90 million miles from us
is the power that shapes our world.
Our very own star.
The sun.
We see it shine in the sky above us.
But beyond our sight,
something dramatic is happening.
The sun is going into overdrive.
Our star is more active now
than it's been for a decade.
It's sending
eruptions of superheated plasma
and vast waves of radiation
towards our planet,
with the potential
to disrupt our lives
in completely unexpected ways.
At the same time,
a new generation of satellites
is showing us the sun
in more detail than ever before.
It's almost pulsating.
I'm Kate Humble.
And I'm Helen Czerski.
Together, we're going to unravel
what's happening to our sun.
From Britain's leading centre
for solar research,
we'll use the latest satellite images
and a team of world-class experts
to decode the sun's inner workings.
Something in the sun's atmosphere
snapped.
We'll explore the sun's
most spectacular displays.
I love your laboratory,
it's brilliant!
Investigate its mysterious
cycles of activity.
So it took seconds to get from the
sun to the satellite. That's right.
And discover how our sun
is behaving right now.
70 miles west of London
lies Britain's answer to NASA.
This is the Rutherford Appleton
Laboratory in Oxfordshire.
At RAL, satellite instruments
are designed and tested
before they're launched into space.
And scientists are analysing
the latest information
these satellites beam down
around the clock.
It's one of the most important
centres of solar research
in the world.
We've set up inside one
of RAL's giant research facilities
so that we can talk to some
of Britain's leading solar scientists
and see for ourselves
the extraordinary images
they're using to study our star.
We can't look directly at the sun
without damaging our eyesight,
but a new fleet of satellites
are allowing scientists here at RAL
for the first time
to get a unique picture of the sun.
In 2006, NASA launched
the twin STEREO spacecraft
to observe the sun
from two sides simultaneously.
The Solar Dynamics Observatory
followed four years later.
It's able to visualise the sun in
high resolution for the first time.
These satellites show the sun
as far more than simply the burning
disc in the sky that we see.
Here at RAL, head of space science
Richard Harrison
is responsible
for analysing those images.
So, Richard,
how are these new satellites
advancing our knowledge of the sun?
Well, the whole point
is that we have now built up
a fleet of spacecraft, an
international fleet of spacecraft,
that are really studying the sun
in phenomenal detail.
We can see the sun from both sides.
We can see a complete star,
and we'd never done that before.
And these satellites can detect
types of light from the sun
that are invisible to the naked eye.
The brighter regions here
are what we call active regions,
and they're regions
a bit like volcanoes and earthquakes
on the Earth, if you like,
regions where the sun is active,
and there's a lot of interesting
stuff happening in here.
You can see it with your own eyes,
it's so complex,
it's moving all the time,
like a plate of writhing spaghetti.
And I mean,
this is an extraordinary image.
We can see several colours
put together,
showing you the full complexity
in all of its glory, if you like,
the truly complex atmosphere
writhing in front of your eyes.
And this sort of illustrates it,
puts it in a nutshell,
how fantastic it is
to be studying the sun
as it approaches a peak in activity
with this wonderful fleet
of spacecraft.
This peak in activity
is known as a solar maximum.
It's the high point in a cycle
the sun goes through
on average every 11 years.
From relative calm...
..to intense activity...
..and back again.
A cycle that's fundamental
to how the sun works.
Understanding this solar cycle
will help us discover
the secret life of the sun.
But for most of us on Earth,
the sun is something we rarely
examine in any sort of detail.
To begin to understand
its extraordinary power
and its changing cycles of activity,
we need the help
of one of the most dramatic events
in the astronomical calendar,
a total solar eclipse.
And to see that, I had to travel
to the other side of the world.
November 2012.
I've come to Cairns, Australia.
I'm joining people
from across the globe
because in 48 hours,
there's going to be a total eclipse.
But this one is special
because it promises to reveal
something crucial about our sun.
Cairns is a relatively small town
in Australian terms.
It's home to about 130,000 people.
But that number could swell
by as much as 50,000
in the next couple of days,
and all for an event
that's going to last
just two minutes and two seconds.
It's an emotional experience, it's a
lovely way to sort of see the world.
Everyone is happy. It's fanta...
It's a natural spectacle of science.
I'm getting excited, yeah!
I've never seen
a total eclipse before
and we've got our glasses,
and we're all set to go.
We've got our fingers crossed
for clear skies.
You can't safely view an eclipse
unless you have glasses
with powerful filters.
Hi. Hello.
That's what I'm after.
The very last pair.
No way! Three dollars.
Did you want some as well? Oh, yeah,
we've been searching everywhere!
This is the very last pair in Cairns.
I'm really sorry.
Oh, you're joking!
We could share them.
Don't film this. This is horrible.
This is like breaking my heart!
No...
It's once every 50 years or so,
so make the most of it.
Thank you very much. Thanks, bye!
Seriously, your last pair?
Last pair. No more, all gone!
To get an eclipse, the moon
must drift between the sun and us.
At what's called first contact,
the moon begins to block it.
But what's extraordinary
is what happens
when the sun is completely covered.
That moment of totality
reveals something that's normally
hidden by the sun's glare -
the sun's faint atmosphere,
the corona.
And it's the corona that's key
to what this eclipse can tell us.
The corona is due to reveal itself
at precisely 6.38 in the morning
the day after tomorrow.
But the fact that we get
total eclipses in the first place
is thanks
to an astonishing coincidence.
Earth is the only planet
in the solar system
from where you can witness
a total eclipse,
and the reason for that
is down to pure luck.
The moon is 400 times smaller
than the sun.
But it's also 400 times closer
to the Earth.
So when the moon's orbit brings it
between the Earth and the sun,
it appears to be
exactly the same size as the sun,
and it's able to block out
its entire surface from our view.
There's a total eclipse
on average every 18 months,
so they're not exactly rare.
But catching one isn't easy.
The narrow shadow paths
they trace on the Earth's surface
are far more likely
to pass over uninhabited regions,
such as the oceans,
than a populated area like Cairns.
And the timing of this eclipse
is significant.
Right now,
we're due to be at solar maximum,
the period of greatest activity
in the sun's cycle.
But each maximum
is slightly different,
so scientists need to confirm
that we have actually reached it.
One way to do that is to study
the sun's corona during totality.
Click on that.
'And that's what makes this eclipse
especially exciting.'
Delivery!
Jay...I think we've got
the box you wanted.
'Even to the most hardened
eclipse chasers.
'Astronomer Francisco Diego
has seen 17 total eclipses.
'This time, he's advising a group of
a hundred British eclipse chasers.
'But he's also brought
his own equipment.'
The sun, as far as it is...
You're not the most hi-tech
scientist I know!
This is an ideal container for
a very delicate part of equipment.
You're like a Blue Peter scientist,
it's brilliant!
Can you hold this for me? Careful
with the wind. I've got it, yeah.
'A camera and some home-made filters
'are all he needs to take detailed
photographs of the corona.'
So what I do,
I remove the lens cap here...
'And it's the shape of the corona
in his photos
'that will tell Francisco
if we're at solar maximum.'
So the eclipse gives
that opportunity to admire
and to study the outer layers
of the solar atmosphere.
These layers,
the chromosphere and the corona,
are an indication of solar activity.
The shape of the solar corona
is changing all the time.
For example,
when the corona is very round,
that means the solar activity
is at a maximum.
Francisco will have only two minutes
in which to get a successful
picture of the corona.
THUNDER RUMBLES
But that brief window of opportunity
is threatened
by a more familiar force of nature.
Cover the telescope!
Oh, man!
The eclipse is tomorrow morning
and the forecast
is not looking good.
This is tropical Australia,
we're going into the rainy season,
and the weather
could obliterate the old thing.
2am, the day of the eclipse.
I'm following Francisco
and his eclipse chasers
inland from Cairns
to get away from the rain clouds.
We have to reach clear skies
before dawn,
or we'll miss the eclipse.
We've pulled off...the road,
finally.
It's...ten past five.
And the sky is lightening
dramatically quickly.
Sunrise is going to be...
in about half an hour,
and first contact...
Follow me, quick! OK, OK.
..and first contact
is ten minutes after that.
Wow!
That's incredible.
The sun has just made
an appearance...
..above the clouds...
..and it's got a chunk
out of the top left corner.
The moon has begun to block the sun,
but the sun is so bright
that we won't notice
any darkening of the daylight
until it's almost
completely covered.
What do you think, Francisco?
It's looking quite skinny now.
It's quite skinny, yes,
about ten minutes before totality,
so this is where things are going
to happen faster and faster.
The darkness is going to really
come much quicker.
You... You feel it, it's physical.
And it's sort of terrifying,
actually!
HE CHUCKLES
Isn't it? It is!
I mean, just look at it.
It's just...
Every moment you can feel the light
just dropping and dropping.
It's like somebody's
stealing the sun.
And it's now just a tiny...
..hair's breadth in the sky. Yeah,
two minutes, two minutes to go.
And it's so cold, the temperature
has just completely dropped.
It's like everyone's collectively
holding their breath.
SHE GASPS
Oh, my goodness!
SHE LAUGHS
OBSERVERS CHEER
It's the most amazing thing!
SHE LAUGHS
I can't believe how beautiful it is!
Oh, amazing!
The moon has completely blocked
the disc of the sun.
A delicate halo is all that remains.
It's the corona.
Francisco now has
two minutes and two seconds
to get the photos he needs.
Here it comes!
CAMERA SHUTTER WHIRRS
It's ridiculous! I...
Isn't that amazing?
Amazing.
It was worth getting up
at two o'clock in the morning.
HE CHUCKLES
Absolutely worth getting up
at two o'clock in the morning!
I challenge anyone to watch a total
eclipse without being deeply moved.
It's a glimpse into
the hidden workings of the sun.
It makes you kind of look at it in
a slightly different way afterwards,
doesn't it? Absolutely, yes.
Somehow, you can't take it
for granted any more.
No, you cannot, and then...
Well, life on Earth depends on it,
has depended on it
for billions of years, really.
That was the first time
I've ever seen a total eclipse.
But what has the corona revealed?
Has the sun reached solar maximum,
its peak of activity?
Back at RAL, we can now get the
answer from Francisco's photographs.
An eclipse is a fabulous thing
to experience,
but there was a scientific reason
for taking those photographs.
So are we at solar maximum?
It looks like we are.
We have pictures
taken in solar minimum.
For example, this one, that
was taken in 1994, two cycles ago,
when the solar activity
was at a minimum.
Can you see an axis here?
Really clear, isn't it?
Yeah, the sun is very orderly,
very steady, very quiet.
There's a very clear pattern.
By contrast, last year in Australia
we saw the corona
in a completely different way.
This is the picture we took there.
Now, tell me where is the axis.
It's just the same all the way round,
isn't it?
It's all over the place,
it is all over the place,
Because the solar activity has blown
the corona in all directions.
The sun is extremely dynamic here.
So this is an interesting time
to study the sun.
Very, very interesting.
We are very excited
about solar maximum,
and then again the sun will come...
in the next years
will come down to a quiet stage,
and then this whole cycle repeats
every 11 years.
So what causes these solar cycles?
To understand, we first need to know
what's going on deep inside the sun.
It's a place we can never go,
but we can learn a lot
from something that makes the journey
all the way from the core of the sun
to us here on Earth.
Sunlight.
Sunlight, the light from the sun.
We take it completely for granted.
But it's still mysterious.
Where did it come from?
How did it get here?
We think of sunlight as simply
coming from the sun's surface.
But its journey
begins deep within our star.
And what makes sunlight's journey
so epic is the sheer size of the sun.
The mass of the sun
is 2 followed by 27 zeroes,
that is the mass of sun in tonnes.
And so that makes up 99.85%
of the entire solar system.
The solar system
is basically just sun
with a few little fragments
circling round the outside.
And it's the sun's enormous mass
that creates the conditions
to produce sunlight.
Its intense gravitational pull
forces the sun into layers,
each with its own special properties.
Beneath the thin outer peel
is a 200,000-kilometre thick layer,
where hot material rises and falls.
The layer underneath
carries the sun's heat outwards.
And around 550,000 kilometres down
is the core,
a 16-million degree furnace.
Here, the entire mass of the sun
is pushing inwards,
exerting vast pressure.
And this is where sunlight is born.
To understand how
that vast pressure creates sunlight,
I've come to the National Ignition
Facility, NIF, in California.
Sunlight exists because of a process
going on deep in the core of the sun
called fusion.
And what's happening there is that
the pressures and temperatures
right in the middle of the sun
are so enormous...
..that hydrogen atoms
can fuse together.
And when that happens,
a tiny, tiny bit of mass is converted
into a huge amount of energy.
And that little process
is the key to a star like our sun.
Without that single process,
the sun would be a cold, dead star
and the Earth would be
a cold, dead planet.
So the key to the behaviour
of the sun
and to life on Earth
is fusion.
I'm about to see
how the scientists at NIF
are trying to make a tiny sun
and recreate fusion.
All this is about getting ignition
that could change the world.
Here, in this dust-free environment,
Beth Dzenitis
creates hydrogen fuel capsules
smaller than a grain of rice
and destined
for a very violent fate.
This is called
the capsule fill-tube assembly.
It's a two-millimetre diameter
plastic capsule.
192 laser beams converge
on the capsule,
and that plastic material
blows away from the capsule
when it gets hot
and under high pressure.
And that causes a subsequent
reaction of the fuel there
to be compressed
so that the hydrogen atoms fuse.
To get those atoms to fuse,
they need to generate similar
pressures to those at the sun's core,
340 billion times
the pressure on Earth.
It's a tall order.
But there is a way.
The 192 individual laser beams
they use
are each more powerful
than any other laser on the planet.
And they all fire at a spherical
chamber at the heart of the complex.
This is the target chamber,
and when the lasers hit
the fuel capsule at its centre,
they bring the atoms together with
the same force as in the sun's core.
But to truly mimic our star,
the NIF team needs to pull off
an even greater trick.
Proceeding to system shot
countdown state.
Once ignited, the fusion reaction
must keep itself going.
Starting system shot sequence
on my mark.
Three, two, one, mark.
May I have your attention?
Preparations for shot operations
in laser bay two are under way.
Leave laser bay two now.
It's not without its dangers.
Before every shot,
the area is evacuated.
Steel and concrete doors a metre
thick enclose the target chamber.
A misfire from the most powerful
laser in the world
could cause a catastrophic explosion.
MOR ready for system shot
countdown clock.
And even the smallest
fusion reaction
unleashes a lethal blast of neutrons
and high-energy light.
..Three, two, one.
The only visible sign
is this flash from the world's
biggest laser as it fires.
But inside that fuel capsule,
they're hoping to create a tiny sun
and with it, man-made sunlight.
Another day, another shot.
The NIF team routinely achieve
short-lived fusion.
But today,
still no self-sustaining fusion.
Yet if we could achieve it on Earth,
we'd have the sun's energy on tap.
Recreating a small sun
in this target chamber
that's not too far away is always...
daunting, in a lot of respects.
We will get there eventually.
It's that elusive trick
of generating endless energy
that makes our sun so miraculous.
The result is the birth of sunlight
in the sun's core,
in particles of light energy
known as photons.
But their journey is far from over.
Imagine this pinball
is a newly created photon.
That light must now reach
the sun's surface.
And that is a really complex
and difficult journey,
because in-between
the core of the sun and the surface
there is a seething mass of stuff
that we call plasma.
Like my pinball
dodging the flippers and bumpers,
the photon now has to navigate
through that plasma.
But my pinball - or photon -
can't take a direct route out.
It's forever colliding
with particles of plasma
moving at thousands of miles
per hour.
And with hundreds of thousands
of miles of plasma to cross
between the sun's core
and its surface,
a journey that should take two and
a half seconds at the speed of light
takes much, much longer.
Even though it's travelling
at the speed of light,
as fast as anything can go,
it's still estimated that
it'll take 10,000 to a million years
just to get from the core of the sun
to its surface.
And then...freedom.
What we think of
as sunlight's journey,
the 90 million miles
from the sun to the Earth,
is only the last eight minutes
of an odyssey that could have taken
thousands and thousands of years.
It's...lovely, fantastic,
to think that this gentle light
that's touching me now
started off in a violent,
dramatic beginning
right in the centre of a star
and then spent 100,000 years
finding its way out of that star,
and finally spent
just eight minutes
travelling as fast as anything
in the universe can travel,
the speed of light,
to get to me here.
But this extraordinary journey
raises a question.
Fusion in the core never stops.
So why does the sun's activity
go up and down
with the 11-year solar cycle?
Back at RAL,
that's one of the questions
that interests solar scientists.
The key lies in how the fusion
reaction affects the sun's plasma,
that seething mass
between the core and the surface.
To explain
why this leads to solar cycles,
we've been joined at RAL
by solar physicist Lucie Green.
The heat generated
by this reaction inside the sun,
it heats up the gas
and, in fact, it superheats it,
so the gas is...
the particles of gas are torn apart
to form a plasma.
Just as the hot air in the room
around us is rising in packets,
so the gases in the outer layers
of the sun do the same thing.
This is called convection.
So gases get heated from below
and they rise up
to the surface of the sun.
But because this gas, the plasma,
is so hot,
it's also electrically charged.
So as it moves up and down
with the convection currents,
it creates powerful magnetic fields.
And that's not all.
The sun, like the Earth,
spins on its axis,
so plasma also flows sideways.
Which has a dramatic effect
on those magnetic fields.
You start to see the magnetic
field lines being wound up,
and eventually it becomes so strong
that the magnetic fields rise up
and penetrate the surface
of the sun,
and that's when we have
the build-up to solar maximum.
At times of solar maximum,
those magnetic loops break out
from the surface of the sun,
drawing the sun's plasma with them.
This one loop
is many times bigger than the Earth.
But the sun doesn't stay like that.
Eventually,
the magnetic fields disperse
and they rearrange themselves,
and we go back to solar minimum
again,
where you have the nice ordering
of the magnetic field.
It does this every 11 years,
and though the sun
may be 90 million miles away,
this cycle matters
to us here on Earth.
What is the implication of times
of solar maximum for us on Earth?
What do we experience?
Well, the sun is constantly
expanding out into space.
Its outer atmosphere,
with the magnetic field,
is being drawn out into something
that we call the solar winds. Yeah.
Now, at times of solar minimum,
the wind is fairly, erm...ungusty,
it flows quite slow.
Quite light. Quite light!
But at solar maximum, the magnetic
fields start to get more complex,
and that leads to vast streams
of solar winds coming our way.
The solar wind
is a constant stream of particles
flowing out from the sun.
It bombards the Earth.
Most of it is deflected
by our planet's own magnetic field.
But a small amount of its energy
does get through,
with extraordinary effects.
Effects I'd always wanted to see
for myself.
If you want to see this evidence
on Earth of solar winds,
you need to head right up
into areas that are cold,
rather sunless and rather dark.
This is Lapland in Arctic Sweden.
It's February,
it's minus 19,
and a long winter's night
is about to fall.
I'm here to see an old friend.
She's an extraordinary woman
who, 15 years ago,
left her home in Birmingham
and came to live here permanently.
And all because
she became bewitched
by the strange and astonishing
phenomenon
that I'm hoping to witness too.
It's called the aurora borealis,
also known as the northern lights.
The aurora is the solar wind
made visible on Earth.
As the wind encounters
our planet's own magnetic field,
it sends energy down the magnetic
field lines towards the poles,
causing our atmosphere to luminesce
in ghostly colours.
Right now at solar maximum
is the best time to see the aurora.
But I still need a cloud-free,
moonless night.
My friend, Patricia Cowern,
knows the challenges.
She's photographed the aurora
countless times.
Wow, so that's above here, isn't it?
It is above the house, yes.
That's one of the early ones
that I took when I very first started
northern lights photography.
Oh, my goodness!, Look at that!
This is where we're sitting now.
Really?! Yeah.
You see, I just think
I'm going to pop with excitement
if I see a sky that looks like that.
When we go out this evening,
am I going to get to see them?
Hopefully!
If we can get rid of the clouds.
We have the darkness, we actually do
have activity at this moment. Right.
So what we need
is for these clouds to go away.
OK, well,
I'm going to get outside...
And start blowing. Yes!
Near the poles,
there's a ring-shaped zone
where our atmosphere is most
affected by the solar wind's energy.
Lapland is slap-bang in that zone,
which is why it's such a hotspot
for the aurora.
My first attempt to see it.
To the naked eye, it's very faint.
But with time-lapse cameras,
we can see there's definitely
aurora going on up there.
But although there's no moon
to spoil it,
there are clouds in the way.
Well, it's coming up
to 11 o'clock at night
and the cloud is still
stubbornly hanging around.
There's a few breaks in it.
I've had sort of
tantalising glimpses
of wisps of green smoke
across the sky,
but nothing like the scale that
we know that they're capable of.
I have one more night
before the moon returns
and wrecks my chance
of getting a clear view.
But it's not just sightseers like me
who are drawn here.
I love your laboratory,
it's brilliant! Isn't it?
'It's a perfect backdrop for
scientists like Gabriela Sternberg.
'She's interested
in an important question -
'how well is our magnetic field
holding up
'to the constant battering
of the solar wind?'
So, let's use this nice snowball
to demonstrate this.
So if this now is the Earth... Yeah.
..and we have the sun,
the beautiful sun, over here,
so from the sun now comes solar wind.
Yeah.
And at some point, it encounters
the magnetic field of the Earth.
Most of the solar wind
now goes around, like this.
How powerful is this solar wind?
I mean, obviously, we can't feel it
because of all these layers
of protection,
but is it gale force?
Is it like a hurricane?
What happens is, it comes particles,
and they come very quickly,
so they move with the speed of, like,
400 kilometres per second. Wow.
So they move really, really fast.
So you get this gigantic shock wave
where the solar wind slows down.
This boundary separating us,
or our space, from the solar wind,
it's very, very, very, very thin.
It's like a thin,
almost transparent, veil
separating us from this blowing wind,
from the solar wind.
And that, we think, is really cool.
How can these really thin boundaries,
how are they formed?
And why are they so thin?
So the aurora is but a faint trace
of the solar wind's true strength.
Out there is a violent collision
where it meets our magnetic field.
That thin shell gives us
vital shelter.
Last night in Sweden.
It's tonight or never.
It's about...minus 30 outside,
and it's absolutely clear,
it's been clear all day.
So we're going to go out
and see what's happening.
Oh, my goodness,
look at those stars.
It's so clear!
Oh, my goodness, look at that!
Look what's happening in the sky!
With ordinary cameras,
you can see it faintly.
But it's with the time-lapse cameras
that we can capture the full glory.
Look at that, it's just...spanning
the whole of the eastern sky,
like a giant sort of green rainbow.
Under this balaclava,
I am grinning like the Cheshire cat.
It's mesmerising, isn't it?
Beautiful.
You can't kind of take your eyes
away from it.
The aurora is a stunningly beautiful
display of the solar wind,
but also a reminder
of its enormous power
and the protection we get from
the Earth's thin magnetic shield.
So what would happen
if we were ever exposed
to the full force of the sun?
It's a question that
the scientists back here at RAL
have been studying intently.
The solar wind is a mere hint
of the vast amount of radiation
and particles
that the sun sends our way.
It's known as solar weather,
and its impact on Earth
can have a more alarming side.
Richard Harrison,
head of space science at RAL,
is an expert on
its most violent form, solar storms.
So, Richard, we know
that the Earth is protected
from the full force of solar weather
by the Earth's magnetic field,
but is there any danger that that
magnetic field could be breached?
Well, the best way to answer that
is actually to look back
at the sun's atmosphere again
and these wonderful magnetic loops
in the sun's atmosphere,
like elastic bands sort of writhing
around, being tied up in knots.
And you might expect occasionally
something might break,
so in these regions you see here,
that happens.
This image here is actually
from helium in the sun's atmosphere,
and you see a huge cloud
erupting there.
That's a billion tonnes of mass from
the sun being ejected into space,
so something in the sun's atmosphere
just snapped.
These gigantic solar storms
are called coronal mass ejections.
They are the most high-energy events
in the solar system
and the sun unleashes more of them
at solar maximum
than at any other time.
They can hurl clouds of plasma
towards us at alarming speeds.
To cover the 90 million miles
from the sun,
seen here reduced in scale
on the right,
to the Earth on the left
can take less than a day.
And as Helen found out,
they have the power
to overwhelm the Earth's defences.
Solar storms can destroy satellites,
silence communications,
ground aircraft.
Order up!
But the link they threaten most
in our modern lives
is our dependence on electricity.
If you have any doubt,
take a look at this booklet.
It's published by Lloyd's of London,
who are insurers,
and they wrote it with
the Rutherford Appleton Laboratory,
and I think one of
the most interesting sections
is where it lists
the potential impacts
that disruption to the power supply
would have.
And this is important, because
our power grid is one of the things
that's most vulnerable
to a big solar storm.
The highly charged particles
of coronal mass ejections
can induce powerful electrical
currents on the Earth's surface,
overloading circuits
and melting transformers.
And the reason it matters so much
is that everything is interconnected.
And so if we lost power, we'd not
only lose lighting and heating
and the ability to cook our food.
We also, for example, lose our fuel,
because pumping stations
rely on having electricity
to pump the fuel
out of their reservoirs.
Sanitation, water supplies,
communication systems.
We know we're vulnerable
because we've been hit in the past.
In Quebec, the entire power grid went
down after a solar storm in 1989,
plunging millions
into freezing darkness.
But we're not helpless.
There are precautions we can take
against the effects of solar weather.
We're already building systems
and technologies that are resilient.
But it would be even better if
we could prepare for specific storms.
But for that, we need to know
when they're going to arrive,
we need an early warning system,
and fortunately, there's one
in this building right here.
Forecast's now trending downward.
There were several filaments
that either erupted...
The Space Weather
Prediction Center in Colorado
is the only team on the planet
solely dedicated
to watching for solar storms.
No alerts or warnings
are currently issued...
The aim is to alert governments,
power companies
and the aviation and space industries
that a storm is on its way.
Even a few hours' warning
can help them prepare.
Chief forecaster Bob Rutledge
is going to teach me
how to predict solar storms.
Space weather really starts
with sunspots.
What that sunspot is doing,
how much is it changing,
and how complex are those magnetic
fields underneath those spots
are really what we use
to say how likely are we
to have significant activity.
So what are the different events
that could happen?
So when we get a solar flare, it's
essentially the start of the event.
That's the giant explosion.
We see that, essentially,
in this image in X-ray,
so it's a brightening in light
and radio waves,
so that's our first clue.
The last piece is, does the portion
of the sun's outer atmosphere
that sits above that, you know,
a billion tonnes of plasma,
does it get blown into space
as well?
So we start to watch other images
of the sun,
like this, for example,
where we've blocked out the centre.
We watch for the faint pieces of
atmosphere being blown into space.
So the ones that go off to the side,
albeit beautiful,
don't really matter to Earth. Right.
It's really looking and seeing
if it's coming our way or not,
and if so, how fast, and when
do we expect it to get here?
These images are coming from the same
new generation of satellites
used by the scientists at RAL.
They're our eyes in space
that keep watch over the sun.
I can see it with visible light.
Magnetic fields.
X-rays.
On a typical day near solar maximum,
the sun will send out
three coronal mass ejections.
Fortunately,
today there haven't been any.
But dramatic events
can happen with little warning.
You've got a video here
of a very special event.
I've picked out
from late October 2003
probably the last significant,
really big round of space weather
activity that we had.
We've blocked out the sun
so we can see the atmosphere.
You'll see the eruption.
Oh, yeah! Really symmetrical.
Look at that. Massive cloud.
It looks like a halo,
coming straight at you.
It was going at tremendous speed,
so it made it here in under a day.
So we have levels one through five,
just like a hurricane or tornado,
and it was pegged at that five level
storm. It was as big as it gets.
That solar storm took out the power
grid in the Swedish city of Malmo.
Tens of thousands
were left without electricity.
On that occasion, the Earth
was only struck a glancing blow,
but we can't be sure
that next time we'll be so lucky.
Today,
if we saw this happen again,
we'd be able to give our partners
in the key industries,
like the electric-power industry,
a heads-up to say,
"Hey, prepare your systems,
keep them as safe as you can."
We're only just beginning
to understand solar weather,
but we can't afford to ignore it.
I've been looking at the sun all day
and yet I haven't actually seen very
much sunlight, and now it's got dark.
But here's what gets me about today.
Imagine the big weather events
we have on Earth,
you know, thunderstorms and
even bigger than that, hurricanes.
And then take a step back,
and all those massive events suddenly
become tiny specks on the Earth,
sailing through this solar weather,
which is even bigger.
We've come a long way
from the idea of the sun as simply
a giver of light and warmth.
Its effects on our planet
are far more complex.
Thanks to solar scientists,
our sun is being revealed
as a dynamic, vigorous
fusion reactor,
pulsing through its 11-year cycle
and belching plumes of highly
charged particles in our direction.
As the scientists at RAL
have shown us,
that 11-year solar cycle
has become the heart
of how we understand the sun.
Many of the more surprising effects
the sun has on our lives
depend on how its activity
rises and falls through the cycle.
But scientists are now beginning
to explore a radically new idea,
that these cycles are not as set
as we once thought.
The latest research suggests that the
cycles themselves could be changing.
We could be living through bigger
shifts in the sun's behaviour
than we thought.
The clue comes from a phenomenon
that astronomers have been
observing for centuries -
sunspots.
They've been known about since
long before the era of satellites,
or even telescopes.
Looking directly at the sun
without proper filters
is clearly a terrible idea,
because you could really, really
damage your eyes.
But that didn't stop
early astronomers from trying.
And just sometimes, maybe at sunrise
or sunset or on a cloudy day,
they'd see something
that made the sun worth looking at -
tiny dark spots.
And for years,
they just assumed that those spots
were planets that were passing
between the Earth and the sun.
And then the telescope was invented,
and Galileo could draw
diagrams like these
and map out
where these dark spots were.
And it became apparent
that they're actually part of
the surface of the sun.
Thanks to those early astronomers,
sunspots are one of
the few bits of evidence we have
about the sun's long-term behaviour.
And new research is revealing
something surprising about them.
The key is how they're created.
Sunspots are caused by the magnetic
fields deep inside the sun,
and we can't see
those magnetic fields directly,
but the sunspots are offering us
some clues as to what's going on.
And we know that the more active the
sun is, the more sunspots there are.
As the sun approaches solar maximum
and the magnetic field lines
beneath its surface become tangled,
the flow of plasma within
is disrupted.
Hot material from the interior
can't rise to the surface.
The result is zones of cooler plasma.
Sunspots.
They're like windows
in the sun's surface,
through which we can study what's
happening inside the sun itself.
The McMath solar telescope in Arizona
is the largest in the world.
17 years ago,
a study of sunspots began here,
led by a group of astronomers,
including Matt Penn.
'They began to look
at the average strength
'of the magnetic fields
in the sunspots.'
So here we have the main mirror...
'Something no-one had tried before.'
So what got you started
on this study?
So we wanted to take
regular observations of the sun
to find out what sunspots were doing
over time.
We know that the number of sunspots
increases and decreases
in the solar cycle.
Actually, that's how the solar cycle
was discovered,
by early observations of sunspots.
During solar minimum, there'd be
zero or five sunspots on the disc.
During maximum, there could be 100.
During that 11-year period,
we wondered what was happening
to the magnetic fields in sunspots.
Was it increasing
along with the number of sunspots?
Was it flat, or was it doing
something else? We just didn't know.
And is it what you'd expect?
Well, no, it turns out
that the data showed us
something completely different.
Matt and colleagues are using
an ingenious way of measuring
the strength of the magnetic field
and sunspots.
A change in the infrared light
coming from them.
So this is a really lovely,
simple method,
because you can point your telescope
at any point on the sun
because you can point your telescope
at any point on the sun
and from the light coming out of it,
this simple thing of watching
how these spectral shapes change,
you can see exactly
how strong the magnetic field is
anywhere on the face of the sun.
Exactly, so we measure the magnetic
field with the spectral line,
and we've done a survey of 3,000
sunspots over the past ten years,
measuring the magnetic field
strength in each sunspot.
And what they've discovered
is surprising.
Instead of rising and falling
in line with the solar cycle,
as expected,
the magnetic strength of sunspots
has been steadily decreasing
year by year.
Right back in 2000,
the magnetic field was quite high,
and it's just gradually
gone down and down and down
over the past ten years,
quite consistently.
So a decreasing trend
means that in the future,
we may not have any sunspots at all.
It's an extraordinary result.
The trend suggests
that, over and above
the familiar 11-year solar cycle,
there are bigger patterns
in the sun's activity.
And in the long-term, we may be
heading for an extended quiet period,
what solar scientists call
a grand minimum.
Intriguingly, we've been here before.
Thanks to those historical records,
we know that around 350 years ago,
sunspots almost vanished
for 70 years.
So it looks as though
the sunspots could be dying away.
If that happens,
what difference does that make to us?
Right, if sunspots do go away
and we enter a new grand minimum,
there are possible effects
on the climate.
Records suggest the temperature
in Europe, for instance,
decreased during
the last grand minimum.
A grand minimum
would be a double-edged sword.
It might mean fewer solar storms,
something in our favour.
But it could also mean
a dramatic change in our weather.
The previous grand minimum
coincided with a period
of brutally harsh winters
in Europe and North America.
The River Thames in London
famously froze solid.
It was known as the Little Ice Age.
So this is a sort of intriguing time,
right?
You can see maybe just the start
of these big changes,
but you can't quite see
why they're happening.
But there are potentially very big
impacts if they do. Exactly.
This data suggests that the sun
is going through a major change,
a global change on the sun.
So in the long-term life of the sun,
we'd love to know what's going on.
If this trend does continue,
it may be evidence of a bigger
cycle in the sun's behaviour
that we've only just begun
to glimpse.
But the sun works
on such vast timescales,
even several hundred years of data
can give us only a tantalising clue.
So we've been watching the sun
for a few centuries,
but we don't know what was happening
when the pyramids were being built,
or when the dinosaurs were alive,
or a billion years ago.
And we don't know
what's going to be happening
a billion years into the future,
so we're just seeing this tiny, tiny
sliver of the lifetime of the sun,
and it's really hard to imagine that
in this enormous timescale.
And that's the big challenge
that lies ahead for solar scientists.
What's emerging is that even
the pattern we thought we knew,
the 11-year solar cycle,
isn't the full story.
There are bigger, longer-term
patterns in the life of our sun,
and they could have profound
influences on our planet and others.
What's incredibly exciting
is just how quickly our knowledge
of the sun is growing.
And thanks to huge technological
and scientific advances,
its surprises are gradually
being uncovered.
And next time you feel the sun
warm your cheeks
or you admire a sunrise,
it's worth remembering
just how complex and wonderful
our local star really is.