BBC英语六分钟 第08期:地核

发表时间:2017-04-03内容来源:VOA英语学习网

Rob:Hello and welcome to 6 Minute English. I'm Rob.

大家好,欢迎来到英语六分钟。我是罗伯。

Alice:And I'm Alice. Hello.

我是爱丽丝。大家好。

Rob:Hi there, Alice! Now, have you read any books by Jules Verne?

你好,爱丽丝!你读过儒勒·凡尔纳写的书吗?

Alice: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。我小时侯最喜欢他的《地心历险记》了!它讲的是一个德国的教授带着两个同伴进入了一座火山去寻求地心,或者说是地核。

Rob:Hmm. Very exciting but it doesn’t sound very realistic. How do they get out again?

嗯,很有趣但听起来不太现实。他们是怎样出来的呢?

Alice:Well, they shoot to the surface from the mouth of Mount Etna during a volcanic eruption.

他们是在埃特纳火山爆发时从火山口被射出来的。

Rob:Wow! That sounds very uncomfortable! Well, on today's show we're going to discuss what scientists really know about the Earth's core.

哦!那肯定舒服不了!我们今天的节目要讨论的是科学家们到底对我们的地核有哪些了解。

Alice: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?

是的。我们地球稠密的内核由一个液态的外核包裹着。说明一下,Dense是指体积一定时重量大。但是罗伯,和往常一样,我要问你一个问题:你觉得内核的体积是多大?和以下哪一个体积相当:a)月球 b)木星 c)火星。

Rob:Right! Well, I haven't a clue to be honest so I'm going to take a guess and say c) Mars.

好吧!说实话我不清楚,所以我只能猜一猜了,我猜 c)火星。

Alice: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,我们会在稍后的节目之找出答案,看你是否猜对了。但这之前,让我们再多了解一些地球是由什么构成的。

Rob:Well, the Earth has layers, a bit like an onion.

地球有地层,像洋葱一样。

Alice:I like your technical language, Rob!

我喜欢你说术语,罗伯!

Rob:But I'm trying to keep things simple for you, Alice!

但是我想说的让你容易理解一些,爱丽丝!

Alice:Thanks.

谢谢。

Rob: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.

地球的外层也就是地壳居住着我们人类。这一层包括我们的大陆以及海床。地壳下面的一层叫做地幔。地幔的下面就是地核了,它在地面以下6000千米的位置。

Alice:Right. But what's the Earth made of, Rob?

对,但地球是由什么组成的呢,罗伯?

Rob:It's a good question. 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.

这个问题问得很好。它取决于你说的是哪一层!地表和地幔由岩石和硅酸盐组成,硅酸盐是玻璃的组成物质。但是地核的内外两层的主要成分都是铁。

Alice:And the core is very hot. Am I right?

而且地核部分的温度很高,我说的对吗?

Rob: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!

你说的没错。那个博士和他的同伴不可能在那里存活很长时间!外壳是融化的或者说是液态的漩涡,它的温度和太阳表面的温度一样高!

Alice: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.

哇!那一定特别热!让我们听西蒙·雷德芬给我们介绍一下地球内核的情况吧。

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.

所以随着时间的推移,地球开始冷却。在地球冷却的过程中,地球中心的位置,也是最高压点,的温度降到了铁的结晶点,也就是铁的冻结点,因此地心的铁开始凝结。这样在地球中心位置的铁心的体积开始变大。

Alice:I'm a bit worried that the Earth is freezing in the middle!

地心在冻结,这使我很担心!

Rob: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.

别担心,爱丽丝!由于地心处的极高压力,铁的凝固点高达6000度!在过去的十亿年里,那里的铁的降温凝结速度仅仅是每年半毫米。

Alice:Ah well, yes, that sounds like slow progress.

啊,那听起来确实很慢。

Rob: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。那么我们继续,我们还应该提到的是产生磁场的是地球液态的外核,正是有了磁场我们人类才得以在地球上生存。让我们听一下这方面更多的内容。

Deuss: Well, the magnetic field is very important because it protects us against cosmic radiation so that's one really...

磁场十分重要,因为它保护我们不受宇宙辐射,它十分……

Bragg: How does it do that?

它如何保护我们?

Deuss: 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.

它会产生一层屏障,这层屏障可以折射从太阳射到地球表面的宇宙射线。所以它能保护我们。

Bragg: So it goes up there…

所以射线都在地球上层。

Deuss: Yeah, so you would see that the radiation kind of goes right into 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。

Alice: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!

所以地球周围有一个磁场,它保护我们不受太阳的宇宙射线辐射。我想要我的周围也有一个磁场,它就成了我的超能力——像《X战警》里那样。

Rob: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。磁圈就是地球周围能够感受到磁场的范围。它保护我们不受辐射,并保证了粒子的流向。如果没有它,这些粒子将会脱离地球周围的大气层。

Alice:Right, I see. And what does 'radiation' mean?

我明白了。那么辐射又是什么?

Rob:Well, radiation means heat or energy or particles in the form of rays – in this case, the Sun's rays.

辐射是指热、能量或者粒子以射线的形式呈现——这里就是太阳射线。

Alice:OK. And 'deflect'?

哦,那折射呢?

Rob:To deflect means to make something change direction.

折射就是使某物改变路径。

Alice: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。接下来,罗伯,你记得吗?节目的开始我问你太阳的内核有多大?和以下哪一个体积相当:a)月球 b)木星 c)火星。

Rob:Yes, and I had a wild guess and I said c) Mars.

记得,我猜的是c)火星。

Alice: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?

是的。恐怕你猜错了罗伯。答案是a)月球。你想要表现一下,告诉我们今天都学到了哪些单词吗?

Rob:Of course. Good idea. We heard:

当然。好主意。我们听到了:

core

dense

稠密

crust

地壳

mantle

地幔

silicate

硅酸盐

molten

熔化的

magnetosphere

磁层

strip away

偏离

radiation

辐射

deflect

折射

Alice: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.Bye.

是的,谢谢你罗伯。那么,今天的英语六分钟就要结束了。我希望你们喜欢今天学到的核心词汇。请收听我们的下次节目。再见。

来自:VOA英语网 文章地址: http://www.tingvoa.com/html/20170403/450841.html