I was just praying with my eyes closed
that this was gonna work.
Things, if they're gonna go wrong, do go wrong.
This thing could fail, you know?
If it doesn't work, it's over.
Lights off.
Exploring the solar system
is not for the feint of heart.
It requires courage, determination, and ingenuity.
This is like the first renaissance voyage over the oceans,
but it's to another planet.
Can we send a spacecraft through that environment?
There's no question whatsoever that this is
one of the most difficult technological jobs
that the human species has ever tried.
It's a very violent, dangerous, deadly place.
But the rewards of risking everything
are worth it.
Holy gosh.
I was stunned.
We found the holy grail.
Mars has a sense of romance about it
because it's a place, it's a planet,
it's another world.
79 moons, each one their own world of ice or rock.
It's definitely the most interesting place
in the solar system.
Pluto is the Everest of the solar system.
The farthest and coldest and hardest to reach.
Wouldn't that be cool, if Pluto has or had life?
We're thinking holy crap, Batman.
This series reveals
how we explored our solar system.
I felt this is a more thrilling moment than Apollo 11.
Told by the people who dared to do it.
When I first saw the images I was amazed.
We had a rock from Mars, a smoking gun.
Risking reputations on missions
that were decades in the planning,
that could fail at any time.
NASA are taking a big risk here.
This is it, this is actually the end.
It definitely led to a lot of tears.
These are the missions that changed
how we see the solar system, and ourselves.
We are the only generation that will ever
explore the solar system for the first time.
(gentle music)
As I take man's last step on the surface
for some time to come,
but we believe not too long in the future.
I believe America's challenge of today
has forged man's destiny of tomorrow.
We leave as we came, and God willing as we shall return.
With peace and hope for all mankind.
The exploration of our solar system
really is part of the quest to understand
our place in the universe.
And without or solar system, we wouldn't exist.
Why did this one little blue-green planet
appear around this perfectly ordinary star?
Is this a story that is repeated time and again
throughout the universe?
The solar system is both vast and ancient.
At least 4.5 billion years old.
Now, for the first time in human history,
we have images in stunning detail of all the major planets,
and many moons, asteroids and comets,
taken from space by machines of human design.
From the surface of the sun
to the frozen highlands of Pluto and beyond,
these images bear witness to the talents
of the men and women who went in search of
answers to the biggest questions.
And this episode is about how and why they went looking.
The moment we discover that life developed somewhere else
will be the greatest scientific discovery of all time.
The sun at the center of the solar system
is an incredibly hot object.
This hot, raging ball of gas.
In order to be able to truly see the sun,
the interior, the surface, the atmosphere,
we have to go into space.
Status check. (dramatic music)
Go gentlemen.
First station is propulsion.
Go.
Hydraulics.
Go.
Locks.
Go.
This mission has been a long time coming, you know,
that for 60 years we tried to do this mission.
We're gonna go to the most extreme environment
in our entire solar system.
We're gonna go in and we're gonna touch the sun.
Eight, seven, six, five, four,
three, two, one, zero.
Lift off of the mighty Delta IV Heavy rocket,
with NASA's Parker Solar Probe,
a daring mission to shed light on the mysteries
of our closest star, the sun.
(melodic music)
Humanity I think has a general quest for knowledge.
We tend to just ask questions and wonder why.
The nature is to look up and to look around you
and to want to understand your surroundings,
and so the first thing anyone looked up
and wondered about was the sun.
I think it's been, over the years,
seen as sometimes friend and at other times as foe.
The sun is a constant in our lives.
It rises every morning, it sets every night,
and yet when you look at the sun,
you will see that it is anything but constant.
It is a continually changing, incredibly active star.
The story of the sun is very much
the story of the solar system.
Finding out how it works is still a work in progress.
That hazy atmosphere that you see during
a total solar eclipse, the sun's corona,
is hotter than the surface of the sun.
And that really doesn't make sense,
it breaks the laws of physics.
You move away from a hot body, it should get colder,
but something is happening in this region
that really heats this material.
And we don't know why.
If it's that hot, why does the gas stay on the sun?
Hot materials move really fast,
and if the gas molecules are traveling
faster than escape velocity,
there should be a wind streaming away from the sun.
And this radical idea was predicted
by an American astronomer, Eugene Parker.
(gentle music)
In 1958, space was thought to be a hard vacuum.
And while the light and heat from the sun
could pass through space,
the enormous gravity of the sun would prevent
any matter, such as gas, from reaching us.
But, Parker thought differently.
The idea was contradicted by several observations.
He went through the mathematics,
he went through the physics,
and he predicted the hot atmosphere of the sun
has a high pressure,
so the gas is wanting to push outwards.
And there's a really important consequence of that.
The gas streams out into the solar system.
The sun is literally expanding into space.
I realized that we had a supersonic expansion
of the outer atmosphere of the sun.
A completely radical idea.
Eugene wrote up a scientific paper,
submitted it to the Astrophysical Journal,
and it got rejected.
Hardly anybody took it seriously.
I received several polite and not so polite declinations.
Parker asked the then editor
of the Astrophysical Journal, Subrahmanyan Chandrasekhar,
to look at his paper again.
Chandrasekhar couldn't find any mathematical flaws
in Parker's work.
The editor said to Eugene, "Do you really think
"there's something in the work you've done?"
And he said, "Yes."
And the editor published it.
But still, it's ridiculed.
Just because the paper was published,
had no positive effect.
They were not behind it because they just
believed it was wrong.
Three, two, one, zero.
Four years after I made the proposal
there was a spacecraft flying to Venus.
And they did indeed discover that the sun
does have this outflow of gas coming from it.
The solar wind does exist.
The rest is history.
(uplifting music)
This discovery was momentous.
All of a sudden space is no longer a void,
it's no longer a vacuum, it's filled with material,
it's filled with this wind from the sun.
The speed of the solar winds, it's almost beyond belief.
It's moving between 250 and 750 kilometers per second,
and it has some really significant affects on our planet.
In 2018, NASA launched a spacecraft
called the Parker Solar Probe.
Two, one.
Lift off of the mighty Delta IV Heavy Rocket
It's the only spacecraft ever to bear the name
of a living scientist.
To shed light on the mysteries of our closest star,
the sun.
Wow, go baby go.
The sky lights up and you realize that
it's never coming back.
(applause)
What a way to start.
10, nine, eight, seven, six, five...
Being the closest planet to the sun,
Mercury is a world of extremes.
But even here, explorers were to find something
that few expected.
When I became the head of planetary science,
Messenger had launched, and it was on its way to Mercury.
Messenger was all about exploring the full surface
that we'd never seen before,
but also we had to really think about how
we develop our technology to survive this environment.
One of the main concerns for us with an orbiter
is we go from one side to the other
in a very short time period, a few tens of minutes.
The day side of Mercury +450 degrees,
the night side about -180.
So the extreme in temperature is over 600 degrees swing
between one side and the other.
The Messenger spacecraft
went into orbit around Mercury seven years after launch.
It was designed to study the smallest of the planets
using a whole suit of sensitive instruments.
What Messenger did was it provided,
as its top science priority,
a high resolution image of the entire surface of Mercury.
But the mystery was that there were bright spots.
There were small bright spots.
And then one of the Messenger scientists
took all of the bright spots and laid them down
on the map of Mercury.
Every single bright spot was inside of a crater
that is permanently shadowed.
We found what we believe is ice, water ice at Mercury.
It's in one of the hottest regions in our solar system.
So how did the ice get in there?
Has it been through meteor strikes?
'Cause meteors have water.
Has it been through comets hitting the body?
Comets have a lot of water.
It's really an enigma.
It used to be thought that Earth is the cradle for life,
therefore all organic chemistry in the solar system
is probably concentrated in the band
that the Earth's orbit maps out around the sun.
But we're now studying the water cycle,
literally throughout the solar system.
So when you're talking about where life is
and where the kind of chemistry and ultimately biology
that might produce something like this could take place,
at the moment it's looking like it might be
broader than just one little planet
at the Goldilocks distance.
(dramatic music)
The Soviet Union, they understood the huge
propaganda value of victories in space.
The best way to prove superiority
would be to get to Venus first.
We should not forget that every launch
is also perfecting essentially military technology.
This was a giant military missile development program.
Space exploration has a dark side.
We can't deny that we rode to the moon
and to the other planets on the wings of war.
The reason we have these rockets that can
launch payloads into orbit and beyond
is because they were developed to destroy cities.
The Cold War made possible
ever more ambitions missions in the 60s and 70s,
each a matter of national pride.
None more so than Venera 9.
This huge, complex spacecraft was built to enable Russia
to be the first nation to send back an image
from the surface of another planet.
Venus.
On 20th of October of 1975,
this giant stack of spacecraft of Lander and Orbiter
approached Venus and separated from each other.
Immediately they started their separate missions
which were culminating at the same time.
The Orbiter approached Venus and started
braking manually with its engines
to slow down its speed just enough
that the gravity field of Venus would
capture it and leave it in the highly stretched
elliptical orbit around the planet.
This component of the Venera 9 spacecraft
had become the first manmade object
to enter orbit around Venus.
But the mission was far from over.
And at the same time, the Lander started going
into the atmosphere of Venus on the side of the planet
which was not visible from Earth,
but thanks to the Orbiter,
which was so high in the sky over Venus,
it would later act as a relay station
for the Lander to send pictures back
to mission control on Earth.
The Lander was a ball shaped capsule
covered with a special ablative surface.
And once it entered the atmosphere of Venus,
it started breaking, layer by layer,
burning the ablative surface,
and at the same time slowing down tremendously
from its usual entry speed.
The searing heat shield
decelerated the Lander from 10.7 kilometers per second
to around 250 meters per second.
Then, once it slowed down enough,
it was safe enough to open small opening
in the top of the capsule and release
two small braking parachutes.
One of those parachutes was then used to release
the top part of the capsule and reveal the top of the Lander
which was inside of that hood.
The speed dropped from
250 meters per second to 150 meters per second
before a third parachute was deployed.
And once that happened, there was an antenna,
a transmission antenna exposed.
And that allowed it to immediately start
transmitting data to the Orbiter
which in turn relayed back to the ground control.
The third parachute brought
the velocity of the Lander down to just 50 meter per second.
And then that parachute was separated
and it pulls out three canopy main parachute system,
which allows the Lander really slow and gentle descent.
After all the drama of its journey so far,
the Lander would then spend 20 minutes
calmly taking measurements of the atmosphere.
But its brutal voyage was not over yet.
When the probe is around 50 kilometers over the surface,
a command is sent to cut the main lines of the parachute.
And then you keep falling and the atmosphere
gets hotter and hotter and more and more dense,
to the point where it's 100 times as dense
as the atmosphere on Earth,
and that means that you're falling through,
it's not quite a liquid but it's a gas that is
approaching the properties of a liquid,
and that would slow your fall.
And then when you get to the surface
it's almost like going through the ocean.
Venera 9 wasn't the first Lander
to get to the surface of Venus.
But it was the first to send back pictures.
Finally, this image, the first image ever seen
by humans of the surface of another planet came back.
Everybody, without any question,
who was involved, were understanding the historic
and scientific significance of that achievement.
That was a real triumph of exploration.
These rovers were not inanimate objects to us.
We were part of them and they were part of us.
The exploration of Mars
has long been a top priority.
In 2004, two rovers, Spirit and Opportunity,
landed on the red planet.
For the people who sent them there,
it proved to be an emotional experience.
Gusev Crater has a drainage channel
that extends for thousands of kilometers
through the ancient highlands and looks like
it filled that crater up with a lake.
This was a location where sedimentary rocks
that could tell us about the environment
when it was active would be.
We got images pretty quickly.
Unfortunately we got there and all we could see
basically was volcanic stuff.
Gusev was basically a basaltic plain,
which is lava flow.
So if the lake had ever been there
it had been covered by volcanic materials.
We were crestfallen that none of our predictions
about what materials would be there,
you know, that we were wrong.
Opportunity was completely different.
Opportunity really hit the bullseye
because it landed in a place called Eagle Crater,
in which mother nature has done you a big favor.
At some point she slammed a meteorite
into the surface of the planet,
excavating this big hole.
It basically gave you this archeological dig if you will.
You land in the middle of it,
and all you gotta do is look around
and here's the history of Mars.
And we saw sedimentary rocks.
When geologists go out in the field here on Earth,
they wanna look for layers of sediment
that have accumulated over time.
This is literally the historical pages
of the book of the Earth.
This level was where the dinosaurs were,
and in this level they died,
and in this level new life became.
You can just read that book of history.
There was this treasure trove of information
and it just came flooding back.
These were not igneous rocks, these were sedimentary rocks
that would have been formed by liquid water.
And it was a classic sedimentary sequence
that we've seen on the Earth in many places.
And this is where it really gets interesting.
We see these little bead-like things in the soil.
We thought what could these be?
People started conjecturing.
But when you put the infrared eyes on them
we can see iron and oxygen in them.
We're thinking holy crap, Batman.
We found hematite.
Hematite is a mineral here on Earth
that's formed in water, and a lot of it,
and moving water, that allows this mineral to be formed.
And they were all over the place.
Holy gosh.
We found the holy grail.
So the whole point of the Mars exploration rovers
was roving.
We wanna move.
The rovers were expected to last just 90 days,
but as both of them explored the martian surface,
they proved they could go for much longer.
They outdid their warranty by factors of hundreds.
We're several years into the mission
that we had wheel trouble with Spirit.
Spirit had lost one drive wheel.
In doing so we got stuck in a sandy crater,
and it was very difficult.
And that was the end of Spirit, yeah.
But Opportunity just shines like a radiant star,
'cause this rover keeps going and going and going.
Opportunity had really began to show evidence
of past water.
We started to see the kind of mineral signatures
that were the stuff of dreams,
and support water as a persistent liquid phase.
(mixed crosstalk)
This is just this ongoing saga of water.
Water, water everywhere.
Then in 2012 a new rover drops into the party.
Curiosity.
Equipped with a drill and carrying
an entire laboratory on its back.
This machine rolled into town and immediately
changed our view of the red planet.
As we dug into the soils, and we found,
to our delight, it had carbon, hydrogen, oxygen,
nitrogen, phosphorous and sulfur.
That's everything between these two fingers.
All the right stuff that life is made of is on Mars.
Meanwhile, after 15 years on the surface,
Opportunity had covered a record breaking 45 kilometers,
documenting every step of the way.
It's this unstoppable machine.
It just keeps driving.
And then in June of 2018,
here's a dust orbit in the distance.
It turns out to be a whopper.
The sun was almost blacked out.
And at that point there was no power getting to the panels,
and we tried for months and months and months
until there was just nothing.
And at that point you eventually, you know,
you say that's the end.
We had one final day where they called the team
out to JPL, the Jet Propulsion Laboratory,
where anybody that wanted to come and be there
when they sent the final commands could come.
We had all gathered in this area called the dark room
overlooking mission operations,
and we're watching the flight commanders
sending off the last commands to the rover.
We did basically four final pings.
The light time delay comes and goes, we got no signal,
and everybody just kinda sits there in silence.
And then the manager of the mission, John Callas.
This concludes operations for MER one,
Spacecraft ID 253.
Says, "Thank you for your 15 years of service."
Thank you.
But this is the end,
so this is MER signing off the net.
MER project off the net.
In the darkroom it was just silent,
everybody's kind of looking around
and we're like this is it, this is actually the end.
It definitely led to a lot of tears.
We were there, we are there, our consciousness is there,
our species consciousness is on Mars.
We're already a multi planet species.
(gentle music)
Comets are the leftover rubble
of the solar system.
They never quite made it into planets,
but they preserved the material that are
the building blocks of everything we can touch,
feel, taste, smell or see today.
To learn more you want to go and rendezvous with a comet.
You want to fly alongside it.
And of course then the idea comes up
you would want to touch down on the surface,
you want to land there, sample material.
To do all of that in one mission is incredibly gutsy.
Dix, neuf, huit, sept.
The first time I heard about the mission
I thought they must be joking.
Six, cinq.
The Rosetta mission was incredibly ambitious.
But we jumped on it.
We launched in March 2004.
The whole travel to the comet was an adventure for Rosetta.
The comet is on an orbit with a different energy level
compared to the one of the Earth,
so we had to actually impart this energy to our spacecraft
to get to the same orbit.
So we did this thing, to use the planets
and to use their gravity to slingshot us through space
on a different trajectory with more speed
in order to be able to get to the comet.
After this, we came back to Earth.
This one gave us the last big kick.
We were really launched very fast
but getting far from the sun.
We could not keep all the systems on board active,
because the illumination of our solar panels
was getting very weak.
So the decision was made in fact to turn it off.
I hated that concept from the very beginning.
I'd been fighting it for years.
I was convinced we would never do it,
it was too crazy.
Switching off the radio signal is like cutting a vital link.
We've been flying a spacecraft for seven years,
it's hundreds of millions of kilometers away,
and what do you do?
You send a command to switch it off
and wake it up three years later.
It just doesn't make sense.
And this is what we did.
We spent two and a half years without contact.
And we waited.
We couldn't talk to it while it was in hibernation,
we needed it to wake up, which it was due to do
on the 20th January 2014.
(alarms ringing)
Wake up!
We were sitting all in the control room,
waiting for the signal to come,
and this was probably the most tense moment of the mission.
This was everything or nothing.
Life or death.
Why is it not coming?
Everyone was getting very nervous.
It was very difficult to bear.
We started really getting worried.
Have we lost the mission?
Then suddenly a signal came.
(applause)
When the signal came it was a big relief
for me personally.
It was an explosion of joy.
A little blip on a noise spectrum
told us Rosetta was there and it was calling home.
And this for me was the toughest emotion
I went through on the story of Rosetta.
We made it.
Yes, yes.
It's a big success for everyone.
We have it, we're ready.
We now have the spacecraft back,
we can go and do the rest of this mission
and finally get to the comet.
(applause)
But now the mission starts because now we have to
get to the comet, fly around the comet,
orbit the comet and land on the comet,
all within the next 10 months.
Rosetta took 10 years from launch
til we finally got to the target
that we were going to study.
The comet we ended up deciding to go to
was 67P/Churyumov-Gerasimenko.
At the beginning the comet was just a very small dot.
And then day by day the comet was growing
in the field of view of the camera.
You have this spacecraft visiting
an a ambassador from the solar system
from four and a half billion years ago.
It's modern technology visiting an ancient relic.
It's really profoundly emotional.
We saw this incredible shape.
Some people have described it as a rubber duck.
It was amazing, it was beautiful.
Scientists were just stunned with their mouths open.
Comet 67P is about four kilometers in size.
If you were standing on the bottom of the comet
you might see a flat dusty plain.
If you were standing on the head of the comet
it might look more rocky.
If you were standing on the neck of the comet
you would be in this interesting valley,
kilometer high cliffs on either side,
and running along the neck between your legs
is a huge crack.
There's so many different types of surfaces and variety,
you could spend the rest of your life
exploring every little part of the comet
and not see the same type of thing twice.
Jupiter, the largest and most
intimidating of the planets,
is certainly one of the most beautiful and intriguing.
In 1995, a spacecraft named Galileo arrived
and soon got to work.
The Galileo spacecraft carried along with it a probe,
and it's sort of like this size.
And it had a big heat shield to protect it around it.
So in July 1995 we launched that probe
and sent it in the direction of Jupiter.
Now it didn't have engines so we weren't guiding it
and saying, "Go there."
We just sort of sent it on a trajectory towards Jupiter.
Five months later, on the 7th of December 1995,
the Galileo probe was due to arrive in Jupiter.
There were no cameras on board, only sensors,
and a little probe that was going to have
an extremely violent introduction to Jupiter.
It was coming in at something like 130,000 miles an hour.
It was pulled in by the gravity of Jupiter,
and we had to slow it down.
And so this heat shield heated up to about three times
the temperature of the surface of the sun.
(dramatic music)
And then eventually we kicked off that heat shield,
put out some parachutes.
So as it went down, we were able to get a sense
of what it was like.
What we were expecting was three separate layers of clouds.
And we went down, it's like where are the clouds?
Where are the clouds?
We're not seeing the clouds.
What's going on?
So everybody was completely confused.
Well the hint came from the ground.
Telescopes on Earth were looking in the infrared,
at Jupiter, at the same time we sent the probe in,
and we realized that the probe went into a hotspot,
somewhere where there's very little water.
So I think we realized that our whole idea
of exploring these planets with single probes
is a little bit susceptible to going into the wrong place.
By the time the probe had got down
to about 160 kilometers,
something like 23 times atmospheric pressure,
it was now starting to get really hot.
So at that point the electronics is just
not working anymore and it stops communicating
and sending signals back to the Earth.
What happened to it after that?
Well it was so hot that it basically vaporized.
But let's imagine what it would be like
if you could be in a pressurized capsule
as you get deep down.
I mean it's either a hang glider's nightmare
or his dream, depending on how risky they wanna be.
As you went deeper and deeper it would get
a little calmer, a little less turbulent.
The pressure would get higher and higher.
It's so hot, everything's vaporous.
Eventually you get down to material
that are almost like rock clouds,
and they're probably precipitating.
Now when you get down something like 10% of the radius,
you're now getting to the point where
the pressures are about a million times
Earth atmospheric pressure,
and the density is getting really high.
And at that point hydrogen changes its phase.
It's no longer molecules,
protons and electrons connected together,
but the protons and the electrons are moving separately,
and it becomes metallic.
That is it becomes electrically conductive.
I suspect it would look like mercury,
a glob of mercury is what it would probably look like.
If you existed, you would be unbelievably thin,
flat out pancake.
You get to the center of Jupiter,
we're talking four times the temperature
of the surface of the sun,
50 million atmospheres in pressure,
and a density that's denser than
the heaviest metals that we have on Earth.
One seconds and counting,
this is Titan launch control.
Without any doubt, the most risky element
of any space mission is the launch.
T minus 15 seconds.
When you've put eight years of your life
into designing and building and testing something
which is going to go into space.
Nine, eight, seven.
And then seeing it on the top of a rocket
that's being vibrated and accelerated
on its way to Saturn, it is quite a feeling.
When it did go off it created a huge amount of light,
and then the rocket went behind the cloud.
When it went behind that cloud it was very impressive.
The whole cloud like lit up.
We all thought oh goodness has something gone wrong?
And then the nose cone came out and you went...
(exhales sharply)
Exploring a planet such as Saturn
is a very risky business.
This mission, called Cassini-Huygens,
was one of the most technically demanding ever undertaken.
When Cassini was approaching Saturn for the first time
our experiment was systematically scanning
back and forth planet Saturn.
And we were amazed to discover that
the system was filled with molecules of oxygen.
And we mapped this out and we noticed
that the peak in the distribution
was just a distance four times Saturn's radius
from the center of the system.
We knew that the moon Enceladus
was orbiting just at that distance.
Enceladus is a tiny moon,
just 500 kilometers in diameter.
Enceladus originally was on the itinerary,
but only marginally so.
It was another very interesting Saturn moon.
Small, very shiny, very white and very bright,
but other than that, too small to be interesting.
It was in the first close flyby
that the magnetometer team detected
something interesting that they didn't expect.
It looks like it has an atmosphere.
Anybody that knows anything about moons,
that's too tiny, it can't have an atmosphere,
it's way too small to hold anything.
If you flew by the south pole
it looked like there an atmosphere,
but if you flew by at the equator
you couldn't see anything at all.
But then we went back again and again
and all of a sudden realized that not only
did it have an atmosphere, it was this icy atmosphere,
but it had these plumes coming out of the southern pole.
And here's water geysers, on a tiny moon.
And that water that was coming out of
what we later found out to be an interior ocean.
Not only did it contain water vapor,
but it had traces of ammonia, methane, H2, Co2,
and then there was a whole host of organic compounds
that we could also see.
And now we could put all that information together
to get a picture of the shape of the eruption,
and also the material that's being erupted
from inside of Enceladus, and amazingly enough,
that material has the basic building blocks of life.
This says to me that would be a good place to go
and see if there's any form of life there.
Far out near the edge of the solar system
lies a world that until recently
was completely unexplored.
Pluto.
As we were flying up to Pluto,
and imaging it day after day
and week after week on approach,
we could see this bright feature on the surface.
One morning we got an image back,
and as soon as it came up on the big screen
I remember a NASA official who said,
"Do you see that looks like a heart?"
And as we got closer and closer,
amazingly it looked more and more like a heart.
I think that's what emblazoned Pluto into the public mind
as this amazing place at the frontier of our solar system.
Pluto's heart measures 1,600 kilometers across
and is composed of nitrogen ice.
We believe that structure might be
supported by water underneath the surface.
(dramatic music)
There could be an ocean underneath Pluto's surface.
There probably is some kind of liquid water ocean.
It's very deep down inside, but we think there's
a pretty good chance that it's there.
It's one of those things where if you find water,
is there a chance for life?
Wouldn't that be cool, if Pluto's actually
one of those places in the solar system
that has or had life.
That's just mind blowing right there.
The exploration of our solar system
is far from over, but it has already taught us
what a rich, varied and strange place it is.
But perhaps the biggest realization
is just how special and precious our home planet is.
(uplifting music)