Solar Storms - The Threat to Planet Earth Horizon

Something is stirring on the face of our nearest star.

Something powerful and unsettling.

Because the sun is becoming more active

it will have an impact in the lives of millions of people.

To understand what's coming our way,

they are doing something we cannot,

stare directly into the sun.

If the sun keeps carrying on like this,

we could be in for some really big storms over the next 12 months.

What they are expecting in the next year

are colossal eruptions from the sun

that fling billions of tonnes of plasma towards our planet.

Our hi-tech society has never been so vulnerable,

for when a solar storm strikes,...

..it could shut us down.

If we don't understand space weather more clearly,

we could easily end up in the electronic dark ages.

We are playing a game of Russian roulette with the sun.

If we play that game long enough, we will lose.

We all worry about the weather,...

..but now there is a new kind of weather to worry about.

This weather comes not from over the horizon,

but from 93 million miles beyond it.

'Winds blowing once again...

'..But we still enjoy the clear sky and bright sunshine during the day

'so we should be bright, dry and quiet in the middle and latter portion of the week.'

Outer space is about to get a whole lot closer to home.

The giver of life, light and heat,

that looks so placid, is anything but.

When violence erupts on its surface,...

..it has the power to bring our modern life to a standstill.

This power was demonstrated to the world in 1989.

The target, Quebec.

Well, in 1989, there was a storm where we saw for real

how serious these problems could be.

What happened was the solar storm

changed the magnetic field of the Earth.

This caused currents to be induced in the ground,

and those currents overloaded a power station.

'There has been a big power failure in Quebec.

'Most of the province is in darkness, including much of Montreal.'

They went from normal operating conditions

to complete province-wide blackout in an elapse time of 92 seconds.

'It's so strange to see a major city like Montreal in darkness.'

'This morning, 6 million Quebecers woke up cold and in the dark.'

'..speculating it could have been caused by solar storms.'

And the power was shut down for nine hours.

This was a wake-up call for scientists.

The secret to understanding this violent weather from space

is a mysterious phenomenon that has bewitched scientists for centuries.

The Arizona desert.

Matt Penn spends more time than most

thinking about space weather's starting point.

Wonder if there are any up there today.

The birthplace of space weather.

Sunspots!

I mean, they're a mystery, right?

We've seen them in records from Chinese astronomers dating

thousands of years back into history.

But the details of how you form a sunspot are still a mystery

and understanding that is really intriguing to me and fascinating.

Now a sunspot itself is actually a bright object.

If you took a sunspot off of the sun and put it into the night-time sky,

it would be brighter than the full moon,

but compared to the rest of the solar disc,

it's cooler and darker and that is why it appears as a black spot.

But to really understand how sunspots trigger solar storms,

you need something rather more impressive

than a piece of smoked glass.

So we are at the prime focus of our solar telescope now.

And what we see is a white light image of a disc of the sun.

On the disc today we see several active regions, several sunspots.

Each active region is perhaps five or ten times the size of Planet Earth.

So that's a huge sunspot that we have here.

Absolutely massive.

Were you able to measure the magnetic field...

The reason Matt and his team study these beautiful shapes so carefully

is because hidden within sunspots is a unsettling truth.

Sunspots can cause the biggest and most damaging space storms,

solar storms, that occur.

They follow sunspots as they travel across the face of the sun...

That's bigger than the Earth there, right?

It's eight, nine times the diameter of Earth, so it's a massive region.

..just waiting for them to explode.

That's a huge storm coming in.

It is.

It's like looking down the barrel of a loaded gun.

Sunspots are kind of like thunderstorms on Earth.

A big sunspot can cause a big storm, just like a big thunderhead

can cause a big tornado on the Earth.

Now we can't exactly predict when tornadoes will occur

and which thunderstorms will produce tornadoes, just like on the sun

we can't predict exactly which sunspots will spawn solar storms,

but that's one of the main focuses of our research.

So why is it that some sunspots

just pass calmly across the sun's surface,

while others erupt?

Professor Cary Forest is at the forefront of the effort to find out.

He's exploring the hidden world of chaos and violence

inside our nearest star.

The force that makes sunspots erupt is something invisible,...

..a part of everyday life that few of us even think about.

But it is a force so powerful,

it can trash billions of pounds' worth of modern technology

in a split second,...

..bringing our modern world crashing around our ears.

So what is this mysterious force?

It's this!

The same force of magnetism that's lifting this washer,

when scaled up to solar scales, becomes strong enough

to cause the storms that fly off the surface of the sun.

But how these explosive levels of magnetism are created

inside our nearest star is an urgent question for scientists.

Cary and his team have built a daring experiment

to study a star inside this building.

So when we began this business, we built this crazy-looking device

to figure out where space weather comes from.

Inside it, they will generate the dynamics of a star.

If you want to understand space weather,

ultimately you have to understand the engine

that creates some very intense powerful magnetic fields

from a complex flow, a turbulent flow,

of plasma inside the sun.

This superheated plasma churns ceaselessly as the sun rotates.

We have this device which is supposed to mimic those processes

here on Earth.

But this is a dangerous experiment.

They need to fill it with an explosive element.

So here we have a pressure vessel that holds inside of it

flowing liquid sodium,

which is a very dangerous, complex liquid to work with.

Let me show you the inside.

Watch your fingers.

All right, that's great.

So looking inside here you can see we have these two propellers -

one spins this direction, the other spins in the opposite direction,

and we create these flows that are out along the poles

and are spinning in opposite directions

and it's those flows which can take very small magnetic fields

and can amplify them up into big loops of magnetic field,

that ultimately bubble out

and emerge from the surface of the sphere,

and would basically be the same sort of process that happens on the sun.

He's hoping to generate these.

OK, guys, let's fill the experiment.

This is the experiment.

It is exactly the same as the experiment I showed you earlier,

except it's covered with insulation,

we have it at very high temperature,

these pipes coming in bring hot oil to the surface of the experiment,

to keep it at the 100 degrees Celsius at which sodium melts,

and then all of the wires going in go to magnetic field sensors

that measure the magnetic field that comes out of the vessel.

Now they have to pump 300 gallons from an underground storage tank

into their sphere.

There are many steps to that

and many places for things to go wrong, so we're completely on edge

as we are trying to get the sodium up into the vessel.

Check the temperature of the transfer line.

There's enough potential chemical energy in this volume of sodium

to blow this building to smithereens.

Reset the offset of the amplifiers and then we're good to go.

When we do the experiment itself, we're going to leave this room

go to the remote control room and do the experiments

from outside the room so we're completely safe.

-Can we go ahead and turn things on here?

-Yeah.

-Yep.

Right now we're at 100rpm and what you see here

is a very weak magnetic field

generated deep inside the experiment.

At low speeds, this experiment creates a magnetic field

a bit like the Earth's.

But as you increase the speed, the dynamics of the experiment change.

At maximum speed, it starts behaving like a star.

We're going to change the motor speed

and really increase the drive of the generator

and so the next thing here is to...

is to look and see what changes when we make that change in speed.

We're going up to 1400 rpm.

We're really pushing the limit of the experiment here - it gets hot,

the power levels are high,

it's about as fast as the propellers can go.

And we are there.

-Wow!

-We're up to speed.

-This is amazing.

So, you can see, the turbulence levels are coming way up...

Cary's discovered magnetic power

doesn't just rise gently with motor speed,

it takes a massive leap.

These are flux loops that are popping out of the surface of the sphere.

They're very noisy, very chaotic,

much like the surface of the sun would be.

This gives you a sense of what's happening inside our nearest star,

the process that gives space weather its teeth.

So just imagine what would happen if we took this experiment,

which is really small,

and we increased its size to something like the surface of the sun

and we increased its engine to the power of the thermonuclear engine

of the core of the sun and what would be generated.

Those are really astronomically big numbers that we'd be talking about.

The power that can be generated in the magnetic field

on the surface of the sun is really enormous

and you can really see why space weather is really a scary thing.

Ultimately, this magnetic energy has to find a way out.

Sunspots are one way that twisted magnetic energy

finds its way to the surface of the sun.

But why do some sunspots then explode,

releasing a storm that can threaten our way of life?

The team at Tucson are measuring sunspots

to investigate the moment one goes critical.

-You look for the lowest intensity on the meter here.

-Exactly.

So you can see we're raising in intensity here.

They examine infrared light from the telescope

to try and understand when the twisting of the magnetic field

could create a solar eruption.

So that's a big sunspot, Bill. It might produce some solar storms.

-The one to watch.

-Right.

Yeah, that's the most complicated active region.

And the structure here is...

Looks like it's changing with time.

-Right.

-Which can produce a stress on the system.

-Right.

It can store energy on the magnetic field and then erupt as a storm.

As the sunspots evolve on the surface of the sun,

flows and other gas dynamics

can cause the sunspots to twist up their magnetic field.

And if this continues for a long period of time,

a twisted magnetic field can store energy,

just like a twisted rubber band can store energy,

and just like a rubber band, when the magnetic field becomes too twisted,

it can snap.

It is this snap that ultimately propels a solar storm

from the sun's surface and sends it hurtling towards the Earth.

But this on its own does not explain solar storms.

Something else has to happen on the sun.

Something has to pull the trigger.

Paul Bellan reckons he might know what it is.

That's because he's in charge

of a highly sophisticated piece of equipment.

What we believe is that just as I'm blowing bubbles,

the sun is blowing magnetic bubbles off of its surface.

When I blow a bubble, if I blow it just a little bit,

it expands but it doesn't break off,

but if I blow it harder, it breaks off and forms a bubble.

The same with the sun,

if the magnetic fields on the sun blow a little bit,

the structures stretch out but they don't break off.

However, if the sun blows a lot,

with its magnetic field, then a structure breaks off,

and this bubble of plasma and magnetic field

can fly towards the Earth.

To understand what makes the plasma break off,

Paul has built a machine

which can do something that sounds impossible -

create a mini solar storm right here on Earth.

To do that, they must create a piece of the sun's surface

inside this chamber.

Massive electric currents supply the magnetic field through this rod,

generating a cloud of plasma just like the surface of the sun.

These conditions only last a split second,

and have to be imaged by this high-speed camera

that captures the moment of eruption.

-Are you ready to turn on the high voltage?

-Yep.

-OK, let's go for four kilovolts.

-OK.

Charging.

One kilovolt,

one and a half,

two, two and a half,

three,

three and a half,

four.

Well, we've got a nice shot here.

This is a plasma loop with very large currents and magnetic fields.

It's exploding outwards at very high velocity,

tens of kilometres per second.

The electric currents here are very large,

the electric power that we're using of the order of a 100 million watts,

the sort of power you would use for running a small city.

So here we have an electric current of probably about 50,000 amps

going from a top electrode to a bottom electrode.

That produces a magnetic force

that effectively is producing a pressure inside

that's pushing this plasma out,

just like the air pressure on the bubble pushes the bubble out.

Just like a bubble, these loops on the sun need to re-connect.

And when it gets pushed out to a certain point, it can break off.

That's magnetic re-connection - it's like the bubble popping

and the popping here isn't a pop like the sound you hear,

it's actually X-rays being shot out

and energetic particles being shot out.

So what you get is energetic particles, X-rays,

and the actual plasma can head towards Earth.

Plasma can plough into the Earth and wreak havoc.

So this is how a solar storm comes our way,

one with the power to black out a city in seconds.

First, the awesome magnetic power of the sun

is twisted into a threatening sunspot.

Then, this twisting hurls field lines out into space.

But they are still anchored.

Finally, some get dangerously close and then they reconnect.

A solar flare explodes in a flash of visible light,

energetic particles and X-rays.

It is the power of a billion atom bombs exploding all at once.

But there's more.

A nanosecond later, a coronal mass ejection, or CME, erupts.

Billions of tonnes of the sun hurled into space.

This is the sun's plasma wrapped in a magnetic field.

Not surprisingly, scientists want to know when the next one is coming.

'..tomorrow we'll hang on to the sun,

'but temperatures don't move much at all.

'We're going to climb to the mid-50s Tuesday,

'with lots of sunshine in the forecast Wednesday.

'That's when temperatures are going to start to creep up, but still...'

I don't usually listen to the weather

so sometimes I wake up to maybe a bit of a surprise.

This is Bob.

Bob is a weatherman.

But he couldn't care less if it is about to snow.

-Morning, guys.

-Morning, Bob.

-How's it going?

-Ready to take over?

-Pretty quiet night?

-Pretty quiet.

Numerous CMEs, in fact, that are...

Right now you can just see this one right here,

filling an eruption along this channel here,

generated this large CME.

Looks pretty far south of the ecliptic

so it doesn't appear to be Earth directed.

Plenty happening overnight but nothing coming our way.

Another close shave for Planet Earth.

Other than that, we're doing good.

Here at the Space Weather Prediction Centre in Boulder, Colorado,

Bob and his team are the first line of defence for the entire planet.

Running a zero-three over here.

They provide forecasts to airlines, power and satellite companies,

all vital services that need protection from solar storms.

No space weather storms were observed for the past 24 hours,

no space weather storms are predicted for the next 24 hours.

A wealth of data is fed here, live, to the control room, 24/7.

Just on the edge so we can still get some of the X-rays.

They can monitor our nearest star in real time,

in almost every conceivable wavelength of light.

But all these hi-tech marvels are vital

when you consider what is at stake.

There's billions of dollars' worth of satellites up there.

Our critical infrastructure, such as the power grid,

relies on the things we do.

If you turn off power, all kinds of things go wrong.

And if things do go wrong, our first warning comes from here.

The ACE satellite,

floating 1.1 million miles from Earth.

It has been protecting our planet since 1997.

Once a storm hits ACE, it will hit Earth less than an hour later.

It's nail-biting stuff.

It's our little beacon in space.

Any storm that's coming from the sun is going to hit the Earth,

and has to pass over ACE.

That gives us, in worst case,

only 15 minutes before that CME slams into the Earth.

But that's about it. Once it hits ACE we've got, at most,

an hour's warning before that storm is going to begin on Earth.

This control room was put to the test in October of 2003.

The 2003 Halloween storms were really a series of significant space weather events.

There wasn't just one big region, there were three of them.

And they were popping off large flares and fast CMEs all the time.

And initially, the CMEs were missing the Earth

and we were just getting the effects of the flares.

The solar flare itself is light,

so it's getting from sun to Earth in eight minutes.

As soon as we're measuring it with our satellites, it's here.

As the regions marched towards disc centre,

we had to worry more and more

about coronal mass ejections hitting the Earth.

We really had, kind of, the perfect storm

of all of the big phenomena associated with space weather.

But this was just the beginning.

The next day, Tuesday October 28th,

began much like any other on Planet Earth.

Then, at 11.12am, Planet Earth came under attack.

October 28th was to me the key date

because we had a huge X10 solar flare

that erupted with a coronal mass ejection,

travelling faster than 2,000 kilometres per second.

X class is the biggest flare you get.

Here you can see what happens

when the flare hits the space telescope camera.

'It may sound like the plot of a science-fiction movie,

'but the Earth is currently under attack from the sun.'

'A mass of material hurtling towards the Earth

'at five million miles an hour.'

We knew it was going to get here fast.

In fact, it got to the Earth in 19 hours.

That's almost the fastest on record.

The problem with that was,

such a fast event drives large populations of energetic protons.

Those protons blind part of the ACE satellite data.

It's too close. The spacecraft is right in front of the sun

so we can't see it.

We had a satellite looking at the sun but it's blinded by the sun.

That happens.

The ACE satellite hung on long enough,

despite serious proton damage,

to keep sending the magnetic field polarity of the storm.

Now there's two things we're looking for in the magnetic field -

the total intensity, cos that tells us how big the storm could be,

but the other thing that's important

is the direction of the magnetic field.

Is it up and northward or is it down and southward?

When it's up and northward it's going to be a big storm.

When it's down and southward it's going to be a monster storm.

That's because the Earth's magnetic field

naturally repels storms that have a northward polarity.

But when the polarity is southward,

it allows the storm through the open gate of the Earth's magnetic field.

And in October 2003,

ACE was telling them the door was wide open.

Early on the 29th, the CME slammed into the Earth,

driving a G5 geomagnetic storm,

the biggest on the scale that we measure these storms on.

Power grid in Sweden went down,

there were problems with the power grid in Africa.

In the US,

GPS systems that helped airlines get more accurate readings

became less reliable and they had to change the operating procedures.

Airlines were prohibited from making flight alterations

or flying above certain latitudes.

The power grids around the globe responded.

This was a monster storm.

This was one of the worst storms of recent years.

Around the world, the people who keep the lights on

are now on high alert.

But they are battling a powerful foe.

The UK's National Grid is no exception.

Could this cause a power cut in England?

It could, because the sun is so vast

that we can never entirely protect against it.

If it hits the Earth as it goes round on its orbit,

a huge magnetic shock gets delivered to the Earth

and that causes currents to flow along our conductors,

down these lines here,

right down into the core of the transformer below us.

It can set fire to the insulating material

that is there to protect the device.

And when that happens we get catastrophic failure,

and a machine like this has to get replaced.

The National Grid, though, have developed a way to protect us.

It turns out that the best thing to do to keep the lights on

is the last thing you'd expect.

Mad as it sounds, we turn every single bit of our kit on.

That means that lines that have previously been out

because they weren't needed

or because people were working on them temporarily,

we cease all work, we bring the lines back in,

and what happens is that the currents

induced by the coronal mass ejection hitting the Earth,

spread out along all these different routes that it can follow

and that reduces the amount at any one point,

where the induced current is trying to get back down to the Earth again.

And that protects our transformers,

it means there's much less risk of them overheating

and we ride out the storm that way

and ensure that we prevent a blackout.

It's like in a storm when you've got a huge amount of flood water

rushing down and we turn on extra storm drains just to

drain the power of this surge away.

These electromagnetic storm drains may soon be put to the test.

During the next two years, we expect the number of sunspots

visible on the disc of the sun will reach a maximum.

Now that's interesting because we know that

sunspots are the source of a lot of space weather, solar storms,

so we expect a larger number of solar storms here at the Earth.

The reason this is important to understand is because

it can impact our daily lives,

either through our power system or through our communication system,

or through our navigation system,

and we expect to have more disruptions in our daily lives

in the next two years because of the solar activity.

Over the next two years, we're likely to see more storms.

But there's one problem that takes you to the heart

of cutting-edge solar storm research.

Why is it that some storms hurtle from the sun

so much faster than others?

Scott McIntosh believes he might have the answer.

And it all comes from a completely new and revealing

set of images of the sun,

taken by the state-of-the-art SDO satellite.

It is a brand new camera in space,

taking a high-resolution image of the sun

in ten different wavelengths of light, once every ten seconds.

It's the content in those images,

and the frequency of them, how often they happen,

that's really going to help us push through and understand better

space weather storms.

In these precious new images, Scott has noticed something.

It may provide the answer why some storms

are so much faster than others.

He's been focusing his attention here, the sun's superheated corona.

This is the area of the sun's atmosphere

20 times hotter than its surface.

This superheated layer holds in all the loops of magnetic power

and all the hot plasma that goes to make up our nearest star.

So you see here, the corona in super slow mo.

And what we're looking at is that detailed evolution

of all these coronal loops.

These are fibres, magnetic fibres, that make up the whole corona.

The corona is like a pressure cooker.

And these loops are like the top of the pressure cooker.

So watch, this is a coronal mass ejection in action back at the sun.

If you watch really closely... Boom! You see that?

As the material rips away, you get these two very dark patches

either side of the active region, and watch again, boom!

You see them. The corona gets instantaneously dark.

Over hundreds of thousands of kilometres.

And then it slowly patches in.

These, as we call them, transient coronal holes,

may provide a clue for the energy source for these superfast CMEs.

These transient coronal holes, virtually invisible until 2010,

are part of a mechanism that can super-charge a CME,

ripping a hole in the corona, tapping into the sun's energy

back down on the surface.

If you watch closely, the coronal loops that just happened to be there

before the corona erupted, just disappear.

In fact they don't just disappear,

it seems like you rip into the lower part of the atmosphere.

All that energy that was keeping the corona at a million degrees

now has an avenue to escape. You've basically opened the gates of hell.

These gates are at the heart of space weather.

Through them all the power of the sun,

this massive reservoir of energy, has a channel to escape.

So it's this tapping in of this reservoir of energy,

this boundless amount of energy, that may give the CME its kick.

The thing that gives the CME its kick to 1,000 kilometres a second,

that lets it get to Earth that little bit faster

than we can currently understand.

Scott hopes to use these weird dark patches

as a way of answering the billion-dollar question -

is this storm hitting today or tomorrow?

Understanding the amount of energy contained in one of these things,

and in these transient coronal holes, will ultimately improve our ability

to forecast their arrival time at Earth.

An extra day's warning is of course helpful

but the challenge is to go further,

to give a week's warning.

To do that, you need to do something else.

Something that sounds a little bit unlikely.

Listen to the sun.

And that is what Stathis Ilonidis is doing.

If we only use light to study the sun

then we can only observe the surface or higher,

but with sound, the sun is transparent, in sound.

We can use sound to learn more about the interior of the sun.

The turbulence of the plasma inside the sun

means it is constantly vibrating.

These vibrations makes sound waves

that travel through the sun's interior.

Here, they are sped up so we can hear them.

This is the sound of the sun.

By using this sound, he has tracked the positions of sunspot regions

thousands of kilometres beneath the sun's surface.

This is the surface of the sun.

Here is where we observe the solar vibrations.

We select a pair of points on the solar surface

with a specific distance of 150,000 kilometres.

Acoustic waves originating at one of these two locations

will propagate down up to a depth of 60,000 km

and they will return back to the surface

close to the location of this point.

Sunspots are born deep inside the sun.

They then travel to the sun's surface

and trigger space weather storms.

When sound waves bump into a sunspot region,

something remarkable happens.

They speed up.

In this case, the acoustic waves propagate a little bit faster

in this region, inside the sunspot region.

So the total travel time is a little bit shorter.

This is 12 to 16 seconds shorter.

And this is an indication that there is a sunspot region

along the acoustic path.

Now, in reality, we don't know where the sunspot is,

so we don't select only one pair of points,

but we select thousands of pairs of points on the solar surface,

we compute the travel times, and we identify locations

where the travel time is significantly shorter.

That shows that there is a large sunspot region at these locations.

So we have one to two days' extra warning

before the sunspots appear at the surface and become dangerous.

But Stathis is not satisfied to stop at two additional days' warning.

He believes that in future he can go even deeper,

listening for storm-bearing sunspots far earlier.

Apparently, we can only detect sunspots at a depth of 60,000km.

And this gives one to two days' heads-up

before they appear on the solar disc.

So in the future, we hope to refine this technique,

and detect sunspots much deeper than 60,000km.

And this can give a week of extra warning,

before they appear on the solar disc.

It sounds like a brighter, safer future,

if one day we can rely on Stathis' technique to warn us.

And in this fast-evolving technological age,

this warning is becoming more and more critical.

John Kappenman has spent the last 30 years

studying exactly what could happen to our modern world.

We think these large storms are something that is probable

in a one-in-50 to one-in-100-year sort of basis.

It's really only over the last half century or so

that we've grown this very large interconnected infrastructure.

What's coming more to the fore now is this immediate need,

given our technological society,

we need to study the impact of the sun on the Earth.

Big storms have occurred before and they are certain to occur again.

The difference is that we've now built a big vulnerable infrastructure

that impacts all of society.

And key to our new vulnerable infrastructure are these...

Satellites.

Our modern world is built on them.

Navigation, communications,

plus everything from warfare to banking relies on them.

Satellite electronics can be destroyed by space weather storms.

But space weather can also affect our atmosphere,

plucking a satellite out of its orbit

and sending it crashing to Earth.

A remote Arctic monitoring station,

home to an ambitious project.

A project to protect our civilisation,

350km inside the Arctic Circle.

It's a place on the planet where you can test something

that could end up protecting our satellites.

Norway, northern Norway, is very good for these types of experiments,

because we're in the high polar region,

and it's in the high polar regions,

that the Earth's magnetic field comes down to ground, almost vertically.

And this is very important,

especially when you're doing radar experiments,

so that you can map along the magnetic fields, out into space,

several thousand kilometres,

and that's not possible anywhere else on the Earth.

Mike Kosch is attempting to do something artificially,

invisibly, that happens naturally up here.

The aurora is caused by particles coming from space,

crashing into the top of the Earth's atmosphere.

These particles come from the sun,

they get trapped on the Earth's magnetic field,

and because the magnetic field in polar regions,

comes down to the Earth's surface vertically,

the particles can track along those magnetic field lines,

down in the polar regions, into the atmosphere.

When they collide with the oxygen and nitrogen that we're breathing,

they activate those gases, which causes optical emissions to appear.

Red and green, typically, is for oxygen, blue is for nitrogen.

The aurora is just the most beautiful and surreal experience.

The same process that creates the aurora

happens much more powerfully during a solar storm.

Mike is using this massive dish to precisely measure

how a solar storm changes our atmosphere

and the threat that this poses.

When that wave of material comes towards the Earth,

it heats the atmosphere and that causes the atmosphere to expand.

This expansion makes the region of the upper atmosphere

satellites fly through, denser.

The resulting extra drag

can have serious consequences for our satellites.

During a big storm,

this expansion can increase the density of the gases here tenfold.

The results can be catastrophic

for any satellite flying through this region after a storm has hit.

Forced to travel through a thicker gas,

satellites can be dragged out of their orbit to crash to Earth.

In 1979, even Skylab was vulnerable.

The upper atmosphere Skylab was travelling through

was heated by a series of solar storms.

Eventually she crashed uncontrollably to Earth.

Now we're not always in a position to wait for space storms to come

so we have another instrument here on site called the heater

and we can then simulate these space weather events, using the heater,

to heat the atmosphere at high altitudes,

cause the atmosphere to expand,

so that we can study the atmospheric expansion

and therefore the effect on satellites.

Mike is ready to run the experiment.

If successful, this will be a scientific first,

one that could lead to a new type of forecast

that could keep our satellites from crashing in future.

This experiment has never been done before,

so we're not quite sure if the experiment will work.

We're a little bit worried and a little bit nervous

about whether we may get a good result or not.

..nine, eight, seven, six, five,

four, three, two, one, now.

OK, roll on.

Yeah, something's happening certainly.

You could definitely see how the density was going up.

I think there's Langmuir turbulence here,

and I think we may be producing suprathermal electrons.

Yeah, but what's the flow doing?

After several hours heating the atmosphere in 15-minute bursts,

the team have gathered the findings.

Well, it's 8.00 in the evening

and we've just completed running this new experiment,

and we have the initial results on the screen here, from the radar.

When you heat the atmosphere you heat a gas, you expect it to expand.

So if the gas is expanding and the atmosphere is lifting,

then you would expect at the altitude that a satellite normally flies,

that the density would be increasing.

And you see that very clearly over here.

This is the panel that shows density.

The red colours, let's say 500km,

where a satellite normally flies, indicate high density,

and every time we turn the heater on,

we see that the density is increasing.

Now, the importance of this experiment

is that we can make this measurement very precisely.

So when we see a space weather storm, a space weather event,

coming from the sun, we can estimate the amount of energy,

the amount of heat it is bringing to the Earth,

and therefore we could make an accurate calculation

of what the density increase would be, for a satellite.

So if we can predict that accurately,

then the operator of a satellite

would be able to make a correction, take some action,

for example, fire the rocket engines, to compensate for the drag,

and therefore prevent the satellite from crashing back to the ground.

That's the important point here.

With such a precise level of data,

Mike hopes to provide the Space Weather Prediction Centre

with a real-time feed of atmospheric density to give satellite companies

enough information to protect their satellites.

Now that we are looking more closely,

listening more deeply,

measuring more precisely,

a new question is coming into focus -

what solar storms can we expect in the distant future?

Back in Tucson, the scientists know the next two years

could see more solar storms.

What they are now trying to understand

is what's happening over the next half century.

So what we've seen is an overall decrease

in the magnetic field strength inside sun spots.

Now, during any given year, sun spots appear on the disc of the sun

that have a variety of magnetic field strengths.

But if you take the sun spots that you see in an entire calendar year,

and average the magnetic field strengths,

and then look at that average magnetic field strength

over the past 13 years, it's decreased very steadily.

Now if we extrapolate this into the future,

eventually we'll see only half of the number of sunspots

that we're used to. And if it continues even further,

the sun won't be able to form dark sun spots on its surface.

So in general, we would expect less energetic solar storms to be erupting

and perhaps space weather will be calmer in the future.

I got rid of this 15,

so that's really good, I should be able to go back now.

But the complexities of predicting the future of the solar climate

mean a definitive scenario is hard to come by.

Back at the Space Weather Prediction Centre,

they are not waiting for the sun to calm down.

There are some people that say we're going to go into what's called

a grand minimum, we're going to see well below average solar cycles.

I think those are very controversial at the moment.

There are many people that say the sun is not predictable

on that long a time scale. It doesn't matter, though.

Space weather is always happening and in fact

severe space weather can happen,

outside of a large sunspot number sort of period.

We can never take our eye off the ball.

We may be more vulnerable

but we've never been better prepared.

One thing is certain - we ignore this phenomenon at our peril.

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