Original subtitles

*

There is an unbreakable bond between life on Earth...

..and the stars above.

Everything we see up there and down here is made from the same stuff...

..atoms.

The question is, how did these atoms come together to make us?

And are we the only life asking this question?

Everything we see in the universe is made from the same building-blocks.

The universe is only made up of a handful of basic ingredients -

hydrogen, helium, lithium, carbon and so on.

All of these chemicals, in different proportions, are what make us up,

and these same chemicals in different proportions

make up everything.

The same chemicals that form galaxies and stars,

do something amazing on Earth, perhaps even unique...

..they become living things.

Organisms that can grow...

..reproduce and think.

We are bits of the universe made conscious.

I think that's a... It's a biological miracle.

You look out into the sky

and you know you're connected to that somehow. It's pretty fantastic.

The story of life on Earth actually began long before Earth even existed.

Immediately after the Big Bang,

the universe was a vast cloud of hydrogen gas.

Pockets of the gas cloud collapsed to form stars.

The stars turned hydrogen into more complex atoms and molecules.

I don't think there's any way you could make life

out of just hydrogen.

You need other compounds to give you the more complex chemistry.

The start of life was really the start of the first stars,

probably about half a billion years after the Big Bang.

Deep inside the cores of these early stars,

heat and pressure crushed hydrogen atoms together so powerfully,

they fused...

..creating helium atoms and releasing a burst of energy.

Over time, helium atoms fused together, too,

creating carbon, nitrogen, oxygen and even heavier atoms.

Over hundreds of millions of years,

ancient stars built up all the elements

that make up our solar system today, including the atoms in your body.

But in doing so, these stars paid a catastrophic price.

Drained of energy, the ancient stars collapsed and then exploded.

A supernova...

spreading their chemically rich stardust across space.

The iron in your blood, the calcium in your teeth, in your bones.

These were created in a supernova explosion,

probably different stars that blew up billions of years ago,

seeding the space around them with this stuff.

We are the product of not just one stellar explosion,

but many stellar explosions and the atoms in our left hand

probably came from a different star than our right hand.

The carbon, nitrogen, oxygen, iron,

all of that was only created in stars.

And the only way it could get here on Earth

is if those stars exploded

and that material was later amalgamated in our solar system.

Blasted into space,

these complex atoms pepper the clouds of gas

that then themselves become the nurseries for new stars.

4.6 billion years ago,

one particular cloud began to collapse under its own gravity...

..and the sun ignited.

Most of the ancient stardust was sucked into the sun.

What little remained went on to form the asteroids,

comets, planets and even the plants and the animals

that inhabit the Earth today.

I actually think of myself as a very complicated rock.

I am made of things like iron and copper and manganese.

When you sit down on a mountainside and you're there with the rock,

those are your cousins, too.

Thanks to the remnants of ancient stars,

the Earth formed with all the atoms needed to create both rocks and life.

But what is it that distinguishes life from mere chemistry?

There are essentially three main parts to a living organism.

You've got to have some metabolism

or some kind of system of chemical reactions that powers your life.

You've got to have some kind of bag or sack that walls you off,

your internal systems from the outside environment.

And thirdly, you've got to store some kind of blueprint,

some kind of description of yourself.

Three things set life apart...

..a power source, a protective sack,

and the blueprints for making duplicates of itself.

On Earth, every living thing has the same kind of blueprint.

It's a chemical code called DNA.

DNA contains the instructions for how to build the cell's engine,

using small molecules called amino acids.

DNA also tells the cell how to make lipids,

the fatty molecules that form the protective sack,

and that's it.

The most basic form of life - a cell.

The chemistry set for life is actually quite simple.

It's 20 amino acids,

it's a few nucleotide bases for making DNA and RNA,

a few lipids and that's it.

Think of it as like a Lego kit.

Scientists wanted to find out where the ingredients

for this simple kit-of-life came from.

In the 1950s, chemist Stanley Miller set up an experiment to find out.

He filled a series of flasks with water vapour and volcanic gases

to recreate the early atmosphere of the Earth.

And then he sent an electric spark across the mixture

to simulate lightning.

The result was a foul-smelling gunk...

..that included one of the three basic building-blocks for life.

We find, produced in these experiments, some amino acids.

Some of the same amino acids that are produced in life.

Before Miller's experiment, it was assumed

that this kind of organic material could only be produced by biology,

which is why it was called organic.

Miller showed that it's not biological,

it's occurring, we would expect, lots of different places.

Because amino acids were so easy to make,

scientists wondered whether these same molecules

could have formed in the gas cloud that made the sun even before the Earth itself was born.

If the theory was right, then asteroids,

the leftovers from this period of planet-building,

might still contain these ancient molecules today.

Proof arrived in the 1960s

when a space rock, older than the Earth, fell on Murchison, Australia.

When you pick up pieces of this meteorite, it just reeks.

It stinks of kind of organic, volatile chemicals.

And when you analyse what's in there,

we find there's plenty of amino acids,

are the building-blocks of proteins.

We find kind of fatty molecules

that make these envelopes, these membranes around all of ourselves,

and incredibly, we find the basis of DNA.

The Murchison meteorite proved

that the component parts of a living cell are everywhere.

They were in the clouds of stardust that formed the Earth...

..the atmosphere of the early Earth made more.

And asteroids containing organic building-blocks

continued to rain down for millions of years after the crust cool.

The early Earth was steeped in the building-blocks for life.

And how these building-blocks come together...

..in just the right way to form a cell...

..could be described as miraculous.

*

*

The Earth, four billion years ago.

There was land, sea and a newly formed moon.

The moon was much nearer than it is today.

Its close proximity raised huge tides

that swept miles in land.

Volcanoes belch choking fumes into the broiling-hot atmosphere...

..and asteroids and comets rained down from space.

It was a time of no oxygen in the atmosphere.

It was much hotter because of the radioactive heating

left over from the accretion of the Earth,

the impact heating left over from the accretion of the Earth.

An incredibly alien place,

and not anything like the Earth we see today.

And yet life arose there.

If we're going to search for the origins of life on Earth,

we have to bear those conditions in mind.

Similar conditions exist on Earth today.

Scientists study them to understand how life could have come to exist

on our hostile young planet.

The early Earth wouldn't have had great continental land masses

like we see on the globe today,

but more like archipelagos of volcanic islands.

You would have had these enormous tides washing miles upland

and then receding back again.

And leaving behind them something a lot like this landscape

we see here, with rock pools of warm, steamy water.

Some scientists believe life could have started

in these warm rock pools.

The building-blocks of life was suspended in the water.

They would have concentrated together

as the water evaporated in the strong sunlight,

forcing the molecules to interact.

At this geothermal site in Iceland,

a similar process concentrates minerals into a thick, white paste.

One of the most important kinds of chemicals

that might have been concentrated down in these volcanic rock pools

on the early Earth for the origins of life, are lipid molecules, so fatty molecules.

And these are able to pull off a very clever trick.

They naturally self-assemble.

On the early Earth,

individual lipid molecules floated free in the oceans.

But trapped together in rock pools,

these fatty molecules joined up to form bubbles.

And this is important for the origin of life

because they form the outside membrane

of all cells of all life on Earth.

And to show you what I mean, I can use these fishing floats here.

Now, these fishing floats have an end which hates water

and an end that loves water, just like a lipid molecule.

Let's see what happens.

So no matter which way they go in,

they've all naturally orientated themselves with one end sticking out

and one end staying in the water.

And we can see they've clumped together.

The fatty molecules were drawn to each other like oil droplets

on the surface of water to form a thin membrane.

And whenever these waters lapped against land,

the films would have coated the inside

of the volcanic rocks with oily bubbles.

This rock has got a very spongy texture to it.

So if these lipid molecules form naturally into these films

and bubbles and line the inside of these vesicles in the rock,

you've essentially built a protocell.

With the protocell in place, the fatty sack would have been filled

with organic molecules like amino acids,

from the concentrated soup left behind in the rock pool.

Perhaps these simple building-blocks joined together

to form proteins and DNA.

Maybe that was a great environment to get things concentrated.

You had water,

but you had a chance for things to sink together into shallow pools,

where molecules could really be forced to interact.

Rock pools show us that it's possible

for the organic machinery of cells to assemble.

But as a place for the origin of life,

rock pools had a huge drawback.

Four billion years ago,

the sun's UV radiation

was up to 1,000 times stronger than it is today.

This intense radiation would have destroyed the DNA

that formed in the shallow rock pools.

So in an effort to understand

how a cell could have come together away from the sun...

..scientists took a closer look at what a cell needs to work.

You can think of it like an industrial city.

Tiny structures inside the cell operate like factories.

They take in raw materials

and transform them into more complex forms

such as the hardware to build new cells.

And just like a city,

cells also need energy to keep their industrial units running.

Some scientists believe that the key to the origin of life

is hidden in the way life gathers and uses energy.

It all comes down to energy.

Energy is what drives complexity and development and technology.

We see it in human history.

It drove development and complexity into the story of life.

Today, cells have complex biological power stations built inside them.

These structures help to drive chemical energy

in and out of the cell membrane.

And this chemical flow ultimately provides the cell with power.

But the very first cell wouldn't have had the luxury

of such a complex system to generate power.

And the energy from the sun

would have been tainted with lethal radiation.

So the quest to find the place where life first arose,

lead scientists to search the Earth

for a shady spot with chemical energy already moving through it.

In the 1970s, scientists embarked on a daring submarine mission

to a long volcanic crack on the bottom of the Pacific Ocean.

They discovered tall chimney-like structures...

..belching hot volcanic water.

Incredibly, these structures were covered with life.

What really blew people's minds

when we first discovered these was the ecosystems.

Like oases of life huddled around these black smokers

miles deep in the water in the sea

where the light of the sun never shines.

Before these vents were discovered,

nobody knew that life could exist without light.

But here were creatures thriving on the chemical energy

jetting directly from the seabed.

Scientists began to wonder if the same chemical energy

could have kick-started life...

..but there was a problem.

These vents that were first discovered

were really too hot to be the site for the origin of life.

In the year 2000,

scientists working 14km to the west of the Mid-Atlantic Ridge

discovered a new, much cooler type of vent.

They named them "alkaline vents", after their unique chemistry.

What we find with these alkaline vents,

we have this warm mineral-rich water seeping out in the seabed

and then kind of mixing and interacting with the cold seawater around it,

is it deposits the solids and kind of builds up these vast chimney kind of towering-type structures.

The temperature inside the towers was perfect

for organic molecules to assemble into more complicated forms.

Scientists then searched the vents for a source of energy

that could potentially turn chemistry into biology.

Laurie Barge is part of a NASA team that grows alkaline vents.

Now we're beginning to test in the lab

what specifically could be happening on vents on the early Earth.

We have to take into account the conditions of the early atmosphere,

the early ocean,

the type of ocean crust and reactions that would have been occurring.

Laurie starts by injecting alkaline fluids into a simulation

of an early Earth ocean.

The ocean here contains dissolved iron

as it would have on the early Earth.

And then the chimney that you're seeing

is the precipitate that forms

when you have two contrasting solutions like this.

A delicate chimney builds up inside the flask.

And because this structure is alkaline,

it reacts with the acidic water around it...

..drawing chemical energy into the walls of the chimney.

And this chemical flow is almost identical

to the one generated by living cells today.

But energy and temperature aren't the only features

these alkaline vents share with living cells.

The curious thing about these alkaline vents

is that the pockets and the pores and the kind of channels and tunnels we find riddling their way

throughout these structures, these chimneys, are about the same size as cells.

On the early Earth,

these tiny pockets would have provided a warm crucible

for the three basic building-blocks of life to come together.

Chemical energy flooding through the chimney walls

may then have jump-started

the tiny metabolic engines inside these protocells.

After millions of years,

the protocells could have developed a way to make energy for themselves

and then broken free.

This could've been the moment chemistry became life.

Alkaline vents are the leading theory for the origins of life on Earth.

But the theory faces competition.

Some scientists believe that life arrived on Earth

from another planet...

..and that our ancestors were aliens.

*

*

The Earth, four billion years ago.

The crust has cooled,

it's warm and wet.

The asteroids and comets that brought water

and organic molecules to the Earth are a distant memory.

Some scientists believe that simple life may have taken hold

at the bottom of the sea,

but this may not be the life that turned into us.

Because a radical theory called panspermia

suggests that our ancestors are about to arrive...

..from outer space.

A second wave of rocks pummel the Earth,

and according to the theory, they're carrying alien hitchhikers.

So panspermia is the idea that life rose on some other planetary body,

or other environment,

and came to Earth and was delivered by falling debris.

We don't know, but I think the idea

that panspermia may have played a role must be considered,

because a lot of evidence points us in that direction.

The story of how alien hitchhikers arrived on Earth starts 4.1 billion years ago...

..when the giant outer planets flung Neptune off-course

and threw a belt of comets and asteroids.

The giant planet sent a hail of mountain-sized space rocks

towards the inner solar system and the Earth.

It's called the late heavy bombardment.

We're just orbiting the sun, happy as can be,

and the outer planets are throwing these gigantic objects at us,

and they just kept coming in and kept coming in and kept coming in.

There were giant asteroids and comets raining down on the Earth,

and occasionally even the oceans would be set to boiling.

Even if simple life had started in Earth's oceans,

it might not have survived this onslaught...

..but the Earth wasn't the only planet in the firing line.

Asteroids and comets also hit Mars...

..and back then, it was a different planet.

Mars is smaller than the Earth, it would have cooled more rapidly.

It could have had a thick atmosphere and oceans of water

before the Earth did.

Ancient oceans would have given Mars a head-start

in the race to foster life.

Perhaps by the time the late heavy bombardment struck,

hardy bacteria had already evolved on the Red Planet.

We've seen life on Earth

that are cryptoendolithic, so they hide in those rocks.

And they survive the radiation and the harsh environment

by hiding and thriving inside of that surface.

A giant impact on the surface of early Mars

could have thrown rocks filled with bacteria high into space.

These are organisms pre-packaged, ready to fly.

You could imagine some of them trapped in a rock,

kicked off a planet, flying through space thousands of years later,

landing on another world, popping open and being able to reproduce and grow.

So did a Martian rock seed the Earth with life?

It's possible.

But only if the Martian hitchhikers

could survive the long journey through space.

NASA engineer Moogega Cooper knows exactly how hardy bacteria can be...

..because her job is to kill them so that no super-bacteria from Earth

contaminates space missions to other planets.

If we send a rover and it's covered in bacteria,

it could potentially propagate in that environment.

So we're kind of like a bug inspector.

In the ideal case, we would like for every piece of hardware

to be sterile.

The reason for this vigilance

is the freakish ability of bacteria to survive in space.

Certain bacteria on Earth, when they experience a stressful environment,

they start forming what we call "spores".

And spores, if you imagine a seed,

has all of the genetic information in the middle

and it's protected by numerous layers of defence.

They really seal themselves up in little spaceships,

and that would allow them to survive in space.

You could take a spore, put it in space,

bring it back and it would still be viable.

Spores allow bacteria to stay alive in a dormant state

for incredible lengths of time.

The record on Earth

is a spore that formed before the age of the dinosaurs

and was recently resuscitated after a 250-million-year sleep.

You know that spores can survive in theory

for millions and millions of years.

But to actually see evidence of a spore being revived

is pretty fantastic.

The final challenge for the Martian hitchhikers

is to survive the impact with Earth's surface.

Planetary scientists simulate this violent event

with high-speed guns loaded with rocks.

Not every bit of the projectile is destroyed

and highly shocked in an impact.

When we do these experiments,

we often find little bits of the projectile left over

in the impact chamber.

If there are bacteria living in that portion of that rock,

they could potentially survive the impact back onto the planet.

The science shows us that panspermia is possible...

..but does it take us any closer to understanding the origins of life?

The fundamental problem with panspermia

is that it's just removing one step of the problem

and putting it someplace else.

We don't know how life originated on Earth,

now it's gonna originate on Mars.

But we don't know how it originated on Mars,

so you still have this basic problem,

and that is, how did life start?

A lot of people say, well, panspermia shouldn't be considered

because it just moves the question somewhere else.

But that may be important

cos then we'd say that we need two planets

to create what we see on Earth.

One to get it started and one to carry it on further.

At the moment, we don't know whether life arrived from space

or rose up from the oceans of the Earth.

All we know is that the next stage of life's journey

is filled with danger...

..because before life can get clever, it must face oblivion.

*

*

Our planet is filled with a dazzling diversity of life.

Plant life and animal life...

..simple life...

..and complex, intelligent life like us.

Yet every living thing on Earth

can trace its family tree back to the same tiny cell

that lived billions of years ago.

All life on Earth is related to each other.

We share 50% of our DNA with a banana.

I mean, we feel like we're pretty different from a banana,

but when you look at its core, what its DNA looks like,

it's almost identical.

DNA is the operating system for life.

It stores the program that tells cells how to grow complex structures,

how to generate energy, and ultimately,

how to make an identical copy of themselves.

When we look at life, we tend to focus on what it's made out of it,

and that's important.

It's made out of amino acids and molecules, et cetera.

But the key difference between life and just simple chemistry

is the information content.

So using the computer words, it's not the hardware

that's so amazing, it's the software.

The greatest property of DNA is its ability to change.

Over billions of years, tiny mistakes in the structure of DNA

have led to the vast diversity of life we see today.

These mutations can happen when DNA gets damaged.

The missing section is normally patched up with a perfect copy...

..but from time to time,

a different set of nucleotides slot into place instead.

Sometimes there are mismatches that occur,

and these mutations are sometimes harmful,

but sometimes, it could be a good thing.

Sometimes a random change might make you process food better.

It might make your eyesight a little bit better,

make you a slightly better hunter.

It might make you a little bit taller

so you can see above the grass a little bit better.

Those are advantageous changes and they're random.

They don't happen very often, but they do happen,

and that has led, basically, to the way we are now.

Of all the mutations that led to human life,

the most important is also one of the earliest -

the jump from simple, single-celled life to complex, multicellular life.

It's hard to imagine that without multicellularity,

intelligence is possible.

You've got to have a big enough organism

so that specialisation is enough that some of the cells,

some of the fraction of that organism, can just focus on being a brain.

The jump from simple life to complex life

began around 2.4 billion years ago...

..but what was the trigger for this revolutionary change?

Scientists have boiled it down to a single, game-changing mutation

called photosynthesis.

What happened was a mistake.

A mutation led to a true superpower.

The first organism to develop this superpower

is called cyanobacteria.

It was green and able to use sunlight to create its own food supply.

For the first time, life had its own internal energy source,

wherever you are, as long as you have sunlight, you have food.

So you could cut the umbilical cord and break free

and start to really branch out into the environments of the Earth.

The cyanobacteria thrived.

But the waste product of photosynthesis was oxygen,

a gas that was highly toxic to almost all other primal life -

a weapon of mass destruction.

At that point, there wasn't any free oxygen in the atmosphere.

This was the first time this happened,

and as these things evolved and flourished,

they started dumping this basic poison into the atmosphere.

The oxygen killed off most of the life on Earth...

..but the creatures that survived evolved to use oxygen

and turbocharged their evolution.

Oxygen is so dangerous cos it's so reactive,

but that makes it a very good fuel.

So the tiny percentage of life

that wasn't killed by the poisonous gas oxygen,

all of a sudden could speed up, it had a more efficient fuel to use.

And more energy means more complex molecules,

more complex chemistry, more complex biology,

and that meant that these creatures could evolve more rapidly.

Boosted by oxygen,

some single-cells evolve to do something they hadn't done before -

they joined forces.

Single-celled microorganisms really were smart

when they knew to cluster together.

Because it allowed them to have protection

and worked kind of as a community.

Different cells within these communities

started to specialise in different tasks.

Eventually, the communities started to function as a single organism.

The stage was set for the next superpower -

multicellular life.

But a second global catastrophe was coming...

..because in the background,

cyanobacteria populations were still exploding.

As they released the oxygen as they grew,

it would have changed the chemistry of the entire planet.

As oxygen filled the air, it reacted with the early atmosphere,

removing greenhouse gases such as methane.

The result was a rapid cooling of the Earth's climate.

And this, we think,

would have tipped the climate of the entire planet

to a very, very cold, kind of glaciated world.

What we call the "Snowball Earth".

And it was probably the first climate catastrophe that happened

after life originated on Earth.

Snowball Earth came very close to wiping all life off the surface

of our planet.

But some creatures must have made it through,

otherwise we wouldn't be here today.

Geothermal hot springs like this one in Iceland

offer a clue as to how our tiny ancestors

managed to survive this trial by ice.

This temperature's shooting up. 160, 170, 180...

..190...

..over 200 degrees Fahrenheit. Now, that's very, very hot.

That's practically the boiling point of the water,

and you can see it's kind of churning away like cooking soup

or something in the kitchen at home.

The heat source for hot springs like these

is buried deep within the molten core of the Earth.

Radioactive metals sank here during the formation of the Earth,

and they decayed, slowly releasing heat into the rocks

that sit below the surface of our planet.

Where the Earth's crust is thin,

rainwater can seep down onto these hot rocks

and shoot back up at near boiling point.

Warm pools like these

would have kept on bubbling all the way through Snowball Earth.

What probably would have helped us in that process and survival

would have been regions like this.

There would have been volcanic activity and geothermal hot-spots.

And they would have thawed out the ice,

and provided kind of oases of warmth

where life has an opportunity to cling on.

So maybe it was less of a Snowball Earth,

and more of a kind of a slush-ball.

Maybe there were periods and regions around the equator,

and around hot-spots, where life was able to persist.

Snowball Earth lasts for 200 million years.

Eventually, volcanoes released enough greenhouse gases

for the climate to recover.

And the organisms that survived

inherited a warm, oxygenated world perfect for multicellular life.

Multicellularity really booms,

and it seems to coincide with a rise in oxygen.

Over the next 500 million years, oxygen levels continued to rise...

..and life grew bigger and more complex.

Most of the major animal groups we see today evolved.

Fish turned into reptiles.

Reptiles turned into small mammals

and then primates.

Finally, just 200,000 years ago, the first humans walked the Earth...

..beings with the capacity for intelligent thought.

If we think of landmarks in evolution, there aren't very many.

I would just have three.

The origin of life,

the rise of complex life associated with oxygen,

and the rise of intelligence.

That's it. To me, that's the story of life on Earth.

It started, it got complex, then it got smart.

Now scientists are investigating

whether the same process of evolution could have happened elsewhere.

I've become more and more confident over the last few decades

that life is everywhere in the universe.

Now, is there intelligent life?

That's a much more difficult question.

One way to answer it

is to look at the key factors that made our evolution possible,

and see if they exist elsewhere.

By studying the light from distant dust clouds,

astronomers now know that the building-blocks for life

are common throughout the galaxy.

And they've detected over 1,000 potential planetary homes

for life around nearby stars.

The stage for simple life, at least, seems virtually infinite.

But for complex, multicellular life, you need something else -

an oxygen-rich atmosphere.

Is there oxygen on these worlds?

That's the question I want to live to see the answer to,

and if the answers for any of them is yes, that's phenomenal.

That is really an important milestone

in our understanding of life in the universe.

NASA is developing a new generation of telescopes

to find planets around nearby stars

and scan for oxygen-rich atmospheres.

But a recent surprise result from the planet next-door,

suggests oxygen-rich worlds may be much more common than we thought.

I think we can do it right here.

Nina Lanza works with NASA on the Mars Curiosity Rover.

She's interested in a mysterious black glaze

that appears to be present on both Mars and the Earth.

Great, thank you.

So what we're looking at here is called rock varnish.

And this is a coating on the surface of the rock

that is very high in manganese oxides.

Living cells on Earth contain manganese.

These dark deposits are thought to have been formed

when this manganese leached out of dead bacteria.

The manganese then reacted with oxygen in the air

and became fixed to the rock.

Nina wanted to understand

the chemistry of similar-looking stains on Mars.

So in 2014,

she requested the Mars Curiosity Rover to fire at a set of dark rocks

with its chem-cam laser.

Wherever we zap the rock, it vaporises a little bit of material.

And so if we keep shooting the rock in that one place,

then we can find out

the composition through the coating, if there is one.

There was this one sample that had such a big peak

that we noticed it right away,

and we were like, "This has to be a mistake."

We need to check our data to make sure we haven't mis-calibrated it.

And absolutely not,

we looked at the raw data, we recalibrated it,

and it was still a huge amount of manganese.

The surprise result

suggests life may once have thrived on Martian rocks

inside an oxygen-rich atmosphere.

Even if the manganese came from another source,

the dark stains would have still required atmospheric oxygen

to fix them to the rocks.

So finding a coating like this on Mars,

or even just a layer made of a similar composition,

opens up the possibility that there was oxygen

in the Martian atmosphere sometime in the past.

Mars lost its atmosphere billions of years ago...

..but the possibility it once had oxygen is significant.

Because if two planets in the same solar system

can both have all the ingredients needed to develop complex life...

..then the odds on their being more intelligent life out there look pretty good.

When we look at the story of life,

it seems like the universe started off with hydrogen

and has now ended up with intelligence, human beings.

Well, that's a wonderful story.

Are we the only chapter in that book, though?

That's the question.

Whether or not there's a person in some far away galaxy

having the same thoughts as I am,

I'm not sure.

It's hard to say no, because this universe is so large.

We are a collection of atoms

that understands that it's a collection of atoms.

That's amazing.

This is the universe knowing that it's the universe.

I think it's really important that we figure out how that's possible.

I actually have a bottle of very nice champagne

chilling in my refrigerator.

I think we're gonna find evidence of life on other planets

sometime in my lifetime.

I'm ready to celebrate.

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