It is dawn and the sun is rising
as it has every day for the last 5 billion years.
For millennia it has been a constant golden disk
shining its unchanging light onto the Earth.
But look through the glare and the true face of the sun is revealed.
Not constant, but constantly changing.
Turbulent, and violent.
Its worst tantrums can wreak havoc on the Earth.
To understand the sun is to understand
the forces that drive the universe.
If we can control those forces we can unlock the power of the stars.
The power of our sun.
The story of the sun
starts 13 billion years ago with the Big Bang.
In an instant the universe was born
and since then it's been expanding at the speed of light.
Within the universe there are a hundred billion galaxies.
Our galaxy is but one of them.
In it there are 100 billion stars.
And towards the edge of one of the spiral arms
is an almost insignificant dot.
A medium-sized, not very bright, undistinguished star.
Up close it is a different story.
On the planets closest to the sun,
Mercury and Venus, the heat is intense,
their surfaces scorched.
Further out through the solar system the sun's rays weaken.
Until they are powerless against the chill of space.
The outer planets are frozen.
But in the middle lies the Goldilocks planet.
Not too hot, and not too cold.
In fact it's just right,
and life has flourished in the warm glow.
All life on Earth owes its existence to the sun.
It powers every natural system.
And sustains every plant and animal.
Without the sun the planet would be a barren,
lifeless ball of rock.
Recognising that power humans have always worshipped the sun.
But we have also always striven to understand it.
These monuments are more than just temples.
They are calendars and observatories.
Tools for studying the sun.
And some of them are still operational.
This is Orkney to live here is to know the importance of the sun.
In the summer the days are long and full of light.
In December it's a different story.
It's midwinter.
It's about 11 in the morning and it's still not light completely.
There's a strong wind coming in off the Atlantic.
And it's cold and it's wet and
that's pretty much typical of this time of the year up here.
Yet despite the cold, in the stone age,
5000 years ago a civilisation thrived here.
The island is covered in the remains of their society.
The ruins are full of mystery.
We know little about the people who lived here.
But they did leave evidence of the important role
the sun played in their lives.
MaesHowe - a thousand years older than the pyramids
is one of finest examples of stone age architecture.
On entering MaesHowe you have to crouch right down
and you're confronted with a passage
which seems to actually go on and on and on,
slightly, feel an impression of going uphill, up a slope.
And coming through clearly another doorway.
Suddenly the whole thing opens out into the most amazing chamber.
This alone is probably the highest and largest enclosed space
the Neolithic Orkadians would have experienced.
When it was excavated,
when it was first entered back in the 19th century the clay floor
was littered with broken pieces of human skull.
This is a place of the dead.
This is a house of the dead.
Most of the time the occupants of
the tomb were left in complete darkness.
Then at sunset on the Winter Solstice
the shortest day of the year something amazing happens.
The light of the setting sun shines straight up
the entrance tunnel and illuminates the interior.
Well the significance is that it's marking
the shortest time of the year,
with the least light, and from that point on,
slowly and gradually, the light is going to increase,
the days are going to grow longer.
So what's happening here, is that the dead,
the ancestors, are being awoken on that shortest day.
The winter solstice events at Maeshowe demonstrate
an intimate and precise knowledge of
the sun's movements through the sky.
It was the first step on ourjourney to understand
the sun and its many effects on us.
To complete thatjourney we've had to travel to
the furthest depths of space and to the heart of the smallest atom.
And with every closer look the sun has always surprised us.
To our ancestors, its power was its reliability.
Always on time. Never changing.
But the reality is proving to be very different.
Most people think of the sun as quite a boring,
constant sort of thing, but in fact it's not at all,
it's changing all the time,
and if you look you can see those changes on a matter
of minutes or hours.
And it's far from er static and boring,
it, it's changing and it's got a life of its own.
Modern solar observatories magnify and filter the sun's light,
to get past the constant glare,
and give a clear view of the surface.
This is the actual face of the sun.
It is turbulent and boiling.
Never the same from one second to the next the surface bubbles
like a giant bowl of porridge.
Each bubble is a 1000 miles across.
The heat and light brought to the surface
raises its temperature to 6000 degrees centigrade.
Enough to vaporise solid rock.
And the sun is huge.
You could fit the Earth inside it a million times over.
Periodically huge explosions rip through the surface,
releasing the energy of a billion atomic bombs in seconds.
All this is on the surface.
To understand the sun we must know what is going on deep inside.
That is where the power is generated.
So for centuries scientists have been devising ways
to probe the heart of the sun.
Some of them have been complex and some of them are very simple.
And the first step is to figure outjust how powerful the sun is.
It's easy to appreciate the power of the sun
on a nice hot summer's day like here on the Texas Gulf Coast.
And you can feel the power of
the sun on your skin, sunscreens is on.
But man the sun is just you know
the actual physics of what's going on inside the sun,
the power of the sun,
the energy that the sun is releasing
is almost beyond comprehension.
But it is only almost beyond comprehension.
And you can measure its power output with some simple apparatus.
One of the earliest experiments to try and measure
the actual power of the sun was by astronomer William Herschel
in the 19th century,
where he had the brilliant idea ofjust watching a piece of ice
melt to see how long it would take and therefore
from the properties of the ice work out
how much sunlight was coming to the ground.
As a demonstration of the sun's power
it doesn't look that impressive.
But Hershel realized that he could use the time
it takes to melt one bit of ice to
calculate the sun's total power output.
So here we see the ice is almost completely melted
in roughly 29 minutes almost half an hour.
But Herschel was able to use this experiment
and the time that it took to,
to melt the ice to work out some basic properties of the sun.
Here's how Herschel's thinking worked.
In the time it takes to melt a slab of ice on Earth
the sun is radiating heat in all directions
enough to melt a complete shell of ice around it
a diameter of 300 million kilometres.
A shell half a centimetre thick
and 300 million kilometres across contains a lot of ice.
Enough to make an ice cube bigger than the Earth.
To melt that much ice in just 30 minutes
would take an energy input of a billion billion billion watts.
It's a rough, but surprisingly accurate experiment
modern satellite readings confirm the figures to within a few percent.
It's an almost unimaginable amount of energy.
If we could harness the sun's power output
for a single second it would satisfy the world's energy
demands for the next million years.
But it's one thing to know how much power the sun is producing.
It's something else to know how it is doing it.
Until the middle of the 20th century no-one had any idea
what made the sun work.
For scientists in Hershel's time it was a mystery.
Well one of the issues was of course what powered the sun.
And - um - some very clever people actually
considered the fact that the sun might be powered by burning coal.
I mean it seems ludicrous but why not coal.
That was an important source of energy on the earth.
Er in that part of the 19th century
If the sun was made entirely of coal,
there would be one unfortunate consequence.
It would burn itself out in just a few thousand years.
Today that sounds ridiculous.
But two hundred years ago it didn't seem so unlikely.
It was widely believed that
the Earth was only a few thousand years old.
But in the mid-nineteenth century a new science
was emerging that was painting
a very different picture of the age of the Earth.
By looking at the deepest layers of rocks geologists
were discovering that the Earth was much older
than anyone had previously imagined.
If that was true then the sun also had to
have been burning for much, much longer.
You can see the strata and the lines in the rock in back of you
that represent hundreds of
millions of years of geological history.
The top of Sacramento Peak up beyond this,
we find fossils that are 300 million years old.
Below Sacramento Peak you've got more than a kilometre
of these strata that are far older than that.
From the age of these strata geologists knew
that the earth was at least a billion years old.
At the same time astronomers thought
the sun was only 10, 000 years old.
If the geologists were right then astronomers
had to find some other source for the Sun producing its energy.
The search for the source of energy
that could power the sun for billions of years
lasted for nearly a century.
Eventually scientists would find the answer in the forces
that hold atoms together and in the nature of matter itself.
But first you have to know what the sun is made of.
To find that out you need to take a very close look at sunlight.
When you take the light from the Sun and pass it through a prism,
spread it out into the colours,
as you look through it you notice that it isn't uniform,
that there are places that are darker.
Each of those dark lines is due to a specific chemical element.
Each element has its own series of lines that are specific to it.
Each chemical element absorbs light at specific frequencies
removing a strip from the spectrum.
As the light passes through the sun,
all the elements leave their mark.
So when the light arrives at the Earth it contains
the complete chemical formula of the sun.
If we take the spectrum and spread it out to fine details
and what we've done here is stacked up
pieces of the spectrum one on top of each other
you see all of these dark areas.
The key to figuring out how much of these elements
are there is the breadth and the depth of the line;
how dark is the line and how broad is it.
The composition of the sun lies in this bar code.
All the thin lines are caused by tiny amounts of complex elements
metals like iron and magnesium.
But there are 3 very deep, broad lines,
and they are all caused by
an enormous amount of a single element.
There's some helium and traces of heavier elements.
But over 90% of the sun is Hydrogen.
It is the simplest and most common element in the universe.
The secrets of the sun's power must lie in this gas.
Look carefully into the night sky
and you'll see huge clouds of
hydrogen floating in interstellar space.
These are nebulae.
And they can be hundreds of light years across.
They are some of the brightest areas in the sky
lit up by the intense light of newly formed massive stars.
In them we can see stars being born.
It is to areas like this that astronomers turn
their telescopes when they want to study how our sun was formed.
There she is, okay, so now let's recentre on her.
By studying different nebulae it's possible to
piece together the stages in which stars are made.
And it all starts in a cold dark cloud,
floating around waiting for something to happen.
Cold clouds like this are actually quite stable.
They will sit there for a very very long time,
for thousands and in some cases millions of years
before they'll actually do anything.
What you need to do to get the star formation process going
is you need to kick it with something.
That can be the impact on the cloud
from one side by a supernova blast wave;
a massive star nearby has gone boom at the end of its life
and that sends out in all directions very energetic
compression waves that hit the gas and compress it.
The shock waves knock the cloud out of balance.
Causing localised clumps of hydrogen to form.
These are the seeds from which stars grow.
The increased gravity of the seeds sucks in more
and more hydrogen in a runaway process
that lasts for a million years.
As more hydrogen is squeezed into the clumps the temperature rises.
They are not yet producing light
but they are well on the way to becoming stars.
As they grow bigger and bigger,
they start to spin and throw out a disk of debris
that will coalesce to form a solar system.
This kind of process is exactly the kind of process
that would have formed our solar system.
When we look at our solar system,
all of the planets rotate around the sun in the same direction
and they all are in the same plane the same flat sheet around our sun,
and this is exactly a consequence of the fact
that the early solar system formed out of a broad disc.
With the solar-system in place all
that is left is for the young star to light up.
When it happens it is sudden and irreversible.
Ultimately the process starts
and because it liberates so much energy with that first fusion,
then the process takes off.
Um - it lights up a large area and it starts to shine on its own
within a matter of minutes.
It's a very quick process.
In that first burst of light the star
has begun its lifelong activity as a factory
for making other chemical elements.
Every atom in everything around us was made in the heart of a star
and all were made from the same starting ingredient.
The simplest element that we have is hydrogen
and it's actually the building block
for all the other elements that we have.
In the heart of the sun hydrogen nuclei
protons - are stuck together to make heliumlt sounds straightforward
but it can only happen in the most extreme conditions.
In order for these protons to come together,
because they're both positively charged
they don't want to come together,
they've actually got to be pushed together.
In order to do this you need very high temperatures
so they're moving very fast and you also need very,
very high pressures.
The only part of the sun that is hot and dense enough is the core.
An area that contains over half the star's mass
in less than 2 percent of its volume.
Here at 15 million degrees the protons
are bashed together so hard that they fuse.
A helium nucleus is a tiny bit lighter
than the combined mass of the 4 protons it is made from.
And as Einstein tells us it is
that tiny bit of lost mass that provides the power.
Energy is equal to mass times the speed of light,
times the speed of light.
Now the speed of light is a very, very big number.
So if we just take a small amount of mass,
you get a huge amount of energy.
And that's the energy which actually powers our sun.
Every second 5 million tonnes of the sun is converted to pure energy.
And although it has been burning for 5 billion years
it is only half way through its supplies of hydrogen.
The light produced in the core must travel
over half a million kilometres to the surface.
And it does so very slowly.
The heart of the sun is so dense that the speed of light is less
than 1 mm a second.
It can take two hundred thousand years
for the light to travel from the core to the surface.
It takes just another 8 minutes to get to the Earth.
This is what the power of nuclear fusion looks like
from 150 million kilometres away.
This is what it looks like close up.
The H bomb was man's first attempt
at recreating the sun on Earth.
A balloon full of hydrogen squeezed
until it released its energy.
In contrast to its destructive power it's long been realised
that controlled nuclear fusion
could solve the world's energy problems.
It has been one of the holy grails of science for half a century.
This kind of power, the H-bomb,
is a man-made version of this, the sun.
In 1958 Britain announced that
she could produce this power in the laboratory,
in a machine called Zeta.
There is a real prospect of unlimited energy
from controlled thermo-nuclear fusion.
Unfortunately it wasn't that easy.
But now, nearly fifty years later,
in the same laboratories in Oxfordshire scientists
are finally managing to create their own star on Earth.
...ready when you are.
Okay, ready.
...shot, one four six five eight...
shot eighty five seconds.
It might not seem like much
but slowed down by 300 times the pictures reveal how the gas plasma
is being squeezed and heated to create
the most extreme conditions in the solar system.
Plasmas I always like to think of as being like naughty children.
They're full of energy and they are,
want to misbehave and it's ourjob to try
and control that misbehaviour.
For the particles to fuse on Earth
the temperatures need to be raised to 10 times
those found at the heart of the sun.
Bombarding the gas with a stream of fast neutrons
raises the temperature to over 100 million degrees.
Only then can the energy of nuclear fusion be released.
After years of learning to control the plasma,
scientists now believe they are
within sight of harnessing the sun's power.
The aim of it is to be able to produce cheap,
clean and effectively an inexhaustible supply
of electricity for future generations.
This is only small experimental reactor.
It can only run for a few seconds
and sucks up more energy than it creates.
But the next generation of bigger reactors
is already being built.
When operational they will produce 10 times
more power energy than they use.
They will be stars on Earth.
Power stations that won't deplete natural resources
or produce dangerous waste products.
It sounds great.
But recreating the sun isn't easy
and it may be another 50 years
before the fusion power station becomes reality.
Until then we'll just have to make do
with the real thing.
But that's not so bad.
Just seeing sunlight is enough to cheer us up.
Well many people think it's the warmth of the sun
that is associated with us feeling good
and of course that's true.
But in fact research has shown that it's not really
the warmth it's actually the light that's important.
Sunlight controls our daily cycle
making sure we wake up in the morning and go to sleep at night.
When there's not enough light those patterns get disturbed
with miserable effect.
It's a clinical fact that depression is more common in winter
because of the lack of sunlight
they call it SAD seasonal affective disorder.
Seasonal affective disorder is a depressive illness
in the starts during the autumn and early winter.
And usually goes away completely during the spring and early summer.
Some people feel quite miserable and depressed
and gloomy during the winter months.
And some people, a small proportion,
will go on to develop clinically significant depression
which requires treatment.
This is Rattenburg,
a fairy tale Austrian village cursed by lack of sunlight.
Due to a quirk of geology it gets no sunlight at all
between November and February.
During those winter months the sun never rises high enough
to clear the brow of Rat mountain.
And the town lies in permanent shadow,
while it's neighbour across the river basks in the sunshine.
In winter of course it's very cold,
it's shadow and as you can imagine it's cold,
we are freezing and if you want to have some sun
you have to move to the next village.
It makes you happier to sit in the sunlight
and not to freeze in the shadow.
Frozen and in the dark the residents have been
forced to take desperate measures to bring
some light into their lives.
Helmar Zangirl is a lighting expert who specialises
in bringing natural light in to some of
the world's biggest buildings.
He may be the salvation of Rattenburg.
Evolutionary speaking,
man has adapted to natural light and has adapted to the sun,
and if you deprive man of the sun er,
clearly its, it's a different quality of life.
How do you feel if you sit for one week in a,
a place with fog?
And how do you feel when you sit for one day
in a place where the sun shines?
I personally feel so much happier in the sunshine,
I can tell you that.
The solution for Rattenburg is simple.
Steal some of the sunlight from the other side of the valley.
Eventually a huge system of mirrors will reflect the light of
the sun to a second set of mirrors on the castle above the town
and then reflect it down into the streets
to brighten the lives of the citizens of Rattenburg.
Well the main effect for the people in town will be
that er part of the facades of the buildings
and parts of the street at least, of the main street,
will be brightly illuminated and
will clearly be recognised as sunlight.
It sounds crazy but it's true.
People will go to the extraordinary lengths for a bit of sunlight.
But the sun is much more than a giant lightbulb.
There are other forces at work in the sun.
Forces that change over minutes and over years.
Forces that tear the surface apart.
We are only now beginning to understand these forces
and the effects they have on the Earth.
But we have known about them for hundreds of years.
Because the sun gets spots.
Sun spots are dark regions on the surface of the Sun,
typically about the size of the Earth in terms of area.
Here's a live shot of one today.
Unfortunately we've got a very windy day with high thin clouds,
so the picture's bouncing around and not very sharp,
but with very high resolution images we can show
detailed structure in the sun spot.
The inner part of the sun spot,
the dark umbra as we call it is dark
only in comparison to the rest of the sun.
It's actually bright enough that it would blind you
if you looked at it alone.
The spots are not static.
These video images show the edges of the spot crawling,
almost as if it was alive.
The movements of sunspots have been studied for four hundrand years.
Ever since Galileo trained his telescope on the sun
and made the first crucial discovery about its behaviour.
Surprised to see black dots creeping over the surface
he kept track of them over a number of days
and found that they were all moving in the same direction.
To Galileo the meaning was clear
the sun was rotating
and was turning faster at the equator than at the poles.
It was a discovery that was to prove critical
in our understanding of how the sun works.
Ever since Galileo records have been
kept of the coming and goings of sunspots
and variations soon became clear.
Sometimes the sun is covered in hundreds of spots
other times there are none at all.
And after a while a pattern emerged.
If you observe sun spots over several years,
they come and go with an about an eleven year cycle.
From solar minimum where there can be no spots at all
on the sun for weeks or months at a time,
to at maximum where you can have a hundred spots visible
on the surface of the sun, and then they decline again,
usually over about six years or so, to, back to minimum.
Until recently no-one knew what was driving the solar cycle.
Or where sun spots came from.
But people had always suspected that the scars on the suns surface
had an effect on the Earth.
But no-one could quite put their finger on what it was.
It has been correlated with all kinds of different things,
er the price of wheat, the thickness of fur on animals,
I'm inundated with it every day.
I got a guy that comes to my website to try and predict the,
the stock market from the daily sunspot areas.
You know, 'oh, you didn't post them today, I gotta know! '
So, are you making money or what, I want some if you are.
One effect sun spots do have on the earth is on the climate.
But it is a subtle effect.
Its greatest impact was
only noticed 3 hundred years after the event.
It was discovered in Greenwich by the astronomer Robert Maunder
who was studying the hundreds of years of sunspot records
held at the Royal Observatory.
And in the late part of the 19th century he er
became particularly interested in the sunspots.
He discovered that there had been this peculiar effect
in the second half of the 17th and the 18th centuries
when the sunspot numbers diminished to a real,
really a fraction of what they are today.
And he described this as the Maunder minimum.
For seventy years, from 1645-1715 sunspots disappeared.
It was as if the engine that drives the solar cycle had stopped.
And it correlated almost exactly with the last period
of prolonged cold to strike the Northern hemisphere.
They call it the Little Ice Age.
What's interesting about a period like the little ice age is
that you don't necessarily see a very large dip in temperatures,
but nonetheless even a degree or two
is enough to see some really quite dramatic effects,
like pack ice advancing south from the north pole,
like the Viking colonies in Greenland being wiped out
by the changing climate and the population
of Iceland falling by half.
Now in Britain the weather was cold enough
that the Thames would regularly freeze in winter
and one of the classic depictions of life at the time is Frost Fairs,
when the population would hold a fair on the frozen river.
So things really must have been a lot harsher than they are today.
When the sunspots disappeared something on the sun changed
that cooled the Earth down.
But it wasn't that the solar output changed.
No matter how many sunspots there are
the sun doesn't get any hotter or brighter.
So the spots must have another effect.
And to see it we need a different way to look at the sun.
It's notjust heat and light that that the sun
is throwing at the Earth.
As every sunbather knows, there's ultraviolet light too.
Enough UV reaches the surface to burn our skin,
but it is only fraction of the sun's UV output.
The rest is filtered out by the atmosphere.
It means we don't get a complete picture of the sun from the Earth.
To see the sun in all its glory you have to go into space.
From here you can see the changing sun.
In the extreme UV the sunspots burn a brilliant white.
In the X-ray frequencies they look even more dramatic.
Huge plumes of superheated gas spout from the spots.
When you're seeing the visible
you're really seeing the surface of the sun.
But when you're seeing the ultraviolet
or the x-rays you're actually seeing that very hot atmosphere,
and that's about a million degrees,
whereas the surface is about six thousand degrees.
So you're seeing a different part of the sun
And you're seeing a part that's constantly changing.
These phenomenal displays of solar power
were only discovered in the 1970s, by the astronauts on Skylab.
No-one had seen the sun like this before.
Since then a number of Space telescopes have been deployed
whose sole purpose is to look at the sun.
The most used is Soho the Solar and Heliospheric Observatory.
It sits a million miles away from the Earth
at the Lagrangian point
where the gravitational pull from the Earth and the sun is equal.
Fixed in space it has an uninterrupted
view of the sun and its tantrums.
It has completely transformed our understanding
you can essentially see right from inside the sun,
right through to the coronal mass ejections
as they're leaving the sun,
so you're seeing way out to 30 solar radii.
Soho has played a key role in understanding
the explosive power of the sun.
By blocking out the discit simulates an eclipse,
revealing the outer atmosphere and
the true scale of the sun's largest eruptions.
These are solar flares and coronal mass ejections
and they erupt from the heart of sunspots.
The temperatures in a solar flare will be tens of
millions of degrees so it's an extremely hot,
very dramatic change in temperature over a short period of time.
When they erupt completely you can get masses
which are roughly the mass of Mount Everest
being flung out into the solar system.
At solar minimum, flares are infrequent.
But every 11 years when the cycle peaks, at solar max,
the sun puts on the best firework display in the solar system.
Solar astronomers are now beginning to
understand the cause of these explosions.
They are not caused by the power of fusion.
There is another force at work.
It is the force of magnetism.
The sun is covered in a complex network magnetic fields.
A magnetic map of the sun a familiar patchwork
on the face of the sun.
The areas of the strongest fields coincide exactly
with the position of sunspots.
Here the magnetic field strength can be amplified 10,000 times.
It turns out that the regions of the strongest magnetic field
on the sun are in the sunspots.
And in the units that we use sunspot magnetic fields
are roughly a thousand,
two thousand, maybe three thousand gauss.
But if you look at magnets like the ones I'm playing with here,
the magnetic field in these magnets
is about a thousand to 1500 gauss.
So these have roughly the same
magnetic field strength as a sunspot.
They key difference of course is that a sunspot's
an awful lot bigger and so the total energy,
or the amount of energy in the magnetic field
on the sun is enormous but the field strength
at any given locationis something you can hold in your hand.
Sun spots are just the visible effect of magnetic fields
so strong that they can prevent the heat
and light rising from the sun's interior.
With the right viewing equipment you can even see the magnetic fields.
Magnetic loops arch off the surface,
like iron filings around a bar magnet they're shapes
are mapped out by plasma heated to a million degrees.
The largest are 200,000 kilometres high.
And they are packed full of unstable energy.
When you add up the total energy content
in these loops it comes out to roughly 10 to the 21 joules
of energy and that's roughly ten times the annual energy
consumption of the united states.
Of course we can see thousands of them at any one time.
The loops are caused by the twisting
of the sun's basic magnetic field.
Because the sun rotates faster at the equator
than at the poles it drags the field lines with it
stretching and twisting them like elastic bands.
As the solar cycle goes on the fields get more
and more twisted and break through the surface.
Until at Solar Max the whole sun is covered
in loops stretched to breaking point.
Solar flares are what happen
when the strain gets too much and the loops snap.
Basically all that energy comes out of the catastrophic
release of energy that's been stored in the magnetic fields.
So like if you wind up an elastic band too much,
if you let it go with your fingers
that elastic band flies across the room.
When the energy bound within sunspots is released,
billions of tonnes of plasma are fired far into space at huge speeds.
And sometimes they are aimed straight forthe Earth.
The flares fly through space for 2 days.
When they reach us
the earth's own magnetic field deflects most of the blow.
But it is the impact on the magnetic field
which causes the effects on Earth.
It's called Space weather and the best of its effects are magical.
The auroras dancing displays of celestial light
are caused by particles from the solar storm smashing
through the magnetic field at the poles.
When they strike the upper atmosphere
they light up the polar skies.
In the strongest storms at the peak of the solar
cycle the Northern lights can be seen
as far south as Athens and Cuba.
But the buffeting of the magnetic field has other unseen effects.
Migratory animals that navigate using the magnetic field
can lose their bearings.
Racing pigeons don't come home.
And whale strandings have been
seen to increase with solar activity.
But most worrying for us is the effect
that the disrupted magnetic field can have on electronics.
The strongest storms can damage
or destroy satellites with devastating effects.
We're sort of more sensitive to the sun
than we probably realise because when the sun releases these,
this magnetic energy in the form of solar flares and,
and coronal mass ejections,
maybe you don't notice it at first, but um,
the crackle on your cell phone or your cell phone going out
may actually be caused by enhanced activity on the sun.
Mobile telephones, television,
airplane navigation even weapons guidance systems
all rely on satellite communication
and all can be disturbed by space weather.
The more we are reliant on these systems
the more we will feel the effects of the sun's tantrums.
But we still don't understand all of the effects of Space Weather.
No-one can explain the effect on the climate.
Or why the disappearance of sunspots should cause an ice age.
It may not matter.
The small effect that solar variation has on the climate
has long since been drowned out by man-made global warming.
As the world warms up,
the sun may yet prove an unlikely source of cooling.
The greenhouse effect could be stopped by harnessing its heat.
The American Indians of the Southwest deserts
have understood the importance of living sustainably
with their environment for 100s of years.
We have these natural disasters like the big old fires,
the volcano's erupting,
the big old earth quakes, the tsunami.
That's the earth telling us that it's getting pretty tired.
It's warning us that we need to slow down.
On the Mesas of Arizona,
far beyond the reach of the electricity grid lies Old Oraibi.
The oldest occupied settlement in North America.
For 1000 years the Hopi Indians have lived here in harmony
with their environment.
But that doesn't mean that they have to live
without the conveniences of modern life.
They have just realized that they are already
getting all the power they need.
Under the clear skies of the desert a family
can be supplied with electricity from a couple of solar panels.
Being that we pray to the sun every day,
it's got our heart felt desires, he receives it every day,
we thought the best source of energy should come from the sun.
A few miles across the desert the idea is finally catching on
with the rest of American civilization.
But, naturally, it's on a much bigger scale.
These are Stirling Dishes the Daddy of solar power systems.
And they may be about to solve the energy crisis
facing the cities of the American west.
People want to run their air conditioners,
their computers, their lights during the day
and we run out of energy.
We have a solar furnace 90million miles away
that provides life for all of Earth.
In the past we have been unable to harness that potential
because the efficiency, the cost etc.
Of the systems didn't make it viable
what's changed is technology.
The technology now allows us to build large scale,
highly efficient, cost effective systems.
Each dish tracks the movement of the sun across the sky,
focusing the heat onto a single point.
Where it is converted to electricity.
They are twice as efficient as any other solar power system.
With one you could power a small village.
A fieldof them could power a city.
Each system produces about 25 kw
which is enough to power about 10 homes.
However we plan to deploy these on a large scale.
20,000 of these,
which is massive about five hundred megawatts
which is the equivalent to a coal fired plant,
or maybe even a nuclear plant.
The ink is just drying on the contract to
build the first commercial solar power station.
It will fill 5 square miles of the vast Californian desert
with mirrors and will supply electricity
to the city of San Diego.
In time, as the technology and efficiency
improves systems like these may spread around the world.
These dishes are direct descendents
of the stone monuments of Stonehenge and Orkney.
Separated by 5000 years they all embody
our desire to understand the sun,
to be bathed in its light and to tap into its awesome power.
He's quiet, he's clean, he's powerful.
This was the way I was raised.
Raised to respect him and to offer those prayers to him for keeping us
for the length of time that he has.
He's done this for generations,
and generations and hopefully he will you know in the future.
The sun will probably shine down on our civilisations
for as long as they exist.
If we survive for another billion years
the sun will still be there.
Butjust as the sun was once born, it will one day die.
And when it does so, it will take the Earth with it.
In about 5 billion years time the sun will run out of hydrogen.
When it does it will become a red giant.
Deprived of fuel the core will shrink.
Generating so much heat that the outer layers
will balloon into the solar system.
The inner planets will be swept up.
It may even swallow the Earth.
Whether it is engulfed or not the Earth is doomed.
The sun, burning 2000 times hotter than it does now
will melt and seal the outer layers of the planet.
Then suddenly the sun will stop burning.
As the remains of the solar system is plunged into darkness
the sun's core will collapse and with its last gasp it
will blow its remaining shroud of gas into space.
It will be forever night.
The story of the sun and the earth will have ended.
And a small part of the outer arm of the Milky Way
will be a little bit darker.
But around it in the rest of the universe
the same story will be being told
by a billion other small insignificant stars
twinkling in the vastness of space.