科学美国人60秒 为望远镜建造更好的镜面

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To study the heavens, it's all about the photons. "We in astronomy are always greedy. We want every photon we can collect." Drew Phillips, astronomer¹ at University of California Observatories². More photons, he says, basically means more science about incredibly faint, distant objects.

研究天空，就是研究光子。“研究天文学的人都很贪婪，因为我们总是奢望能收集到每一个光子。”加州大学天文台的天文学家德鲁·菲利普斯如是说。他所说的想要收集更多光子，基本上意味着收集关于那些极其微弱且遥远的物体更多科学信息。

And that's where the optics problem comes in. Because incoming light reflects off several mirrors before it comes out the business end of a telescope. And mirrors aren't perfectly³ reflective. The traditional mirror coating, aluminum⁴, reflects only about 90 percent of light. Bounce that light around a few times in a telescope, and you lose valuable photons.

就是这样才引发了光学问题的出现。因为入射光在射出望远镜的尖端之前，会反射出好几个镜面。而镜面却无法完全反射。传统镜面镀膜的材质是铝，它只能反射90%的光。光线在望远镜里来回反射几次，就会失去有价值的光子。

"The throughput, the actual number of photons that are detected in the end in a modern spectrograph, you're doing good if you get thirty percent."

“在现代光谱仪中最终能检测到的光子数量能达到30%就已经很不错了。”

So you want the most reflective material for your mirrors. Like silver, which reflects 97 to 99 percent of visible and infrared⁵ light, respectively. Big improvement over aluminum. But silver's got problems too. "It is finicky. It's subject to tarnish⁶, and oxidation, and corrosion⁷."

因此我们需要反射能力最好的材质来做镜面。比如银，它能分别反射97%的可见光和99%的红外光。比铝的反射率要高出许多。但银也有它的问题。“它很难掌控，易于失去光泽、被氧化和腐蚀。”

So Phillips and his team have borrowed a trick from the computer industry, called atomic layer deposition⁸. The technique allows them to take a silver-coated mirror—and coat it with extremely uniform layers of transparent⁹ aluminum oxide¹⁰, to protect against corrosion.

因此，菲利普斯和他的团队借用了计算机行业中的一个技巧，即“原子层沉积”技术。这种技术可以让他们采用镀银镜，并为其涂上极其均匀的透明氧化铝层，以防止其被腐蚀。

And unlike the small-scale atomic deposition used in the electronics industry, this new machine--recently installed in a lab at U.C. Santa Cruz—is scaled up to coat mirror segments up to a meter in diameter. Meaning you could coat all 500 mirrors of a state-of-the-art telescope—like the planned Thirty Meter Telescope—in a matter of months.

与电子工业中使用的小规模原子沉积不同，最近安装在加州大学圣克鲁兹分校的实验室里的这台新机器，镜面被放大到直径为一米。也就是说，你可以在短短几个月内，将一台最先进的望远镜——比如那台30米长的望远镜中的500个镜面全部涂上一层透明氧化铝层。

When put to use, these better mirrors might allow astronomers¹¹ to capture more photons… and shed more light—literally—on faraway galaxies¹² and stars.

如果它被投入使用，天文学家将能够利用这些更优质的镜面采集到遥远的星系和恒星上的更多光子，并分出更多光线发现更多奥秘。

1 astronomer   

n.天文学家

参考例句：

• A new star attracted the notice of the astronomer.新发现的一颗星引起了那位天文学家的注意。
• He is reputed to have been a good astronomer.他以一个优秀的天文学者闻名于世。

2 observatories   

n.天文台，气象台( observatory的名词复数 )

参考例句：

• John Heilbron, The Sun in the Church: Cathedrals as Solar Observatories, 3-23. 约翰．海耳布隆，《教会里的太阳：教堂即太阳观测台》，第3-23页。 来自互联网
• Meteorologists use satellites, land observatories and historical data to provide information about the weather. 气象学家使用卫星、上天文台和历史资料来提供有关天气的信息。 来自互联网

3 perfectly   

adv.完美地，无可非议地，彻底地

参考例句：

• The witnesses were each perfectly certain of what they said.证人们个个对自己所说的话十分肯定。
• Everything that we're doing is all perfectly above board.我们做的每件事情都是光明正大的。

4 aluminum   

n.(aluminium)铝

参考例句：

• The aluminum sheets cannot be too much thicker than 0.04 inches.铝板厚度不能超过0.04英寸。
• During the launch phase,it would ride in a protective aluminum shell.在发射阶段，它盛在一只保护的铝壳里。

5 infrared   

adj./n.红外线(的)

参考例句：

• Infrared is widely used in industry and medical science.红外线广泛应用于工业和医学科学。
• Infrared radiation has wavelengths longer than those of visible light.红外辐射的波长比可见光的波长长。

6 tarnish   

n.晦暗，污点；vt.使失去光泽；玷污

参考例句：

• The affair could tarnish the reputation of the prime minister.这一事件可能有损首相的名誉。
• Stainless steel products won't tarnish.不锈钢产品不会失去光泽。

7 corrosion   

n.腐蚀，侵蚀；渐渐毁坏，渐衰

参考例句：

• Corrosion is not covered by the warranty.腐蚀不在保修范围之内。
• Zinc is used to protect other metals from corrosion.锌被用来保护其他金属不受腐蚀。

8 deposition   

n.免职，罢官；作证；沉淀；沉淀物

参考例句：

• It was this issue which led to the deposition of the king.正是这件事导致了国王被废黜。
• This leads to calcium deposition in the blood-vessels.这导致钙在血管中沉积。

9 transparent   

adj.明显的，无疑的；透明的

参考例句：

• The water is so transparent that we can see the fishes swimming.水清澈透明，可以看到鱼儿游来游去。
• The window glass is transparent.窗玻璃是透明的。

10 oxide   

n.氧化物

参考例句：

• Oxide is usually seen in our daily life.在我们的日常生活中氧化物很常见。
• How can you get rid of this oxide coating?你们该怎样除去这些氧化皮？

11 astronomers   

n.天文学者，天文学家( astronomer的名词复数 )

参考例句：

• Astronomers can accurately foretell the date,time,and length of future eclipses. 天文学家能精确地预告未来日食月食的日期、时刻和时长。 来自《简明英汉词典》
• Astronomers used to ask why only Saturn has rings. 天文学家们过去一直感到奇怪，为什么只有土星有光环。 来自《简明英汉词典》

12 galaxies   

星系( galaxy的名词复数 )； 银河系； 一群（杰出或著名的人物）

参考例句：

• Quasars are the highly energetic cores of distant galaxies. 类星体是遥远星系的极为活跃的核心体。
• We still don't know how many galaxies there are in the universe. 我们还不知道宇宙中有多少个星系。