Part I
Professor: Now, astronomy didn't really bloom into the science it is today until the development of spectroscopy. Spectroscopy is basically the study of spectra and spectral lines of light, and specifically for us, the light from stars. It makes it possible to analyze the light emitted from stars. 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.
Before we get into that though, it's probably a good thing to back up a bit. You all know how when you take a crystal prism and pass a beam of sunlight through it, you get a spectrum, which looks like a continuous band of rainbow colors. 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.
一直到光谱学发展起来，天文学才真正进入今天的科学领域。
我们人用肉眼可以看到的彩虹色带的光，属于我们称作可见光范围。
1. bloom |blu:m|
verb. If someone or something blooms, they develop good, attractive, or successful qualities. 繁荣；兴盛；茁壮成长；变漂亮
E.g.: She bloomed into an utterly beautiful creature.
她出落得亭亭玉立。
2. spectral line
A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from emission or absorption of light in a narrow frequency range, compared with the nearby frequencies. Spectral lines are often used to identify atoms and molecules.谱线是在其他均匀且连续的光谱中的一条暗线或亮线，与附近的频率相比，是由于在较窄的频率范围内发射或吸收光而产生的。光谱线通常用于识别原子和分子。
3. emit |iˈmɪt|
verb. (formal) to send out sth such as light, heat, sound, gas, etc. 发出，射出，散发（光、热、声音、气等）
E.g.: Sulphur gases were emitted by the volcano.
硫磺气体由火山喷发出来。
4. prism|ˈprɪzəm|
noun.a transparent glass or plastic object, often with ends in the shape of a triangle, which separates light that passes through it into the colours of the rainbow 棱镜；三棱镜
E.g.: A soft body, with or without a head, a muscular foot - that's the mollusk.
柔软的身体, 有头或没头,强健的脚,这就是软体动物。
5. fall |fɔ:l|
verb. to belong to a particular class, group or area of responsibility 属于（某类、群体、责任范围）
E.g.: Out of over 400 staff there are just 7 that fall into this category.
400多个职员中只有7人属于这一类。
Part II
And visible light spectroscopy is probably the most important kind of spectroscopy. Anyone want to take a stabat the scientific term for visible light? And I'm sure all of you know this because you all did the reading for today.
Student: Optical radiation. But I thought being exposed to radiation is dangerous.
Professor: Yes, and no. If you are talking about radiation, like in the element Uranium, yeah, that's dangerous. But radiation as a general term actually refers to anything that spreads away from its source, so optical radiation is just visible light energy spreading out.
OK, so we've got a spectrum of a beam of sunlight and it looks like the colors bleed into each other. There are no interruptions, just a band flowing from violet to green, to yellow, to... you get the idea. Well, what happens if the sunlight's spectrum is magnified? Maybe you all didn't do the reading. Well, here's what you'd see. I want you to know this that this spectrum is interrupted by dark lines called spectral lines.
但是辐射作为一个通用术语实际上指的是任何从其源头散发传播出来的东西，所以光辐射只是可见光能量的散发传播。
可能你们都没看阅读材料吧。（可能老师课前已经要求学生看某些相关的阅读材料）
1. stab |stæb|
noun. (informal) an attempt to do sth 尝试；企图
E.g.: Countless people have had a stab at solving the riddle.
无数人试图解开这个谜。
2. radiation |ˌreɪdiˈeɪʃn|
noun. powerful and very dangerous rays that are sent out from radioactive substances 辐射；放射线
E.g.: a radiation leak from a nuclear power station
核电站的辐射泄漏
3. bleed|bli:d|
verb.to spread from one area of sth to another area 散开；渗开
E.g.: Keep the paint fairly dry so that the colours don't bleed into each other.
涂料尽量干一些，以免颜色相互渗透。
4. interruption |ˌɪntəˈrʌpʃn|
noun. something that temporarily stops an activity or a situation; a time when an activity is stopped 阻断物；中断时间
E.g.: The birth of her son was a minor interruption to her career.
她儿子的出生对她的事业造成一个小小的中断。
5. red 红, orange 橙, yellow 黄, green 绿, blue 蓝, indigo 靛, violet 紫
Part III
If you really magnify the spectrum of the sunlight, you could identify more than 100,000 of them. They may look like kind of randomly placed, but they actually form many distinct patterns. And if you were looking at the spectrum of some other star, the colors would be the same.
But the spectral lines would break it up at different places, making different patterns. 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.
Student: So how do we know which spectral patterns match up with which elements?
它们看起来可能像是随机放置的，但实际上它们形成了许多截然不同的图样。
每个图样代表一种不同的化学元素，因此不同的光谱线组或者图样就意味着那颗恒星有着不同的化学成分构成。
1. distinct |dɪˈstɪŋkt|
adj. clearly different or of a different kind 截然不同的；有区别的；不同种类的
E.g.: Jamaican reggae music is quite distinct from North American jazz or blues.
牙买加的雷盖音乐完全不同于北美的爵士乐或布鲁斯音乐。
Part IV
Professor: Well, a kind of spectroscopic library of elements was compiled using flame tests. A known element, say a piece of iron for example, is heated in a pure gas flame. The iron eventually heats to the point that it radiates light. This light is passed through a prism, which breaks it up into a spectrum. And a unique pattern, kind of like a chemical fingerprint of spectral lines for that element appears.
This process was repeated over and over again for many different elements, so we can figure out the chemical make-up of another star by comparing the spectral pattern it has to the pattern of the elements in the library.
一个已知的元素，例如一块铁，在纯气体火焰中加热，那块铁最终会加热到发出光的程度。它发出的这个光通过棱镜将其分解为光谱。一个独特的图样有点儿像是这个元素特有的谱线化学指纹一样，就会出现。
1. library |ˈlaɪbrəri|
noun. a collection of similar things (such as books or recordings) 类似事物的合集（例如书籍或录音）
E.g.: He has an impressive library of jazz records.
他有一个很厉害的爵士乐唱片合集。
2. compile |kəmˈpaɪl|
verb. to produce a book, list, report, etc. by bringing together different items, articles, songs, etc 编写（书、列表、报告等）；编纂
E.g.: We are trying to compile a list of suitable people for the job.
我们在努力编制一份适合做这项工作的人员名单。
3. say|seɪ|
verb.to suggest or give sth as an example or a possibility 比方说；假设
E.g.: Say you lose your job: what would you do then?
假设你把工作丢了，那你怎么办呢？
4. make-up
noun. the different things, people, etc. that combine to form sth; the way in which they combine 组成成分；构成方式
E.g.: the page make-up of a text (= the way in which the words and pictures are arranged on a page)
文本的版面设计
Part V
Oh, an interesting story about how one of the elements was discovered through spectroscopy. There was a pretty extensive library of spectral line patterns of elements even by the 1860s. 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. 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.
Any guesses about what that element is? It actually turned out to be pretty common and I'm sure all of you know it. OK. Let's try something else. Any of you happened to be familiar with the Greek word for “sun” by chance?
Student: Something like “Helius” or something like that. Oh, it must be “Helium”. So you are saying that Helium was discovered on the sun first.
Professor: Yes, and this is a good example of how important spectroscopy is in astronomy.
所以他据此推断了一下，确定太阳上存在一种地球上尚未发现的元素。
1. extensive |ɪkˈstensɪv|
adj. covering a large area; great in amount 广阔的；广大的；大量的
E.g.: She suffered extensive injuries in the accident.
她在事故中受了重伤。
2. put two and two together
to guess the truth from what you see, hear, etc. 根据所见所闻推断
E.g.: You weren't home so I put two and two together and went back to your office to find you.
你不在家，所以我猜你大概在办公室，就去那儿找你了。
3. chance|tʃɑ:ns|
noun.the way that some things happen without any cause that you can see or understand 偶然；碰巧；意外
E.g.: I met her by chance (= without planning to) at the airport.
我碰巧在机场遇见她。
4. hydrogen 氢， nitrogen 氮， oxygen 氧， chlorine 氯， fluorine 氟，helium 氦
