The Planets (2019) s01e03 Episode Script
The Godfather: Jupiter
1 Lift off of Messenger on Nasa's mission to Mercury.
They'll say no-one can see us That we're estranged and all alone They believe nothing can reach us And pull us out of the boundless gloom They're wrong They're wrong They're wrong.
Beyond the inner solar system past the asteroid belt lies Jupiter.
The largest of the planets is a giant swirling ball of gas its marbled appearance generated by violent winds that rage through its clouds.
Jupiter is a world as strange as it is remote.
If you fly upwards, only about 100km or so, you reach the edge of our atmosphere and the blackness of space.
It's really not that far.
But once you're in space, the distance scales are sort of incomprehensible.
I mean, Venus, the closest planet, is over 40 million kilometres away.
Jupiter around 650 million kilometres.
It takes our fastest spacecraft years to get there.
So, the idea that those planets could have any influence on us here on Earth seems fanciful.
And, indeed, if you're talking about your chances of meeting a handsome stranger or your life plans requiring a moderate reconfiguration about a week on Wednesday, then you would be right.
However, if you ask more profound questions, deeper questions like, "Why is the Earth the way that it is? "Why is there life on Earth? "Why do we exist at all?" then it turns out that the planets, and Jupiter in particular, have had a profound effect.
Early in its life, the young Jupiter went on the rampage.
The giant planet embarked on a voyage of destruction across the solar system that transformed the destiny of the planets, and the course of life on Earth.
Jupiter is the godfather of the planets.
Understand it and you understand how the solar system came to be.
On Earth, we can see glimpses of Jupiter's power in the scars it's left on the face of the planet.
This is the famous Barringer Meteor Crater in Arizona.
It is about a kilometre across, 170 metres from the rim to the crater floor and it was created about 50,000 years ago when a meteorite, 50 metres across, entered the Earth's atmosphere travelling at about 13km per second.
That means it would have taken around, what, seven seconds to go from the top of the atmosphere to the ground and it hit with such force that the energy released was equivalent to ten megatons of TNT.
And that is a very large nuclear bomb.
The meteorite that hit the Earth here is thought to have come from the asteroid belt the ring of rocky debris that orbits at the edge of the inner solar system.
And it was deflected from its orbit most likely by the gravitational influence of Jupiter.
Jupiter is a completely different class of planet to the Earth.
A gas giant.
A swirling ball of hydrogen and helium so large you could fit 1,300 Earths inside.
Jupiter can exert such a powerful influence on the asteroids because it's so massive.
It's about two-and-a-half times the mass of all the other planets, moons and asteroids in the solar system combined.
And, therefore, it has a strong gravitational pull.
And this means that Jupiter exerts an influence across the entire solar system that's second only to the sun.
And that influenced us far more than create the odd crater.
It can change the history of worlds.
To understand how Jupiter rose to such dominance, you have to go back to a time before the solar system even existed.
Nearly five billion years ago, a distant exploding star sent a shock wave across the galaxy causing the cloud of gas and dust that would become our solar system to collapse as the sun began to form.
But further out, something else was growing.
After 50 million years the sun's nuclear furnace ignited.
The light of its first dawn revealing Jupiter the solar system's first world.
A planet born so early, it swept up most of the material left over from the formation of the sun.
Because of its dominance, Jupiter had a profound effect on the newly forming solar system and paved the way for our living world to form.
This is a model of our solar system.
So, here's the sun, and then we have the four inner rocky planets, Mercury, Venus, Earth and Mars.
Then comes the asteroid belt, the ring of millions of smaller pieces of rock orbiting around the sun.
And then the gas giants.
Jupiter, Saturn, Uranus and Neptune.
Now, this has a pleasing regular structure about it.
All the rocky planets close to the star and the gas giants further out.
And we thought that this must be the natural order of things, the way that solar systems have to form, until we started to detect planets around distant stars and then we found that this arrangement is not typical at all.
Our sun is just one of around 300 billion stars in our galaxy and almost every one of those stars is home to its own system of planets.
In most other systems, the region where our planet orbits is empty.
Instead, closer to the star, we see super-Earths, vast rocky planets many times bigger than our own.
But, crucially, these worlds are thought to have thick toxic atmospheres, making them completely inhospitable to life.
And that raises a very interesting question.
Why, then, is our solar system the way that it is? To answer that question, we've sent spacecraft to every one of the planets and they've uncovered strange anomalies that reveal our solar system's past.
Our missions to Venus found that it once had far more water than you'd expect for a planet so close to the sun just as Earth does today.
The spacecraft we've sent to Mars touched down on a world that is curiously just half the size of her sister planets Earth and Venus.
And in the asteroid belt, we've uncovered a graveyard of failed worlds their growth mysteriously cut short.
To cause all these anomalies, it's thought that something catastrophic must have happened very early in the solar system's history.
All the evidence suggests that around 4.
5 billion years ago, Jupiter's orbit began to change, triggering a period of unprecedented violence which completely transformed the face of the young solar system.
And we know this because the marauding planet left a trail of destruction in its wake.
Early in its life, Jupiter began to move inwards towards the sun and the effects of that journey can be seen to this day.
In between the orbits of Mars and Jupiter lies the asteroid belt a desolate wasteland of debris left over from the beginning of the solar system.
Rocky bodies too small to be planets in their own right.
In science fiction films, the asteroid belt is often depicted as an un-navigable mass of tumbling rubble.
But it's not like that at all.
So much so, in fact, that modern spacecraft engineers can fly a spacecraft through without making any course corrections.
The reason for that is there's not much mass in the asteroid belt.
A sum total of all of them is only about 4% the mass of the moon and they're spread out in a huge sort of ring, out beyond the orbit of Mars.
So, it's a vast amount of space.
That means that the average distance between any two large asteroids is about eight times the distance between the Earth and the moon.
So, I could stand on one of those large asteroids and look out into space and my nearest neighbour would just be a dim star in the dark.
But scattered amongst the rubble are objects that are far more than mere rocks.
Five, four, three, two, main engine start, one, zero and lift off of the Delta II Rocket.
In 2007, Nasa's Dawn mission was sent to explore the two largest objects in the asteroid belt.
After a year in orbit around the giant asteroid Vesta in March 2015 Dawn made its final approach on a body so large it makes up almost a third of the mass of the entire asteroid belt Ceres.
On arrival, the first images Dawn sent back to Earth contained something entirely unexpected mysterious bright patches in one of Ceres' largest craters.
Spectral analysis of the images showed that the patches were, in fact, the salty residue left behind by liquid water suggesting there must be large amounts of ice just beneath the crust.
Dawn went on to discover over 300 bright spots all over the surface.
And this means that beneath this thin crust, Ceres has a thick ice rich mantle surrounding its rocky core evidence that the dwarf planet is made up of multiple layers.
The interior of Ceres is like nothing else in the asteroid belt.
The differentiation, that separation into layers, observed by Dawn is more characteristic of a planet than an asteroid.
So, 4.
5 billion years ago, Ceres was well on its way to becoming a fully-fledged world.
It's thought that's in its infancy Ceres was very different.
The water that now lies frozen within its interior was once liquid.
Protected beneath a thin layer of ice Ceres was once covered by a deep saltwater ocean.
Before Ceres had reached its full potential, a great disturbance sent shock waves through what would one day become the asteroid belt and cut its development short.
As Jupiter circled the young sun, it started to clear a path through the gas and dust that shrouded the early solar system but that process caused it to do something alarming.
Gravitational interactions with the gas made the giant planets spiral inwards towards the sun ploughing straight through the region of space that would become the asteroid belt scattering the material from which Ceres would otherwise have grown.
Computer simulations of the early solar system suggest that the asteroid belt once contained enough material to build a planet the size of the Earth.
And perhaps that was Ceres's destiny.
But when Jupiter passed through, it scattered 99.
9% of the material away, and Ceres's fate was sealed.
Within 100 million years, Ceres's ocean froze and was buried beneath its crust.
The young planet's development cut short before it could fulfil its promise.
But Jupiter's reign of terror was far from over.
It would continue its journey inwards towards the place our planet was beginning to form threatening the very existence of Earth.
Jupiter had such an overwhelming effect on the young solar system because of its powerful gravitational field the effects of which we can still witness today.
Jupiter exerts its influence across the solar system through its gravitational field which is by far the most powerful of all the planets, because Jupiter is the most massive of all the planets.
It's about 320 times the mass of the Earth.
That's why it was so destructive in the past.
And we see the power of that gravitational field today in its influence on the closest of Jupiter's largest moons, Io.
Io is the most volcanic world in the solar system.
Its surface covered with hundreds of active volcanoes and lakes of molten lava.
The largest, known as Loki Patera, is more than 200km in diameter.
A million times the area of any lava lake on Earth.
Its surface tormented by waves of molten rock.
Io is a vision of hell created by the moon's proximity to Jupiter.
Volcanism here on Earth is powered by the internal heat down below the surface.
Now, much of that is residual heat left over from the Earth's formation four-and-a-half billion years ago, about half of it, and the other half is down to radioactive decay of elements around the Earth's core.
Now, on Io it's different.
Io's a much smaller world and so it didn't retain much residual heat.
So, there, the volcanoes are powered by a different process.
It's known as tidal heating.
The energy that drives Io's volcanism doesn't come from heat stored within the moon.
It's generated by gravity because Io orbits just 350,000km from the tops of Jupiter's clouds.
Io orbits at about the same distance from Jupiter as our moon orbits the Earth.
But because Jupiter is so much more massive, Io goes around much more quickly.
In fact, it goes around once every 42 hours.
Now, if Io were Jupiter's only moon, that orbit would be circular, but it isn't.
The next moon out - Europa - goes round Jupiter precisely once for every two orbits of Io which means that every second orbit, Io and Europa fall into alignment.
It's what's known as an orbital resonance.
That gives it a gravitational kick and that moves Io's orbit into an ellipse.
Now, that means that the gravitational force's on Io are constantly shifting and changing and that stretches and squashes the moon, and heats it up - by friction.
Now, that is called tidal heating and that is the origin of Io's volcanoes.
This process raises the temperature in Io's interior, which would otherwise be frozen solid, to more than 1,000 degrees Celsius creating its lava lakes and powering immense volcanic plumes that rise up to 300km from the moon's surface and out into space.
Io provides the solar system with a vivid reminder of the giant planet's power.
Jupiter's intense gravitational field is the source of Io's volcanism today.
But we don't feel that gravitational pull here on Earth, because Jupiter is so far away, but four-and-a-half billion years ago, Jupiter was migrating inwards towards the inner solar system, approaching the region where Mars and Earth were forming.
After passing through what would become the asteroid belt Jupiter entered the inner solar system continuing its journey, spiralling towards the sun.
Back then, the area where Mars and Earth orbit today was densely packed with gas and rock.
But as Jupiter approached, it wrought havoc scattering the rocky material in all directions some sent careering into the sun others thrown out into interstellar space.
And it's this that may explain our solar system's unusual structure.
Here's the solar system today.
The sun, the four inner rocky planets, the asteroids and Jupiter.
And what we think may have happened is Jupiter made it inwards through where the asteroids are, as far in as the orbit of Mars.
And that would have cleaned out quite a lot of the material in the inner solar system, leaving less for the formation of planets.
And that's why we don't see super-Earths in our solar system.
Those big massive rocky worlds that we see in orbit around so many other stars.
This also might explain why Mars is so small.
See, if Jupiter was orbiting in the region that Mars was forming, there would have been much less material here.
And that might explain why Mars is only a tenth of the mass of Venus and Earth.
Had Jupiter continued to move inwards, it would have had a similar effect on the Earth meaning the world we inhabit might never have formed.
But just as it looked as if Jupiter would sweep everything away, something stopped the giant planet in its tracks because in the shadows of the outer solar system, another planet was forming.
The solar system's second gas giant Saturn and its birth changed everything.
When a planet forms in a disk of material around a star, as Jupiter did in our solar system, it tends to clear out a gap in the disk.
Now, the material tends to fall inwards towards the star.
It's called the accretion and that drags the whole thing inwards.
And that's what happened to Jupiter.
But, then, a less massive planet, Saturn, formed further out.
It cleared out its own disk and it too fell inwards towards the sun, but more quickly than Jupiter.
That meant that Saturn got into a resonance with Jupiter.
It went round once in orbit around the sun for every two orbits of Jupiter and that has the effect of cleaning out the whole region between the two planets.
And that has the effect, through a series of complicated gravitational interactions, of slowing and stopping the in-fall and eventually causing the two planets to move back out again.
And that is what happened to Jupiter and Saturn in our solar system.
Saturn caused Jupiter to retreat leaving behind just enough material from which the inner planets could form.
Mercury.
Venus.
Mars.
And our home the Earth.
By preventing the formation of much larger super-Earths, Jupiter allowed our planet to grow.
And even as Jupiter's reign of terror was drawing to a close, it provided one last parting gift to our world.
The young Earth formed in an arid region of the inner solar system.
There was very little water that close to the sun, but as the Earth was forming, Jupiter was already tacking back outwards again into the outer solar system through the region that we now call the asteroid belt, a region populated by many icy, water rich comets and asteroids.
And they were scattered back inwards again, bringing water back into the inner solar system.
So, I think it is quite a wonderful thought, that Earth is a water world today because of the motion inwards and then back outwards again of the massive planet Jupiter.
This idea does seem quite contrived, almost fantastical, but the more we learn about the formation of solar systems, and the more we try to model a system like ours, with four terrestrial, water-rich planets close to the star and then the gas giants further out, the more we learn that perhaps all these things had to happen, these unlikely movements and interactions between the planets, in order to produce a system like ours and a planet like ours.
So, places like this may be extremely rare.
Today, Jupiter has settled into a regular orbit back beyond the far edge of the asteroid belt its days of marauding through the solar system at an end.
Jupiter has been established in a stable orbit for almost four billion years.
If I was to sit here on Earth 3.
8 billion years ago when life began and look up into the night sky, I would have seen it shining there as a point of light the same as it looks today, distant and seemingly detached.
And it's remained that way for the vast expanse of time it's taken for evolution by natural selection to transform those first populations of organisms into all this, to transform the Earth into an oasis of life in the desert of the solar system.
But Jupiter's influence over the Earth remains to this day and that's because, despite its great distance from us it retains a vice-like grip over the asteroid belt.
It's easy, I think quite natural, to think of the asteroid belt as a single structure.
A sort of ring of rock surrounding the sun.
But that's not what it's like at all.
In reality, each one of those millions and millions of pieces of rock is following its own individual orbits.
And this remarkable animation is made up of ten years of astronomical observations.
And every point you see on this animation is a single asteroid, apart from all the planets.
And so you see Earth and Mars and Venus whizzing around the sun.
But the interesting one is Jupiter orbiting just outside the asteroid belt.
What you can see is that the asteroid belt dances to Jupiter's tune.
It's the conductor of the asteroid belt, if you like.
There are complex patterns here, but there's also structure.
And the reason for that is the delicate interplay between the gravitational pull of the sun and the gravitational force from Jupiter.
Now, what can happen is that perhaps because of an interaction between two asteroids, perhaps they collide with each other, or perhaps on their orbit they line-up perfectly with Jupiter and get an extra gravitational kick, those asteroids can be disturbed from this structure and be sent inwards to the inner solar system.
And by that mechanism, Jupiter has a profound influence on the planets closer to the sun.
Around 100 million years ago, an asteroid 10km across was ejected from the asteroid belt.
Dislodged by Jupiter's gravity, it was set on a collision course with the Earth.
When it struck, it generated a fireball so hot, anything within a 1,000km radius would have died instantly.
The impact threw 300 billion tonnes of sulphur into the atmosphere.
And during the nuclear winter that followed, 75% of all species were wiped from the face of the Earth.
In one fell swoop, Jupiter changed the course of our planet's history.
There are a few places on Earth today where you can catch a glimpse of lost worlds, you can see Earth as it was millions of years in the past and perhaps glimpse the Earth as it might have been.
And this is one of them.
Today, this is the Colorado Plain, over a kilometre in altitude, south of Denver close to the Rocky Mountains, but 200 million years ago, this was at sea level.
It was an ancient lake and the ghosts of those lost worlds, the imprints of the past, can be seen over there, because there are literally thousands of dinosaur footprints.
And here they are, the dinosaur footprints.
I find this absolutely remarkable.
This is the footprint of a sauropod dinosaur.
That's one of the big ones.
The big herbivores with the long necks.
This animal would have weighed about 30 tonnes.
It was tall enough to peer over a two-storey house.
What happened here is, probably a herd of them, a group of them came lumbering across this lake bed and, then, perhaps that same afternoon, predators came, maybe following the herd.
And that's these footprints here.
The allosaurus', these three-toed footprints.
Much smaller animal, maybe about twice the height of me, about two tonnes, very nimble and agile.
So, you see a whole story played out here, frozen in time.
Today, just their traces remain but were it not for Jupiter they might still be here.
There are so many chance events, not only throughout the history of Earth, but also spanning the entire history of the universe for 13.
8 billion years, without which we wouldn't exist.
There's an unbroken chain of life stretching back four billion years here on this planet.
You interrupt or interject at any point and life on Earth is different.
But having said that, there are major events that affected life.
And one of them is the asteroid that wipes out the dinosaurs.
And, in that sense, it is certainly true to say that without Jupiter, we wouldn't be here.
The godfather of the planets paved the way for us to inherit the Earth.
And although it occasionally flings rocks from the asteroid belt our way it also protects us because for objects heading towards the Earth from the far reaches of the solar system, Jupiter's gravitational field acts as a shield.
Around a century ago, a lump of rock and ice 4km across and weighing 17 billion tonnes was hurtling towards the inner solar system until Jupiter intervened.
Five, four, three, two, one We have ignition and lift off of Atlantis and the Galileo Spacecraft bound for Jupiter.
70 years later, we witnessed just how effective a shield Jupiter can be.
Onboard the space shuttle Atlantis the Galileo orbiter.
Three years after Galileo launched, comet Shoemaker-Levy-9 had been captured by Jupiter's gravity.
Locked in the giant planet's embrace tidal forces now began to tear it apart.
Its journey cut short the comet now faced annihilation.
After crossing the inner solar system, Galileo passed through the asteroid belt approaching the spots from where it would witness the comet's final moments.
On July 16th, Galileo saw the first fragments of the comet enter Jupiter's southern hemisphere.
Pieces of comet Shoemaker-Levy-9 struck Jupiter over the course of six days.
It was the first time a comet strike had ever been witnessed.
The most destructive impact released energy equivalent to six million megatons of TNT leaving behind a giant dark cloud 12,000km across.
By capturing objects and incinerating them on impact Jupiter sweeps up bodies from the outer solar system that might otherwise collide with Earth.
Jupiter, the oldest and largest of the planets, is the godfather of our solar system.
In youth it went on the rampage.
For some young planets, it spelt disaster.
But for others, like our own world, it cleared the way for their formation.
And in adulthood, it created the conditions that allowed us to rise so we owe Jupiter a great debt.
But as the dinosaurs found to their cost, it's a debt that could be recalled at any time.
To the naked eye, Jupiter is one of the brightest points of light in the night sky, and through a small telescope, it is a beautiful banded world.
But it feels distant, eternal, disconnected from events here on Earth.
But the more we've understood about the history of the solar system, the more we've come to understand that that is not the case.
Jupiter has played an important and perhaps decisive role in the stories of all the planets, including Earth.
So, the solar system is just that.
It's a system.
Complex, interconnected and interdependent.
So, next time you see Jupiter, just hold your gaze.
Maybe think for a minute, because it is so much more than just a point of light, or a planet, even.
It is the great sculptor of the solar system, the destroyer and creator of worlds.
I think people are drawn in by Jupiter because it's very mysterious.
It's covered by clouds that hide what's underneath.
It's very violent.
And it's very intimidating.
It's also very beautiful.
It has all these things going on and it's hard not to be taken in.
T-minus ten, nine, eight, seven, six Such is Jupiter's mystique, it's been a recurring target for space exploration.
And lift off of the Atlas V with Juno on a trek to Jupiter.
In 2011, Nasa launched its latest mission - Juno.
When we launched the Juno spacecraft away from the Earth out towards Jupiter, we didn't have enough speed to get away out of the gravity of the sun, so we actually had to come back to Earth, get a gravity assist from Earth, and then go out to Jupiter.
After travelling for five years, Juno finally arrived.
This is a mission that goes closer to the planet in its orbit than any other mission ever has.
Only a few thousand kilometres from the cloud tops and very, very fast.
We go from pole to pole in two hours, slipping between the radiation belts in the cloud tops, getting the data as fast as we can and getting out.
So, in every way, Juno is breaking new ground and that's allowed us to see things that we couldn't have ever imagined.
Juno's mission is to explore the planets inside and out.
And amongst the many scientific instruments it has on board is its camera, JunoCam.
You see all these swirls, you see all sorts of spots coming up.
You see all these vortices, you see dramatic storm systems interacting.
It's mind-blowingly beautiful pictures that this little camera has been taking.
JunoCam was able to see the Great Red Spot from up close.
We can see height to the clouds.
We can see features that look like storms.
Maybe it's hailing or snowing ammonia on Jupiter.
And the most startling thing that we saw from JunoCam's imagery was that the poles of Jupiter are actually blue.
They are nothing like the orange and white planet that we grew up thinking about as children.
Juno has just begun to unlock Jupiter's secrets.
And so, at last, the godfather of the planets has begun to talk.
A planet that began life as an unremarkable rocky world but transformed into one of the jewels of the solar system where shimmering rings of ice harbour a potential home for life.
Saturn.
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They'll say no-one can see us That we're estranged and all alone They believe nothing can reach us And pull us out of the boundless gloom They're wrong They're wrong They're wrong.
Beyond the inner solar system past the asteroid belt lies Jupiter.
The largest of the planets is a giant swirling ball of gas its marbled appearance generated by violent winds that rage through its clouds.
Jupiter is a world as strange as it is remote.
If you fly upwards, only about 100km or so, you reach the edge of our atmosphere and the blackness of space.
It's really not that far.
But once you're in space, the distance scales are sort of incomprehensible.
I mean, Venus, the closest planet, is over 40 million kilometres away.
Jupiter around 650 million kilometres.
It takes our fastest spacecraft years to get there.
So, the idea that those planets could have any influence on us here on Earth seems fanciful.
And, indeed, if you're talking about your chances of meeting a handsome stranger or your life plans requiring a moderate reconfiguration about a week on Wednesday, then you would be right.
However, if you ask more profound questions, deeper questions like, "Why is the Earth the way that it is? "Why is there life on Earth? "Why do we exist at all?" then it turns out that the planets, and Jupiter in particular, have had a profound effect.
Early in its life, the young Jupiter went on the rampage.
The giant planet embarked on a voyage of destruction across the solar system that transformed the destiny of the planets, and the course of life on Earth.
Jupiter is the godfather of the planets.
Understand it and you understand how the solar system came to be.
On Earth, we can see glimpses of Jupiter's power in the scars it's left on the face of the planet.
This is the famous Barringer Meteor Crater in Arizona.
It is about a kilometre across, 170 metres from the rim to the crater floor and it was created about 50,000 years ago when a meteorite, 50 metres across, entered the Earth's atmosphere travelling at about 13km per second.
That means it would have taken around, what, seven seconds to go from the top of the atmosphere to the ground and it hit with such force that the energy released was equivalent to ten megatons of TNT.
And that is a very large nuclear bomb.
The meteorite that hit the Earth here is thought to have come from the asteroid belt the ring of rocky debris that orbits at the edge of the inner solar system.
And it was deflected from its orbit most likely by the gravitational influence of Jupiter.
Jupiter is a completely different class of planet to the Earth.
A gas giant.
A swirling ball of hydrogen and helium so large you could fit 1,300 Earths inside.
Jupiter can exert such a powerful influence on the asteroids because it's so massive.
It's about two-and-a-half times the mass of all the other planets, moons and asteroids in the solar system combined.
And, therefore, it has a strong gravitational pull.
And this means that Jupiter exerts an influence across the entire solar system that's second only to the sun.
And that influenced us far more than create the odd crater.
It can change the history of worlds.
To understand how Jupiter rose to such dominance, you have to go back to a time before the solar system even existed.
Nearly five billion years ago, a distant exploding star sent a shock wave across the galaxy causing the cloud of gas and dust that would become our solar system to collapse as the sun began to form.
But further out, something else was growing.
After 50 million years the sun's nuclear furnace ignited.
The light of its first dawn revealing Jupiter the solar system's first world.
A planet born so early, it swept up most of the material left over from the formation of the sun.
Because of its dominance, Jupiter had a profound effect on the newly forming solar system and paved the way for our living world to form.
This is a model of our solar system.
So, here's the sun, and then we have the four inner rocky planets, Mercury, Venus, Earth and Mars.
Then comes the asteroid belt, the ring of millions of smaller pieces of rock orbiting around the sun.
And then the gas giants.
Jupiter, Saturn, Uranus and Neptune.
Now, this has a pleasing regular structure about it.
All the rocky planets close to the star and the gas giants further out.
And we thought that this must be the natural order of things, the way that solar systems have to form, until we started to detect planets around distant stars and then we found that this arrangement is not typical at all.
Our sun is just one of around 300 billion stars in our galaxy and almost every one of those stars is home to its own system of planets.
In most other systems, the region where our planet orbits is empty.
Instead, closer to the star, we see super-Earths, vast rocky planets many times bigger than our own.
But, crucially, these worlds are thought to have thick toxic atmospheres, making them completely inhospitable to life.
And that raises a very interesting question.
Why, then, is our solar system the way that it is? To answer that question, we've sent spacecraft to every one of the planets and they've uncovered strange anomalies that reveal our solar system's past.
Our missions to Venus found that it once had far more water than you'd expect for a planet so close to the sun just as Earth does today.
The spacecraft we've sent to Mars touched down on a world that is curiously just half the size of her sister planets Earth and Venus.
And in the asteroid belt, we've uncovered a graveyard of failed worlds their growth mysteriously cut short.
To cause all these anomalies, it's thought that something catastrophic must have happened very early in the solar system's history.
All the evidence suggests that around 4.
5 billion years ago, Jupiter's orbit began to change, triggering a period of unprecedented violence which completely transformed the face of the young solar system.
And we know this because the marauding planet left a trail of destruction in its wake.
Early in its life, Jupiter began to move inwards towards the sun and the effects of that journey can be seen to this day.
In between the orbits of Mars and Jupiter lies the asteroid belt a desolate wasteland of debris left over from the beginning of the solar system.
Rocky bodies too small to be planets in their own right.
In science fiction films, the asteroid belt is often depicted as an un-navigable mass of tumbling rubble.
But it's not like that at all.
So much so, in fact, that modern spacecraft engineers can fly a spacecraft through without making any course corrections.
The reason for that is there's not much mass in the asteroid belt.
A sum total of all of them is only about 4% the mass of the moon and they're spread out in a huge sort of ring, out beyond the orbit of Mars.
So, it's a vast amount of space.
That means that the average distance between any two large asteroids is about eight times the distance between the Earth and the moon.
So, I could stand on one of those large asteroids and look out into space and my nearest neighbour would just be a dim star in the dark.
But scattered amongst the rubble are objects that are far more than mere rocks.
Five, four, three, two, main engine start, one, zero and lift off of the Delta II Rocket.
In 2007, Nasa's Dawn mission was sent to explore the two largest objects in the asteroid belt.
After a year in orbit around the giant asteroid Vesta in March 2015 Dawn made its final approach on a body so large it makes up almost a third of the mass of the entire asteroid belt Ceres.
On arrival, the first images Dawn sent back to Earth contained something entirely unexpected mysterious bright patches in one of Ceres' largest craters.
Spectral analysis of the images showed that the patches were, in fact, the salty residue left behind by liquid water suggesting there must be large amounts of ice just beneath the crust.
Dawn went on to discover over 300 bright spots all over the surface.
And this means that beneath this thin crust, Ceres has a thick ice rich mantle surrounding its rocky core evidence that the dwarf planet is made up of multiple layers.
The interior of Ceres is like nothing else in the asteroid belt.
The differentiation, that separation into layers, observed by Dawn is more characteristic of a planet than an asteroid.
So, 4.
5 billion years ago, Ceres was well on its way to becoming a fully-fledged world.
It's thought that's in its infancy Ceres was very different.
The water that now lies frozen within its interior was once liquid.
Protected beneath a thin layer of ice Ceres was once covered by a deep saltwater ocean.
Before Ceres had reached its full potential, a great disturbance sent shock waves through what would one day become the asteroid belt and cut its development short.
As Jupiter circled the young sun, it started to clear a path through the gas and dust that shrouded the early solar system but that process caused it to do something alarming.
Gravitational interactions with the gas made the giant planets spiral inwards towards the sun ploughing straight through the region of space that would become the asteroid belt scattering the material from which Ceres would otherwise have grown.
Computer simulations of the early solar system suggest that the asteroid belt once contained enough material to build a planet the size of the Earth.
And perhaps that was Ceres's destiny.
But when Jupiter passed through, it scattered 99.
9% of the material away, and Ceres's fate was sealed.
Within 100 million years, Ceres's ocean froze and was buried beneath its crust.
The young planet's development cut short before it could fulfil its promise.
But Jupiter's reign of terror was far from over.
It would continue its journey inwards towards the place our planet was beginning to form threatening the very existence of Earth.
Jupiter had such an overwhelming effect on the young solar system because of its powerful gravitational field the effects of which we can still witness today.
Jupiter exerts its influence across the solar system through its gravitational field which is by far the most powerful of all the planets, because Jupiter is the most massive of all the planets.
It's about 320 times the mass of the Earth.
That's why it was so destructive in the past.
And we see the power of that gravitational field today in its influence on the closest of Jupiter's largest moons, Io.
Io is the most volcanic world in the solar system.
Its surface covered with hundreds of active volcanoes and lakes of molten lava.
The largest, known as Loki Patera, is more than 200km in diameter.
A million times the area of any lava lake on Earth.
Its surface tormented by waves of molten rock.
Io is a vision of hell created by the moon's proximity to Jupiter.
Volcanism here on Earth is powered by the internal heat down below the surface.
Now, much of that is residual heat left over from the Earth's formation four-and-a-half billion years ago, about half of it, and the other half is down to radioactive decay of elements around the Earth's core.
Now, on Io it's different.
Io's a much smaller world and so it didn't retain much residual heat.
So, there, the volcanoes are powered by a different process.
It's known as tidal heating.
The energy that drives Io's volcanism doesn't come from heat stored within the moon.
It's generated by gravity because Io orbits just 350,000km from the tops of Jupiter's clouds.
Io orbits at about the same distance from Jupiter as our moon orbits the Earth.
But because Jupiter is so much more massive, Io goes around much more quickly.
In fact, it goes around once every 42 hours.
Now, if Io were Jupiter's only moon, that orbit would be circular, but it isn't.
The next moon out - Europa - goes round Jupiter precisely once for every two orbits of Io which means that every second orbit, Io and Europa fall into alignment.
It's what's known as an orbital resonance.
That gives it a gravitational kick and that moves Io's orbit into an ellipse.
Now, that means that the gravitational force's on Io are constantly shifting and changing and that stretches and squashes the moon, and heats it up - by friction.
Now, that is called tidal heating and that is the origin of Io's volcanoes.
This process raises the temperature in Io's interior, which would otherwise be frozen solid, to more than 1,000 degrees Celsius creating its lava lakes and powering immense volcanic plumes that rise up to 300km from the moon's surface and out into space.
Io provides the solar system with a vivid reminder of the giant planet's power.
Jupiter's intense gravitational field is the source of Io's volcanism today.
But we don't feel that gravitational pull here on Earth, because Jupiter is so far away, but four-and-a-half billion years ago, Jupiter was migrating inwards towards the inner solar system, approaching the region where Mars and Earth were forming.
After passing through what would become the asteroid belt Jupiter entered the inner solar system continuing its journey, spiralling towards the sun.
Back then, the area where Mars and Earth orbit today was densely packed with gas and rock.
But as Jupiter approached, it wrought havoc scattering the rocky material in all directions some sent careering into the sun others thrown out into interstellar space.
And it's this that may explain our solar system's unusual structure.
Here's the solar system today.
The sun, the four inner rocky planets, the asteroids and Jupiter.
And what we think may have happened is Jupiter made it inwards through where the asteroids are, as far in as the orbit of Mars.
And that would have cleaned out quite a lot of the material in the inner solar system, leaving less for the formation of planets.
And that's why we don't see super-Earths in our solar system.
Those big massive rocky worlds that we see in orbit around so many other stars.
This also might explain why Mars is so small.
See, if Jupiter was orbiting in the region that Mars was forming, there would have been much less material here.
And that might explain why Mars is only a tenth of the mass of Venus and Earth.
Had Jupiter continued to move inwards, it would have had a similar effect on the Earth meaning the world we inhabit might never have formed.
But just as it looked as if Jupiter would sweep everything away, something stopped the giant planet in its tracks because in the shadows of the outer solar system, another planet was forming.
The solar system's second gas giant Saturn and its birth changed everything.
When a planet forms in a disk of material around a star, as Jupiter did in our solar system, it tends to clear out a gap in the disk.
Now, the material tends to fall inwards towards the star.
It's called the accretion and that drags the whole thing inwards.
And that's what happened to Jupiter.
But, then, a less massive planet, Saturn, formed further out.
It cleared out its own disk and it too fell inwards towards the sun, but more quickly than Jupiter.
That meant that Saturn got into a resonance with Jupiter.
It went round once in orbit around the sun for every two orbits of Jupiter and that has the effect of cleaning out the whole region between the two planets.
And that has the effect, through a series of complicated gravitational interactions, of slowing and stopping the in-fall and eventually causing the two planets to move back out again.
And that is what happened to Jupiter and Saturn in our solar system.
Saturn caused Jupiter to retreat leaving behind just enough material from which the inner planets could form.
Mercury.
Venus.
Mars.
And our home the Earth.
By preventing the formation of much larger super-Earths, Jupiter allowed our planet to grow.
And even as Jupiter's reign of terror was drawing to a close, it provided one last parting gift to our world.
The young Earth formed in an arid region of the inner solar system.
There was very little water that close to the sun, but as the Earth was forming, Jupiter was already tacking back outwards again into the outer solar system through the region that we now call the asteroid belt, a region populated by many icy, water rich comets and asteroids.
And they were scattered back inwards again, bringing water back into the inner solar system.
So, I think it is quite a wonderful thought, that Earth is a water world today because of the motion inwards and then back outwards again of the massive planet Jupiter.
This idea does seem quite contrived, almost fantastical, but the more we learn about the formation of solar systems, and the more we try to model a system like ours, with four terrestrial, water-rich planets close to the star and then the gas giants further out, the more we learn that perhaps all these things had to happen, these unlikely movements and interactions between the planets, in order to produce a system like ours and a planet like ours.
So, places like this may be extremely rare.
Today, Jupiter has settled into a regular orbit back beyond the far edge of the asteroid belt its days of marauding through the solar system at an end.
Jupiter has been established in a stable orbit for almost four billion years.
If I was to sit here on Earth 3.
8 billion years ago when life began and look up into the night sky, I would have seen it shining there as a point of light the same as it looks today, distant and seemingly detached.
And it's remained that way for the vast expanse of time it's taken for evolution by natural selection to transform those first populations of organisms into all this, to transform the Earth into an oasis of life in the desert of the solar system.
But Jupiter's influence over the Earth remains to this day and that's because, despite its great distance from us it retains a vice-like grip over the asteroid belt.
It's easy, I think quite natural, to think of the asteroid belt as a single structure.
A sort of ring of rock surrounding the sun.
But that's not what it's like at all.
In reality, each one of those millions and millions of pieces of rock is following its own individual orbits.
And this remarkable animation is made up of ten years of astronomical observations.
And every point you see on this animation is a single asteroid, apart from all the planets.
And so you see Earth and Mars and Venus whizzing around the sun.
But the interesting one is Jupiter orbiting just outside the asteroid belt.
What you can see is that the asteroid belt dances to Jupiter's tune.
It's the conductor of the asteroid belt, if you like.
There are complex patterns here, but there's also structure.
And the reason for that is the delicate interplay between the gravitational pull of the sun and the gravitational force from Jupiter.
Now, what can happen is that perhaps because of an interaction between two asteroids, perhaps they collide with each other, or perhaps on their orbit they line-up perfectly with Jupiter and get an extra gravitational kick, those asteroids can be disturbed from this structure and be sent inwards to the inner solar system.
And by that mechanism, Jupiter has a profound influence on the planets closer to the sun.
Around 100 million years ago, an asteroid 10km across was ejected from the asteroid belt.
Dislodged by Jupiter's gravity, it was set on a collision course with the Earth.
When it struck, it generated a fireball so hot, anything within a 1,000km radius would have died instantly.
The impact threw 300 billion tonnes of sulphur into the atmosphere.
And during the nuclear winter that followed, 75% of all species were wiped from the face of the Earth.
In one fell swoop, Jupiter changed the course of our planet's history.
There are a few places on Earth today where you can catch a glimpse of lost worlds, you can see Earth as it was millions of years in the past and perhaps glimpse the Earth as it might have been.
And this is one of them.
Today, this is the Colorado Plain, over a kilometre in altitude, south of Denver close to the Rocky Mountains, but 200 million years ago, this was at sea level.
It was an ancient lake and the ghosts of those lost worlds, the imprints of the past, can be seen over there, because there are literally thousands of dinosaur footprints.
And here they are, the dinosaur footprints.
I find this absolutely remarkable.
This is the footprint of a sauropod dinosaur.
That's one of the big ones.
The big herbivores with the long necks.
This animal would have weighed about 30 tonnes.
It was tall enough to peer over a two-storey house.
What happened here is, probably a herd of them, a group of them came lumbering across this lake bed and, then, perhaps that same afternoon, predators came, maybe following the herd.
And that's these footprints here.
The allosaurus', these three-toed footprints.
Much smaller animal, maybe about twice the height of me, about two tonnes, very nimble and agile.
So, you see a whole story played out here, frozen in time.
Today, just their traces remain but were it not for Jupiter they might still be here.
There are so many chance events, not only throughout the history of Earth, but also spanning the entire history of the universe for 13.
8 billion years, without which we wouldn't exist.
There's an unbroken chain of life stretching back four billion years here on this planet.
You interrupt or interject at any point and life on Earth is different.
But having said that, there are major events that affected life.
And one of them is the asteroid that wipes out the dinosaurs.
And, in that sense, it is certainly true to say that without Jupiter, we wouldn't be here.
The godfather of the planets paved the way for us to inherit the Earth.
And although it occasionally flings rocks from the asteroid belt our way it also protects us because for objects heading towards the Earth from the far reaches of the solar system, Jupiter's gravitational field acts as a shield.
Around a century ago, a lump of rock and ice 4km across and weighing 17 billion tonnes was hurtling towards the inner solar system until Jupiter intervened.
Five, four, three, two, one We have ignition and lift off of Atlantis and the Galileo Spacecraft bound for Jupiter.
70 years later, we witnessed just how effective a shield Jupiter can be.
Onboard the space shuttle Atlantis the Galileo orbiter.
Three years after Galileo launched, comet Shoemaker-Levy-9 had been captured by Jupiter's gravity.
Locked in the giant planet's embrace tidal forces now began to tear it apart.
Its journey cut short the comet now faced annihilation.
After crossing the inner solar system, Galileo passed through the asteroid belt approaching the spots from where it would witness the comet's final moments.
On July 16th, Galileo saw the first fragments of the comet enter Jupiter's southern hemisphere.
Pieces of comet Shoemaker-Levy-9 struck Jupiter over the course of six days.
It was the first time a comet strike had ever been witnessed.
The most destructive impact released energy equivalent to six million megatons of TNT leaving behind a giant dark cloud 12,000km across.
By capturing objects and incinerating them on impact Jupiter sweeps up bodies from the outer solar system that might otherwise collide with Earth.
Jupiter, the oldest and largest of the planets, is the godfather of our solar system.
In youth it went on the rampage.
For some young planets, it spelt disaster.
But for others, like our own world, it cleared the way for their formation.
And in adulthood, it created the conditions that allowed us to rise so we owe Jupiter a great debt.
But as the dinosaurs found to their cost, it's a debt that could be recalled at any time.
To the naked eye, Jupiter is one of the brightest points of light in the night sky, and through a small telescope, it is a beautiful banded world.
But it feels distant, eternal, disconnected from events here on Earth.
But the more we've understood about the history of the solar system, the more we've come to understand that that is not the case.
Jupiter has played an important and perhaps decisive role in the stories of all the planets, including Earth.
So, the solar system is just that.
It's a system.
Complex, interconnected and interdependent.
So, next time you see Jupiter, just hold your gaze.
Maybe think for a minute, because it is so much more than just a point of light, or a planet, even.
It is the great sculptor of the solar system, the destroyer and creator of worlds.
I think people are drawn in by Jupiter because it's very mysterious.
It's covered by clouds that hide what's underneath.
It's very violent.
And it's very intimidating.
It's also very beautiful.
It has all these things going on and it's hard not to be taken in.
T-minus ten, nine, eight, seven, six Such is Jupiter's mystique, it's been a recurring target for space exploration.
And lift off of the Atlas V with Juno on a trek to Jupiter.
In 2011, Nasa launched its latest mission - Juno.
When we launched the Juno spacecraft away from the Earth out towards Jupiter, we didn't have enough speed to get away out of the gravity of the sun, so we actually had to come back to Earth, get a gravity assist from Earth, and then go out to Jupiter.
After travelling for five years, Juno finally arrived.
This is a mission that goes closer to the planet in its orbit than any other mission ever has.
Only a few thousand kilometres from the cloud tops and very, very fast.
We go from pole to pole in two hours, slipping between the radiation belts in the cloud tops, getting the data as fast as we can and getting out.
So, in every way, Juno is breaking new ground and that's allowed us to see things that we couldn't have ever imagined.
Juno's mission is to explore the planets inside and out.
And amongst the many scientific instruments it has on board is its camera, JunoCam.
You see all these swirls, you see all sorts of spots coming up.
You see all these vortices, you see dramatic storm systems interacting.
It's mind-blowingly beautiful pictures that this little camera has been taking.
JunoCam was able to see the Great Red Spot from up close.
We can see height to the clouds.
We can see features that look like storms.
Maybe it's hailing or snowing ammonia on Jupiter.
And the most startling thing that we saw from JunoCam's imagery was that the poles of Jupiter are actually blue.
They are nothing like the orange and white planet that we grew up thinking about as children.
Juno has just begun to unlock Jupiter's secrets.
And so, at last, the godfather of the planets has begun to talk.
A planet that began life as an unremarkable rocky world but transformed into one of the jewels of the solar system where shimmering rings of ice harbour a potential home for life.
Saturn.
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