Name: 探索抽象的黑暗天空(In Search of Pure Dark Skies)
Uploaded: 2013-04-08T10:43:37.000Z
Duration: 5 min 55 s

Cloudy skies may be nice from an artistic point of view, but clouds are an astronomer's

從藝術的角度來看，陰天可能是不錯的，但云是天文學家'的。

nightmare. And while illuminated cities are a night-time

噩夢。而燈火通明的城市雖然是一個夜間的

beacon of modern civilization, bright night skies are also a no-go zone for world-class

現代文明的燈塔，明亮的夜空也是世界級的禁區。

So, in the pursuit of pristine skies, ESO, the European Southern Observatory operates

所以，為了追求純淨的天空，歐洲南方天文臺（ESO）營運著

its telescopes far beyond Europe, in the remote and arid landscape of the Atacama Desert in

它的望遠鏡遠在歐洲之外，在阿塔卡馬沙漠的偏遠和乾旱地區。

A top-class site for astronomical observations must meet several criteria. To begin with,

一個一流的天文觀測點必須符合幾個標準。首先：

of course, you need a sky that is free of clouds pretty much all year round. But in

當然，你需要一個一年四季幾乎都沒有云的天空。但在

addition to that, you also need excellent atmospheric conditions, as well as very dry

除此之外，你還需要優良的大氣條件，以及非常乾燥的環境。

air with as little water vapor content as possible. And this is exactly the kind of

儘可能少的水蒸氣含量的空氣。而這正是一種

environment that you find in the Atacama Desert in Chile.

在智利阿塔卡馬沙漠中發現的環境。

The Chilean Coast Range. Here, the cold offshore Humboldt current creates a coastal inversion

智利海岸山脈。在這裡，洪堡近海寒流形成了海岸逆流。

layer of cool air, which prevents rain clouds from developing. Often, a layer of fog is

一層冷空氣，可以防止雨雲的發展。通常，一層霧是

created, which rapidly disperses in the foothills above the desert. A view from the Paranal

在沙漠上方的山腳下迅速散開。從巴拉那爾看

Observatory towards the Pacific Ocean clearly shows the top of the cloud layer.

朝向太平洋的天文臺清楚地顯示出雲層的頂部。

Chilean coastal range Coastal clouds gathering at the foothills. In addition to the coastal

智利沿海山脈 沿海雲霧在山腳下聚集。除了沿海地區的

inversion layer, a region of high pressure in the south-eastern Pacific Ocean creates

反轉層，在東南太平洋的高壓區形成了 "反轉層"。

circulating winds, forming an anticyclone, which helps to keep the climate of the Atacama

循環風，形成反氣旋，這有助於保持阿塔卡馬地區的氣候。

The Andes lie to the east, acting as a natural barrier for clouds coming from this direction

安第斯山脈位於東部，對來自這個方向的雲層起到了天然的屏障作用。

- so all the possible paths for moisture to reach the Atacama Desert are literally blocked.

- 所以所有水分到達阿塔卡馬沙漠的可能途徑都被封鎖了。

This results in extremely dry air and clear blue skies. Ideal conditions for astronomical

這就導致空氣極為乾燥，藍天白雲。是進行天文觀測的理想條件。

But we're not done yet with our checklist of ideal observing conditions. In addition

但我們'還沒有完成理想觀測條件的清單。此外

to cloudless and dry skies, astronomers need dark sites and unpolluted air in order to

到無雲和乾燥的天空，天文學家需要黑暗的場地和無汙染的空氣，以

make the best observations. In most places, the world at night is far from being a dark

做出最好的觀察。在大多數地方，夜晚的世界遠不是一個黑暗的地方

place and the light pollution caused by modern civilization can easily be spotted. However,

地方和現代文明造成的光汙染很容易被發現。然而。

light pollution hinders astronomical observations, as it brightens the night sky and makes faint

光汙染妨礙了天文觀測，因為它使夜空變亮，使微弱的

Only in places that are far from any cities - like some regions in the Atacama Desert

只有在遠離任何城市的地方--比如阿塔卡馬沙漠的一些地區。

- is the night sky pitch- black. Furthermore, because Chile's cities are relatively far

- 是夜空漆黑。此外，由於智利的城市相對較遠。

apart, the air in the Atacama Desert is almost completely free of pollutants and is extraordinarily

此外，阿塔卡馬沙漠的空氣幾乎完全沒有汙染物，而且是特別的

Now, astronomical observations are disturbed by the turbulent motions of pockets of air

現在，天文觀測受到了空氣袋的湍流運動的干擾

in the atmosphere. Essentially this turbulence blurs our images of the night sky. In addition,

在大氣中本質上，這種湍流模糊了我們對夜空的印象。此外，

the atmosphere also absorbs and scatters light. In order to minimize these effects an observatory

大氣層也會吸收和散射光線。為了將這些影響降到最低，一個天文臺

should be located in an area with a calm atmosphere above it and on top of a high mountain, in

應位於上方氣氛平靜的區域，並位於高山之巔，在

order to reduce the amount of atmosphere between your telescope and the stars. Once again,

以減少您的望遠鏡和星星之間的大氣量。再次強調：

the high-altitude of Atacama Desert fits this description perfectly.

高海拔的阿塔卡馬沙漠完全符合這一描述。

The Atacama Desert offers many sites at high altitude, ranging from extended plateau in

阿塔卡馬沙漠提供了許多高海拔地區的景點，從延伸的高原到高海拔地區，再到高海拔地區。

the Altiplano highlands to high mountain tops close to the Pacific Coast. The Chajnantor

從阿爾蒂普拉諾高原到靠近太平洋海岸的高山之巔。查伊南托爾

plateau, at an altitude of 5000 meters, offers ideal conditions for observing in the millimeter

海拔5000米的高原，為毫米級的觀測提供了理想的條件。

and submillimeter wavelength domain. This is where ESO, together with its partners,

和亞毫米波域。這也是歐空局與其合作伙伴一起：

has chosen to construct the Atacama Large Millimeter/submillimeter Array, or ALMA for

已選擇建造阿塔卡馬大毫米/亞毫米陣列，即ALMA。

short. At such high altitudes there is very little water vapor in the air and the disturbing

短。在這樣的高空，空氣中的水蒸氣很少，而擾人的

effects of the atmosphere are kept to a minimum.

大氣層的影響保持在最低限度。

Cerro Paranal is an isolated mountain top in the Atacama Desert, only 12 kilometers

Cerro Paranal是阿塔卡馬沙漠中一座與世隔絕的山頂，距離阿塔卡馬沙漠只有12公里。

inland from the Pacific Coast. This is the home of ESO's Very Large Telescope, which

在太平洋海岸的內陸。這裡是ESO'超大型望遠鏡的所在地。

makes good use of Cerro Paranal's approximately 320 cloud-free nights each year.

充分利用Cerro Paranal'每年約320個無雲之夜。

Further inland, within sight of Paranal, another mountain has been identified as an ideal place

再往內陸走，在帕拉納爾的視線範圍內，另一座山已被確定為理想的地方。

to conduct astronomical observations: Cerro Armazones. This will be the future site of

以進行天文觀測。Cerro Armazones。這將是未來的天體觀測點。

ESO's Extremely Large Telescope, or the E-ELT, for short.

ESO'的超大型望遠鏡，簡稱E-ELT。

The Mars-like landscape of the Atacama Desert is really a wonderful gift of nature. Its

阿塔卡馬沙漠火星般的地貌，實在是大自然的奇妙饋贈。它的

unique climate makes it a first-class location for ESO's powerful telescopes so that night

獨特的氣候使它成為歐洲南方天文臺強大的望遠鏡的第一流的位置，是以，夜間

after night ESO's astronomers can observe the crystal clear skies. This is Dr J signing

夜晚後，ESO'的天文學家可以觀察到晶瑩剔透的天空。這是J博士的簽名

off for the ESOcast. Join me again next time for another cosmic adventure.

關閉ESO廣播。下次再和我一起參加另一場宇宙冒險。