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托福TPO-03 Lecture 4

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Listen to part of a lecture in an astronomy class.

听下面天文课程讲座的一部分。
Now astronomy didn't really bloom into the science it is today until the development of spectroscopy.
现在天文学直到光谱学得以发展才真正发展成为今天的科学。
Spectroscopy is basically the study of spectra and spectral lines of light,
而光谱学基本上是研究光的光谱和光谱线,
and specifically for us,the light from stars.
以及专门我们而言,来自恒星的光。
It makes it possible to analyze the light emitted from stars.
它可以分析来自恒星发出的光。
When you analyze this light, you can figure out their distance from the earth, and identify what they are made of, determine their chemical composition.
当你分析这道光,你可以计算出它们和地球的距离,并确定其组成成分及化学成分。
Before we get into that though, it's probably a good thing to back up a bit.
但在我们深入之前,温习一下上节课的内容可能也不错。
You all know how when you take a crystal prism and pass a beam of sunlight through it, you get a spectrum,
你们都知道当你用一个水晶棱镜并让一束阳光穿过,你就得到一个谱,
which looks like a continuous band of rainbow colors.
它看上去就像一条彩虹般连续的颜色组合带。
The light that we see with our human eyes as a band of rainbow color falls in a range of what's called visible light.
而我们通过人类的肉眼所看到的彩虹颜色组合光是被成为可见光的范围。
And visible light spectroscopy is probably the most important kind of spectroscopy.
而可见光光谱可能是光谱学最重要的一类。
Anyone want to take a stab at the scientific term for visible light?
有没有人想要尝试用科学术语定义下可见光?
And I'm sure all of you know this because you all did the reading for today.
我肯定所有人都知道,这是因为你们每人都为今天做了温习。
Optical radiation.
光学辐射。
But I thought being exposed to radiation is dangerous.
但我认为暴露于辐射中是危险的。
Yes, and no.
是的,没有。
If you are talking about radiation, like in the element Uranium, yeah, that's dangerous.
如果你在谈论辐射,比如铀元素,是的,那是危险的。
But radiation as a general term actually refers to anything that spreads away from its source.
但是作为总体术语的辐射实际上指的是从其源头发散出的任何物质。
So optical radiation is just visible light energy spreading out.
所以光学辐射只是可见光能量的传播。
OK, so we've got a spectrum of a beam of sunlight and it looks like the colors bleed into each other.
好的,所以我们现在这束太阳光的光谱,看起来颜色已经互相融合。
There are no interruptions,
没有间断,
just a band flowing from violet to green, to yellow, to… you get the idea.
只是一种从紫色到绿色,黄色的色带…你懂的。
Well, what happens if the sunlight's spectrum is magnified?
嗯,如果放大太阳光光谱会发生什么?
Maybe you all didn't do the reading.
也许你们所有人都没有提前读书。
Well, here's what you'd see.
嗯,这就是你会看到的。
I want you to know this that this spectrum is interrupted by dark lines called spectral lines.
我想让你们注意到的是这一光谱是被叫做光谱线的暗线所打断。
If you really magnify the spectrum of the sunlight, you could identify more than 100,000 of them.
如果你真的放大太阳光的光谱,你可以分辨出多达10万条的光谱线,
They may look like kind of randomly placed,
它们或许看起来是随机分布,
but they actually form many distinct patterns.
但实际上有很多不同的模式,
And if you were looking at the spectrum of some other star, the colors would be the same.
如果你看一些别的恒星的光谱,颜色会是一模一样的,
But the spectral lines would break it up at different places, making different patterns.
但是这些光谱线会在不同的地方断裂,形成不同的模式。
Each pattern stands for a distinct chemical element, and so different sets or patterns of spectral lines mean that the star has a different chemical composition.
每种模式代表着特别化学元素,而光谱线这样不同的属性和模式意味着这个恒星有着不同的化学组成。
So how do we know which spectral patterns match up with which elements?
我们如何了解哪个光谱模式对应于哪种元素?
Well, a kind of spectroscopic library of elements was compiled using flame tests.
一种光谱线库通过火焰测试累积起来。
A known element, say a piece of iron for example, is heated in a pure gas flame.
比如铁这种熟悉的元素在纯净的气体火焰中加热,
The iron eventually heats to the point that it radiates light.
最终铁被加热到一个点,辐射出光。
This light is passed through a prism, which breaks it up into a spectrum.
这道光通过棱镜被打断形成光谱。
And a unique pattern, kind of like a chemical fingerprint of spectral lines for that element appears.
而一种独一无二的模式,类似于那种元素指纹的化学光谱显现出来。
This process was repeated over and over again for many different elements,
对于许多不同的元素而言,这个过程一遍又一遍地重复,
so we can figure out the chemical makeup of another star by comparing the spectral pattern it has to the pattern of the elements in the library.
所以通过比较它的光谱模式与库里元素的光谱模式,我们能够弄清另一个恒星的化学组成,
Oh, an interesting story about how one of the elements was discovered through spectroscopy.
哦,这里有个有趣的故事是关于一个元素是如何通过光谱被发现的。
There was a pretty extensive library of spectral line patterns of elements even by the 1860s.
即使是在1860年,就已经存在一个强大的元素光谱模式库了。
A British astronomer was analyzing a spectrograph of sunlight, and he noticed a particular pattern of spectral lines that didn't match anything in the library.
一位英国天文学家在分析太阳光的光谱时注意到一种特殊的光谱线模式与库里的任何模式都不匹配。
So he put two and two together, and decided there was an element in the sun that hadn't been discovered here on the earth yet.
于是他两两组合对比,并确定有太阳上的一种元素在地球上还未被发现。
Any guesses about what that element is?
有人能猜出是哪种元素吗?
It actually turned out to be pretty common and I'm sure all of you know it.
实际上它很普通,我肯定你们都认识。
OK. Let's try something else.
好的,我们换个角度来试试。
Any of you happened to be familiar with the Greek word for sun by chance?
你们有人碰巧知晓太阳在希腊语里的说法吗?
Something like Helius or something like that.
可能是helius ,或者类似的。
Oh it must be Helium.
哦,肯定是Helium。
So you are saying that Helium was discovered on the sun first.
你是说氦是首先在太阳中被发现的。
Yes, and this is a good example of how important spectroscopy is in astronomy.
是的,这是光谱学在天文学中何等重要的一个显著例子。

重点单词   查看全部解释    
band [bænd]

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n. 带,箍,波段
n. 队,一群,乐队

 
distinct [dis'tiŋkt]

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adj. 独特的,不同的,明显的,清楚的

联想记忆
fingerprint ['fiŋgə.print]

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n. 指纹,特点 vt. 取 ... 的指纹,鉴别特征

 
determine [di'tə:min]

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v. 决定,决心,确定,测定

联想记忆
astronomy [əst'rɔnəmi]

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n. 天文学

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astronomer [ə'strɔnəmə]

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n. 天文学家

 
figure ['figə]

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n. 图形,数字,形状; 人物,外形,体型
v

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beam [bi:m]

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n. 光线,(光线的)束,(横)梁,桁条
vt

 
rainbow ['reinbəu]

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n. 彩虹
adj.五彩缤纷的

 
unique [ju:'ni:k]

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adj. 独一无二的,独特的,稀罕的

联想记忆

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