if this rain of rock and fire
also brought life to our world?
What if a rock from an alien world
arrived carrying alien cargo...
...us.
A theory known as "panspermia."
panspermia is the notion that life here began out there...
...that a planet with an active ecosystem can have an impact...
...and that impact
can knock material with biology aboard into space.
Some forms of life are sufficiently robust
that they can actually survive that impact...
...and then, if you like, pollute that planet.
NARRATOR: Maybe we are aliens from outer space.
Sounds crazy. Sounds like science fiction.
Except we have seen there's meteorites
that have landed on Earth that contain amino acids...
the building blocks of life.
NARRATOR: If life did spring from an extraterrestrial rock,
where did that rock come from
scientists may not have to look far
to find a place that could have spawned life
when the Earth was young.
In 2003, the Hubble telescope took a closer look
at the largest object in the asteroid belt...
...Ceres,
a mini planet among the rocks and debris.
Dr. Reid: Ceres is the largest asteroid.
Hubble's been studying it for a number of years,
trying to understand its composition,
trying to understand what the solar system was like
during its earliest years.
NARRATOR: But Ceres is more
than just a lump of asteroidal rock.
What's really exciting about Ceres
is that it's spherical
and the fact that it seems to be coated in ice.
NARRATOR: But the data also reveals
that Ceres is warmer than expected.
Garvie: The surface temperature on Ceres is actua
it's only around minus-30 centigrade,
and that's at a temperature
where we could actually get an environment
that could be conducive to some life-forms.
NARRATOR: So while Earth was still burning
3.8 billion years ago,
Ceres could have been a safe haven for life.
That doesn't explain how life arrived on Earth,
but a giant white spot on Ceres' surface offers a clue.
The spot is as large as Indiana.
Astronomers suspect that it's actually a giant chunk of Ceres
which has been ripped away...
...the result of a cataclysmic impact
4 billion years ago.
What if a chunk of Ceres
was ripped from the asteroid's surface
and hurled towards the Earth,
infesting it with alien life?
What if it embedded itself deep into the bedrock...
...colonizing our virgin world?
NASA takes the idea of life surviving in space
very seriously.
In 1984, the agency launched 12.5 million seeds into orbit.
The seeds spent six years in space
on board the long duration exposure facility
before they were brought back to Earth.
They brought them back down
and distributed them all over the United States
to plant and see if they grew.
And sure they did.
NARRATOR: If a terrestrial seed
can survive a voyage through space,
so could the seeds of life billions of years ago.
Dr. McKay: We don't really know where life started or how.
The universe could be full of the seeds of life,
and a planet like Earth gets those seeds from outside.
NARRATOR: NASA's search for life
has taken us to far-flung worlds with alien environments,
revealed mysterious phenomena that defy our physical laws,
and tested astronauts with unimagined danger.
NASA's files reveal strange new horizons,
weird encounters, and mind-blowing forces.
Still, many of these anomalies remain unexplained.
NASAs.Unexplained.Files.S01E04.Black.Knight.Rises.1080p.WEB.x264-CRiMSON English HI/SDH CC Converted SRT Subtitles - UF (v1.04)