The Secret Life of the Sun Page #2

---

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

Rate this script:0.0 / 0 votes