Original subtitles

Human civilization

everything we can know, feel and hope for

is for us here on Earth.

A ball of rock, just 8 thousand miles wide.

But out there, across the vast heavens

there could be countless other civilizations

each with knowledge, history, and ambition vastly different

from our own. And one day, perhaps sooner than think

humanity and alien civilization will collide.

How will that day change us?

Will it be our greatest leap forward?

Or the end of everything we know?

Space, time, life itself.

The secrets of the cosmos lie through the wormhole.

♪ Through the Wormhole 03x01 ♪ Will We Survive First Contact? Original Air Date on March 6, 2012

== sync, corrected by elderman ==

Think of everything you learned in school.

Think of everything that Einstein, Buddha and Shakespeare knew.

The entire experience of humanity

is overwhelming to a single mind.

But if aliens are out there,

all that is nothing

compared with the sum total of knowledge in the galaxy.

The day we make first contact with an alien race

will be the dawn of a new era for humanity.

It could spur a renaissance that will change us utterly.

Or it could be the darkest day in human history.

[ Creature growls ]

Most kids in the '40s and '50s

grew up reading tales of adventure on other worlds.

And most of us imagined we were Earth's first line of defense

against alien invaders.

These days, I would like to think we were wrong,

that extraterrestrials might be friendly.

[ Growls ]

[ Boys scream playfully ]

[ Imitates gunshot ]

But many scientists believe basic forces of biology

make aggressive aliens a safer bet.

Charles Cockell is a Professor of Astrobiology

at the University of Edinburgh, Scotland.

He thinks deeply about alien life

and how evolution might determine their actions

at first contact.

It's not clear that a civilization

just because it can travel through space

would be altruistic.

Humanity, for example,

landed spacecraft on the freezing moon of Titan,

and yet we still go to war.

So it's not the case that technological advancement

necessarily is -- comes hand in hand with altruism,

and it's possible that an alien civilization

could actually be quite dangerous.

Freeman: Charles studies the forces of evolution

that gave us the intelligence necessary

for an advanced civilization,

forces he believes could drive aliens to tear ours apart.

It's a question of autotrophs or heterotrophs,

or in layman's terms...

What's for dinner?

An autotroph is a type of life

that uses light as a source of energy.

For example, the grass here is an autotrophic organism.

It's using sunlight from the sky

to power itself and to grow and reproduce.

Autotrophs generally are not intelligent.

Gathering sunlight is a very good way of gathering energy,

but it never really gathers sufficient energy

for a creature to become intelligent.

Freeman: Autotrophs have another weakness.

They're easy prey for heterotrophs.

Cockell: These sheep behind me,

these are heterotrophs,

but they're feeding off autotrophs.

They're feeding off the grass in this field.

Freeman: Charles believes that the food chain is just as real

of a force for alien life as it is for terrestrials.

The smarter the creature,

the more food it must consume to keep its brain working.

All right. Thanks. Just what I ordered.

You can see the hors d'oeuvre I have here,

and you can get some idea of the amount of grass

I would have to eat a day to power a sheep's brain.

But it's a completely different matter

when you need to power a human brain.

Freeman: If we spent all of our waking hours

eating the pounds of grass

it takes just to power our brain,

we would have little time for the imagination and ambition

that sent us to the Moon.

But nature provides a solution.

It's not pretty, but it is a fact of life.

Cockell: Lamb.

Thank you.

[ Sheep bleats ]

Freeman: Our massive brains

require colossal amounts of energy.

And being a predator is the cleanest, quickest,

and most effective way to acquire the energy necessary

for advanced intelligence,

whether human or alien.

Intelligent creatures,

particularly very intelligent creatures, would be predatory.

They would be at the end of a food chain,

and they would eat other creatures

that would eat other creatures.

So they're bound to be predatory in some way.

Freeman: Charles is confident that at first contact,

we will meet an intelligent race of predators,

predators that most likely developed a war-like culture

just like ours.

Cockell: Conflict in human beings

is definitely linked to predation.

It's all about grasping territory.

It's all about having resources and commanding those resources

in times of a famine or in times of difficulty.

Freeman: Predatory aliens who show up on our doorstep

may well be in need of new resources.

If so, the existence of humanity could be in jeopardy.

If they need oxygen to burn their food,

just as in the same way we need oxygen to burn our food,

they might find the environmental conditions

on this planet very conducive for their civilization.

And oxygen-bearing planets like ours

with high levels of oxygen in the atmosphere

might actually be quite rare in the universe.

And when you find them, they might be good places to go.

Freeman: It is a scenario we usually see in the movies.

Aliens arrive as a conquering armada,

and mankind engages them in a desperate battle for survival.

But one scientist begs to differ.

Let's say that a civilization is hostile.

Hollywood has brainwashed us into thinking

that it's gonna be a Titanic battle

between David and Goliath.

I mean, give me a break.

More than likely, it's gonna be between Bambi and Godzilla.

Freeman: Physicist Michio Kaku of the City College of New York

tries to be more scientific

about mankind's relationship to alien civilizations.

We physicists like to classify alien civilizations

in outer space by energy.

A type-one civilization harnesses planetary power.

They can, for example, control hurricanes,

control volcanoes.

Type two can control an entire star.

They play with stars.

Type three controls the power of an entire galaxy.

On this cosmic scale of energy, what are we?

Do we control hurricanes and volcanoes?

Do we play with stars?

Do we roam across the space lanes of the galaxy?

No. We are type zero.

We don't even rate on the scale.

Freeman: But we may have a chance to survive

in the galactic jungle after all.

Michio believes that we can rise in the ranks of civilization

by learning from our superior neighbors.

And the safest way to acquire their knowledge...

Is eavesdropping.

Even aliens have to obey the laws of physics,

and the laws of physics tell us that electromagnetic radiation

is the fastest, most convenient way

to communicate between stars.

Freeman: The heavens are buzzing with electromagnetic radiation.

Almost all of it occurs naturally.

And around Earth, most is manmade.

But buried in all that static could be some radiation

that aliens are using to send a message.

Finding such an alien signal is really tough,

like looking for a single car

in the swarm of traffic that clogs the streets

of New York City.

We send messages by electromagnetic radiation,

whether it's in the form of e-mail, radio, radar,

microwaves, F.M., or A.M.

Let's say that this car represents a message

that we send into outer space.

Most messages are sent by you and me, by the human family.

However, what I'm looking for is much more rare.

I'm looking for this --

a message sent by an alien civilization

using electromagnetic radiation.

Freeman: For the past 40 years,

armies of large radio telescopes

have tuned into the frequencies of the Universe,

just like turning the radio dial to find a station.

So far, scientists have heard only empty static.

But Michio believes that is because they have been listening

the wrong way.

Kaku: We are only listening

to one frequency at a time

among an infinite number of possible frequencies.

It's like trying to find this alien decal

on a car on a freeway by taking pictures.

[ Camera shutter clicking ]

How long would it take for me

to finally identify that alien decal?

A week? Months? Years?

Maybe even never.

Freeman: Michio believes

that even if we stumble upon an elusive alien message,

we might not even recognize it.

There may still be hope

to discover these rare signals, however,

if we broaden our perspective.

Let's say that I want to send this alien message

across outer space.

And let's say that each car represents a photon

vibrating at a certain frequency.

Well, perhaps the silliest way to send such a message

is to put the entire message on one photon at one frequency.

The message could be lost.

The message could be degraded.

A more efficient way

is to cut up the message into different frequencies,

creating what is called a broadband,

and then you put each fragment of the message on each photon.

Freeman: Using multiple channels to send a message

is faster in the same way

broadband is faster than dial-up.

But if aliens communicate this way,

their signals would be harder to detect.

Now, here's the irony.

If you were to eavesdrop on an alien conversation

and you would pick up all these pieces,

you would just hear gibberish.

So in other words,

we could be in the middle of an intergalactic conversation

and not even know it.

Freeman: If Michio is correct,

the heavens could be filled with alien chatter.

We do not see this radio traffic

because our signal-frequency search

only picks up fragments of their conversations.

But if we were to look at the broadband,

we might find what has been there all along.

If we do learn to detect alien communication,

how can we ever hope to understand it?

What language would they speak?

Now, one scientist believes

he knows how to crack the code of any language,

no matter how alien.

Around the world,

we speak to each other in about 7,000 different languages.

Most of us understand only one or two.

But there is no living language that cannot be translated,

because they all have one thing in common --

the human brain.

What languages might alien brains create?

Could we ever hope to understand them?

Could we even recognize their communication

as language at all?

Doyle: Well, I actually only speak English and Swahili

a little bit.

I've learned a little Navajo,

and I can write a little bit in Cherokee.

Oh, I took Russian, too, for a couple years.

Freeman: Laurance Doyle is a communications expert

with the Institute of the Search

for Extraterrestrial Intelligence, or SETI.

He is working to add one more language to his list,

one no human has ever spoken.

Bottle-nose dolphins are perfect.

We know they're intelligent.

Seriously, Chomp.

Wow, that's interesting.

They communicate in very complex ways.

They make bubbles. They play.

They have complex society.

But we don't have any common reference system.

We can't talk about movies.

We can't talk about the most elementary things.

Freeman: Laurance decided to see

whether he could extract any meaning from dolphin speak.

He and his colleagues recorded and studied

hundreds of hours of dolphin chatter.

[ Dolphins chitter ]

Doyle: Because they have this huge range

over which they can communicate.

[ Dolphins lowing ]

When you look at the relationship of whistles,

a structure starts to emerge

that's not unlike syntax in human languages.

Freeman: But are these whistles and clicks an actual language,

one that could be translated?

Laurance searched for patterns in the sounds

using a statistical technique called information theory,

a theory powerful enough to find a needle of meaning

in a haystack noise.

Information theory is built on the probability

of occurrence of a given signal.

How often does it occur,

and how often does it have a relationship

with other signals in that occurrence?

"Perseus best wishes tiger cow

accepting printing ink hydro lories shovel in..."

So, this is kind of a random distribution of words.

I can add up how frequently each word occurs.

What I am going to get

from this random distribution of words

is that each word occurs with about the same equal frequency.

Freeman: In this page of gibberish,

plotting a chart of words against how often they are used

gives us a straight line.

That means there's virtually no linguistic information

being transmitted.

It is a random distribution,

and you can't actually transmit knowledge this way.

Freeman: A message with meaning and information

shows an entirely different pattern.

"No one would have believed in the last years

"of the 19th century

"that this world was being watched keenly

"and closely by intelligences greater than man's

and yet as mortal as his own."

Freeman: According to Laurance, all languages,

be they human, dolphin, or alien,

must have common and uncommon words.

The most common words are ranked in descending order

from left to right.

Well, the most frequent word here is "the,"

and it'll appear here.

The second-most frequent word is probably "of."

Freeman: When plots this word chart

from a message that is not gibberish,

a pattern emerges.

Doyle: This is a plot of a frequency of occurrence,

and this is the words in "War of the Worlds."

And we see that it has this 45-degree slope.

So this is a way to tell

if there's linguistic or knowledge content

within a random page

even if you don't understand what the symbols mean.

Freeman: This 45-degree slope

appears for any message in any language,

in any medium,

be it a book in French or a phone call in Japanese.

And when Laurance's team applied information theory

to the chatter of dolphins, a 45-degree slope emerged.

[ Dolphins chirp ]

Doyle: This was proof right away,

without understanding what the dolphin signals are,

that dolphins are transmitting knowledge to each other.

Freeman: Laurance has not yet learned to speak dolphin,

but knowing a language when we hear it is the first step.

And he is now applying the same technique

to the electromagnetic buzz that fills the Milky Way.

Doyle: There are all sorts of things in space that make noises.

We could examine each one and find out which one's random

and which has the information we're looking for,

has a sign of intelligence.

Freeman: Even if alien communication

sounds like empty noise to the human ear,

it will still produce a 45-degree slope.

Doyle: We can now actually start to examine

the complexity of the message,

and that's gonna tell us something

about the species that sent it.

And that's why you want to practice

on non-human species on Earth.

Thank you. You were lovely.

I think that was dolphin for "see you later."

[ Chuckles ]

Freeman: But we may not have to wait

to intercept an alien message to make first contact.

Many scientists now suspect an advanced spacecraft

will soon forge a direct link between two worlds.

And that spacecraft could come...

From Earth.

In 1903,

Orville Wright guided the first powered flight

in human history.

He traveled just over 100 feet.

Only 66 years later,

three men flew a quarter of a million miles

and landed on the Moon.

The next quantum leap in travel may be close at hand.

It would take us trillions of miles from Earth,

and we could find aliens before they find us.

And that is thanks in part to this man.

John Brophy works at NASA's Jet Propulsion Laboratory

in Pasadena, California.

His expertise...

Is exotic propulsion.

So, this is an ordinary balloon,

and I'm gonna rub it on my hair,

which will separate some of the charges,

leaving a net charge on the balloon,

which will allow it to stick on my shirt.

Freeman: The same force that holds a balloon to a piece of fabric

can be used in reverse to push a vessel through space.

Brophy: So, as we just illustrated

where we can use oppositely charged particles

to attract each other,

if we use particles with the same charges,

we can actually repel them.

Freeman: This electrical repulsion

is the heart of John's revolutionary machine,

the Ion engine.

Xenon gas is ionized with a positive charge,

then placed against the engine's positively charged body.

Brophy: And those like charges repel each other

and push the ions out at a very high speed.

And by pushing the ions out,

it pushes the spacecraft in the other direction.

Freeman: NASA recently charted John's Ion engine

to send the Dawn spacecraft on a two-billion-mile journey

to the asteroid belt.

The engine stayed lit for more than three years.

This groundbreaking achievement...

was made possible by the same high-performance engineering

found in the unbridled, uncompromising,

unrelenting power of an all-American...

[ Motor whirs ]

...golf cart.

Brophy: We're gonna have a race between these two vehicles.

And it looks like an unfair race, but actually,

we're gonna give each vehicle the same amount of fuel,

and we're gonna see how far and how fast these two vehicles go.

[ Engine revs ]

[ Tires squeal ]

Freeman: Unlike the fuel-guzzling chemical rockets

that took us to the moon,

the Dawn spacecraft

is an extremely fuel-efficient vehicle.

But, like the golf cart,

it's a bit slow off the mark.

Brophy: The Dawn spacecraft,

it accelerates very slowly like we've done.

In fact, it'll go 0 to 60 miles an hour in about four days.

So, not something you'd write home about.

But, after four years,

it'll be going over 26,000 miles an hour

and have used only 60 gallons of fuel.

It is exquisitely fuel-efficient.

Freeman: The old chemical rocket gets going faster,

but it burns out quickly.

An ion-powered spacecraft, however,

can keep on accelerating for years...

[ Motor whirring ]

...and eventually travel faster and farther

than a chemical rocket ever could.

It's completely impractical to use chemical-rocket technology

to travel to the stars,

and that's because you just cannot carry enough propellent

to make that trip.

Freeman: The closest star, Proxima Centauri,

is about 25 trillion miles away.

That is a very long journey.

Brophy: Imagine the sun at the center of this quarter

and Pluto's orbit around the outside edge of the quarter.

Every planet that you learned about in school,

everybody that you know is contained within this quarter.

With our current electric-propulsion technology

or advances that we can readily make,

we can get around this region of space relatively well.

What we really want to do

is see what it takes to get to the nearest star.

The question is, where is that?

And this is the closest star.

Freeman: Astronomers now believe

there are 17 alien solar systems

within 100 trillion miles of Earth.

With some engineering improvements,

future versions of John's Ion engine

could reach any of these new worlds.

But for the foreseeable future,

an ion-powered vessel will not have the power

to take human beings along for the ride.

Brophy: The payloads have to be small

to go to the stars

primarily because you have to accelerate that mass

to a very high speed,

and the lighter weight the vehicle is,

the easier that is to do.

Freeman: One day,

an alien spacecraft will pierce the clouds

of an unexplored world.

And the aliens might be us.

Crossing the vast emptiness of space

is not the only challenge of making first contact.

We must also figure out what we're going to say

when we get there.

How does one communicate across language barriers?

Here on Earth, our faces can express fear, love, or happiness

even better than words sometimes.

But what ideas and emotions could we share with aliens,

and how can we avoid sending the wrong message?

Kakalios: There's a story from U.S. soldiers in Iraq.

They wanted cars to stop at a checkpoint.

They used what they thought was a universal symbol for "stop"

by holding up their out-raised palm.

Unfortunately for the people in Iraq,

this is the symbol also for "welcome," not "stop."

So the cars kept approaching the checkpoint

even though the soldiers

were signaling violently for them to stop.

[ Machine-gun fire ]

Freeman: Jim Kakalios is a physicist

who explores the hard science

behind the dreams of science fiction.

He thinks he has identified

a universal communication medium.

Kakalios: We're all familiar with waves --

sound waves, light waves.

Ever matter has waves -- or water waves.

Any disturbance on the surface,

and we get mechanical vibrations on the surface.

The molecules move up and down but coherently,

forming concentric rings that expand outwards.

Freeman: Because waves move in predictable and regimented ways,

they could be used to communicate mathematics,

a language any advanced civilization

will surely understand.

But waves do not add and subtract like numbers.

We're used to arithmetic based upon the counting of objects --

one apple and two apples equals three apples.

But if you were to base mathematics

based upon the addition of waves,

such as light waves, sometimes it works,

sometimes you get confusing results.

Here, we've assigned numbers

to the different colors of light.

One for red, two for orange, and so on.

If I take a one, red light,

and a five, blue light,

add them together, and I get six, purple light.

That works.

But it doesn't always work.

Let's try another color combination.

One is red.

Three is yellow.

One plus three should give us four, green.

But no, we get orange -- two.

One plus three equals two?

That doesn't seem right.

Freeman: Even though they do not add up like simple numbers,

it is still possible to communicate

complex mathematical ideas through waves.

Because whether they move in water, light,

or the air around us, all waves have frequencies.

Kakalios: If you can give me a "C"...

[ Note plays ]

Very good.

And how about a bouncy "G" sharp?

[ Different note plays ]

Those are two distinct frequencies.

Freeman: Aliens may describe the frequency of a wave

with numbers that are indecipherable to us.

But the ratio between those two frequencies

will always be the same,

no matter what number system is used.

And the ratios could be the key

to two species expressing their knowledge

of the fundamental laws of the universe.

Measure the circumference of a circle.

Now divide by its diameter.

The ratio is the number pi,

or about 3.14.

No matter what unit you used to make the measurements --

inches, your arms...

Or anything else --

the ratio pi will always be the answer,

and pi is one of only a handful of fundamental ratios

in the universe.

They must certainly have noticed this

because it is so common.

It is one of the foundations of our understanding of nature.

Freeman: At first contact,

we could beam aliens a pair of waves,

the ratio of their frequencies equal to pi.

We could send another pair

whose ratio is the same as the ratio of the proton mass

to the electron mass.

Sending these messages would prove we understand the physics

of the universe around us.

There's no guarantee it will work,

but there's another way

of looking at a series of changing frequencies.

On Earth, we call it music.

[ Rock music plays ]

If aliens lack ears,

they might still be able to appreciate the performance

of the high-tech rock band Arcattack,

because Arcattack can play the same song simultaneously

in sound waves, light waves,

and the buzzing discharge of one-million-volt Tesla coils.

Kakalios: A Tesla coil generates waves

both in radio-wave signals and electric fields.

It generates heat by heating up the atmosphere.

It generates sound, and it generates light.

[ Music continues ]

Freeman: This performance could initiate

the greatest peaceful exchange of knowledge in our existence.

[ Music stops ]

We could try one of the most beautiful pieces of music

that we have developed.

It may just get on their nerves.

Freeman: But what if aliens will not or cannot meet us face-to-face?

There is still a chance to make contact,

because aliens could have already sent us a message

hidden on Earth for hundreds of millions of years.

If you compress the entire history

of planet Earth into 24 hours,

human beings would only appear in the final few seconds.

If aliens have already come here,

we probably were not around to greet them.

But what if they left a record of their visit?

Where would it be?

One scientist thinks he may have found it,

hiding inside us all.

Paul Davies is a physicist

and astrobiologist who has spent many years

trying to work out how aliens might communicate with us.

And he has realized it is all about timing.

Let me make a call on this cellphone.

[ Cellphone beeps ]

It's ringing.

Freeman: An electromagnetic signal

flies through space at the speed of light,

and it only passes by our antennas

for a fleeting moment.

Hello?

If the person at the other end doesn't connect with me,

the message has gone off in these radio waves

off out into space

off into the proverbial ether, never to return,

and they're lost.

Freeman: If aliens wanted to make contact,

Paul believes they would choose to send messages

with much more staying power.

[ Scratching ]

Davies: I'm scratching a message in a rock here

in the way that people have been doing it

for thousands and thousands of years.

And why do they do it?

Well, it's a message for posterity.

This thing will be around for a long, long time.

Freeman: But even a rock

will eventually crumble or get buried.

Paul discovered that there is a material on earth

that could preserve a message for tens of millions of years.

We all have it...

Inside us.

Davies: Every living organism on earth

carries genetic information

encoded in a molecule called DNA.

It's a whole sequence of molecular information,

which carry all that is needed to reconstruct that organism

and to enable it to go about its business.

So we've got genes in our bodies dating back billions of years.

Freeman: DNA is made up of four chemical building blocks --

adenine, thymine, cytosine, and guanine.

The particular arrangement of those blocks

creates a unique genetic code,

instructions for building our bodies

from proteins and other materials.

But not all of that code is used.

You total up the length of each gene,

and you soon see that only a small fraction

of the total amount of DNA in our bodies

is actually coding for proteins.

So what you've got in this big, dark, mysterious chunk of DNA,

the majority of it is undoubtedly some real junk.

Freeman: Think of one person's genetic code

like objects in a house.

Most everything an individual needs is easily found.

But not everything is out in the open.

If you look around,

what you see is some functional space used every day.

And then when you go down to the garage,

you see some space that really is storage.

It contains things

that we may never use for years and years on end

but we haven't thrown out,

and if we move house, probably will take it with us to the next place.

Freeman: Nearly every living thing carries this genetic junk,

innocuous sequences of DNA

that are faithfully passed along for countless generations.

Paul realized this junk DNA

could be the perfect hiding place for a coded message.

Imagine that there is some way that we could etch or embellish

the fundamental structure of DNA with some sort of message,

in such a way that it didn't compromise

the functionality of the organism.

Then it could endure for tens of millions of years

or even longer.

Freeman: Paul believes that long ago,

alien genetic engineers could have rearranged sequences of DNA

inside living organisms on Earth,

maybe in our earliest mammalian ancestors.

Their descendants would carry the message

through the eons unnoticed,

until one of them is finally smart enough

to sample his own DNA and read the message.

Researchers have begun scouring the genetic code of humans

and other species, searching for unusual patterns in DNA.

It is an endeavor called genomic SETI.

Supposing you saw a sequence of prime numbers

spelled out in the language of DNA,

which is the four bases -- "A," "G," "C," and "T."

Well, there's no way that natural selection

would ever produce such a thing.

It would leap out at you

as being of obviously artificial origin.

Freeman: If genomic SETI does find something,

one of the first questions we will ask is,

"Why did aliens go through all the trouble

of sending such a message?"

Davies: People have all sorts of different ideas.

Some people think, "Well, could be a religious symbol."

Some people, "it could be a monument."

We go to Egypt, for example.

We see these huge monuments.

What are they for? Well, they're for posterity.

They're put there because people feel

that their civilization was great, it has something,

it can speak to people all down the generations,

they want to leave something behind.

Freeman: A message in our DNA

could also communicate something much more fundamental --

that DNA is the language of all life in the galaxy.

It sounds like wild speculation, but it is not,

because this man may have found the common bond

between us and alien life.

We have always looked to the stars

in our effort to make contact with aliens.

Now that quest could be taking an unexpected turn,

because we may find a link between ourselves and aliens,

not in the heavens

but in the life-creating code of DNA.

In the vast, frozen emptiness of Antarctica,

researchers recently stumbled across fragments

of a four-billion-year-old meteorite,

a piece of cosmic shrapnel

that dates back to the very birth of our solar system.

This is one of the most precious objects known to man.

Unscathed, it is worth a small fortune.

But sometimes science requires sacrifice.

First thing I'm thinking to myself is, "don't mess up.

Don't mess up, and don't cough on it."

Freeman: Mike Callahan is a chemist

at NASA's Goddard Space Flight Center.

His studies focus on a rare type of meteorite

called carbonaceous chondrites.

Callahan: These meteorites are very, very rich in carbon

and contain a wealth of organic molecules.

You can think of our meteorite extractions

kind of like making a cup of tea.

When we place the tea bag into our liquid,

you can see that you're extracting out all the herbs

and all the flavors

into your solution,

and this is what we're doing with our meteorite.

Freeman: Mike is trying to brew up conclusive evidence

that molecules essential to life were present in space rocks

4 1/2 billion years ago.

People have found lots of interesting molecules

such as amino acids,

which are the building blocks of your proteins,

and other essential molecule in other meteorites for years.

But there was always this missing puzzle piece

with nucleobases.

That's been a scientific question

that's been out there for over 50 years.

Freeman: Nucleobases are the letters of DNA --

"A," "G," "C," and "T" --

the molecules that zip together the double helix.

For decades, biochemists have struggled to synthesize them

and puzzle over how they could have been created

on our primordial earth.

But in Mike's meteorite tea,

the answer may finally have arrived.

We find these simple building blocks,

these nucleobases, like adenine and guanine, in meteorites.

Freeman: The same molecules that make up the DNA

common to all life on Earth

have existed in outer space for billions of years.

They were created when our solar system formed.

Callahan: It's amazing when you start looking

at what's inside these meteorites,

what you actually truly find.

And now we're looking at this and thinking,

ell, if these meteorites are coming into Earth

"and now they're being scattered everywhere in the solar system,

"everywhere in the universe,

"I think maybe aliens do look very similar to us,

because maybe we're all composed of the same building blocks."

Freeman: Mike's finding

shows that the building blocks of DNA

could be scattered all over the galaxy,

that DNA might be the basis not just of life on Earth

but of alien life, as well.

First contact could be with our distant cosmic cousins.

But there's no guarantee it will be a warm family reunion

for them or us.

The impact of a first contact

would be absolutely stupendous,

on the level of the discovery of fire.

Davies: We would have access to new technologies

that would solve some of our immediate problems.

But the big problem is,

we'll also need to have the wisdom

to be able to implement those changes

in a way that won't cause massive economic

and social disruption.

That wisdom part is really difficult.

An extraterrestrial signal, I think, would begin to go,

"Guys, we're inhabitants of the galaxy,

"and we have to start thinking that way.

It's time to grow up."

One thing we do is think a lot more about the planet.

"Oh, my gosh.

"We've got this giant spaceship called planet Earth,

and we better take care of it.

Freeman: It could happen tomorrow,

or a message from aliens could already be here,

waiting to be discovered.

But when we finally experience first contact,

our species will be forced to come of age.

To realize, that we are members of a family of life forms

that inhabit the cosmos.

== sync, corrected by elderman ==