NARRATOR: NASA's mission is to explore the unknown.
Kavelaars: 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.
Man: 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 craft and symbols in space,
aliens that live for millions of years,
death rays capable of destroying worlds.
NASA's missions have uncovered disturbing anomalies...
Man: Okay, we're seeing three or four objects.
Jett: There are... there are three objects.
NARRATOR: ...that continue to perplex
our finest scientific minds.
These are "NASA's Unexplained Files".
NASAs.Unexplained.Files.S01E03.Alien.Death.Ray.1080p.WEB.x264-CRiMSON English HI/SDH CC Converted SRT Subtitles - UF (v1.03) ... Captions by VITAC ... www.vitac.com
Three objects float in a triangular formation.
Doesn't look like anything I've ever seen
on the outside of the shuttle.
That's for sure.
NASA says it's space junk.
Why are they filming if it's just space junk?
Oberg: You don't start by eliminating the obvious.
You start by opening your mind to all the possibilities.
NARRATOR: But these unidentified objects
could threaten an entire shuttle mission.
Okay, we're seeing three or four objects.
Yeah, there are... there are three objects.
Man: Okay, copy. The next is to mate p5 to j5.
NARRATOR: September 20, 2006.
Space Shuttle Atlantis prepares to come home.
Its crew has spent the last 12 days
assembling the International Space Station.
Then something happens that no one expects.
Man: Okay. Um...
Houston. Atlantis.
Go ahead.
The day before the shuttle returns back to Earth,
the commander reports kind of sighting something
that he's not seen before.
Jett: There's some kind of reflective structure.
NARRATOR: Mission control asks commander Brent Jett
to describe what he sees.
Jett: A structure that's definitely not rigid or...
It's not a, you know, solid, metal structure.
Doesn't look like anything I've ever seen
on the outside of the shuttle.
That's for sure.
Mission control take remote control
of the payload bay camera.
That's when things start to really get interesting.
Okay, we're seeing three or four objects.
Jett: Yeah, there are... there are three objects.
Strangely enough, at that point, you have multiple objects...
three, you know, two more that join in,
essentially form some sort of triangular formation.
NARRATOR: For 20 minutes,
Atlantis tracks the flashing lights across the sky,
beaming images back to mission control.
Man: They're going over the video
that you guys sent down.
The video is looked at right away.
And engineers jump on it right away.
"find out what it is."
NARRATOR: When news of the sightings
reaches the media,
it causes a sensation.
Woman: Everyone's buzzing
about these three objects that were seen.
[ beeping ]
[ keyboard clacking ]
We are awash with stories about unexplained craft.
But when you get these from astronauts,
you pay a little bit more attention.
In the lore of what are termed unidentified flying objects,
one of the most iconic shapes in all of that is the triangle,
so this fits the bill.
NARRATOR: Based on the way the objects are moving,
NASA assumes this is space debris
reflecting the sunlight.
You are flying through a vacuum,
so things that are out in space
will generally tend to hang out together.
Having three objects, you always have a triangle.
NARRATOR: But not everyone agrees
with the official explanation.
NASA's explanation of space junk, to me,
is just, you know, just ridiculous.
They should be able to recognize what space junks are.
These guys are astronauts, okay?
They're trained for this.
NARRATOR: But NASA really does suspect
they're tracking space junk, and they're worried.
Because three years earlier,
shuttle debris brought down the shuttle Columbia.
Following what occurred on STS-107,
when we lost Columbia,
NASA is very interested
in tracking virtually every piece of debris.
NARRATOR: NASA fears the Atlantis is seeing
a critical piece of its hardware that's broken off.
Oberg: In mission control,
we really want to get pictures like this
of anything floating nearby any shuttle,
especially if it appears to have come off the shuttle.
This kind of warning that was missed in 2003
are the warnings you want to get every time.
And you want to find them out, you want to see them,
you want to report them, and you want to react to them.
NARRATOR: Unsure what these unidentified objects are,
NASA doesn't take any chances.
Man: They decided that based on this object that we saw
that we're gonna wave off tomorrow.
So our next deorbit opportunity is gonna be on flight day 13.
Woman: Atlantis, we copy.
NARRATOR: NASA delays the landing
so they can check that Atlantis has not been compromised.
Woman: This is mission control Houston.
I'm doing the survey to confirm
the integrity of Atlantis' heat shield.
In this case, it looks like
it's more likely to be an incidental object
broken free accidentally from the shuttle.
And I believe that's, in the end, the NASA decision.
NARRATOR: One day after first sighting
the mysterious flashing lights,
STS-115 is finally cleared to land.
Man: 15,400 miles an hour.
Off 2 to 25 feet.
NARRATOR: When they later examine Atlantis,
NASA confirms that it was hit by a micro-meteorite.
Man: Touchdown.
Man: Welcome back.
Congratulations on return to assembly.
NARRATOR: No one knows if this was related
to the triangular formation spotted by the crew.
But NASA's caution brings the shuttle safely home.
Man: Atlantis was a terrific ship.
It was really critical that she perform well, and she did.
NARRATOR: Triangles are not
the only strange symbols found in space.
A stunning observation shocks
astronomers searching for rogue asteroids.
What is this thing?
NARRATOR: A force of nature or an alien symbol...
It doesn't look like something that was made naturally.
NARRATOR: ...marking a point in space.
Wow, look at that.
It's like someone had put an x in the sky and said,
"Look here.
Something interesting is going on."
NARRATOR: Kitt Peak Observatory, Arizona.
Astronomer Jim Scotti hears reports
of an unusual-looking comet streaking through space.
He decides to take a look.
Scotti: I set up with my 1.8-meter telescope
and take some images.
And, in fact, it does have sort of a weird look.
NARRATOR: The object is unlike any comet he's ever seen.
It's got a long, narrow tail
and a little funny business going on
around the head of the comet.
It's really hard to tell exactly what's going on,
but something is interesting there.
NARRATOR: The fuzzy image appears to have a probe-like arm
reaching out from the main structure.
News of the bizarre object
hurdling through our solar system
prompts NASA to take a closer look
using the most powerful tool in its arsenal,
the Hubble Space Telescope.
Images from its giant 8-foot mirror
are sent directly to NASA scientists.
What they see is completely unexpected.
When you first see it, you think,
"well, that can't be normal.
That can't be natural."
we all step back from the screen.
And in every image, it's there.
It's in the shape of an X.
It's an X in the sky.
Little X going on.
Very peculiar.
NARRATOR: The X shape
isn't commonly found in astronomy.
Why does it look like an X?
It doesn't look like something that was made naturally.
NARRATOR: The object is traveling at 11,000 miles per hour.
is it some kind of construction? Is it some kind of spacecraft?
NARRATOR: The giant X is more than 1,500 miles across.
No machine remotely like it is manufactured on Earth.
But it also doesn't resemble any known natural phenomenon.
Astronomer J.J. Kavelaars puzzles over the evidence,
concluding that the intersecting structure
is a result of a freak event
perhaps a collision between two asteroids.
When you do the simulations...
...You see that, in fact, it would have resulted
in such a structure being formed.
NARRATOR: But this remains only a theory.
Kavelaars: There's more that we don't know than we do know.
That's just the nature of the universe.
NARRATOR: We may never know
if the glowing X moving through space
at 15 times the speed of sound
is a sign of extraterrestrial life.
Some scientists believe
we should be looking for something slower-moving.
McKay: To them, a million years
might be the natural reproductive time scape.
NARRATOR: While others hope that they don't find us first.
NARRATOR: Alien creatures, millions of years old...
[ creature growls ]
...existing in slow motion
on a stinking, hellish planet.
McKay: Their life form would be so different than ours
that we can't imagine it, nor could they imagine us.
NARRATOR: Such alien life could exist
in our own cosmic backyard.
After tearing through space for seven years,
the Cassini orbiter finally arrives at saturn in 2004.
It carries a precious payload
the Huygens probe.
Its mission...
to land on the ring planet's most mysterious moon, Titan.
Permanently shrouded with clouds,
we've never seen the moon's surface until now.
As Huygens plummets through Titan's atmosphere,
mission control sees
a completely unexpected landscape.
Titan has mountains...
Rivers...
Even lakes.
They had no idea that when we arrived at Titan
we would find all these surface forms
just like what we have on Earth.
NARRATOR: To some, Titan looks like
prehistoric Earth before it had life.
d'Antonio: Titan represents a snapshot
of what we might have looked like
in our early evolution.
NARRATOR: It may appear earthlike,
but our rivers and lakes are full of water.
Titan's contain freezing-cold liquefied methane.
And on Earth, one source of methane
is the foul gas from animal waste,
a product of life.
Here on Earth, we know that methane is created
predominantly by life forms.
So, if you look at Titan and you see this methane,
well, your first thought might be,
"Gee, maybe there's life on Titan."
could there be life living in that liquid,
using that liquid the way life on Earth uses water?
Pope: If you can have life in water,
why not life in methane?
It's all life.
It's just life, but not as we know it.
NARRATOR: But with an average temperature
of -289 degrees Fahrenheit,
Titan is beyond frozen.
No Earth organism could survive here.
McKay: I think it'd be a big mistake
is gonna look anything like life on Earth.
Living in water is very, very different
than living in liquid methane.
NARRATOR: Titan is so cold
that the metabolism of any life forms living in the methane
would be incredibly slow.
McKay: On Titan, temperatures are so low
that the pace of life would be so slow that to them,
a million years might be
the natural reproductive time scape.
Think of them as being like a big, giant, flat sheet of paper,
maximizing their surface area
because they're living at very low temperatures.
Temperatures are low, things go slow.
If we find life on Titan, we have certainly found
something that is different from us
and that fundamentally expands
the possibilities for life in the universe.
NARRATOR: The vastness of the cosmos
who've evolved over billions of years.
Such ancient civilizations
would almost certainly be technologically superior to us,
and their weapons could pose a threat
to the very fabric of the universe.
An orbiting satellite detects a death ray.
Where the heck did that come from?
NARRATOR: Massive X-ray pulses rip through the cosmos.
Could those X-rays emanating from Cygnus be a weapon?
NARRATOR: The power behind the X-ray beam
is the most destructive force in the universe.
Maybe it was advanced civilizations
engaging in interstellar warfare.
[ machine beeping ]
NARRATOR: As the beam hits our solar system,
NASA springs into action.
NARRATOR: In December 1970,
small astronomy satellite uhuru launches into space
on a quest to seek out X-rays.
X-rays are extremely energetic electromagnetic waves.
So, basically like light on steroids.
We don't detect X-rays on Earth
because the atmosphere protects us,
which is bad for X-ray astronomers.
It's very good for humans in general
'cause X-rays are bad for you.
NARRATOR: In tiny doses,
we use X-rays for medical purposes,
allowing us to see through flesh to diagnose illness.
Higher-energy X-rays can be focused
to kill cancer cells.
But above Earth, uhuru detects a source of X-rays
billions of times more powerful
than the energy needed to kill all life on this planet.
To find this source of X-rays
it's not coming from the sun or any nearby things,
but from some place in space
hundreds, maybe thousands of light-years away.
NARRATOR: The death ray is coming
from the constellation of Cygnus.
Scientists label the source of the X-rays Cygnus X-1,
but no one can see it.
What the heck is that? That can't be just another star.
They don't make enough X-rays for us to see
from 1,000 light-years away.
In terms of Cygnus X-1,
we just didn't understand exactly what it was.
What was producing those X-rays? It wasn't stars.
Could it be some sort of,
I don't know, extraterrestrial activity?
Could it be interstellar warfare using advanced weapons?
[ machine beeping ]
NARRATOR: It may sound like science fiction,
but X-ray weapons exist.
That was part of Ronald Reagan's Star Wars program.
...to defend ourselves from nuclear attack.
One of its elements
was to use micro atomic bombs in just the right way
so that their explosion powered a laser made of X-rays.
Part of our weapons research focuses on lasers.
Using very powerful X-rays to destroy guided missiles.
Now, think about an older civilization than ours
that's been around for millions of years with lasers
and what they could do with it.
I hope they'll be wise enough to be careful
and to only use it when it's really, really needed.
NARRATOR: But if Cygnus X-1 is a weapon,
it's part of a very destructive war.
The energy it's producing is powerful enough
to destroy any civilization attempting to harness it.
Once you fire it, man, you just got to leave fast.
NARRATOR: But the Cygnus X-1 force
is more likely to be natural.
In 2009, scientists using high-powered radio telescopes
received a clue about what that force could be.
It was dark. It wasn't emitting any light.
And yet, there was all this X-ray radiation coming from it.
This was not interstellar warfare.
This was the result of a... Black hole.
NARRATOR: This is the most powerful force in the cosmos,
a collapsed dead star consuming everything around it.
Brin: All of that mass gathered in there
is pulling spacetime into a funnel
so that it's so intense that light that tries to escape,
it never makes it.
NARRATOR: The black hole's gravity is so powerful
that it's tearing a neighboring star apart.
As the star is consumed,
its super-heated matter produces X-rays,
and this creates the X-ray pulse of Cygnus X-1.
Slowly, the material that makes up that star
is being sucked into the black hole.
NARRATOR: Before it finally succumbs
to the black hole's awesome power.
Capps: I love the explanation that Cygnus X-1
is cool, alien X-ray weaponry, but, come on.
It's a black hole, if not, and black holes are cool enough.
I mean, there's one at the center of our galaxy
keeping us spinning, right?
It's just amazing.
NARRATOR: The weird signals of Cygnus X-1
are not evidence of apocalyptic alien technology
thousands of light-years from Earth.
But one astronaut has filmed
something disturbing much closer to home,
something lurking in the northern lights.
Man: This object looks just like
the starship Enterprise from "Star Trek".
NARRATOR: Is this first contact?
NARRATOR: Something has invaded Earth's atmosphere.
This image looks like a craft.
This object looks just like
the starship Enterprise from "Star Trek".
NARRATOR: It's hovering in the Aurora Borealis,
A.K.A. The northern lights.
Capps: I'm thinking this is someone watching us.
This is the first step towards intelligent life and contact.
NARRATOR: Is this really first contact
or is it all in the eye of the beholder?
In 2006, the 13th crew arrives
at the International Space Station.
Over the next six months,
they orbit Earth almost 3,000 times.
NASA astronaut and keen photographer Jeff Williams
documents everything...
From life inside the station
to the deserts, volcanoes, weather systems on Earth...
And the captivating light show at the top of the world.
What is the most beautiful thing that we get to see from space?
The Aurora.
Anytime we're by the Aurora, nobody's working.
Everybody's at the window.
NARRATOR: But when Jeff Williams photographs the Aurora,
he captures more than its inner light.
He snaps something straight out of science fiction.
Capps: It looks just like a spacecraft parked in our Aurora.
Game changer.
NARRATOR: A starship wouldn't accidentally hover
in the sky above the northern lights.
The Aurora Borealis is an electromagnetic phenomenon.
Birnes: Is it feasible... and I believe it is...
that this craft can be actually refueling wirelessly
from being inside the Aurora Borealis?
And if so, does that mean
that there are energy sources all around us?
Maybe we can't use them, but extraterrestrials can.
NARRATOR: Any anomaly in the Earth's magnetic field
could be dangerous if it affected its stability...
...because the aurorae are more than a pretty light show.
They're patterns of force caused by the Earth's magnetic field.
They protect the planet from charged particles
sent hurdling through space by solar explosions.
Raftery: If the Earth's magnetic field failed,
we on the surface of the planet would be exposed
to whatever radiation was coming from the sun.
Brin: If it weren't for our own
magnetic field around our planet,
diverting all these charged particles
down to the poles where they make beautiful aurorae,
well, we'd be in trouble here on the Earth's surface.
NARRATOR: Solar physicists don't believe
this is an alien vessel assigned to Earth.
It's not a starship. [ laughs ]
I'm afraid that's the least likely explanation.
Perhaps it was a cosmic ray hit
that did some damage to the detector in the camera.
Capps: It seems like all the best stuff
is explained away with cosmic rays.
One little thing we saw just for a moment,
what could it be?
Cosmic rays is a little to easy of an explanation for that.
NARRATOR: No one knows
if a starship really hovered over the Aurora,
but it was gone in the wink of an eye.
Perhaps it had fulfilled its mission and returned home.
You know, I grew up on science fiction, not science.
So my first thought
when I see a little dark spot in the picture,
I'm thinking, "maybe this is someone watching."
and then the scientist in me takes over,
and I start looking for explanations.
But every now and then,
there aren't any good explanations,
and that's where the exciting mythology is.
NARRATOR: The explorers of past centuries
would often return from their voyages
with fantastic tales of fabulous creatures.
Hundreds of years later, space explorers continue
to see things that defy explanation.
I got no answers.
NARRATOR: A secret shuttle mission,
at a critical moment, is interrupted.
All of a sudden...
It wasn't there, and now it's there.
NARRATOR: Slithering through space,
a weird entity.
It's moving like a snake.
NARRATOR: Are there creatures living above our atmosphere?
The tail is there, right there.
NARRATOR: 230 miles above Earth...
And you're go to maneuver to...
NARRATOR: ...Space Shuttle Atlantis
operates covertly in the void.
Astronaut Story Musgrave deploys a secret defense satellite.
It was an infrared satellite, very powerful infrared camera,
which is able to detect rocket launches.
NARRATOR: After he releases
the multi-million-dollar spy satellite...
Man: Does the data look okay?
NARRATOR: ..Story makes one last visual check.
I'm looking straight out over the tail.
But all of a sudden, boom.
There's an object that came from nowhere.
It wasn't there, and now it's there.
It's a snake-like object, 6 feet, 7 feet,
and I'm wondering what it is.
NARRATOR: Story watches
as the entity slithers through space.
Musgrave: There's internal motion in it,
and it continues
to move further out right in that direction.
The tail is there, right there.
NARRATOR: The strange, wriggling object
alarms NASA, as well.
Jim Oberg examines the video footage,
looking for the most rational explanation.
Oberg: We know that there are plenty of things
that break loose of the shuttle that look like that.
There are strips of insulation between the tiles.
There are strap-downs on the payload.
And, of course,
their main mechanisms for deploying these payloads
have things designed to be thrown overboard.
NARRATOR: Every nut and bolt on the shuttle
is carefully logged before takeoff.
So NASA believes identifying the missing piece
will solve the mystery.
Man: Main gear touchdown.
NARRATOR: But when Story later checks in
with the shuttle mechanics back on the ground,
the mystery deepens.
The vehicle was normal when it came home.
There was nothing missing
that should not have been missing.
I got no answers.
NARRATOR: If this is not a manmade artifact,
that leaves open other options.
Story Musgrave doesn't rule out life in space.
Space itself is not hostile.
That's the human perspective on it.
It's only hostile to the human condition.
Life is powerful.
It arises, and it happens,
and it lives in all the environments.
And I think life is everywhere out there.
NARRATOR: Recent discoveries
of life in Earth's most hostile environments
support Story's enthusiasm.
Friedman: When you boil it down,
we have found life in all kinds of unexpected places...
life in rocks, life at high temperature,
life at high pressure.
Everybody said, "impossible!"
but it was found.
So, I don't think you can rule it out.
Man #1: Lift-off.
Man #2: 8.1 Bravo.
NARRATOR: In 2007,
a handful of tiny insect-like creatures called tardigrades
were sent into orbit.
After 10 days exposed to the vacuum,
the tiny astronauts are still alive and healthy.
The bugs' endurance is impressive.
But NASA astrobiologist Chris McKay doesn't believe
anything could permanently live in space.
We can wonder if life could live in space...
not on a planet, but just floating in space.
There's certainly enough energy coming from the sun.
The hard thing for me to imagine
is how that life could get material.
How does it get fresh nutrients
and where does it send its waste?
Who knows?
NARRATOR: The eerie, snake-like object
is unlike anything else ever recorded.
And to date,
NASA has no official explanation.
But for Story Musgrave, his encounter with the space eel
highlights just how little we really know about the cosmos.
Musgrave: To what extent
do we understand everything out in space?
We don't understand anything.
She's not gonna undress for us.
NARRATOR: Even on Earth's nearest neighbor,
we find things we don't understand.
We even give them names to disguise our fear.
[ alarm blaring ] coming up...
NASA's mysterious moon pigeons.
Everything starts going wrong when these moon pigeons appear.
NARRATOR: Apollo 10's lunar module
is seconds from catastrophe.
Birnes: Apollo 10, the last mission before the landing,
came this close to absolute disaster.
NARRATOR: What if something tampered with NASA's ship?
Birnes: Everything starts going wrong...
[ alarm blaring ]
...when these moon pigeons appear.
NARRATOR: May 1969.
Apollo 10's eight-day mission to the moon
captivates an entire planet.
Orwoll: Apollo 10 is going to be
for the landing that's going to be occurring on Apollo 11.
But they're not going to actually land.
They're only gonna go down
within about eight miles of the surface.
NARRATOR: After separating from the mothership,
the lunar module orbits
eight miles above the moon's surface,
precisely mapping a landing area for the next Apollo mission.
As they're approaching the lunar surface,
one of the things that they have to do is get a lock.
Because without knowing your exact altitude,
you could run into problems.
[ alarm blares ]
NARRATOR: But the command module's transponder fails,
leaving the mission in jeopardy
and the lunar module hanging helplessly in space.
Without a lock, it won't be able to dock
back with the command module.
[ alarm blaring ]
Orwoll: They try manual override. That doesn't work.
And they repeatedly try, and it is not operating.
So, finally, they're essentially on their last chance.
Men at the consoles in mission control
and the folks in the back room are now frantically trying
to figure out what they might be able to do.
NARRATOR: Lunar module pilot Eugene Cernan
catches the unfolding drama on camera.
As his craft drifts above the command module,
Cernan's camera captures something below him...
what looks like another spacecraft.
NASA has a code for something like these.
They call them moon pigeons.
This is part of the imagery that led NASA
to commission this study of what they call moon pigeons,
things seen out the window.
Friedman: Seems weird that NASA calls these things moon pigeons.
That's a weird title.
We know there aren't pigeons flying out in deep space.
NARRATOR: As quickly as the moon pigeon appeared,
it disappears.
And within moments,
the situation on board the lunar module improves.
Orwoll: They flip the toggle switch one last time
and the radar system starts operating.
They start getting the data.
They confirm this with mission control,
and they get the authorization
to make the approach to the lunar surface.
NARRATOR: The mission finishes without any additional drama.
But when Cernan's film reaches the public,
some see the moon pigeon's sudden appearance
as more than coincidence.
I believe we're being warned off.
"stay away, and don't come back."
NARRATOR: Some speculate that an advanced intelligence
could be jamming Apollo's systems.
Others believe friendly aliens
are somehow fixing the transponder.
I think the extraterrestrials
would be quite concerned about us.
Rule number one for any advanced civilization
is keep tabs on the primitives in the neighborhood.
NARRATOR: The motives of this moon pigeon
are difficult to fathom,
but NASA doesn't believe
that aliens interfered with Apollo 10 at all.
They say this moon pigeon is space debris.
Here again, we have NASA falling back
on its old support for "nothing strange"...
space debris.
Birnes: By calling these anomalies moon pigeons,
NASA is trivializing it.
But what they can't trivialize
is that everything starts going wrong
when these moon pigeons appear.
NARRATOR: Six moon pigeons were reported
during just two Apollo missions.
In 1970,
NASA commissioned a report on moon pigeons.
It concluded that they were space debris.
Case closed, according to NASA.
To date, no NASA mission
has found evidence of life on the moon.
But one groundbreaking experiment
may have found evidence of life on Mars.
Pope: This could be
one of the most important discoveries of all time.
NARRATOR: So why don't we know about it?
NARRATOR: Digging for life on a distant planet.
It's still the holy grail.
It's still what everybody wants to find.
NARRATOR: A spectacular discovery is buried.
If it's wrong, tell me it's wrong.
Why the silence?
NARRATOR: For decades,
one man tries to tell the world.
I have spent the last 40 years
fighting for my results and believing in them.
NARRATOR: Will NASA's latest Mars probe
discover E.T. Next door?
Man: One. We have ignition. We have lift-off.
NARRATOR: In 1975, NASA launches Viking 1,
the first human vessel to land on the red planet.
Its mission... find life on Mars.
As Viking drops toward the planet surface,
NASA engineer Dr. Gilbert Levin
monitors from the heart of mission control.
Levin: The moment Viking 1 touched down...
[ cheers and applause ] man: Touchdown.
Fantastic!
...this was excitement beyond belief.
It beat the world series.
NARRATOR: The lander is programmed
to detect Martian life using a radioactive soup.
Its mechanical claw digs into the blood-red soil.
They take a scoop of Martian dirt
and they pour nutrient solution on top of it.
NARRATOR: It's like fishing.
You put bait on a hook and wait for a bite.
All you're doing is feeding suspected microorganisms.
And if they metabolize what you feed them,
the gas they make from it will be radioactive.
That makes it very easy to detect.
NARRATOR: No radioactive gas, no life.
It's that simple.
For 40 long minutes, the sensors flatline.
Levin: All of a sudden, we see there is a response,
a result coming back showing thousands of counts per minute
of radioactive gas coming out of our sample.
That was the proof
that NASA said it would accept before the mission.
This is a NASA-approved experiment on a NASA mission,
and the results are clear.
This is life.
NARRATOR: Viking repeats the experiments.
Each one confirms signs of Martians.
There is life on Mars.
Levin: I immediately sent out
for a bottle of champagne and a big cigar.
NARRATOR: But when NASA calls a press conference,
to Gil's amazement, he is told to downplay his results.
They put me down as the last one to speak,
and they had cautioned me
not to say I had detected life on Mars.
Pope: Why isn't this information being circulated?
This could be one of the most discoveries of all time.
NARRATOR: According to NASA, the reason is simple.
Gil's results contradict two other experiments
run on similar samples also aimed at detecting life.
They look for organic compounds, just molecules
that are typical of life in that dirt,
and they don't find any.
So they say, "Okay, forget it.
Whatever was happening there, it wasn't life."
NARRATOR: Without this evidence,
NASA isn't convinced they found life on Mars.
And they said, "No organics.
There goes the ballgame."
NARRATOR: But now,
after nearly four decades of uncertainty,
new evidence could explain why NASA's other experiments
contradict Gil's results.
It may be that Gil is right, that we're just confused
because the signal is not exactly what we expected,
but it's still biological.
NARRATOR: In 2008, NASA detects vast salt deposits
across the planet's surface.
Once of the surprising results from Mars exploration
was the discovery that the salt on Mars
was not like the salt on Earth.
Think of it as a bizarre form of salt.
NARRATOR: Crucially, when Martian salt is heated,
it destroys any biological molecules.
And the other experiments Viking conducted
all heated the soil samples
in an attempt to release organic compounds.
So even if life exists in the salty soil,
the other experiments destroyed any trace of it.
Additionally, the salt may do more
than mask the presence of life on Mars.
It could also be a key to its existence.
On Earth, we've discovered bugs that eat this salt to live.
McKay: There are microorganisms that can consume that salt.
They can use that salt the way we humans use oxygen.
NARRATOR: Mars could be a salty haven for life, too.
Mars life would not be very alien.
It would have many of the same characteristics
and features of life on Earth.
NARRATOR: Viking's biological detectors
couldn't have found Martian life
because only Gil's tests left the soil unheated,
preserving evidence of any salt-munching microbes.
It may be time to revisit Gil's findings.
If you want to find out what the data really mean,
you've got to go back.
NARRATOR: In August 2012,
NASA's Curiosity rover lands on the red planet.
Its dual mission...
to find evidence of water
and seek out signs of life in the planet's past.
On board, it has a sophisticated lab
which can continue that search for life.
Yeah, I would love to be able to say we found it,
life on Mars, this is it.
Right now, we don't have convincing evidence.
NARRATOR: If Gil Levin is right,
the Martians will be there...
Waiting.
NASA's search for life has taken us
to far-flung worlds with alien environments.
While mysterious encounters closer to home defy logic,
astronauts have risked their lives
to push back the boundaries of knowledge.
NASA's files reveal strange new worlds,
weird phenomena, and cosmic forces.
Yet many of the anomalies remain unexplained.
NASAs.Unexplained.Files.S01E03.Alien.Death.Ray.1080p.WEB.x264-CRiMSON English HI/SDH CC Converted SRT Subtitles - UF (v1.03)