Original subtitles

WILLIAM SHATNER: Volcanoes scar the surface of a rocky planet...

...hidden under thick clouds of acid rain,

while unimaginable heat makes life impossible.

Welcome to Venus.

For centuries, we've been fascinated

by our nearest planetary neighbor,

even dreaming that it might be an exotic paradise

where humans could live one day.

But in reality, this glowing yellow orb

is filled with poisonous clouds,

and its temperature is hot enough to melt lead.

Will Venus remain a strange, forbidden world?

Or could we turn our neighbor into another Earth?

Well, that is what we'll try and find out.

♪ ♪

SHATNER: When we gaze up at the stars,

we see a vast array of cosmic wonders,

from majestic constellations to sweeping comets...

...and much more.

But there is one particular object

that is perhaps more captivating and mysterious than the rest.

It's a bright diamond that shines above the horizon

which we call Venus.

Venus is very bright in the sky.

It's visible in the evening or in the morning,

depending on the time of year.

And so, people are, naturally, just very curious

about what that bright thing is out there,

especially as we started building accurate models

of the solar system

and realized that it was the closest planet to us.

PAUL BYRNE: On paper, Earth and Venus

are really similar.

They're almost the exact same size,

they're made of about the same materials,

they're about the same age and they orbit the same star.

And so, for those reasons and a host of others,

that's often why we say that Venus is Earth's twin.

SHATNER: Is Venus truly Earth's twin planet?

And if so, what secrets lie within this luminous world

that hangs in our sky?

O'ROURKE: Scientists are...

more ignorant about Venus than we are about

almost any other world in our solar system.

For example, we know very little about the interior of Venus.

On Earth, we know how big our core is

because of seismology,

but we've never measured Venus quakes.

we haven't put the seismometers on the surface

that we would need to make detailed maps

of the interior of Venus.

And so, the planet is just, all in all, a big mystery.

SHATNER: The mysteries of Venus

have intrigued mankind for thousands of years.

Our ancient ancestors could only speculate

about the true nature of the planet.

Venus has been incredibly important

throughout human history.

It is the third-brightest object in the sky

after the Sun and the Moon.

And that has led humanity to associate it

with various deities in different civilizations.

For example, the name "Venus"

was a Latin name that was given to it by the Romans.

The Romans gave the planet the name "Venus"

because it's so beautiful in the sky, and therefore,

they named it after their goddess of beauty and love.

And so, the brightness of Venus

has given people a great deal of fascination about it.

SHATNER: While ancient societies

looked upon Venus as a divine entity,

during the Enlightenment,

scientists were compelled to unravel the mysteries

of Earth's so-called twin.

Astronomer Francesco Bianchini

constructs several large telescopes around the city,

including one directly across from the Colosseum

that measures an unprecedented 72 feet in length.

Bianchini's goal is to give humanity

its first up-close look at Venus.

GRAHAM LAU: Francesco Bianchini was using

remarkably long telescopes-- refracting telescopes--

with large lenses for their time

to make his observations of Venus.

He started seeing

these large, dark regions on the surface of Venus

that he thought were lakes or oceans of water.

He even created the first globes of Venus

and mapped out these features.

And for that period of time,

that would make sense, that there should be

other worlds that, just like the Earth,

have oceans and lakes and rivers.

SHATNER: Bianchini's drawings of Venus amazed people throughout Europe.

But some scientists were skeptical of his claim

that Venus had large bodies of water.

And as it turns out, his critics were right.

LAU: We now know that Bianchini wasn't looking at lakes.

Indeed, he was looking at the clouds of Venus.

And so, when we look at Venus with visible light,

we see a world obscured by clouds.

But even though we now know that what Bianchini thought

he was seeing of Venus is wrong,

his observations using these large telescopes

were a huge step in astronomical observation.

SHATNER: For centuries, the dense clouds that shroud Venus

frustrated scientists who wanted to get

a better look at the planet.

This impenetrable cloud cover inspired wild theories

about what lies on Venus.

Before the Space Age, people believed

that Venus is a sort of swamp world...

...covered in a planetwide jungle,

where heroes rode around on dinosaurs

and fought amid a lot of greenery.

And science fiction writers were convinced that Venus was

a place where humans could not only visit

but perhaps thrive and have great adventures.

SHATNER: By the middle of the 20th century,

curiosity about Venus reached the point

that scientists realized it was time

for humanity to finally glimpse the surface of the planet.

From the Baikonur Cosmodrome,

the Soviet Union launches its Venera 9 spacecraft.

Four months later, Venera pierces the thick clouds

that have hidden Venus for ages,

and a robotic probe lands on the planet,

allowing humans to see the surface of Venus

for the first time in history.

ANNA GÜLCHER: The pictures taken by Venera 9

in 1975 on the surface of Venus, they have this yellow gloom

which is kind of an artifact

from the composition of the atmosphere.

And if you look at those pictures,

you see these plains of dark, smooth rocks

that are fractured and, in places, broken.

It has something alien but also something very familiar.

JACOB HAQQ-MISRA: These pictures are breathtaking.

This is a planet that you cannot see the surface of,

even with a really powerful telescope.

And so, to see photographs from Venus, it's just amazing.

And these are still some of the only pictures

we have that were actually taken from the surface of Venus.

SHATNER: The Venera 9 mission

was a breakthrough in space exploration.

But curiously, the robotic lander

operated for a mere 53 minutes before melting down.

What scientists didn't know at the time--

but would quickly discover-- is that Venus,

for lack of a better word, is a hellhole.

We now know the surface conditions on Venus

aren't anything like they are on Earth.

For example, the surface temperature

is almost 800 degrees Fahrenheit.

That is the same temperature your oven is on

in its self-cleaning mode.

The entire planet has a global layer of clouds

made of sulfuric acid,

and those clouds drop sulfuric acid rain.

These conditions are more than enough

to kill you in several ways simultaneously.

And so, that's why we often refer to Venus

as Earth's evil twin.

SHATNER: With such hellish conditions,

it's easy to see

why Venus is now considered Earth's evil twin.

And yet, some scientists claim that in the distant past,

Venus was more identical to Earth.

So, what went wrong?

One of the big questions we have in planetary science right now

is why did Venus change to become the world it is today?

What killed it and could that mechanism

one day affect Earth?

Or perhaps, why didn't it affect Earth?

Was Venus unlucky, or has Earth remained lucky?

And the short answer is we don't know.

SHATNER: How can we unravel the mystery

of what happened to Venus?

One theory suggests that a clue lies

in the fact that Venus is covered with deadly volcanos.

SHATNER: The shuttle Atlantis launches

from Kennedy Space Center,

carrying the Magellan space probe.

Magellan's mission is to orbit Venus,

and take detailed images of the entire surface.

The photos reveal an up-close look

at a planet covered in massive volcanoes.

One of the really surprising discoveries

of NASA's Magellan radar mission

was about 80% of the surface is covered in volcanic plains.

We know now that there's more than 85,000 volcanoes

that are about half a mile in diameter or bigger.

And so, Venus is an extremely volcanic world.

SHATNER: The volcanoes on Venus are fascinating,

and some experts have wondered:

could they be the reason why the planet

became Earth's evil, and inhospitable, twin?

Many people believe that Venus

could have been a nicer place in the past.

And if Venus formed

in the same way that Earth formed,

it's possible that if we hopped in a time machine

and went back in time one or two billion years,

that Venus had oceans in the past,

that it was a nice place to live just like Earth is today.

So, what fascinates me about Venus is the prospect

that it was a habitable world like Earth,

but then lost its habitability

in some sort of planetary catastrophe.

How did Venus get from a possible

happy, habitable state in its early history

to this world that we see today?

One hypothesis that we've put forward

is that it could be large-scale volcanism.

If you could have these large volcanic events,

then you have all this magma kind of flowing out

over millions of years.

These kinds of events can produce

tremendous amounts of carbon dioxide into the atmosphere.

Adding more carbon dioxide makes the planet hotter.

And you end up with what modern Venus is today.

SHATNER: Did a cataclysmic series of volcanic eruptions

turn Venus into the extremely harsh environment

it is right now?

And if so, is it possible

that a similar catastrophe could take place

on Earth?

It turns out that Earth is an extremely volcanic world.

Over the last 500 million years or so,

there have been some gigantic volcanic eruptions on Earth,

and we know that some of the largest mass extinctions

recorded in the fossil record

are tied to those volcanic events.

And so, you can imagine a scenario

where if you have enough volcanoes

erupting over a short enough period of time,

then possibly you start talking about an Earth

that becomes much more like Venus than it is today.

Right now, we don't have enough information to say

whether that's possible or not,

but it sure has got scientists thinking.

SHATNER: The possibility that volcanic eruptions

could make Earth more like Venus is concerning.

So, how can we learn

whether this doomsday scenario might happen?

Scientists believe that clues can be found

by taking a new look at some old data

about the volcanoes on Venus.

In 1978, NASA launches the Pioneer Venus Orbiter

to perform observations of Earth's neighboring planet.

The probe sends back massive amount of data

about both the atmosphere and the surface of Venus.

Experts spend the next several years

poring over this information

including a planetary scientist named Robert Herrick.

I started my career as a geoscientist

in the oil industry in Texas

and I got hooked up with a guy who was working

with Pioneer Venus gravity and topography data.

That was my entrance into Venus science.

It was the first time where the data was released

on this new invention called the compact disc.

And so we got sent boxes and boxes of CDs,

and you could load up one image every 15 seconds or so.

And so, it was really kind of prohibitively difficult

to do a large-scale scan of the data,

and so nobody did it.

SHATNER: In the early 1990s,

Robert stopped analyzing the information

collected about Venus

and, for decades, this vast amount of data

was largely forgotten.

Until 2020, when Robert was inspired

to take a second look using cutting-edge software.

And this time, he made a remarkable discovery

about a particular volcano on Venus.

I had a list of, you know,

the most likely places on Venus

where there was an active volcano.

And I just sort of started going through them one by one

and flipping back and forth between the images

and looking for something that changed.

Where I hit paydirt was near the summit

of the very largest volcano on Venus.

I found a volcanic vent that had appeared

to change shape over an eight-month period.

It was pretty exciting.

I'm like, I think this is important.

It makes it clear that at least parts of the planet

are currently volcanically active.

SHATNER: When Robert published his results in 2023,

scientists were shocked

because they have long believed

that Venus's once-deadly volcanoes

went dormant sometime in the distant past.

But this discovery proved

that there is ongoing volcanic activity on the planet.

It also showed that we still have a lot to learn

about the volcanoes on both Venus and Earth.

It's so peculiar to think that they used 30-year-old data

and found something that was never found before.

Why didn't we see it earlier?

So, the 2023 discovery was, in my eyes, huge.

Since Venus is volcanically active today,

we can actually get insights into the volcanoes

we have on the Earth,

and the future of our planet, in many ways.

It's an important discovery because both Venus and Earth

are volcanic planets.

Venus is releasing heat

similar to the way Earth is releasing heat.

And so, we need to learn the details

about how that occurs.

Studying the volcanoes on Venus should show us

how we could spare Earth the same fate as its evil twin.

But the mysteries of our closest planetary neighbor

go far beyond its fiery surface.

For instance, scientists are trying to figure out

why Venus actually spins backwards.

In the archives of the Saxon State Library

lies an ancient manuscript known as the Dresden Codex.

Dated to around the 11th century AD,

the Dresden Codex is the oldest

and best-preserved writing of the Maya,

a civilization which ruled Mesoamerica

for more than 3,000 years.

And curiously, the pages of this text

contain a remarkable connection

to the planet Venus.

The Maya worshipped Venus and it appears

that they put Venus as the cornerstone

of their faith and also their civilization.

And when scientists looked at the Dresden Codex,

they found what we now call the Venus Table,

which is able to predict the position of Venus

to a very high accuracy.

In fact, they kept some of the most accurate records

in all of human history

before the advent of modern astronomy.

KANE: The observations of Venus by the Mayans

shows that, actually, Venus has been incredibly important

throughout human history.

And the tracking of Venus's motion

has been something that people have paid attention to

for a long time.

SHATNER: It's astonishing to think that ancient people

were just as fascinated by the movement of Venus

as modern astronomers.

But technology has made tracking the planet much easier

and revealed some curious aspects of Venus's motion.

In 1962, at NASA's Deep Space Instrumentation Facility,

located in the Mojave Desert,

experts discovered something about the rotation of Venus

that no one had ever noticed before.

It actually spins backwards.

WAY: Most of the planets in the solar system are spinning

in the same direction. But Venus is spinning

in the opposite direction.

It's spinning backwards,

compared to Earth's spin axis.

O'ROURKE: Venus spins in retrograde.

You can think of that as Venus spinning backwards,

or you can think of that

as Venus having been flipped upside down.

But however you think about it,

what it means is that Venus's spin is a big mystery.

SHATNER: Is Venus flipped upside down?

It's an extraordinary notion.

And it makes you wonder what it would be like

to live on a planet that spins backwards?

For everything Venus has in common with the Earth,

from its size and its mass, it has some things

that are really different from the Earth, also.

If you were on Venus,

or if Earth was doing what Venus did,

the sun would actually rise in the west

and set in the east.

So, it would-- it would generally be

a bizarre experience.

SHATNER: Curiously, Venus's backward spin

isn't the strangest aspect of its movement.

Because not only is Venus turning

in the opposite direction,

it also spins so slowly

that it's hardly rotating at all.

Venus spins incredibly slowly compared to Earth.

We know that Earth takes 24 hours

to spin once on its axis.

In comparison, if you were living on the surface of Venus,

it would take 243 days to

spin once around on Venus.

KANE: Venus rotates once every 243 days,

but it takes 225 days to orbit the sun,

which means it takes longer to rotate

than it does to orbit the sun.

Its day is longer than its year.

That makes it different to almost everything else that

we observe within the solar system.

SHATNER: Scientists are still trying to learn more about

Venus's unusual spin,

and some have asked what would happen

if Earth rotated at such a slow pace?

Experts theorize that the results would be

nothing short of catastrophic.

VERONICA BRAY: If the Earth had a really slow spin,

we would have sections of the population that would

have to live entirely in darkness

for a large section of the year.

The rest, on the lit side of the planet,

would be scorched mercilessly.

McGEE: Having one side of the planet be

so much hotter than the other would mean there are

torrential winds that would be blown from the hot side

and sucked onto the cold side.

You'd have cyclones and massive storms

at the transition zones.

It would be a really unfriendly place.

SHATNER: Could Venus's slow, backwards spin be one reason

it's such a hostile wasteland?

And if so, what caused Venus to rotate

so differently from Earth?

According to planetary scientists,

a clue may lie in the fact that

while Earth is orbited by a moon,

Venus is not.

BRAY: We think that the Earth's moon made Earth habitable.

One way that the moon has helped us

have a habitable planet

is that it stabilizes our rotation.

So, there's a lot of planets in the solar system,

like Venus, that are wobbling like a spinning top.

And if you have a large enough wobble,

it can lead to extreme seasons.

And for Earth, the Moon stabilizes our rotation

and we only wobble a little bit,

giving us relatively mild seasons,

which helps the development of life on Earth

and keeps things habitable for us.

KANE: The Earth's moon is one of

the distinctive features of the Earth,

and we're not really sure

why Venus doesn't have a moon.

And it is still something that we struggle to understand,

how a planet

can have a rotation that is the opposite to

almost everything else that we observe,

and is now in a permanent state of hostile conditions.

A planet that rotates backwards?

It's enough to make your head spin.

But experts claim what's even more bizarre about Venus

is its atmosphere,

because the poisonous clouds that cover it

may actually contain

the seeds of life.

(siren wailing)

SHATNER: Smoke from more than a thousand wildfires

sweeps over southern Canada

and the northern United States.

A fiery haze envelops cities like Chicago

and New York,

rendering the air so toxic

that experts label it a lethal threat to life.

SUTTER: At the height of the wildfires,

the pictures taken from downtown Manhattan

looked like the city existed on another planet.

But you could be standing in

the middle of the worst atmosphere

you can possibly imagine on Earth,

and it's nothing compared to

a normal day on Venus.

CLARA SOUSA-SILVA: In many ways, Earth is heaven

and Venus is hell.

The surface of Venus is so, so hot

that it can melt lead.

It is extremely dry and extremely acidic,

more than any place we've ever attempted to find life on Earth.

And so Venus has almost no part of it

that isn't absolutely hostile to life.

SHATNER: It's hard to imagine that humans,

or any other life forms,

could ever survive in the brutal

and inhospitable environment of Venus.

But, incredibly, that hasn't stopped scientists

from searching for signs of life

on Earth's evil twin.

SOUSA-SILVA: On Earth, life has been found

in every conceivable place.

However, if we did find life on Venus,

a place so different from Earth, it would mean that life

is not just inevitable, it is common.

It is everywhere.

And so when we look for life on Venus,

we look for the unusual,

we look for the strange,

and we don't just look for the familiar.

SHATNER: Is Venus home to strange life forms that,

against all odds, have somehow managed to survive

in its lethal conditions?

And if so, where on the planet might they be found?

Well, according to one theory,

it could be in an unexpected location.

In the scientific journal Nature,

astronomer Carl Sagan and biophysicist Harold Morowitz

publish an intriguing hypothesis.

They propose that if life does exist on Venus,

it would not be on the planet's surface,

but rather...

in its clouds.

SOUSA-SILVA: Venus is a pretty hostile place to

most life almost everywhere.

However, there are places in the clouds

that are really like a summer day

on the surface of the Earth.

You get just enough light from the sun to get energy,

but still some protection from the atmosphere.

HAQQ-MISRA: The cloud decks of Venus are actually

a fairly Earth-like environment.

And so Carl Sagan and Harold Morowitz

had an idea that perhaps microbial life

has found a way to survive

in the atmosphere of Venus

where you've got these habitable conditions.

Over the last few decades,

we've learned fascinating information

about so-called extremophiles,

microbial life that has adapted to

unbelievable conditions on Earth,

even places where there's virtually no water,

high into the atmosphere.

Now, whether there's life on Venus

remains an open question.

But it sure has got scientists thinking

about what that would mean

for life in the Venus clouds.

SHATNER: Could there be life in the clouds of Venus,

as experts theorize?

Planetary scientists not only believe it is possible,

they also may have actual proof.

And it was found by looking at Venus

in an entirely different light.

In a groundbreaking paper

published in the journal Astrobiology,

biochemist Rakesh Mogul and a team of scientists

made an astonishing announcement.

They discovered that although, to the naked eye,

Venus's clouds appear to be a light-colored, uniform veil,

when the planet is observed in ultraviolet light...

...it reveals that the clouds

contain mysterious dark patches.

Venus looks very different in different forms of light.

And in these dark patches

where we see ultraviolet contrast,

these patches move around in mesmerizing patterns,

and what we saw is that their spectral characteristics

are very similar to

microbial algal blooms that we have here on Earth,

something that is alive and biological.

So we put that theory out there

that those UV contrasts

look like algal blooms.

So, with Venus,

I'm very much interested in the potential

for the clouds to be

a habitable zone, habitable environment.

And that's really exciting.

SHATNER: The fascinating theory that life may have found a safe haven

in the clouds of Venus made headlines around the world,

and it suggests that Earth's twin planet

may not be as evil as we commonly think.

Scientists are still arguing

about life existing in the clouds,

but it's definitely not impossible.

It's a tantalizing possibility,

and it really illuminates

how little we know about Venus

and the fact that we can't exclude the idea

that life exists in the clouds.

Finding microscopic life in the clouds of Venus

would be a monumental discovery.

And what's intriguing is

how NASA plans to search for that evidence.

They're building a revolutionary new spacecraft in the form

of a robotic balloon.

SHATNER: At the dawn of the Space Age,

Venus was a prime target for planetary exploration.

In 1962, NASA's Mariner 2 probe

made the first successful flyby of Venus.

And then, in 1970, the Soviet Union's

Venera 7 spacecraft

made the first successful landing on the planet.

SHATNER: Over the next 15 years, nine more probes landed

on the surface of Venus,

with Vega 2 making the final touchdown in 1985.

But since that time,

no spacecraft have landed on Venus,

or even flown through its atmosphere.

Which begs the question, why did space agencies shift

their focus away from Venus?

The surface of Venus is inhospitable

to all our current spacecraft technologies.

So, when we send things to Venus,

we know that they can only survive for a few hours,

because once the circuitry is as hot as Venus is,

they're cooked, and they die.

And so, the grand challenge for the future

of Venus exploration is to build something that survives.

SHATNER: Will scientists be able to design a probe

that can withstand the lethal conditions of Venus?

As it turns out, NASA is working on this problem right now.

In this remote area, more than 100 miles away

from the closest major city,

a strange, shimmering airship rises into the sky.

Known as an aerial robotic balloon, or aerobot,

the device is a prototype developed

by NASA's Jet Propulsion Laboratory.

NASA specifically chose this barren,

inhospitable location to test the aerobot

because the climate conditions closely resemble...

the upper atmosphere of Venus.

BYRNE: Balloons are the next technology

for how we explore Venus.

Because the atmosphere of Venus at an altitude of

around 40 miles is relatively clement,

where the temperature and pressure conditions are okay,

a balloon could float for weeks, months, or even years.

And so, we would be uniquely positioned to

conduct all kinds of scientific investigations.

SHATNER: To help it endure the harsh environment of Venus,

the aerobot is equipped with advanced features,

such as a puncture-proof metallic skin,

and remote-controlled helium chambers to allow for

precise altitude adjustments.

NASA hopes that these advancements will enable

the probe to conduct the most comprehensive

exploration of Venus to date.

I'm really excited about exploring Venus with a balloon,

because a few years ago, some astronomers claimed

a detection of phosphine gas in the clouds of Venus.

That was incredibly exciting for everyone because

phosphine gas is a biosignature, it's a sign of life.

Scientists are still arguing about how much phosphine

is in the atmosphere of Venus,

but if you sent a balloon to Venus,

you can actually do geophysical investigations

about the possibility that life exists in the clouds.

SHATNER: NASA plans to build a fleet of aerobots that could be

floating through Venus's atmosphere within a decade.

However, the best way to explore our twin planet

would be to send astronauts, instead of robots.

So, could there be a way

for humans to explore Venus?

The biggest obstacle to humans, if we want to explore Venus,

is the fact that the planet is so hot.

This is a very dangerous environment

for humans to venture.

And so, it be comes very difficult to think about

how you would do this in a pragmatic sense.

There have been science fiction stories,

and even people have put good faith effort into

building a kind of domain, like we bring to the bottom

of the oceans, that are protected from

the sulfuric acid, and could have

their own sort of environment.

But all of them are highly speculative and,

of course, very challenging, technologically.

SHATNER: Figuring out how to keep humans alive on Venus

seems like an insurmountable problem.

But some experts believe it's possible,

that science fiction might soon become...

science fact.

NASA announces a new plan

for an experimental vehicle

that would allow astronauts to explore the planet Venus.

The proposed device is called

the "High Altitude Venus Operational Concept,"

otherwise known...

as HAVOC.

HAVOC is essentially an airship, a blimp,

with a gondola underneath

in which humans, actual astronauts,

would spend some amount of time conducting scientific

experiments at about 40 to 45 miles above the surface.

LAU: Basically, we would live on these large,

floating platforms;

our own cloud cities on Venus,

allowing humans to live in the atmosphere,

to do research on Venus without ever going down.

And then when they're finished, they could just

take back off again from these floating platforms.

O'ROURKE: Something like HAVOC really illustrates

how people rise to meet challenges.

The hostile conditions on Venus are a curse

because it makes it hard to do things,

but they're also a blessing in that it forces us

to stretch ourselves and become creative

and think of new ideas.

SHATNER: The notion of humans inhabiting cloud cities above Venus

is fascinating, and hopefully, it will actually be achieved.

But there's an even more ambitious proposal

when it comes to human exploration of Venus.

It involves transforming the entire planet...

to make it more like Earth.

SHATNER: In the journal Science, an intriguing article titled

"The Planet Venus" is published

by astronomer Carl Sagan.

Although Sagan would later write about the possibility of

life in the clouds of Venus, in this paper,

he proposes something far more incredible.

He suggests that it might be possible to transform Venus

into a planet capable of sustaining human life.

This concept is referred to as terraforming.

Terraforming means changing the environment

to be even more like Earth.

Carl Sagan imagined that you could change

the surface of Venus

into something which could have conditions that are similar

to Earth that humans can survive in.

SUTTER: Today, humans would be

simultaneously crushed and melted

if you were to step foot on Venus.

This is just hell in planet form.

And so if we want to turn Venus into a copy of Earth,

we have our work cut out for us.

SHATNER: The idea of terraforming Venus

into an Earth-like world is astonishing.

But how could we possibly achieve

such an extraordinary feat?

Carl Sagan theorized that one way might be to

seed the clouds of Venus with algae,

to convert carbon dioxide into oxygen,

which would potentially trigger a planet-wide transformation.

O'ROURKE: Carl Sagan was brilliant, and he had

almost the right picture of terraforming Venus.

The only thing he got wrong is he thought the clouds

were made of ice crystals and water vapor.

Unfortunately, we now know that those clouds

are sulfuric acid, not predominantly water vapor.

And so, we'd have to get a little more creative

if we wanted to terraform Venus.

But it's definitely not impossible.

LAU: When it comes to the concept of terraforming,

sure, Venus now has this extremely hot

and dense surface, this thick atmosphere.

It doesn't seem hospitable.

But as our ability to geo-engineer

the environment around us changes,

we have to wonder, maybe Earth's twin planet

will truly become our twin planet

as we terraform Venus and give it a biosphere

just like we have.

Maybe in the not-too-distant future,

Venus and Earth will look almost the same.

SHATNER: Today, terraforming Venus remains an intriguing concept

that scientists are still debating.

But in the more immediate future,

NASA and the European Space Agency

are planning exciting missions to study Venus.

The data they collect will hopefully solve

some of the many mysteries of Earth's evil twin.

O'ROURKE: One of the goals of the missions

that NASA and the European Space Agency are sending to Venus

is to make maps of the surface at high resolution

of some of the most exciting types of terrain on Venus.

There's a lot of mountains, a lot of valleys,

a lot of ridges, that have only had relatively imprecise

and perhaps inaccurate measurements thus far.

And so, we could make a variety of interesting discoveries.

LAU: Venus really does beg for further exploration.

Sure, we've had landers go to Venus in the past,

but there may one day be a rover concept design

that allows us to rove on the surface

and get some science for us to better understand

how to avoid undergoing

the cataclysms that Venus underwent.

MOGUL: In science, it's important to push the boundary,

so studying Venus is really exciting

because we don't know a lot about Venus.

There have been a lot of probes that have been sent

to Venus and they have studied A, B, and C, and D,

but there's still a lot left in the alphabet to explore.

In the coming years, the exciting new missions

to Venus may help answer some burning questions

about our twin planet.

Could life exist in its clouds?

Or might humans one day call it home?

It's all cosmically fascinating.

But until we actually journey to the planet

and see it with our own eyes,

the secrets of Venus will remain...

unexplained.

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