Original subtitles

[narrator] The James Webb Space Telescope

is a revolutionary new eye on the universe.

[Hakeem] We haven't had such a giant leap since we got

the Hubble Space Telescope.

And now we've gone even further.

Webb is turning its power toward worlds

orbiting alien stars.

The jump from just, do they exist

to what would it be like to stand on these surfaces --

all of that has happened in the blink of an eye.

What kind of weather rages on planets

where temperatures melt rock into rain?

We're talking about weather on a world

that is light-years and light-years away from us.

How do newborn stars unleash forces that strip away

the atmospheres of planets?

And what does it take for a planet

to hold on to the air, water, and chemistry needed for life?

Webb transforms these distant dots of light into real worlds.

To investigate these new mysteries,

we peel back shrouds of cosmic dust,

split open alien atmospheres,

and rewind history to the moments

when planets are born.

The James Webb Space Telescope

is the latest and greatest in space observatories.

One of its key missions is to unlock the mysteries

of worlds beyond our solar system,

what astronomers call exoplanets.

Webb aims not just to find them, but to understand them.

I think humans are evolved to explore, to check out

what's going on over that next hill, beyond the horizon.

And alien worlds, literally planets orbiting

other stars, I mean, isn't that the ultimate of all of these?

[Grant] With this newfound capability,

thanks to the most powerful space telescope in history,

we are finally, really, truly looking at these worlds

with new eyes and understanding not only how they work now,

but how they might have formed

and how they evolved through time.

Webb is built to see the universe in infrared light.

This allows it to detect heat,

to peer through clouds of dust...

and to read the chemical fingerprints of distant worlds.

[Michelle] The biggest challenge to both finding and then making

detailed observations of exoplanets is that

they are so small and so dim compared to a star.

The starlight just swamps them.

But then you go to infrared light.

You can actually try to isolate the infrared light

coming from the planet as opposed to the star,

and that changes everything.

Using its powerful spectrometers,

Webb splits light into its component colors.

[Grant] Webb transforms these distant dots of light

into real worlds, into fully-realized physical worlds

with their own chemistry, their own weather,

their own atmospheres.

The James Webb Space Telescope is helping astronomers unlock

one of the biggest mysteries of planetary science.

What happens within star systems

when planets first form?

Webb is so powerful that it can look in detail

at the moments when worlds are born.

Across the galaxy, Webb spots stunning structures --

protoplanetary disks, the telltale signs

of recently formed stars.

[Michelle] A disk of dust and gas

that is actually forming planets right now.

Sometimes we'll see these large protoplanetary disks face-on,

so you can actually see the whole thing

with the new star in the middle.

At other times they're more at an angle to us,

maybe even blocking out the light from the star.

Astronomers use Webb to investigate a star system

that could solve the mysteries of planetary birth.

TWA 7, just 6 million years old,

100 light-years away in the Antlia constellation.

Observations from ground-based telescopes show

that it has a debris disk,

oriented face-on to Earth.

[Hakeem] What's really cool about this system is the perspective that

we have on it, and that sort of gives us a view of what

our solar system may have looked like as it was forming.

The star sits inside a thick disk of gas and dust,

where leftover material clumps together

to slowly build ever-larger bodies.

But the observations show this disk is misshapen.

One side is bulging.

Something is disturbing it.

[Grant] When you see warps and bends and gaps in a disk,

you know that something is essentially tugging

on that disk, and gravity is always the culprit there.

Gravity leaves its fingerprints everywhere,

even throughout our solar system.

Webb searches for clues that could reveal what is pulling

on TWA 7's rings.

The telescope deploys its MIRI coronagraph

to block out the star's glare for a better view.

Say you're standing outside on a sunny day and you see

an airplane flying near the Sun and you want to see

that airplane. Well, what do you do?

You go, oh, you put your hand up and you block that light.

We can do that with telescopes by creating what's called

a coronagraph, which is at its simplest just like

a little metal disk that sits in the center

of the field of view of the telescope.

[Michelle] And what it blocks out the light from the star,

anything close to the star has a chance

to kind of come through.

A faint glow appears.

Inside the shroud of gas and dust

is a giant planet, the mass of Saturn,

still in the process of growing.

[Grant] This is Webb's first truly new and unique exoplanet discovery.

This is a system that nobody knew about until

Webb discovered it.

And this is the smallest planet ever directly imaged

outside of our solar system.

No other telescope could have captured this.

Webb's infrared data reveal the planet's temperature.

Its core is two times hotter than the surface of the Sun.

[Michelle] This new world, TWA 7b,

turns out to be a fascinating place,

very different from our own home planet, the Earth.

It's actually well beyond where the orbit of Pluto would be

in our own solar system.

And so you might think that would make it quite cold,

but the measurements suggest it's actually warm

at the cloud tops, maybe about 120 degrees Fahrenheit.

Gravity is still bringing all of the gases together,

and so it's actually radiating all of this heat

because of that gravitational contraction.

So there probably is no solid surface to stand on.

Webb's observations show that many planets are born

as hot, extreme worlds.

Almost immediately,

they begin to reshape their solar systems.

We're at the very beginning of being able to understand

planets around other stars.

And to begin with, we're finding the ones that are

the easiest to find,

the biggest, brightest worlds out there.

So these young planets are still forming.

That means they're very hot.

That means that an infrared telescope

has a better chance of picking them up.

If planets begin life this violently,

what happens to their atmospheres?

Can anything survive the chaos?

Can the James Webb Space Telescope find out?

Since the discovery of the first exoplanet

in the 1990s,

astronomers have found more than 6,000 worlds

orbiting other stars.

But until now, they've just been data points.

[Grant] We now understand that there are probably

more planets than stars, not only in our galaxy,

but throughout the universe.

That's a profound thought.

Think of the untold trillions upon trillions of worlds

that are out there in the void.

But the truth is that thus far, our techniques for finding

alien worlds and solar systems beyond our own is not actually

in looking for the planets directly.

The vast majority of exoplanets that we've found

have been discovered using what's called

the transit method.

If we see that planet orbiting its star edge-on,

every time it passes in front of the star,

we get kind of a mini-eclipse.

As a planet passes in front of its star,

it blocks out a fraction of the star's light.

The more the light drops, the bigger the planet.

Large planets tug on their stars as they orbit,

making them wobble from side to side.

The bigger the wobble, the more massive the planet.

Armed with this information, astronomers can deduce

what the planet might be made of.

Whether they're rocky, like the planets

of our inner solar system,

or made from gas, like the giant planets

of our outer solar system.

Now, Webb can build a picture of what these worlds

are really like.

Because the telescope has a superpower --

its infrared spectrometer.

It can read the atmospheres of planets.

Even ones that Webb is unable to see directly.

[Phil] JWST has opened up a new window

in exoplanet observations because by breaking the light up

into its individual wavelengths, we can find out what's going on

in the atmospheres of planets

light-years and light-years away.

What secrets is Webb unlocking about the atmospheres

of young, exotic worlds?

In 2015, the VISTA telescope in Chile

discovers a giant planet named VHS 1256 b,

40 light-years from Earth in the Corvus constellation.

The ground-based telescope finds nothing remarkable.

Eight years later, Webb takes another look.

It discovers something strange.

The planet is flickering.

[Michelle] The planet VHS 1256 b

was a special type of mystery to us.

The James Webb Space Telescope could detect the heat

from the planet, but it seemed to be flickering and changing

incredibly rapidly, in some cases in just a couple of

hours or days.

There were longer cycles that might be more than a month.

What could cause an entire planet

to change in brightness that quickly?

That kind of variation tells us that the atmosphere

is almost certainly anything but calm.

Webb deploys its special infrared spectrometer

that unlocks what the atmospheres

of exoplanets are made from.

The instrument detects carbon monoxide, methane,

and something unexpected.

[Phil] There are silicates in its atmosphere.

That means rocky material.

Not only that, but the brightness

of this material flickers.

It gets brighter and dimmer, sometimes by as much as 30%.

Peering into the giant planet's atmosphere

reveals rock vaporized by 1,000-degree heat

and raining down in molten mega sandstorms.

[Michelle] It could be that there are large convective currents

bringing huge molten sandstorms that move around the planet

and change the infrared brightness.

[Grant] Think about what we're doing here.

We are watching weather on an alien world,

trillions of miles away,

and this weather doesn't arise by clouds.

These are molten sandstorms of vaporized rock that are raining

down silicates back through the atmosphere.

This is not a planet you'd want to visit.

Webb's analysis of VHS 1256 b

reveals that the atmosphere

of this large planet is weirder than anyone imagined.

[Hakeem] Now, when we talk about discovering exoplanets

and observing them, we're also talking about attempting

to discover life around another world.

[Michelle] There are so many fascinating worlds out there, but you have

to realize what we really want to find is another Earth.

We want to find somewhere that's like our own home.

That will give us a sense about how common planets are

that could support life, at least life as we know it.

Statistical studies show that Earth-sized planets

are the most common type in the galaxy.

[Michelle] There's been this whole progression

in finding exoplanets.

The very first ones that we found were the biggest,

brightest ones, the easier to find.

But very soon after that, we began to find worlds

that were more like our own.

These solid, small, rocky planets.

And in fact, they seem very common.

Webb turns to look

at one of the most studied exoplanet systems.

TRAPPIST-1, a red dwarf star 40 light-years from Earth.

[Grant] Red dwarf stars like TRAPPIST-1

are small and they're cool,

which means that they burn their fuel incredibly slowly.

So the potential lifetime of the TRAPPIST-1 star

is potentially, like, 2,000 times longer

than our sun will ever live.

What that means is that if you have planets around a star

that can be that long-lived, you in principle have

unbelievable amounts of time for complex organic processes

to emerge and evolve, i.e.,

you have a really big period of time for life

to appear on one of these planets.

Seven Earth-sized worlds orbit TRAPPIST-1.

All of them are very close to their parent star.

[Michelle] Sometimes there's a discovery

that just absolutely blows your mind.

The idea that we have found a system

with seven Earth-sized worlds,

all of them well within where the planet Mercury is

in our own solar system.

If you were standing on the surface of one of these

worlds in the TRAPPIST-1 system, there would be

other planets up there hanging in the sky

bigger than the full moon.

You would be able to see whether there are continents,

whether there are oceans.

To me, it should have been in the realm of science fiction,

but it is real. It's a real place.

And the proximity of the planets to their star

could have surprising consequences.

Statistical studies show that Earth-sized planets

are the most common type in the galaxy.

Webb turns to look at one of the most studied

exoplanet systems --

TRAPPIST-1, a red dwarf star.

[Michelle] Sometimes there's a discovery

that just absolutely blows your mind.

The idea that we have found a system

with seven Earth-sized worlds,

all of them well within where the planet Mercury is

in our own solar system.

[Phil] Astronomers have a concept called the habitable zone.

It's basically how far you can be from a star where a planet

or a moon or something like that would have liquid water

on its surface.

So Earth, for example, is in the Sun's habitable zone.

For a red dwarf star, which is much, much cooler than the sun,

the habitable zone is much, much closer to the star.

Habitability is about more than just temperature.

Planets need an atmosphere to keep liquid water

from boiling away into the vacuum of space.

[Hakeem] The first thing that we typically consider is

whether or not the planet is in the star's habitable zone.

But that doesn't tell you whether or not the planet

is actually habitable.

If Earth had no atmosphere, it wouldn't be habitable,

even though it's at the right distance from the Sun.

Webb analyzes each planet in the TRAPPIST-1 system

to find out which ones have atmospheres.

The telescope reveals that the three planets

closest to the star have no atmosphere.

Each one is a barren space rock.

[Grant] Red dwarfs have a violent side.

They're small stars,

but they throw really big tantrums.

And they can power immense flares that plow through

the solar system.

The star TRAPPIST-1 may be small, but its size means

its core touches the convective layer of hydrogen around it.

The extreme heat inside the core drives streams

of superheated plasma to the surface,

like a furiously boiling pot of water.

Huge eruptions of plasma spew from the surface with the force

of a billion hydrogen bombs.

As the flares travel through space,

they fan out into giant waves of UV radiation

that slam into the closest planets,

stripping their atmospheres

and showering the surface with deadly UV rays.

These flares that come off red dwarfs

are extremely energetic.

They blast out X-rays and subatomic particles.

If you're a planet in the habitable zone,

really close to that star, you can get blowtorched

by these things.

[Michelle] Of the seven Earth-sized planets we know

around TRAPPIST-1, we are pretty sure that

the first three are so close to the star,

those atmospheres probably were just blown away

by the heat and the energy of that star.

But further out from the star, just on the edge

of its habitable zone,

Webb's data hints that the fourth planet, TRAPPIST-1e,

does have an atmosphere.

It's rich in nitrogen with traces of methane.

[Michelle] Now, TRAPPIST-1e is at the right temperature.

It's far enough away from the star that it's not too hot

and not too cold, and it could even have the right conditions

for ice or water on the surface.

Perhaps the best analogy for what this planetary atmosphere

might be like isn't the Earth, but it's the moon

of Saturn called Titan.

Titan's thick nitrogen atmosphere

and high methane content make it an intriguing world.

The Huygens lander reveals that Titan has rivers,

lakes, and seas of liquid methane.

And scientists suspect that the moon also has

an underground reservoir of liquid water.

[Michelle] The idea that this planet might be more like Titan is

really intriguing because Titan is one of the few places

in our own solar system that we think might be habitable.

Now, we certainly don't have any proof of life on Titan yet,

but it's the only place in our solar system that has

liquid on the surface. It rains.

There are lakes and rivers.

So you could have the conditions for life,

maybe a different kind of life.

It's possible that the atmosphere of TRAPPIST-1e

could be more like Earth's than Titan's.

Even if it is, this world is far stranger than our own.

The TRAPPIST-1 star is 20,000 times more massive

than its orbiting planets.

Its immense gravity grips them as they huddle in close.

The star's gravity warps TRAPPIST-1e,

pulling out a huge bulge of rock

on the side facing the star.

The planet continues to rotate, but the star's gravity tugs on

the bulge like a handle, slowing its rotation.

Over thousands of years, TRAPPIST-1e's spin becomes

slower and slower, until eventually one side

is locked, always facing the star.

[Grant] So it's pretty hard to imagine what it might be like to live

on a tidally locked world.

Earth is very much not tidally locked.

We have a day and a night.

We do actually see a tidally locked world

in our sky all the time. It's our moon.

The Moon is tidally locked around the Earth,

which means we only ever see one side of it.

The tidal locking makes TRAPPIST-1e

a terminator planet.

One hemisphere is barren and scorched.

The other is dark and frozen,

and a thin strip around the middle is trapped

in perpetual twilight.

[Phil] What this goes to show us is that you have to be careful.

Just because a planet is Earth-sized

and in the habitable zone of a star,

doesn't mean it's Earth-like.

The James Webb Space Telescope is revealing that many

Earth-sized planets lose their atmospheres entirely.

And the ones that keep them can be radically altered.

So how can planets gain and then hold onto the air,

water, and chemistry they need to become habitable?

The James Webb Space Telescope

is unlocking the secrets of alien worlds.

It's revealing that some planets

have extreme atmospheres,

while others have their atmospheres stripped away

by the stars they orbit.

Yet our own Earth followed a different path.

It holds oceans of liquid water.

[Michelle] It may sometimes seem like astronomers have a lack of

imagination, that we're looking for conditions just like

the Earth, where we're looking out there to see what planets

might be habitable, might have life on them.

But remember, we only have one example of how life started,

and water is a really, really useful thing.

The shape of the water molecule separates out

negative and positive charges, and what that makes it

is a phenomenally good solvent.

A solvent is a liquid that can dissolve other elements

within it, and that makes water the perfect medium

for complex chemistry to emerge.

It's pretty safe that you're more likely to find life

on a world in which there is liquid water.

Water changes everything.

It stabilizes climates.

It drives chemistry.

And it allows planets to become habitable.

How do worlds like ours get their water?

[Michelle] The Earth really is something special, but one of the most

mysterious things about our planet is the fact that

there's water here at all.

When the Earth formed 4.5 billion years ago,

it was close to the Sun

and in a region too hot for liquid water to exist.

[Michelle] The Sun was even more active and even hotter than it is now,

and so anything that's light, that could be melted,

that could be evaporated, it was actually blown away

into the outer parts of the solar system.

If rocky inner planets like Earth begin life dry,

where does their water come from?

The James Webb Space Telescope looks for clues in the rings

of frozen debris that surround young stars.

One such system is HD 181327,

a young, sun-like star that's surrounded by

a vast ring of icy debris.

It's a structure that's similar to our own Kuiper Belt,

the ring of icy planetary building blocks

that orbit beyond Neptune.

This is where water can survive,

locked inside frozen worlds, far from the star.

Webb does more than detect water in the ring

around HD 181327.

It also detects a specific kind of ice

called crystalline water ice.

[Phil] Broadly speaking, there are two kinds of water ice.

There's sort of slushy, not very regular ice,

it's just kind of a mess. We call that amorphous ice.

Crystalline ice is what you think of when you think of

like an ice cube.

All the water molecules are locked into place

in a certain pattern.

Crystalline ice only forms when water warms

and then refreezes.

But this debris ring lies far from its star,

where temperatures remain extremely low.

Left undisturbed, ice here should stay cold

and disordered...

yet Webb sees ice that has been heated, reshaped,

and frozen again.

The only explanation is violence.

[Michelle] Anywhere in our own solar system that we find

crystalline ice, like, for example, the rings of Saturn,

we think that that comes from smaller icy bodies

that were broken up.

[Grant] Saturn's rings look permanent and eternal,

and trust me, they are very dynamic.

They are constantly reprocessed by heat and collisions

over many, many millions of years.

Around HD 181327,

icy bodies collide at high speed,

releasing bursts of energy that briefly melt the ice.

As that water refreezes, it locks into

a crystalline structure.

Webb is catching this process in action.

[Grant] Collisions deliver kinetic energy,

and that kinetic energy can be converted into heat.

That heat can be enough to completely transform this ice

into this more regularized,

so-called crystalline structure that we're talking about.

[Hakeem] Before the James Webb Space Telescope,

we really didn't have instruments that were

sufficiently sensitive to study

the chemical composition of the ices

in these planetary debris disks. But now we do.

These collisions do more than reshape distant debris belts.

They scatter water-rich material inward,

towards young, rocky planets.

This is how dry worlds gain oceans...

through billions of years of impacts.

Earth's water likely arrived the same way,

delivered from the outer solar system

by countless icy bodies thrown inward

when the planets formed.

[Grant] Earth was not originally a water world.

It was this molten hellscape that then cooled,

and then very, very quickly, it developed oceans.

It is very possible, frankly likely, that water was

delivered to Earth from the outer solar system

where it originally formed, and it fell inward

as a result of an outermost region collision.

With Webb, astronomers are no longer guessing.

They're watching the process unfold around other stars.

[Michelle] We're seeing the way

the entire planetary system is organized.

There's a mechanism for forming this crystalline ice,

and maybe over time, bring it back to the inner solar system.

We're sort of looking at what we would have looked like

billions of years ago, when the hot, dry world

of the Earth was beginning to get the water back

from the outside, from the colder parts

of the solar system,

and that is entirely necessary to get life started.

We're looking at the same thing

happening in a distant planetary system.

Webb's search for water on distant worlds leads

to a startling discovery.

Webb's search for water on distant worlds leads

to a startling discovery.

It studies LHS 1140,

a star system 50 light-years from Earth.

It finds that one planet in the system,

LHS 1140 b, is 50 percent water.

[Phil] LHS 1140 is a red dwarf, and it's orbited by a planet

called LHS 1140 b.

And we know the mass of this planet by how hard it tugs

on the star, and we know how big it is by how much light

it blocks from the star.

And it turns out from that you can get its density.

Different types of objects have different densities.

Iron is very dense, air is very low density,

water is in between.

What we found from observing the density of this planet

is that it's probably something like

35 to 40 percent water by mass.

[Hakeem] The closest analog we have here in our own solar system

is Neptune's moon, Triton.

It's 45% water,

and its surface, because it's so far from the Sun,

is completely frozen.

But there may be a liquid water ocean under its surface.

[Phil] Triton's a weird place.

We know it's got an icy shell,

probably surrounding a liquid ocean of water.

There's heat inside this world that keeps it warm,

keeps that water liquid.

We have seen plumes of material erupting from the surface.

But LHS 1140 b contains much more water than Triton.

The planet is six times the mass of Earth.

It's not just the fact that this planet is almost

half water, it's how much water it has.

Something like 10,000 times the amount that Earth has.

[Michelle] There's a mystery.

Here you have this very water-rich world,

but it's quite close to its star.

There's so much water, the water couldn't have been

delivered by comets and asteroids colliding

over billions of years.

How does a planet like LHS 1140 b

end up with so much water?

Space scientists believe that the answer lies

in where the planet is born.

Over millions of years,

gravitational interactions can push it inward,

and it slowly migrates towards its star.

As the planet moves closer,

its vast store of ice begins to thaw.

This transforms the frozen world

into one covered in a global ocean

that could be hundreds of kilometers deep.

[Michelle] We also think the planet is probably tidally locked.

It's so close to the star that gravitationally it's been

locked into position where one side

always faces the star, very much like the moon.

This creates a world of extremes.

Ice may dominate the night side,

but on the star-facing side,

the higher temperatures turn the ice liquid.

On LHS 1140 b, this ocean is likely 4,000 kilometers wide,

with a surface temperature of 20 degrees Celsius.

When you think about it, it would look

kind of like an eyeball.

There would be a white surface, but right facing its star,

you might have blue open water.

Webb is showing that watery worlds form

in different ways to Earth.

Some of them form wet, migrate inward,

and become oceans in space.

For other planets, water is built in from the start.

And if Webb can show us that water worlds like this exist...

could any of them support life?

The James Webb Space Telescope is unlocking how planets form,

how atmospheres behave,

and how water shapes alien worlds.

Its findings trigger the question --

what could a habitable world look like?

To find out, astronomers turned to a distant planet

called K2-18b,

a super-Earth that orbits a cool red dwarf star.

It's located inside its star's habitable zone.

Super-Earths are planets that are larger than Earth,

but smaller than Neptune.

So this is a planet that does not exist in our solar system,

but we think that they're very common everywhere else.

They're big enough to hold on to thick atmospheres,

but also easier to detect because they're so big.

And so this makes them a really prime target in the search

for habitable worlds beyond our own solar system.

Webb's spectrometer analyzes the atmosphere of K2-18b.

The data reveals a complex mix of gases -- water vapor,

methane, and carbon dioxide.

Together, those gases point to a warm, water-rich world.

The best-fitting models suggest it has a global ocean beneath

a thick hydrogen atmosphere.

It's what astronomers call a Hycean planet.

[Phil] The idea behind a Hycean world is that the atmosphere

is incredibly thick and that generates a lot of pressure

that pushes down on the water.

When water is under a lot of pressure, it can remain liquid

at much higher and lower temperatures.

[Grant] That hydrogen blanket protects that global liquid water ocean

and might allow liquid water to exist far beyond what we think

of as the habitable zone.

Webb's data indicates that K2-18b could be

the first candidate for a Hycean world,

but it's likely that the conditions on the surface

are completely different to those on Earth.

Now, while a planet covered by a global ocean might sound like

a great place to go fishing, you might want to think again,

because these planets are also predicted to have

incredibly thick, heavy, high-pressure atmospheres.

There's an Earth-sized planet with a high-pressure atmosphere

in our own solar system -- Venus.

In the 1960s and '70s, a series of Russian probes

descend through its cloud tops.

They discover that the temperature

on the planet's surface is hot enough to melt lead,

and that the atmospheric pressure

is a hundred times higher than that on Earth.

[Grant] When the Soviets first started sending missions to Venus,

the first couple of probes imploded as they were

descending through the Venusian atmosphere.

This is because the atmosphere

has such high atmospheric pressure,

it's like you're going halfway down to

the Titanic under the ocean.

The atmosphere of a Hycean planet like K2-18b

would be like Venus on steroids.

The literal weight of the atmosphere above you

would crush you.

But to the surprise of space scientists, Webb detects

something else in this planet's atmosphere.

Another chemical appears

in statistically significant amounts --

dimethyl sulfide, or DMS for short.

[Grant] On Earth, DMS is what we call biogenic.

It is produced almost entirely by organic living organisms,

in this case, microscopic organisms

in the ocean.

[Phil] Detecting this in the atmosphere

of another planet would be very interesting because, hey,

that could be a biosignature, a signature of life.

No known non-biological process can easily explain

large amounts of DMS in a planet's atmosphere.

[Phil] If this observation of DMS in K2-18b is confirmed,

what is that telling us?

It could be telling us that there are just geological

processes that we don't understand that create it.

But it could also mean there could be life there as well.

I found this result personally very intriguing.

And I couldn't believe that maybe the first place we would

find evidence of life, a biosignature,

would be on a planet around another star.

I had always thought maybe we would find it first on Mars,

or maybe one of the icy moons of Jupiter.

But could it be we're going to find the evidence of life

around a planet around another star that far away?

That blew my mind.

The conditions on K2-18b mean this life would be

very different to that on Earth.

If something is producing DMS on this world, it would have to

survive crushing pressures, complete darkness,

unbelievably exotic, inhospitable environment.

But even here on Earth, life finds ways to surprise us.

Extremophiles are organisms that thrive

in inhospitable environments.

Some live inside volcanic vents,

some in frozen ice, and others in toxic lakes.

[Grant] Extremophiles are proof that life can not only survive,

but even thrive in places that we never thought possible.

In many ways, extremophiles are kind of the closest thing

to alien life that we've ever discovered on Earth.

But life, if it exists on K2-18b,

could be stranger still.

Webb's data is far from definitive proof

that alien life exists there.

But it does show that something unusual is happening.

Personally, my attitude as a scientist is to be

a bit conservative and skeptical.

And right now, I don't think we have the proof that it

really is this particular molecule, dimethyl sulfide.

I think we need to draw back until we have

better observations.

But those better observations may be coming

in the next years or decades.

And it doesn't rule out the possibility that

we could have seen a biosignature.

[Grant] With every new planet we study, that is another

stepping stone toward the greatest discovery of all,

the biggest question of all, and that is whether or not

we are alone in the cosmos.

One by one, the James Webb Space Telescope

is revealing the planets beyond our solar system.

Showing us worlds of extremes

and systems that help us understand our own history.

Uncovering what makes worlds habitable

and narrowing the search for the ones that could be

Earth's true cosmic cousins.

Even I am kind of shocked with just how good

the observations have been.

We're now beginning to actually probe the chemistry,

the weather, details about these other worlds that seem

impossibly far away.

[Phil] The idea that these worlds are out there and could be

completely different than what we see here

in our solar system, I think that really stirs

sort of a primal emotional feeling in all of us.

[Grant] We've always wondered what alien worlds are like.

Webb is bringing us from this era of wondering into knowing.

[Hakeem] I just keep going back to the fact that we were in

the Stone Age not very long ago.

And now we're looking at planets around other stars,

finding oceans, potentially finding life.

I mean, come on!