All language subtitles for The Planets - 01x01 - Different Worlds.MVGroup.org.English.orig.Addic7ed.com

On January 2nd, 1959, with
the space age barely a year old,

the Soviet Union
launched Lunik - "little moon".

It was sent to plant
a Soviet pennant on the moon.

Within hours of the launch,
it became clear

that Lunik was going
to miss its target.

As the Soviet scientists
watched their tiny probe

sail out to join the planets

in an endless journey
around the sun,

an inspired thought
occurred to them.

They renamed their spacecraft
Mechta - "The Dream".

In 1926, when this recording of
Holst's Planets suite was made,

there were thought
to be eight planets.

Then, in 1929,

a young man arrived
at an observatory

in Flagstaff, Arizona,
to start the search for a ninth.

At that time, little
was known about the planets.

Closest to the sun lies Mercury,

a tiny world of iron and rock,
barely discernible in the glare.

Then Venus,
perhaps a second Earth,

hidden beneath
a blanket of cloud.

Then Earth.

And beyond us, Mars,
the Red Planet.

It has seasons, polar caps,

and the possibility of life.

Far beyond these rocky worlds
are the distant giants.

Jupiter, over 1,000 times
bigger than the Earth,

and Saturn, with its distinctive
and dramatic rings.

The two remaining planets

are 15 times the size
of the Earth, yet are so distant

that they appear
as the faintest of stars.

Uranus - an aquamarine mystery.

And finally, Neptune,

a world that moved
unevenly across the sky.

This irregular movement

suggested the presence
of a more distant planet,

whose gravitational tug might be
toying with Neptune's orbit -

Planet X.

'February 18th, 1930.

'Clyde Tombaugh,
sitting in an office

'very near to where we are now,

'looking at the photographs he
had taken of the night sky...'

With his eye at the eyepiece of
the blink comparator back there.

'And he had been
searching on the plates

'that were centred on a star

'in the constellation
of Gemini, the Twins.'

He had started that morning.

He had moved slowly across,

click, click, seeing one image,

then the other,
keeping on moving back.

'All these images were
negative, all the stars.

'And anything else would be
black on a white background.

'At 4pm, he crossed
the plate's centre.

'He passed the area
where the guide star was.

'The star Delta Geminorum -'

big, big bright star.

He moved a little bit more,
a little bit more,

'and then he saw a very faint,
a very faint black dot.'

Then he blinked to the other one
on the other plate,

'and he saw it appear
here and there.'

On his plates,
taken several days apart,

Tombaugh noticed that
a point of light had moved.

He knew instantly this was
what he was looking for.

It was an historic moment.

'He took the walk
from the comparator room,

'all the way down
to the director's office,

'and he stopped, did his tie
and combed his hair a little,

'and said "I wanted to appear
a little nonchalant about this."

'Then he stepped
into the office...

(Clears throat)

"Dr Slipher? I have
found your Planet X."

Planet X was soon named Pluto.

It marks the end
of the solar system.

A tiny world of ice,
smaller than our moon,

now known to have
its own satellite, Charon.

But Pluto patrols the outer edge
of the solar system,

in the distant realm of giants.

Worlds of swirling water,
like the azure Neptune,

and Uranus, which
mysteriously orbits the sun

spinning on its back.

Pluto lies way beyond
the gargantuan worlds,

the gas planets
that have no landscapes:

Saturn, with wind reaching

thousands
of kilometres per hour,

and Jupiter,
that has an Earth-sized storm

that has lasted for centuries.

The closest worlds to the sun

are small islands
of rock and iron.

Mars, with its faint atmosphere
of carbon dioxide,

and Venus, smothered
in clouds of sulphuric acid.

Then there is Mercury,

boiling in sunlight,
and freezing at night.

Nine different worlds, with
seemingly little in common,

save that they orbit
a single sun

and are bound together
by its gravity.

And then there is the Earth.

A small planet in the measure
of the solar system.

It has a thin atmosphere
that clings to a rocky surface.

But the Earth is different.
It is special. It has life.

What process could create such
a variety of different worlds?

Hal Levison is at the forefront
of a branch of astrophysics

that is still struggling
with the mystery

of how the planets formed.

'It's amazing,'

when you consider that

all planets in the solar system:

the Earth and the rocky planets,

the cores of the giant planets,
Jupiter and Saturn,

and the majority
of the outer planets,

Uranus, Neptune and Pluto,

formed from material that is
very fine pieces of dust,

much finer than the dust
I'm holding in my hand.

About the consistency or size

of particles of dust
in cigarette smoke.

I was an astrophysicist,

interested in an obscure type
of galaxy, when five years ago

I got the bug
of trying to understand

how material like this can form
the planets we see today.

By the 18th century, astronomers
had discovered that galaxies

are filled with drifting clouds
of gas called nebulae.

Perhaps these clouds were the
raw materials of the planets.

Two men, the philosopher
Immanuel Kant

and the mathematician
Simon de Laplace,

looked at the uniform direction

of the orbits
of the planets in the sky.

They suggested the planets
were a relic of a cloud

of dust and gas that circled
the sun during its formation.

In a single process,
they concluded,

the solar system was born.

The idea was elegant,
and quite brilliant,

but the complex details
of their theory

lay centuries in the future.

Its proof had to wait for
the arrival of the space age.

September 1944.
London was under siege.

Mysterious weapons
were raining down from the sky.

Hitler's vengeance weapon
threw people into confusion.

Nothing had prepared them
for a supersonic missile

that took just six minutes
to travel from mainland Europe.

The technology behind these
missiles was highly advanced.

It had been developed
by a brilliant young engineer

called Wernher von Braun.

Von Braun's rocket
was called the V-2.

Designed to save the war for
the Nazis, eventually it became

the foundation
of our journey to the planets.

When Germany fell,

American troops headed
straight for the V-2 factories.

Before the dust
had settled in Europe,

von Braun and his team
of engineers found themselves

working
for the United States Army.

In the deserts of New Mexico,
the captured rocket parts

were reassembled
by German and US engineers.

The modified V-2s soon flew
beyond the range of cameras.

Engineers fixed
astronomical telescopes

to anti-aircraft gun mounts.

The system
was designed by Clyde Tombaugh,

the discoverer of Pluto,
and his films still survive.

The Americans destroyed
the German rocket factories

to keep von Braun's secrets
from the advancing Red Army.

But when they arrived,

the Soviets found enough
to take back to Moscow.

The man given the task of
piecing together the rockets

was Sergei Pavlovich Korolev,

and Boris Chertok
was his right-hand man.

While their brief
was to develop rockets

which could reach America,

Korolev's eyes were firmly
fixed on the planets.

But it was the Americans
who made all the early running.

By the end of the decade,
they were strapping film cameras

to rockets, and sending them
high above the atmosphere.

The cameras had to endure an
18-mile plummet back to Earth.

Miraculously, some survived,

and astronomers got their
first glimpse of the only planet

they couldn't see
with their telescopes.

For the first time, we could
see the curvature of the Earth.

The arcing horizon
was a humbling reminder

that we were living on a
gigantic ball of rock and iron.

How such a world could have
grown from a cloud of dust

seemed more baffling than ever.

George Wetherill
has dedicated his career

George Wetherill
has dedicated his career

to the question
of planet formation.

When he started, the science
was dominated by one man.

No great scientist
ever devoted his life

to understanding this problem.

It was sort of a hobby,

something they did on the side.

And I think the first person to
really devote his life to this

was a Russian scientist
named Victor Safronov,

who started
working on these problems

shortly after World War II.

And he tried to identify what
all the scientific problems are

that you need to understand
and need to solve,

in order to understand
the grand problem

of the formation
of the solar system.

And to this day, his lists
of problems are essentially

the same problems
that we're working on today.

Victor Safronov
revisited the 200-year-old idea

that the planets formed
from a disc of gas and dust.

He set about structuring
this complex process

into comparatively
simple stages.

The first stage
is still not fully understood.

Remember, we're starting off
with very fine pieces of dust,

and the process
of how you get from that

to something the size of
a boulder, or even a mountain,

is actually
not very well understood.

The party line of what most
people think actually happened,

was that you had
this disc of dust.

Dust settled into the mid plain
of this protoplanetary nebula.

'And you got what's called
gravitational instability

'that formed big clumps,

'things maybe the size
of 100 metres in diameter.'

Safronov's second stage
was less complex.

It was called accretion.

He calculated that in
a remarkably quick time,

the clumps
would gather together,

building the embryos of planets.

As they grew, a new force
became significant - gravity.

'An amazing thing happens that
Victor Safronov discovered.'

That is, as these things
start to grow,

the bigger something gets,
the more it can eat.

So you end up
with this runaway situation,

where the bigger guys
are getting bigger still,

and it's sort of a race
to eat up the little guys.

And so you start off
with an un-countable number

of objects
the size of mountains.

And you end up with maybe 100,

in the inner part
of the solar system,

objects the size of the Moon,
going up to the size of Mars.

Competing worlds
sucked in the surrounding debris

until there was simply
no more to be had.

In the inner solar system, where
there are now four planets,

there were once
upwards of 100.

How that army of worlds became
just four was still a puzzle.

But Victor Safronov had a hunch

that the process
would leave those planets

spattered
with the scars of impact.

Was this what we could
see on the moon?

Unknown to the West, Safronov
had taken a giant stride

towards a theory
of planet formation.

Perhaps, somewhere
in the solar system,

there might be a planet bearing
the hallmarks of his theory.

In 1957, the Americans announced

that they were preparing
to enter the space age.

They were about to launch

the world's first
artificial satellite.

In the Soviet Union,
Korolev acted immediately.

'For Korolev,
it was the beginning

'of the race with Americans.'

And he wanted to be first,

ahead of the Americans,

like all of us.

And I think he wanted to do this

maybe 100 times
more than any others.

'Then he called my father
and told him,

'"I want to launch
this first satellite.'

"Let's do this before the
Americans, as soon as we can."

It would be a huge gamble,

but finally Khrushchev
agreed to let him try.

Now Korolev had to convince his
engineers they could do it too.

On October 4th, 1957,

while the Americans were still
finalising their plans,

Sputnik was launched.

(Beeping)

(Beeping)

(Beeping)

40 years on,

Korolev's achievement
is still celebrated in Russia.

'That evening,
he was very proud,

'he realised
it was a great achievement.'

And next day, he understood the
reaction of the outside world

was much stronger
than it was in our country,

and the feeling was much
stronger than even his feeling,

specially in the United States.

Korolev's rockets
had opened the door to space.

The planets were beckoning.

Bruce Murray is a veteran
of the US space programme.

When his career started,

the planets seemed
a very long way away.

He still remembers
the first time

he saw Mars through a telescope.

And it just blew me away.

I was so taken with the fact

that here was a real object,

it was three-dimensional,
or seemed to be.

'It was colourful, glowed,
and really drove home to me'

there's a place out there,
a real place,

not just something
I studied in school somewhere.

As a young man, Bruce Murray
was taken under the wing

of physicist Bob Leighton,
who had developed a way

to make time-lapsed films
of the planets.

The images were extraordinary
because they could show

the planet rotating, you could
time-lapse it, take one frame,

wait a minute, take another
frame, and make a time-lapse.

And it brought to everybody
the image of Mars

that the most dedicated
astronomers only infer,

because they have to
remember all those frames.

And he did it for fun.

Leighton's films
brought the planets to life.

For the first time,

astronomers could see
one of the moons of Jupiter

orbiting its giant parent.

'The outer planets,

'the ones that are
huge masses of gas,

'in the case
of Jupiter and Saturn,

'you could actually
see some beautiful structure.'

The first thing,
as in the inner solar system,

is diversity - "My Lord,
everything is different."

But Mars,
the Earth's smaller cousin,

was always
the most tantalising.

Leighton could see
mysterious dark patches

rotating with the planet.

But what would a close encounter
with the surface reveal?

In 1964, the American
probe Mariner 4

set off to send back the first
pictures from another planet.

'Bob Leighton was charged
with bringing back the images.'

..and blue clouds, oh, yes...

'He asked Bruce Murray
to join him.'

'I was dragged or sucked along,
however you want to look at it,'

into this wonderful experience,

of becoming the first
experimenters to look at Mars

through a close-up camera.

'This is
Mariner Control Center at JPL.

'The spacecraft is 134.217
million miles from Earth

'and 50,142 miles from Mars.'

After a journey of eight months,

Mariner 4 was homing
in on its target.

'The first picture will
cover an area of approximately

'176 miles square on
the sunlit bit of the planet.'

I wish I was as sure as he is!

'About four minutes from now,
we should be able to determine

'the camera shutter is operating

'and that
the recorder is running.'

The anticipation
of not just the scientists,

but the public and news media,
was incredible,

because Mars was thought to have
life, and in the popular mind,

maybe it had Martians,
as far as we were concerned.

Mariner 4 was a fly-by.

It would get only one chance
at the pictures.

'..the scan position for 5605
is 323. Congratulations.'

323! Exactly where
they wanted her!

10,000 miles from the surface,

Mariner 4's cameras
whirred into life.

These signals came back - if you
think of one picture element,

one sample of light - the rate
at which these came in from Mars

was one of these per second.

- Hey! Here we go.
- There she goes. That's data!

And so it took three weeks for
our 20 pictures to come back.

Give me Bruce Murray's
phone number.

Where the devil are
the Mars picture interpreters?

Yeah, data's coming in, boy.
What are you doing in bed?

There we go.

We got some pictures.

The planet was not
what they had expected.

There was no sign
of life here. No vegetation.

Just picture after picture
of a dull, flat landscape.

It wasn't until frame 12

that the first features
became visible.

'What we could see
were these huge craters.

'300 kilometres, 200-mile
craters across, on Mars.'

Impact craters -

and that meant that Mars
was preserving a signature

from its earliest times,
3 or 4 billion years ago.

So we had a major conclusion,
stunning everybody,

from these
very few pictures we got.

When the news filtered
through to the Soviet Union,

one man wasn't as surprised
as his Western rivals.

Craters were exactly
what Victor Safronov expected.

Soon, Safronov's ideas were
being discussed in the West,

where superior technology
allowed George Wetherill

to take
the accretion theory further.

'I'd called it
the planetesimal problem.'

That says there's a lot
of objects, small planets,

moving around the sun in orbits.

What you want to understand
is how they accumulate together

to form large planets.

Wetherill's computers uncovered

a terrifying period
of planet formation.

'What you find if you do
the problem with the computer'

is that, as they grow, they
start to perturb one another

into orbits which cross
the orbit of another planet.

Soon, the neat orbits
of Safronov's army of planets

became fatally disrupted.

As they started
tugging each other off course,

the solar system
was brimming with loose cannon.

World-shattering collisions
were inevitable.

'George realised that
it was like a wild frat party.'

All hell breaks loose
in the inner solar system.

Stuff either hits the sun
or gets thrown out to Jupiter,

and out of the solar system.

It's a very violent,
happening party.

If Wetherill was right,

during this period,
the inner solar system

must have been strewn
with planetary debris.

The four surviving planets
would have had to endure

a final stage
of intense bombardment.

In 1973, George Wetherill
got the chance to test his work.

Mariner 10
was on its way to Mercury.

78 million kilometres
from Earth, beyond the scope

of the most powerful telescopes,

the surface of this planet
was a total mystery.

'A few months
before the Mercury mission,'

I was in a meeting
where people discussed

what we might find on Mercury,
to get thinking about Mercury.

A very distinguished
planetary astronomer

in answer to a question,
proclaimed that Mercury

would have
no craters, or few.

The curious thing is
that the craters on Mars

were also a surprise
to most planetary astronomers.

After a journey
that took in a fly-by of Venus,

by February, Mariner 10
was nearing its target.

'Subsequently,
I was invited to JPL'

and sat in a little room
above mission control

and saw the pictures coming in.

'The first pictures of Mercury
showed just a fuzzy ball.'

You could imagine seeing
craters, but then it got closer.

Soon, it started
to look like the Moon.

Mercury was the most cratered
planet in the solar system.

One impact was so great

that it left
shock waves set in stone

on the other side of the planet.

It was proof of the final stage
of the accretion theory.

I was just thrilled by this.
I knew they were there,

but actually seeing them,
that I'd been thinking about

all these years,
and now here they are.

It made me very excited.

And all these military
men around kept saying,

"Isn't that beautiful? It's
just like a 52 drop in 'Nam."

Here, then,
are the inner planets.

The survivors
of a life-or-death struggle.

Mercury, Venus and Mars.

Each bearing
the scars of creation.

But what of the Earth?

Surely our planet could not
have survived unscathed?

In the field, Hal Levison gets
a real sense of the violence

that rained down on the planets,
including our own.

This hole in the ground
was made in a matter of seconds.

Despite being an awesome sight,

'something that tells us the
solar system is still active

'and that things are still
running into each other,'

'It's a relatively insignificant
hole in the ground.

50,000 years ago, a 50-metre
fragment of a world blown apart

billions of years earlier
careered into the Earth

in what is now Arizona.

Here is evidence of
the final stages of accretion.

But what of the worlds
that dwarf the inner planets?

How does the accretion theory
account for the gassy giants

that rule the distant regions
of the solar system?

We have different planets
as we get farther from the sun,

because as you get farther from
the sun, the temperatures drop.

About four times more distant
from the sun than the Earth is,

we hit a point where water would
condense and become a solid.

With water turning to ice, the
amount of material available

to form the outer planets
was far greater.

Jupiter and Saturn grew so large
that they started sucking in

the primordial gases
from the original dust cloud,

swelling them to hundreds
of times the mass of the Earth.

This region had many more worlds
than exist today.

Their orbits
were also disrupted.

We can find no traces of impacts
in their gassy atmospheres,

but evidence can be seen
in their rotation.

It is believed that a world
the size of the Earth

collided with Uranus.

Today, Uranus still rolls
around the sun on its back.

When did these planet-building
impacts come to an end?

'I've found a lot of comets.

'I've helped
discover 21 of them.'

There is nothing like the night

we found the Shoemaker-Levy 9.

We had no idea how important
that discovery was going to be.

'It made page 23
in the London Times,

'that Carolyn and Jean Shoemaker
and I discovered this comet.'

Interest increased
several months later,

when it was announced
that Shoemaker-Levy 9

was on a collision course
with Jupiter.

This was not page 23 of the
London Times, it was page 1.

It was a different story.

Shoemaker-Levy 9 was going
to show us what it's all about.

In all civilisation,

since Galileo first looked
through a telescope, in 1609,

and since he first
looked at Jupiter, in 1610,

this is the first time we've
seen a comet strike a planet.

July 16th, 1994. Impact day.

And every available telescope
is trained on Jupiter.

Look! Oh, my God! Look at that!

'It's how the solar system was
built, comets hitting planets.

'Comets first hitting
each other.

'Very slowly, almost an embrace
rather than a collision,'

then these objects get bigger
and their gravity gets bigger,

the speed gets higher,
and it gets more violent.

The teenage solar system
has become dysfunctional.

And finally, when does it end?

'What Shoemaker-Levy 9 taught us
is it hasn't happened yet.'

Right then,
in the summer of 1994,

around Jupiter, there's
a big yellow police fence,

that says danger, keep out,
solar system under construction.

It's still happening.

Jupiter grew a little bit during
the week of July 16, 1994.

'Water was dumped on Jupiter.

'It had more
carbon sulphide down there.'

It was as if nature had said,

"OK, guys, I'm going
to show you how it works,

"and all you have
to do is watch it."

Here, then, are the gas giants.

Jupiter and Saturn
mark the current limit

of the plant builders' theories.

Far beyond these gargantuan
worlds lie the ice giants,

Uranus and Neptune.

But out here, the accretion
theory runs into trouble.

'The formation
of Uranus and Neptune

'are the greatest mysteries
in the solar system,'

because everything goes more
slowly at greater distances

from the sun, so all
these processes slow down.

When we try to run the same
computer programs out there

that we did
in the terrestrial planet zone,

we don't get planets forming.

No matter what we do,
we can't form Uranus and Neptune

using these kind of models.

'I can't make
Uranus and Neptune go away.'

They're there,
and our models can't make them.

So we do indeed
have a long way to go

before we really
figure all this out.

How these worlds formed
so quickly is a puzzle.

Scientists don't know enough
about early conditions

this far from the sun.

What kinds of worlds
went into the formation

of Uranus and Neptune?

In 1992, two astronomers
were surveying the space

beyond Neptune when they found
a substantial chunk of ice.

Since then,
they have found many more.

Called the Kuiper Belt,
it is now thought that they are

the building blocks
of ice giants that never were.

'The Kuiper Belt is a region
where the small ice mountains

'that we've talked about
started accreting and building

'into larger things.

'To me, that's the region
we need to look at,

'because planet formation
started there,'

and it was frozen in

at some intermediate state.

Understanding that will tell us

in detail how accretion started,

but what shut it off
is also going to be interesting,

and will tell us something
about the process.

So to me, the future lies in the
outer part of the solar system.

But there is a planet that lies

at the inner edge
of the Kuiper Belt.

70 years after its discovery,
the strange, tiny world of Pluto

may at last be making sense.

'Pluto was discovered in 1930,'

and it was the oddball
of the solar system.

Most of the planets are in nice
circular orbits. Not Pluto.

Most are set in this plane that
represents the accretion disc.

Not Pluto.

And it was just an oddball,
it was small and icy,

different to anything
else that we knew about.

Could this small, icy world
be a survivor of accretion?

A world that somehow
escaped being swallowed up

by the growing Neptune, or being
hurled out of the solar system?

Could Pluto be the missing link

in the formation
of the ice giants?

'Turns out Pluto was just
the largest known member

'of this population.

'It went from being
this lonely remote oddball,'

to being essentially the
grandfather of a population.

And the Kuiper Belt
probably has more objects

than any other region
in the solar system.

It's the most populous region

and yet we didn't know
about it 10 years ago.

In the 40 years
since Mechta broke free

from the Earth's gravity, we've
sent probes to all the planets.

We've sampled
the corrosive clouds of Venus,

and recorded planet-wide
thunderstorms on its surface.

We've survived
dust storms on Mars,

and seen canyons
that could swallow countries.

We've mapped
the icy moons of Jupiter,

and plunged into its atmosphere.

We've skimmed
the rings of Saturn.

We've seen active geysers

on the most distant and freezing
moon in the solar system.

But just as the first
stage of our reconnaissance

of the planets draws to a close,

we have
a new region to explore.

In 1992, Clyde Tombaugh
got a request from NASA -

permission to visit his planet.

'Clyde was melted. He melted
when he got that letter.

'He felt that all of his life's
effort and work with Pluto,

'his work at White Sands,
was coming to a head.'

He felt that letter
was really a sign that NASA,

through their mission to Pluto,

was finally acknowledging him
as the man that he really was.

Clyde Tombaugh died in 1997.

Pluto Express is planned
to launch in 2003.

It will take 12 years
to reach its goal.

After analysing
Pluto's composition,

it will head out in search
of a Kuiper Belt object.

Perhaps something in their
cratering record or chemistry

will provide the final piece
of the creation jigsaw.

Whatever the craft finds,
Pluto's importance

in the grand order
of the solar system is assured.

It will be a manned mission to
Pluto in a very special sense.

It's not going to have
a real living person,

but you can bet it's going
to have Clyde's spirit on board

on its way to Pluto,
to see what kind of a planet

that little guy really is.