Original subtitles

(dramatic music)

This is a vision of our future.

The fateful day in a far flung corner of the universe

when a probe from Earth initiates the first descent

onto an alien world,

looking for proof of life beyond our solar system.

There are no witnesses,

no cheering crowds in the control room.

A decade or more will pass before news finally reaches us

back across the dark oceans of space.

The seeds of this mission are already being sewn today

by the first generation of scientists

bold enough to believe it could be possible.

When I look up in the sky and I see not stars,

I see planetary systems.

We must understand the journey

to exoplanets is not limited by the laws of physics.

They look to planets orbiting distant stars,

searching for an answer to the oldest human question.

Are we alone?

Is there life on other worlds?

And if not, why not, and if so, how?

This is the first generation in human history

where we have the technological ability

to actually go and answer that great question.

This is the story of humanity

launched into the final frontier

by a new breed of adventurers.

The planet-hunters, engineers, explorers, and dreamers

taking the first steps on an interstellar journey

they know that they will not complete.

A journey of light-years and lifetimes

to another Earth around another sun.

We could not possibly have been forged

in the dying throws of stars

and created in that tremendous explosion

and now turn our back on looking for other creatures

that were formed the same way.

(dramatic music)

I am Artemis,

autonomous robotic exploration mothership

for interstellar space.

I am in the finale phase of construction

in the international cooperative zone of Earth orbit.

I am born of man and woman and I am both,

but I am neither.

I am the first search for life

on a planet outside our solar system.

I am hope.

(dramatic music)

There's been life on Earth

for the best part of four billion years.

A marvelous, complex biosphere

created, shaped, and reformed by the ever shifting forces

of our planet.

Since the dawn of science, we've sought out life

and studied its remarkable diversity

on every inch of the globe.

The technology of the 20th century

took our search into space

as we scoured our neighboring planets

for signs of a second genesis.

We came back empty-handed.

But what about beyond our solar system?

Could life, in all its complexity,

exist out there, on a planet among the stars?

What would have been the development

of human thought if one had not been able to see the stars?

This is an area that inspires dreams.

For as long as we've had eyes to see

and minds to wonder, we've marveled

at the bright lights in the sky.

But it was only on the eve of the 21st century

that a handful of eccentric thinkers

dared to gaze into the gloom between the stars,

believing planets like our own world could be found there.

Michel Mayor was one of them.

It's very strange.

In the first half of the 20th century,

astronomy community and astronomers were convinced

that there were few or no planetary systems in the galaxy

apart from the solar system.

When you went to astronomy meetings or conferences,

you couldn't tell people what you were working on.

If you said you were looking for extrasolar planets,

they'd snicker and they'd move away like you smelled bad

or you were trying to sell some new age religion.

You might as well have been looking

for little green men at that point.

In the 1990s, astronomer R. Paul Butler

was another young radical who gambled his career

on the hunt for exoplanets,

planets orbiting stars other than our sun.

I was working on the problem like 80 or 100 hours a week.

I would work on the problem so intensely

that I would have dreams about the work

and it was totally all-consuming.

At the heart of the challenge

was one fundamental problem.

Even if there were exoplanets out there,

scientists knew they'd be impossible to see directly

because the brightness of the star

would overwhelm the planet.

The planets are very small

and weak in terms of brightness compared to the star.

Therefore, getting a direct picture of a planet,

well, that's the great difficulty.

One is dazzled by the stars.

To overcome this obstacle,

astronomers developed an ingenious method

of hunting exoplanets by stealth.

To detect a planet orbiting a star,

you have to rely on tricks and one of the trick

we have been using is if there is a planet

going around the star, the star will move a little bit.

Tiny motion.

And that's the motion you want to detect.

In 1994, junior planet hunter

Didier Queloz was Michel Mayor's PhD student

on the brink of a breakthrough discovery.

Well, in '94, we started this program

that was looking about 100 stars with brand new equipment,

I had spent almost four years before building it

and designing the software to treat the data.

We are serving with the telescopes

to get the speed of the star

and trying to see a tiny change in the speed with time,

kind of wobbling, would tell us

that there is something orbiting that star.

I was there on the mountain, in a way alone,

because Michel worked in sabbatical,

practically gave me the key of the house

because he was not expecting any detection.

You can imagine my surprise

after just a couple of observations

we see that something was a bit strange on that star.

It took me six months practically to be convinced

that that was real and then I send this message to Michel,

I say, "Michel, I think I found a planet."

It may not look like it,

but this little curve is a planet.

How Mayor and Queloz detected it

is a tale of remarkable scientific creativity.

We are here in the dome

of the Observatory Haute Provence.

It is here that the discovery of exoplanets began.

The planets are bodies that do not emit light by themselves.

They only reflect the light received from their star

and so we will have to find an indirect method

to detect the planet.

To understand the simple idea behind this,

imagine you're in the back row of the stadium

at the Olympics watching an extremely muscular athlete

with arms outstretched.

Imagine the hammer is the planet,

the athlete its star, and the chain between them,

their gravitational bond.

The star pulls hard on the planet, but it's not all one way.

The planet also pulls on the star.

In fact, with every revolution,

it's pulling it a little off balance.

Using a prison-like instrument called a spectrograph,

this wobble effect can be detected

by observing changes in the color of the light

emitted by the star, shifting towards blue

as the star moves closer and red as it moves away.

Measuring this oscillation allowed Queloz and Mayor

to infer the existence of a planet,

to calculate its mass, the distance from its star,

and the duration of its orbit.

It's moving to be here with this instrument

which allowed us, more than 20 years ago,

to discover the first exoplanet.

I think by detecting the first planet,

you break a psychological frontier.

In science, it's very rare, you can change a paradigm

and we've changed a paradigm.

On the 6th of October, 1995,

Mayor and Queloz announced their discovery.

The first ever exoplanet: Bellerophon.

Although they could not see it directly,

its mass suggested it was a giant gas planet,

similar to Jupiter.

But the distance from its star and the period of its orbit

seemed to defy the laws of our solar system.

People thought, well, this is really bizarre,

this must be a total freak because it didn't

look like the solar system.

It's a big planet like Jupiter

but it orbits its star in four days.

The theory of the formation of giant planets

predicted they would only orbit their star

over extremely long periods of time, 10 years or more.

And so it seems completely at odds with the theory of time.

In our own solar system,

giant gas planets exist only in the colder outer orbits,

whereas Bellerophon appeared to be tucked in tight

against the heat of its star.

Much closer even than Mercury is to our sun.

Because it's so close to its star,

it's really, really hot.

It's probably something like upward

of 2,000 degrees centigrade.

And there is no solid surface because it's a gas giant,

so it's not a good place for life,

it's not a place you'd want to visit.

(intense music)

Bellerophon was no second Earth.

But its discovery had opened the window

on the new vision of the universe

where anything is possible.

(dramatic music)

The exoplanet Minerva B was chosen

as the target of my mission by astronomers

who are long since dead.

They died believing they had found the one.

4.7 light-years from Earth.

A world like ours, with liquid water bearing life.

I hope that I will prove them right.

(dramatic music)

When the first exoplanets were found by the wobble method,

there was a debate in the astronomy community.

Some astronomers said this is fantastic,

a new kind of world, completely unforeseen

in terms of our understanding of planet formation,

but another group of astronomers said hold on a minute.

We don't think that these are actually planets.

In 1999, Professor of Astronomy

David Charbonneau was just a young grad student at Harvard

trying to make his mark in the brand new field

of planet hunting.

What he encountered was a minefield.

While artists had rushed to bring these new worlds to life,

skeptics questioned the astronomers'

interpretation of their data.

What they said was we were being fooled.

There was, in fact, a new kind of stellar pulsation

and so as the star expanded and contracted,

we were looking at one side of that star

and so it appeared that the star was coming towards us

and away from us, the very signal,

that would be the telltale motion due to an orbiting planet

but in fact had nothing to do with a planet at all.

What I decided to do was to try

to go and resolve this debate,

first by looking for the light reflected

off of one of these worlds.

We tried very hard for a couple years

and, unfortunately, we did not succeed.

But then, as a second idea, what we decided to do was

instead of looking for the light bouncing off a planet,

wait for the planet to pass in front of its star

and look for that transit.

Charbonneau relocated to Boulder, Colorado

to a small shed in a car park

where a basic four inch telescope

had been set up by a fellow researcher, Tim Brown.

But I had never done this kind of project before,

so as a first attempt, I thought what we should do

is look at one star where we knew that there was

a planet due to the wobble method,

but which we hadn't yet looked for

to see if, in fact, the planet passed in front of a star,

making a transit.

Where the wobble method

allowed one to infer the mass of an orbiting exoplanet,

Charbonneau was attempting to observe the planet's shape

as it passed across its star,

in the manner of a partial eclipse.

The problem was he knew the odds were stacked against him.

Of all the planets that are out there

orbiting their stars, we only get to see

a tiny fraction by this transit method.

The idea is that our line of sight

has to be exactly aligned with the planetary orbit

so that each time the planet swings around,

it'll pass in front of some part of the star,

blocking some of the light,

and that's the signal we can detect.

Tipped off that another so-called hot Jupiter

like Bellerophon had been detected by the wobble method,

Charbonneau trained his telescope

on star HD 209458 and waited, praying for a transit.

There had been about 10 hot Jupiters

discovered at that point, so,

it seemed like if they really were planets,

if we weren't being fooled, then sooner or later,

one of these transits should occur.

And right when we predicted based on the wobble data

that a transit would occur,

that's when we saw this event.

Charbonneau's transit method

was a game changer, confirming the pioneering discoveries

using the wobble method and silencing the skeptics.

The discovery of the transits, of HD 209458

was a big deal in the astronomical community.

For the first time, we knew the actual mass of the planet,

we knew its size, and we could calculate the density.

And we could compare it to the density

of planets in the solar system,

so we confirmed that these worlds really were hot Jupiters,

they were big, gassy planets inflated

due to their proximity to their stars.

The new look universe was populating fast,

inspiring an eager generation of young scientists

to join the hunt.

Timing is everything.

When I was in graduate school mid-1990s

looking on a project for my PhD thesis,

amazingly enough, the first reports of planets

orbiting sun-like stars were coming around at that time.

And my thesis advisor suggested that I work on exoplanets.

MIT Professor of Astrophysics Sarah Seager

arrived in the field after the paradigm had already shifted.

To her, the question was no longer simply

are there exoplanets out there?

It was could there be one like Earth?

When I want to think, I come here to the Great Lake

and I look out on the water and I just think about

how wonderful life is, how fragile life is.

It gives me hope that there's another planet out there

where life could really thrive.

(gentle music)

But what makes our world so special?

What physical characteristics define our planet?

We're looking for a planet that has a solid surface,

predominately rocky planet, but we're not expecting

another planet to be exactly like Earth.

When we talk about the planets we want to find,

it's one that would be able to host life.

Even in the most extreme environments,

like here amidst the glaciers and volcanoes of Iceland,

the conditions that make organic life possible on Earth

can be found if you know where to look.

Life needs water and we think water

is almost everywhere in the universe.

However, we find it mainly in the form of ice

and that's not what we need.

Life as we know it and how we'll recognize it

really needs liquid water and that's not obvious

because it requires the right conditions

of temperature and pressure.

Based on everything we know of life on Earth,

scientists like Francois Forget

believe that for an exoplanet to host liquid water,

like Earth, it needs to lie within a certain distance

from its star, a region called the habitable zone.

(light music)

We calculate that if we move the Earth

just a few percent close to the sun,

the climate would go into overdrive,

because there would be more solar energy.

The oceans would be warmer, more water vapor,

more greenhouse effect, and, very quickly,

the oceans would totally boil and evaporate.

On the other hand, if we move the Earth

a few percent away from the sun, it will be colder.

There would be more snow, more ice, and that snow

will reflect the sunlight which makes it colder and colder

and that continues until all the Earth gets covered in ice.

We call it a snowball Earth.

The reason Earth is suitable for life

is not only that it's covered with liquid water

and oceans today, but it has been

throughout its existence for four billion years,

which allowed life to be born and evolve.

The first mathematical model

of planet habitability, produced in 1979,

placed extremely narrow limits on the habitable zone.

But recent advances in geological science

have broadened the horizon.

Other than being at approximately the right distance

from the sun, the main thing that keeps Earth habitable

is the carbon cycle.

(dramatic music)

Penn State Professor of Geoscience,

Jim Kasting, is a world leader

in the study of planet habitability

and the vital role played by carbon.

On Earth, carbon, in the form of CO2,

traps the sun's heat in our atmosphere.

Without it, temperatures would plummet

to below what life needs to survive.

But CO2 doesn't just stay in the atmosphere.

The trees around us are photosynthesizing

and they're actually exchanging

every CO2 molecule in the atmosphere every 10 or 12 years.

But on longtime scales, it's what we call

the carbonate silicate cycle where

CO2 in the combined atmosphere-ocean system

is exchanging with carbonate rocks.

CO2-rich sediment washes into the ocean

and is drawn into the Earth's crust

at underwater fault lines,

where a final, geological mechanism completes the cycle.

To have a habitable planet like the Earth,

you really need a longterm carbon cycle

and that has to be driven by some process

like plate tectonics on the Earth

that keeps the carbon moving around.

When our planet enters an ice age,

this tectonic feedback restores a habitable climate.

As oceans freeze, the uptake side of the carbon cycle slows

while volcanic activity continues,

pumping CO2 and heat back into the atmosphere.

When you put in the feedback, you find out that

the habitable zone, instead of being very narrow,

is actually quite wide and wide enough

that there's a good chance that planets around other stars,

at least one or more of them,

could be within the habitable zone.

Kasting's research had a momentous impact.

By expanding the boundaries of the habitable zone,

the carbon feedback loop vastly improved

the odds of finding an Earth-like exoplanet

where life might be possible.

But the fundamental challenge of identifying

an Earth-like planet remained.

They're tiny and therefore much harder to detect,

compared to the gas giants that our instruments

had observed so far.

To see these Earth-sized worlds,

a giant leap forward in technology was required.

I was a graduate student

when the very first planet was discovered.

In fact, I was at the conference where Michel Mayor

made that announcement.

NASA astrophysicist Natalie Batalha

graduated with a dream.

I would say my biggest hope was that we find

an Earth-sized planet orbiting a star

very much like our own sun in a similar orbit,

where the conditions for life might be just right.

Five, four, three, two,

engines start, one, zero, and lift off

of the Delta II rocket with Kepler

on a search for planets in some way like our own.

In 2009, scientists launched

a formidable new weapon in the hunt

for life beyond our solar system:

the first dedicated, planet-hunting telescope, Kepler.

At the time, it was the world's largest digital camera,

using an array of 95 megapixel sensors

to detect the infinitesimal dimming of starlight

caused by transiting planets.

So powerful that if turned towards Earth,

it could detect a single porch light turning off.

More importantly, it was the first instrument

capable of detecting rocky, Earth-sized planets.

The first two decades of exoplanets

was kind of like postage stamp collecting.

Kepler really changed that.

(dramatic music)

Kepler monitored a select region of our galaxy

over a four-year period by taking a snapshot

every 30 minutes, like an epic time lapse photograph.

And from that data, we identified over 4,000 periodic

transit events that look like viable planets.

And, in fact, we have confirmed

through other follow-up observations

that over half of them are, indeed, bonafide planets.

Kepler delivered not only the first

rocky exoplanets, it revealed

brand new kinds of rocky planets,

like Kepler-10b, our first encounter

with what scientists would christen lava worlds.

These are rocky worlds,

same kind of density as Earth,

but they're orbiting so close to their star

that the surface temperatures are in excess

of that required to melt not just rock, but iron.

So you've got an entire hemisphere,

something the size of the Pacific Ocean, even larger,

that is an ocean, but it's not an ocean of water,

it's an ocean of molten rock.

Kepler was the first celestial census,

extrapolating the data from the surveyed region,

it gave astronomers a catalog of the exoplanet population.

We've learned, I think, three important things.

First, we've learned that every star that you see

when you look up into the sky at night

has at least one planet.

The other thing that we have learned is that

nature makes small planets more efficiently

than large planets.

The third thing we've learned has to do with the

fraction of stars that harbor Earth-size,

potentially habitable planets.

And we can make the bias corrections

to determine that number and what we find

is that it's about 22% to 25%.

At least one planet for every star in the sky.

And as many as a quarter of them Earth-sized

and orbiting within the habitable zone.

Kepler revolutionized the way we see the stars.

Kepler was the pioneer.

Kepler looked for planets transiting sun-like stars

and Kepler looked at a very distant field of stars

for four years to try to find a planet like Earth

that has a one year orbit.

Inspired by the success of Kepler,

in 2013, NASA joined forces with MIT Lincoln Labs

to develop an instrument that could deliver

a more detailed survey of nearby, Earth-like worlds.

The entire field of exoplanets is funneling towards

the search for another Earth,

a rocky world orbiting a small star,

preferably in the habitable zone of that star.

As the project advanced,

MIT Professor Sarah Seager was named Deputy Science Director

of the Transiting Exoplanet Survey Satellite, AKA TESS.

TESS wants to find stars that are closer,

right in our neighborhood, actually.

The camera has lens assembly of seven lens elements

that refracts starlight onto a detector.

And together, they make a giant strip.

When you think of the sky as a sphere,

from the bottom of one hemisphere

all the way up to the pole.

After one year of doing that, TESS will flip

to the next hemisphere and it will then do the same thing.

And so, over two years, TESS aims to study the entire sky.

By scanning nearby star systems,

TESS aims to identify 50 Earth-sized exoplanet candidates

for further investigation.

But would finding a planet like our Earth

also mean finding a star like our sun?

(dramatic music)

All we know of the stars we know from afar.

All we know of Minerva B is this.

It is a rocky planet, 1.6 times the size of Earth,

hosted by a red dwarf star.

Its orbital period is 39 Earth days.

It lies within the habitable zone.

Its atmosphere contains carbon dioxide,

methane, water, and ozone.

It will be full of surprises.

(rumbling)

After the explosion of discoveries,

a new question emerged.

Could finding the right star be just as crucial

as finding the right planet?

I think the biggest lie that I was told

when I was in school was that the sun is an average star.

The sun is not an average star.

The sun is much bigger, much more luminous,

much more massive than most stars.

Most stars in the galaxy are about

a quarter the size of the sun, a quarter the mass,

and they only put out one-one thousandth the energy.

(gentle music)

These are small, cool stars,

burning not yellow like our sun, but red.

They're classified as M-type stars, or M dwarfs,

but most people call them red dwarfs.

One of Kepler's Earth-sized discoveries,

Planet Kepler 186F, was found to be orbiting such a star,

500 light-years from Earth.

It's about the same size of the Earth

and our observations tell us that planets

the size of Earth are more likely

to have a rocky composition.

So we imagine this planet as being a rocky planet

with a surface, a solid surface.

It's receiving about the right amount of energy

for liquid water to pool on the surface,

but it's orbiting a star that's very different than our sun.

Because red dwarfs burn less hot than our sun,

their habitable zone tends to be much closer in.

But this closeness could spell disaster

for life on the planet.

The red dwarfs and their habitable zones

are so close in that the planets have a

strong chance of becoming tidally locked

and synchronously rotating where they

show the same face to the star all the time,

just as the moon shows the same face to the Earth,

so that poses problems for habitability,

which may be difficult to overcome.

When a planet is close to its star,

the gravitational or tidal force becomes greater.

And this can have the effect of locking

the rotation of the planet,

meaning one side is always lit by its star

while the other remains shrouded in darkness.

(gentle music)

As well as producing one hot side and one cold

by spinning so slowly, the planet may fail to generate

an electromagnetic shield, which, like on Earth,

protects the planet from radiation.

These stars, at the same time,

they're very much dimmer than the sun

but they're more magnetically active,

they give off lots of high energy radiation

that may strip the atmosphere off a planet,

particularly if it's not protected by a magnetic field.

But in 2015, Kasting and other researchers

found reason to hope for life on a tidally locked planet

orbiting a red dwarf.

Using sophisticated climate modeling,

they proposed that if the planet had

the right kind of atmosphere, then heat could be transferred

from the light side to the dark,

like a reverse cycle air conditioning system.

Planet hunters embraced the discovery.

If life could thrive on a planet around a red dwarf

or M-type star, the odds of finding a second Earth

were vastly improved.

M-type stars are the most numerous star in the galaxy.

70% of the stars in our galaxy are these M-type stars,

so if life can seat itself and get started on these planets,

then life is going to be ubiquitous in the galaxy.

For four months at the beginning of 2016,

the seer telescope in Chile

set its sights on the M-type star, Proxima Centauri.

A mere 4.25 light-years from Earth,

it's our nearest stellar neighbor.

(dramatic music)

In a machine room deep beneath the telescope,

light from the star was split by the HARPS spectrometer.

An instrument so sensitive it picked up

the feeblest of wobbles in the dwarf star

caused by a tiny, Earth-sized planet: Proxima B.

The discovery came as a revelation.

The very closest alien star to Earth

hosts a tidally locked, Earth-like world.

And calculations reveal that Proxima B

is orbiting within the habitable zone.

It's an amazing triumph

to discover a planet around our nearest star.

Just think about that.

For thousands of years, people have been wondering

are there any planets around other stars?

And there is one around our very nearest star.

But what about its atmosphere?

Could this planet sustain life?

(dramatic music)

My last cell of Helium-3 propellant

is delivered from Moon Base.

My preparations are complete.

On Earth, the World Astronomical Union

is throwing a party for me on the eve of my historic launch.

And I am honored.

And I am alone.

Tomorrow, I'm going to Minerva.

As the exoplanet gold rush gathered pace,

planet hunting prospectors sought evermore refined methods

of sifting their discoveries in an effort

to give a future interstellar mission

the best possible chance of targeting a world

that might actually host life.

Having identified a rich new vein of distant planets,

the next crucial piece of the puzzle

was yet to fall into place.

How could a telescope be used to sample the atmosphere?

Looking at a planet's atmosphere far away

is the best way we have to find signs of life

on another world because the gases that life produces

here on Earth, actually, imprint on our atmosphere

in a very significant way and so it's just amazing to think

that on another world we can do the same.

If you were an alien astronomer

studying the planets of the solar system,

you would see that there's something very different

about the third planet from the sun.

You would see that its atmosphere is full of oxygen

even though you would know that the oxygen

couldn't possibly be there by geologic processes.

There would be other gases, like methane,

which also shouldn't be present and, yet, there they are.

And you would, we think as we're trying to do ourselves,

when we look at other stars, conclude that life

was the only possible explanation.

In 2000, David Charbonneau

took control of the aging Hubble telescope.

Charged with a single but daunting objective:

to make the first ever observation

of an exoplanet's atmosphere.

The transit method of exoplanet detection,

which Charbonneau had pioneered himself,

provided a clue for how to solve the puzzle.

(gentle music)

Planets orbiting closely to their stars

make more frequent transits and the larger the planet,

the easier it is to detect.

So Charbonneau turned the Hubble's gaze towards Osiris,

a gas giant that transits every 3.5 days.

We had the idea that when the planet

passed in front of its star, some of the light from the star

would pass through the outer parts of the planet

and then imprinted upon that light

would be the fingerprints of whatever atoms or molecules

were present in the atmosphere.

Different atoms absorb different

light frequencies in the electromagnetic spectrum

and allow others to pass through,

producing a signature in color.

No one had ever discovered an exoplanet atmosphere.

And so we needed a guess as to what atom or molecule

would be very prominent,

would be the easiest first thing to see.

So there were some predictions.

Charbonneau put his money on sodium,

the telltale yellow glow of streetlamps.

The observations were gathered a few months afterwards

and it took more than a year to carefully analyze the data.

No one had ever made this detection before,

so we wanted to be absolutely certain

that what we were seeing was robust.

After painstakingly probing the data,

Charbonneau announced his discovery.

The atmosphere around Osiris was, indeed, rich in sodium.

However, this was no second Earth.

Named after the Egyptian god of the dead,

the gas giant Osiris doesn't even have

a solid surface to land on, let alone the climate for life.

What we crave to do is to study the atmosphere

of an Earth-like planet.

Of course, Earth-like planets are simply much smaller

than gas giants and so it's just much more difficult

to detect them and to study their atmospheres.

It's the hurdle that has thwarted

planet hunters from the outset.

The blinding light of the stars

completely overwhelms the smaller exoplanets.

The first instrument to solve that problem

will hold the key to the exoplanet revolution.

This telescope will allow us

to make a leap forward in several fields of astrophysics,

especially in the field of exoplanets.

Indeed, it will allow us to observe

the atmospheres of these exoplanets.

The James Webb Space Telescope

is designed to view the heavens

like they've never been seen before,

making the invisible visible.

Its vast honeycomb-like dish of mirrors

converges light into the eye of a state of the art,

infrared camera that astrophysicist

Pierre Olivier Lagage spent 20 years developing.

An object emits light

in a given wavelength according to its temperature.

For example, the sun emits in the visible range

because it's very hot.

If we take a human, it's much cooler

and will emit in a different wavelength, mid-infrared.

And that's why with a so-called thermal or infrared camera,

you can see people at night.

We don't need lights, we see the heat emitted by a human

in the mid-infrared.

The same is true of exoplanets.

Observe them in the right wavelength

and they glow in the dark.

(light piano music)

But for the infrared vision to work,

it relies on the truly innovative feature

of this telescope.

Inside the camera lies James Webb's secret weapon:

a kind of mask called a coronagraph.

This form of mask is very unique.

The light of the star arrives where it's opaque.

On the other hand, if you have a small object next to it,

like an exoplanet, well, the light will not have

exactly the same path and will shine through.

So, after that, we'll have the light of the exoplanet

without the light of the star.

So thanks to this coronagraphic method,

we'll be able to get a direct image of the exoplanets.

The mask of the coronagraph

intervenes between the overwhelming light of the star,

like an eclipse, allowing the infrared light of the planet

to shine through.

These exoplanets have never been seen

in this wavelength and yet it's a very interesting field

for measuring the temperature of these objects,

their luminosity.

We can also see the composition,

certain molecules such as ammonia,

which is in this wavelength range.

So, the characterization of atmospheres

will be one of the great focuses of this instrument.

Crucial in the hunt for Earth-like worlds,

James Webb is ideally suited for detecting ozone.

Why ozone?

Because there's no ozone without oxygen

and no oxygen without life,

so we think it's really something that is a trace of life

and in the middle infrared,

our telescopes can precisely detect this signature of ozone.

The James Webb promises

to be the missing piece in the planet hunter's arsenal.

With its breakthrough ability to view an Earth-like

exoplanet directly and to study its atmosphere,

the odds of identifying a destination

for a future landing mission have never been better.

You know, I can probably imagine what that would feel like

better than most people can.

I've been sending robotic missions to other planets

my whole career, 40 years of this.

But I can't imagine what it would feel like.

I mean, the problem of getting a spacecraft

with that kind of capability to another star

is so much harder.

The discoveries of the planet hunters

transformed the way we see the universe

and posed to explorers like Steve Squyres,

lead investigator of the Mars Rover Missions,

the next tantalizing question.

What if we could reach out to a nearby alien star

and search for life on a second Earth?

What if we could land on another rocky world,

with running water and a protective, Earth-like atmosphere?

If you could find an Earth-like world

that has been around for billions of years,

enough time to develop advanced biology,

it's had the right conditions all that time,

there are all kinds of possibilities.

I can't imagine what it would feel like.

It's gonna be a shared moment for all humanity

when it happens.

(dramatic music)

Five, four, three, two, one.

I launch.

No fireworks.

No trembling Earth.

For those of you who are watching this,

I thank you for entrusting me

with the greatest adventure in human history.

Wish me luck.

(light music)