All language subtitles for 2) A Perfect Planet-The Sun

A Perfect Planet.

There is a nuclear reactor
93 million miles away.

We call it the Sun.

Its rays, travelling through space,

reach the Earth in just eight
minutes...

..and give power to life
throughout the planet.

Its daily and yearly rhythms

shape the existence of every
creature on Earth...

..and has done so
for over three billion years.

In the beginning...

..there was light.

Surprisingly, perhaps, almost every
part of the Earth's surface

receives the same quantity of
sunlight each year...

..4,380 hours of it.

But it's delivered in varying
amounts

at different times of the year,

depending on where you are.

It's only here in the tropics,
close to the equator,

that there are 12 hours of
guaranteed daily sunlight

the year round.

And, here, that has created
a great richness of life -

the tropical forest.

Each leaf is a natural solar panel
which collects the sun's energy

and fuels a multitude of plants.

And, in Southeast Asia,
gibbons live here.

A five-year-old female...

..and her lifelong partner
are on a mission.

Every morning, they head out across
their territory

to look for ripe fruit.

There is one kind of tree here
that they need more than any other.

The fig tree.

These are the only plants in
the entire forest that produce fruit

all year round.

Their flowers grow in dense clusters

inside undeveloped figs,

but these have not yet been
pollinated

and are not yet edible.

The gibbons will have to wait.

To produce ripe fruit,
the fig still needs two things...

..a large dose of sunlight

and some of the smallest creatures
in the forest.

Tiny fig wasps.

They're only 2mm long.

The figs have a unique partnership
with these insects.

A female wasp
has the space of just a single day

when the fig will allow her to
burrow into the undeveloped fruit.

It's such a tight squeeze
that her wings are ripped off.

But she's not going to
use them again.

Once inside, she makes her way to
the tiny,

tightly packed internal flowers.

And, here within,
she lays hundreds of eggs.

She then carefully unpacks
fig pollen from her abdomen...

..and with it
fertilises the tiny flowers.

When she's finished laying,

she dies...

..inside the unripe fig

alongside her eggs.

The sunlight now slowly
ripens the figs

and helps the young wasps
inside to develop.

After just five weeks,
the eggs start to hatch.

The first to emerge
are the golden, wingless males.

Things now become
stranger than fiction.

These males start to mate
with their unhatched sisters.

To reach them,
they use a telescopic penis

that's twice their body length.

While their now-pregnant sisters
are beginning to hatch,

the males themselves burrow their
way to the outside world.

The brothers' final act
is a chivalrous one.

They sacrifice themselves
to marauding ants.

They're serving as decoys

so their sisters can take
to the skies.

The young females, loaded with
pollen, live for just 48 hours,

in which time they must find another
fig tree at just the right stage

into which they themselves
can burrow, as their mothers did.

With the sun's helping hand,
the figs are now ready to eat.

The gibbons know all the fig trees
in their territory.

And each day they travel up
to two miles

to find one with fruit
that's ready to eat.

Ripe figs at last...

..a major part of their diet
and available the year round.

Thousands of animals
rely on fig trees.

This abundance is only possible
in a world without seasons

and constant daily sunlight.

But this 12-hour cycle
of light and darkness

only happens close to the equator.

Elsewhere, the amount of sunlight
fluctuates across the year.

That is because the Earth
does not spin in an upright way.

Its axis is on a tilt.

23.5 degrees.

So as the Earth makes its annual
orbit around the Sun,

keep your eye on the North Pole.

For the first half of the year,
it's angled away from the Sun,

bringing darkness and winter
to the northern hemisphere.

For the second part of the year,

the North Pole swings
towards the Sun, bringing summer.

The Earth's tilt
gives us the seasons.

And life has adapted

to deal with even the most
extreme changes in light.

The High Arctic.

After six months of being angled
towards the Sun,

it begins six months
of freezing darkness.

This is Ellesmere Island,

the closest land to the North Pole.

It's winter,
and for the last four, long months,

the only light here
has come from the Moon.

Few creatures can survive
this sustained darkness.

They have become specialists in
living for months without sunlight.

Muskox.

Remnants of the last Ice Age.

Having grazed all summer,
they've built up fat reserves

that will enable them to survive
the brutal cold of winter.

And this makes them a prime target
for other sub-zero specialists.

Arctic wolves.

The Moon provides just enough light
for them to see.

This alpha female leads the hunt.

Target in sight.

If her pack is to survive,
they need to make a large kill

at least once every three weeks.

The alpha female signals
the start of the attack.

They run at the muskox
and the herd panics.

The muskox close ranks.

The wolves look for weakness.

Charging risks isolation
from the crowd.

And that is just what
the wolf pack wants.

The wolves can sense victory.

But the herd comes to the rescue.

And, once again, they close ranks.

Most winter hunts end in failure
for the wolves.

As the long polar nights drag on,

the hungry wolves turn to their only
other source of food...

..arctic hares.

They've gathered together
in their hundreds for safety.

Trying to catch one hare among
hundreds

is harder than you might think.

Even if they do catch one,
it's not much of a meal.

Sometimes you just
have to admit defeat.

But life is about to get better
for the wolves.

For the first time in six months,
the sun rises above the horizon.

Its appearance marks the beginning
of half a year of continuous light.

The sun's warmth will allow
the muskox to give birth,

and that will provide
easier hunting for the wolves.

It's early spring,

and much of North America
is still locked in ice.

As our tilted planet orbits the Sun,

the northern hemisphere
receives increasing sunlight...

..and wakens an animal
with an almost supernatural ability.

It is frozen solid,

like a block of ice,

and has been all winter.

An ordinary-looking frog...

..but an extraordinary one.

A wood frog.

Its heart has stopped beating
completely.

But, as the sun's power increases,

almost miraculously,
it begins to change.

Its frozen blood is melting

and begins to flow
through its veins...

..as its heart begins
to beat again.

The wood frog is cryogenic.

In just 12 hours,

it thaws and comes back to life,
as if by magic.

This defrosting ability

means it's ready for the moment
when, at last,

spring arrives.

All across the northern hemisphere,

the sun's warmth
is bringing dramatic change.

As the sun rises higher
and spring takes hold,

the warming air reaches
the ground and the rocks beneath.

Here, thousands of animals
begin to stir.

Garter snakes,

one of Canada's most
northerly reptiles.

After six months of hibernation,

the males are the first to emerge.

They haven't eaten for months.

Even so, it's not food that is on
their minds, it's something else...

..females.

But they stand no chance
of doing anything about that

until they've charged their
batteries.

Snakes are cold-blooded and they
need to absorb the sun's heat

before they're able to move quickly.

After a few hours,
the males are raring to go.

20,000 snakes,

the largest emergence of reptiles

anywhere on Earth.

Now a few females appear.

They're much bigger
than the males...

..and warming
will take them longer.

She releases a scent, a pheromone,

that attracts the males.

They outnumber her 100 to one.

To speed her own return to activity,
she will absorb heat from them.

Intoxicated by her scent,
the males compete for her,

wrapping themselves around her.

She now has hundreds
of males on top of her,

making mating near impossible.

But she has a way of weeding out
the men from the boys.

She'll make a daring ascent
of the nearby cliff.

She barges her way through the
crowd to get to the rock face.

As she climbs, only the strongest,
fittest males can keep up with her.

She's made it to the top.

Only a few of her suitors have
managed to rise to the occasion,

and she may reward them all.

This entire mating
jamboree only lasts

for one short week in the year.

And when it's over, they all
move off into the forest.

There, they disperse to lead
solitary lives searching for food

until winter drives them back to the
shelter of the rocks below ground.

It's June, halfway through
the Earth's annual journey

around the sun, and summer has
arrived in the northern hemisphere.

Karak Lake, in Canada,
north of the Arctic Circle.

The summer will be brief,

but there is sunlight
for 24 hours every day.

So the next few months are vital
for every living thing here.

And this arctic fox knows it.

Winter has been hard for her, and
now with a new family to support,

she must make the most
of the summer's abundance.

Her three-week-old pups
have just emerged from the den.

Each of these little bundles of fur

needs nearly 300 calories
of food every day.

A tall order for Mum.

But a solution for her
problem is just arriving.

Snow geese.

They have flown over a thousand
miles from the United States,

timing their arrival to coincide
with the end of the snow.

More than half a million
will spend the summer here,

nesting and feeding on the grass.

There's fierce competition
between couples

for the safest nesting sites.

The losers will have to nest
on the outskirts of the colony...

..the first part to be
raided by the foxes.

Mother is after eggs...

..but getting them is
not going to be easy.

The geese will risk their lives
to protect their eggs.

If they lose them, they can't
produce another clutch this season.

The fox wins.

She gives the first eggs
to her young pups...

..and then heads back for more.

Some of the eggs she stashes away.

They will be food to help her
through the coming winter.

In just three weeks, she will steal
over 800 eggs from the geese.

But eating a big egg is not easy

if one is rather small.

It's a technique the pups
haven't quite yet cracked.

Mum shows how it's done.

Goslings are now hatching
all across the colony.

And they will need all
the food they can get

to build up their fat before
their journey south.

Now that the chicks have hatched,

they can all find
safety on the water.

In these brief sunlit months,
there's time for the cubs to play.

But there is no playtime for Mum.

But the Arctic is warming,

and the timing of the seasons
and the migration of the geese

is becoming unpredictable.

Although the sun stays above
the horizon continuously

throughout the Arctic summer,

its rays are comparatively feeble.

Closer to the equator,
in our planet's deserts,

cloud cover is rare.

The sun here is not a friend...

..but an enemy.

Africa.

The Sahara.

Few creatures can live here.

Get caught out in the open
at the wrong time of day

and it's game over.

By 10:00 in the morning,
the temperature on the surface

of the sand is pushing
60 degrees Celsius.

Even the toughest will
soon have to take cover.

But one creature is
waiting underground

for the sun to get even hotter.

Temperatures are now so high

that everything else has to shelter.

The desert now belongs to the
Earth's greatest solar specialist...

..the Saharan silver ant.

At midday, when the
sun is at its fiercest,

they emerge to look for creatures
killed by the scorching heat.

They're one of the fastest insects
on Earth, and they need to be,

with just five minutes to find
food before the heat kills them.

Getting lost would
mean certain death,

so every few seconds
they spin round,

taking a bearing from the sun.

When others are frying,
these ants have solar tech

to stop them from overheating...

..special glassy hairs
and shining bodies

that reflect the sun's lethal rays.

It buys them precious time.

To get their prize back
as quickly as possible

to their underground den
demands teamwork.

But shelter is a long way away.

Any technique will do.

The push and slide.

The spin.

Even dune surfing.

The nest is still 70 metres away.

Some are already
collapsing in the heat.

Reinforcements are needed urgently.

Now the heat whips up violent
gusts of hot desert air.

For an ant, these are hurricanes.

They must get their prize
underground as soon as possible,

and blown sand has blocked the
entrance to their den.

Any longer out here
and they will be toast.

One final effort.

The last of the team race home.

Shade, at last.

Much of the land on our planet
could become as scorched

and lifeless as this if
we allow our activities

to continue to change
the atmosphere.

The Sahara alone has expanded by
an area twice the size of France

in just the last hundred years...

..part of a global desert invasion
that threatens a third of all land.

The sun can certainly
be a lethal threat,

but it could also be our saviour.

The solar energy that strikes
our planet in just an hour

contains more power than
that used by all of humanity

in an entire year.

By October, as the Earth
completes its annual journey

around the sun, day lengths
in the northern hemisphere

are shortening once again.

The sun's power is diminishing.

Trees are beginning to
shut down their solar panels.

The green chlorophyll with which
they collected the sun's energy

is broken down chemically
and reabsorbed.

And the forests turn
from emerald to gold.

It's autumn.

Once again, the living world away
from the tropics is transformed.

Plants stop growing

and many animals begin to
prepare for tough times ahead.

The forests of central China...

..home to the golden
snub-nosed monkey.

They will not survive
the fast-approaching winter

unless they stock up
on calorie-rich food.

Top of their autumn
menu - pine cones,

They grew during the summer
sunlight and are rich in fats.

Few are now left,

and time to gather
them is running out.

Dominant males patrol the troop,

making sure they get
the pick of the crop.

As the number of
pine cones dwindles,

tensions between
rival families increase.

Mere threats between two males may
not be enough to settle disputes.

Conflict is in the air.

There's going to be a fight.

Vital food is at stake,

so every pine cone
is worth fighting for.

The victor and his family
enjoy the spoils of war.

The losers get no more
than a few dead leaves

and will have fewer energy
reserves for the coming winter.

The sun's power dims.

Temperatures drop.

Everything slows down.

Ahead lies months of crippling cold.

Most of the life on Earth
away from the tropics

has managed to adapt
to the changing seasons,

but there are some creatures
that have found a way

to avoid the cold
of winter altogether.

Snares Island, New Zealand,

deep in the southern hemisphere.

Here, sooty shearwaters have been
nesting throughout the long summer

and gorging themselves on fish.

As a result, they've piled
on quite a few pounds.

But the sun is now fading, and the
southern winter is approaching.

No time to hang around.

When you're a touch tubby,

launching into the air...

..is a leap of faith.

They won't see land again
for four weeks.

Setting off across the Pacific,
they're starting on

one of the longest journeys
made by any living thing.

Their aim - to avoid the
consequences of the Earth's tilt

and follow the sun's warmth
as it dwindles in the south

and increases in the north.

For those who survive
the 10,000-mile marathon,

there will be a great prize.

The reward for travelling from
one end of the planet to the other

is long summer days the year round.

This is their destination...

..Alaska's Aleutian Islands.

While the south of our planet
is slipping into autumn...

..here, summer is just beginning.

Below the waves, vast clouds
of plankton are blooming.

Triggered by the sunlight,

these tiny marine organisms

are food for crustaceans - krill.

This is the sun-fuelled bounty

for which the shearwaters
have crossed the planet.

By cheating the tilt,

they're able to enjoy the
riches of summer the year round.

But shearwaters are not the only
ones to visit the warming seas.

Humpback whales.

They've been breeding
in the tropics...

..and haven't fed for six months.

Up to 6,000 whales are now
heading for these islands -

the only place where they can find
food in the quantities they need.

The shearwaters begin to dive
into a huge shoal of krill.

The humpbacks attack from below.

Each year, a million
shearwaters join the whales

in these dramatic feeding frenzies.

It's one of the greatest
gatherings of life on Earth.

And it only happens because
some whales and some birds

have found a way to live in
a summer that never ends.

Rolf Steinmann has wanted
to be a wildlife cameraman

since he was a child, even if he has
to remind himself from time to time.

I'm a lucky cameraman.

I'm a lucky cameraman.

I'm a lucky cameraman...

To those who've worked with Rolf,
his love of the wild is legendary.

You know, if he's not on
location, he's at home watching

every other wildlife documentary
that's ever been made.

I think Rolf is motivated
by the beauty in the world.

I think he really
has this pure heart.

Rolf alone with nature
is Rolf at his best.

Rolf is a man obsessed.

The opportunity to be the
first to film arctic wolves

in the polar night is
Rolf's dream of a lifetime.

We have a lot of luggage.
This is a major expedition.

And there's one piece
of luggage that is very,

very special to me, and it's...

It's actually this book
by Jim Brandenburg.

It's 30 years old,
it's from the '80s.

And when I saw this
book the first time,

it really triggered a dream
to become a wildlife cameraman.

And this was the shot.

It's unmatched to this day.

When I saw it, I just wanted
to experience it myself.

To go to Ellesmere now
and to film wolves is...

..is my biggest dream coming true.

If I'm honest, I'm not just
excited about the shoot,

I'm also a little bit anxious.

I haven't worked in -50 degrees,

and actually trying to find wolves
in darkness, in the polar night,

is something that has not
even been tried by anyone.

Ellesmere Island lies just
500 miles from the North Pole.

In the winter, the sun
doesn't rise for four months.

The temperature regularly
drops to -50 degrees...

..making it one of the
coldest places on Earth.

It's such an unreal place.

It's like a... like a frozen dream.

There's so much space.

It's really like a different planet.

The wolves here can range
for thousands of miles

across the frozen landscape.

If you look at that landscape,

how vast it is,

you can imagine how hard
it is to find the wolves,

a white animal in a white landscape.

One wolf has a radio collar,

but this kind of telemetry only
gives a rough direction to explore.

The fjord is just to the south,
so I think the best plan

is cut across on the ice and
see if we can find a way up.

The team race towards the
wolf's last broadcast position

and get lucky.

They find the whole pack,

and something never seen before.

This is so incredible.

A herd of hundreds of arctic hares

are under attack from
Rolf's white wolves.

Wow.

We found our...

..our pack of seven wolves,

in their full beauty,
which is amazing.

Filming the new behaviour
ramps up the pressure on Rolf.

Oh, God, the situation is
just right in the wrong spot.

Rolf is well known
for his self-criticism.

He's a perfectionist.

You know, he wants that image
to be absolutely perfect.

You're amazing,
but I'm stupid, unfortunately.

A day later, the wolves disappear
out of range of the telemetry.

It said they were here,
but now they aren't here

and we don't get any signal
from the telemetry.

So, now I think we realise how hard
it will be to find the wolves

if we don't just run into them.

With no wolves to film,
Rolf is determined

to capture the beauty of
the landscape with a drone.

We just can't get
the thing in the air.

Um, the motors, they've
physically frozen solid.

And the drone's not the
only thing that's freezing.

Look what I just
found under my mask.

A plan to warm up the drone
with a hairdryer and a duffel bag

could mean that the world record
for the coldest flight is still on.

Success!

But the cold soon takes its toll
on Jesse, the drone operator.

Argh! I'm sorry,
I can't feel my hands.

I think we have to drift to
the right a little bit more.

When you're on a shoot with Rolf,
he'll just keep going

and going and going.

We can fly towards the big mountain.

I can get the... Argh!
..the big mountain, you know...

Yeah... like, more centred.

Argh! My hands!

Come on, it's coming, it's coming.
You just fly straight, Jesse.

But I'm losing my sensation
in my hands, Rolf.

Yeah, let's hit roll on it
before we die... Let's record.

Come on, do it.

This feels like a totally
different planet. It's really crazy.

OK, and I think now we could
do a forward view. Yeah.

Argh! Perfect, Jesse.
You can go a bit slower.

If you can, go a bit slower.
My fingers are hurting.

Argh!

That looks really cool!

It's incredible.

With no sighting of
the wolves in weeks,

the team decide to follow
their prey instead.

Muskoxen.

And the tactic pays off.

The herd is being
shadowed by the wolves.

They are very close to
a herd of muskoxen there,

and something might happen.

Rolf is in the perfect spot to
capture the first arctic wolf hunt

ever filmed in the polar night.

God, there was some good stuff,
I think, if I got it in focus.

With the shots in the can, there
is a magical experience for Rolf...

..one he's dreamed of
since he was a child.

It doesn't get better than this.

Oh, my God. This is an absolutely...

..dream of a lifetime.

Honestly, you are the most beautiful
living being I've ever seen.

Incredible.

Next time...

..weather.

This powerful force carries
vital freshwater around the globe.

And all life on land is perfectly
in tune with its annual rhythms.

The Open University has
produced a free poster

exploring our perfect planet.

To order, please call 0300 303 0901.

Or go to bbc.co.uk/perfectplanet

and follow the links
to the Open University.