Rob

Neil: and I'm Neil. Hello.

Rob: Hello, Neil, and what a glorious sunny day

it is today. Not a cloud in the sky! Spring is definitely here! Now, Neil, you're a bit

of a sun worshipper, aren't you? You like sunbathing...

Neil: I do indeed! I love sitting in my deckchair

in the garden, catching some rays...

Rob: Hmm, yes, you look a bit orange actually.

Are you sure that tan's not fake?

Neil: Very cheeky, Rob, very cheeky...

Rob: Now the reason I mentioned sunbathing is because

we're discussing the sun in this programme.

Neil: Yes, that's right. The sun is our nearest

star ─ although it's a staggering 150 million kilometres away. Earth is one of nine planets

that orbit ─ or circle around ─ the sun. And life on Earth couldn't exist without its

warmth and light.

Rob: And we should mention... The sun is absolutely

massive. Its volume is so large you could fit a million Earths inside it.

Neil: That's amazing! It's also incredibly hot.

Hotter than anything you could imagine.

Rob: So Neil, can you answer this question: How

hot is the surface of the sun? Now I'll help you out by telling you that the sun's core

─ that's the centre ─ is a blistering five million degrees Celsius. But how hot

is the sun's surface? Is it...

a) 1.5 billion degrees Celsius b) 1.5 million degrees Celsius or

c) 5500 degrees Celsius

Neil: Hmm. I have no idea. They all sound quite

warm to me. But ... I think it must be a bit cooler than the core. So I'm going to go for

1.5 million degrees.

Rob: Okay. Well, we'll find out if you're right

or wrong later on. But now let's listen to Professor of Solar Physics Louise Harra to

discover what the sun is made of.

Louise Harra: It's just a big ball of gas. And we measure

it... it's made mostly of hydrogen. So it's roughly

90% hydrogen, it's maybe 8% helium, and the rest of it's made up of things like iron,

carbon, oxygen, nickel.

Neil: So the main gas is hydrogen, which accounts

for 90% of the sun's matter. Now, 'matter' means what something is made of.

Rob: And hydrogen creates all the sun's energy.

Heat and light energy is created all the time in the sun's core as a result of gas explosions

or nuclear reactions. And this bit is hard to believe ─ it takes a hundred thousand

years for this light energy to travel from the sun's core to the sun's surface.

Neil: But once it reaches the sun's surface ─ the

photosphere ─ it can escape. In fact, it takes only eight minutes for light energy

from the sun to reach the Earth. Scientists these days are able to see the photosphere

in fantastic detail using powerful telescopes.

Rob: Though Galileo observed dark spots on the

sun through his telescope several hundred years ago, didn't he? Which brings us on to

another question: How old is the sun?

Neil: Well, I happen to know that it came into being

around four and a half billion years ago.

Rob: Did you study solar physics at university,

Neil?

Neil: No, just... you know, just general knowledge.

Rob: Well, the sun came into being ─ or was created

─ a very long time ago! We're going to hear now from Professor of Physics, Yvonne Elseworth.

What does she say about how long the sun is going to stay the same?

Yvonne Elseworth: In terms of its current lifestyle it's here

for as long again, so we're about half way through. And then it becomes a different sort

of star ─ it becomes a giant star and that's probably curtains for us, actually. It'll

get a bit warm, a bit toasty, and we'll get enveloped in the sun, and it won't be nice...

Neil: So the sun is going to stay the same for another

four and a half billion years. But the professor also says that the sun will change. When it

becomes a giant star, it will be curtains for our planet ─ and 'curtains' means the

end, I'm afraid!

Rob: Yes, it does. And as a giant star, the sun

will get hotter ─ it will make the Earth toasty. Now, toasty usually means hot in a

nice way.

Neil: That's right ─ for example, my toes are

warm and toasty in my new slippers. But in reality the giant sun will make the Earth

unbearably hot. It will surround ─ or envelop ─ our planet and burn it up.

Rob: Well, I'm glad we're not going to be around

when that happens. Now, remember at the beginning of the show I asked you how hot is the sun's

surface? Is it a) 1.5 billion b) 1.5 million or c) 5500 degrees Celsius?

Neil: And I said 1.5 million...

Rob: It's way too hot, I'm afraid you were wrong.

The answer is actually 5500 degrees Celsius. But still, if you're planning on visiting

the sun, remember to take your sunglasses and plenty of sunscreen! Now, before we go,

it's time to remind ourselves of some of the vocabulary that we've heard today. Neil.

Neil: orbit, massive, core, energy, matter, photosphere,

come into being, curtains for something, toasty, envelop

Rob: Thanks. Well, that brings us to the end of

today's 6 Minute English. We hope you enjoyed today's programme. Please join us again soon.

Bye bye.

Neil: Bye.