地核 The Earth's core

Hello and welcome to 6 Minute English. I’m Rob...
大家好，欢迎收听六分钟英语。我是罗伯。
… and I’m Alice. Hello.
大家好，我是爱丽丝。
Hi there, Alice! Now, have you read any books by Jules Verne?
你好，爱丽丝！你有读过凡尔纳的书吗？
Yes, I have.Journey to the Centre of the Earth was my favourite book as a child! A German Professor and his two companions climb down a volcano in search of the Earth’s centre – or core.They visit strange lands inhabited by dinosaurs and giant prehistoric humans, and sail across an underground ocean.
读过。小时候我最喜欢的书就是《地心游记》。一位德国教授和他的两个伙伴顺着火山口而下，想要一探地球的中心，地核。他们来到奇特的大陆，那里生活着恐龙以及高大的史前人类，之后他们还穿过了地下海洋。
Hmm. Very exciting but it doesn’t sound very realistic. How do they get out again?
非常刺激，但是听起来不太实际。他们最后是怎么出去的呢？
Well, they shoot to the surface from the mouth of Mount Etna during a volcanic eruption.
埃特纳火山爆发时，他们被扔了出去。
Wow! That sounds very uncomfortable! Well, on today’s show we’re going to discuss what scientists really know about the Earth’s core.
哇，这听起来不太妙。今天的节目我们要谈论科学家所了解的地心。
Yes. The Earth has a dense inner core surrounded by a fluid outer core. Dense, by the way, means heavy in relation to its size.But, Rob, I’ve got a question for you as usual: how big do you think the inner core is? Is it the size of …a) the Moon?b) Jupiter?or c) Mars?
好的。地核密度大，外部裹挟着一层液体外核。密度是指重量与体积之比。罗伯，今天也有一个问题要考考你，你认为内核有多大？相当于什么的大小？a) 月球?b) 木星?还是 c) 火星?
Right! Well, I haven’t a clue to be honest so I’m going to take a guess and say c) Mars.
老实说，我不知道，我猜一下，选c) 火星。
Well, we’ll find out later on in the show if you’re right. But before we get there, let’s find out a bit more about what the Earth is made of.
好的，节目最后我们再看你回答得是否正确。这之前，我们来看看地球究竟是什么成分组成的。
Well, the Earth has layers, a bit like an onion.
地球是分层的，有点像洋葱。
I like your technical language, Rob!
我喜欢你的术语表达！
But I’m trying to keep things simple for you, Alice!It has a thin outer layer or crust where we live.And this includes our continents and the ocean floors.Then beneath that there’s another layer called the mantle. And beneath that, is the Earth’s core – over 6000km below the surface.
我喜欢你的术语表达！我们居住的地方是地球稍薄的外层，也叫地壳。这一层包含我们的大陆以及海洋。这之下还有一层叫做地幔。再之下是地核，据地球表面有6000公里。
Right. But what’s the Earth made of, Rob?
那么地球是由什么组成的呢？
It’s a good question.
问得好。
And it depends on which layer you’re talking about! The crust and mantle are rock and contain a lot of silicate – which is the same stuff that glass is made of.But the outer and inner parts of the core mainly consist of iron.
这取决于你说的是哪一层。地壳和地幔由岩石组成，富含大量的硅酸盐。玻璃也是由硅酸盐构成的。但是地核的外层和内层都是由铁构成的。
And the core is very hot. Am I right?
地核非常热，是吗？
You are indeed.The professor and his companions wouldn’t have survived very long down there!The outer core is a swirling mass of molten – or liquid – metal and it’s as hot as the surface of the Sun!
确实如此。教授和他的伙伴就不能在那长时间生存。外核区就像一块熔化了的金属，和太阳表面一样热！
Wow! That must be so hot! Right. Let’s listen now to Simon Redfern talking about the inner core and what’s happening in there.
那一定非常热。我们来听听Simon Redfern谈论内核，以及内部都会发生什么。
And so over time, the planet has started to cool.And as it cools, eventually at the centre of the Earth, the highest pressure point, we pass over the crystallization temperature – the freezing temperature of iron– and iron starts to freeze at the centre of the Earth. And you get a crystal of iron right in the middle that starts to grow.
随着时间的推移，整个星球开始变冷。随着温度的降低，最终地球中心，压力最高点，我们先不考虑结晶温度，即铁冻结的温度，铁开始在地心冻结。铁开始在地心冻结。之后地球中心的晶体铁体积会慢慢变大。
I’m a bit worried that the Earth is freezing in the middle!
我好担心地球会从中心慢慢冻结。
Don’t worry, Alice!In this case, because of the incredibly high pressure in the core, the freezing point of iron is actually about 6000 degrees! And the iron has been cooling down and crystallizing for a billion years – and at a rate of just half a millimetre every year.
不用担心。因为地核的压力非常高，铁的冰点事实上达到了6000多度。铁冷却结晶要花费十亿年，每年以半毫米的速度增长。
Ah well, yes, that sounds like slow progress.
这听上去是一个非常缓慢的过程。
Certainly. Now moving on, we should also talk about the fact that it’s the liquid iron outer core that generates magnetic fields– and it’s thanks to these magnetic fields that life on Earth is possible.Let’s hear more about this.
当然了。我们继续说，事实上外核的液体铁是产生磁场的原因，多亏了磁场，地球上的生命才有存在的可能。我们进一步了解一下。
Well, the magnetic field is very important because it protects us against cosmic radiation so that’s one really...
磁场非常重要，因为它保护我们免受宇宙辐射。
How does it do that?
是怎么做到的呢？
It just creates a shield, which will just deflect the cosmic rays from the Sun to actually reach us at the surface.So it protects us.
它制造了一个保护盾，使来自太阳的宇宙射线发生偏移，以免其到达地球表面。因此保护了我们。
So it goes up there…
所以射线都在地球上层。
Yeah, so you would see that the radiation kind of goes round the Earth and not actually reach us.
所以你能看见射线围着地球，但是其实接触不到我们。
So there’s a magnetic field round the Earth that protects us from the Sun’s cosmic rays.I’d like a magnetic field round me.It could be my superpower – like in X Men!
地球的磁场保护我们免受太阳宇宙射线的伤害。我想有一个磁场围着我。成为我的超能力，就像X战警一样！
Calm down, Magneto. Now the magnetosphere is the area around the Earth in which the Earth’s magnetic field is felt. It protects us from the Sun’s radiation and the flow of particles, which would otherwise strip away – or remove – the Earth’s atmosphere.
冷静，万磁王。地球周围的磁气圈可以感受到地球磁场的存在。它保护我们免受太阳辐射以及粒子流的危害，粒子流会削弱地球大气层。
Right, I see. And what does ’radiation’ mean?
我明白了。那么“辐射”是什么呢？
Well, radiation means heat or energy or particles in the form of rays – in this case, the Sun’s rays.
我明白了。那么“辐射”是什么呢？
OK. And ’deflect’?
那么“偏斜”是什么意思呢？
To deflect means to make something change direction.
就是改变某物的运动方向。
Right, I see. Thank you. Now, Rob, I asked you, do you remember, at the beginning of the show, how big is the Earth’s inner core?Is it the size of … a) the Moon? b) Jupiter? or c) Mars?
我明白了，谢谢你。罗伯，还记得节目开头问你的问题吗？地球内核有多大？相当于什么的体积呢？a) 月球?b) 木星?还是 c) 火星?
Yes, and I had a wild guess and I said c) Mars.
我大胆猜了一下，选c) 火星。
Yes. And I’m afraid that’s wrong, Rob. The answer is a) the Moon. Would you like to shape up and tell us which words we learned on the show today?
很抱歉你答错了。正确答案是a) 月球。你愿意再回忆一下今天我们节目中提到的单词吗？
Of course. Good idea. We heard:
当然，我们今天听到的单词有：
core
核心
dense
密度
crust
地壳
mantle
地幔
silicate
硅酸盐
molten
熔化的
magnetosphere
磁气圈
strip away
削弱
radiation
辐射
deflect
偏移
Yes. Thank you, Rob. Well, that’s the end of today’s 6 Minute English. We hope you enjoyed our core vocabulary!Please join us again soon.
谢谢。今天的六分钟英语就到这里。今天的六分钟英语就到这里。下次节目再会！
Bye.
再见！