RE5 Unit 10A · COSMIC DAWN (宇宙黎明)

Reading 10A · COSMIC DAWN (宇宙黎明)

智利阿塔卡马高原上的ALMA射电巨眼，如何看透冰冷尘埃云探索恒星与生命的起源？

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many cities reveals the secrets of the universe.

在智利北部阿塔卡马沙漠的高处，矗立在一个海拔5000米、狂风呼啸的高原之上，坐落着人类有史以来建造的最雄心勃勃的科学仪器之一。它被命名为ALMA——即“阿塔卡马大型毫米波/亚毫米波阵列”。这座跨国天文台由66面超高精度的射电天线组成，彼此协同运作，宛如一台口径等同于整座高原的巨型单体望远镜。

An eye on the heavens, telescopes have come a long way since the first ones were invented

early in the 17th century.

Traditional telescopes allow astronomers to view objects in space thanks to the visible light

those objects emit or reflect.

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objects in space.

传统的光学望远镜只能探测人类肉眼可见的光线——这仅仅占据了整个电磁波谱中微不足道的一小截。然而，宇宙中的浩瀚天体大多深藏在厚重、冰冷的星际气体与宇宙尘埃云雾之后，可见光根本无法穿透分毫。ALMA通过调谐锁定毫米波与亚毫米波射电频段，成功看穿了这些宇宙帷幕；正是这些低温气体与尘埃云，在不断孕育着崭新的恒星与行星系统。

Extremely hot objects, such as stars, emit not only visible light but also high-energy

gamma radiation.

Specialised telescopes, such as NASA's Space-based Chandra X-ray Observatory, are built to detect

such radiation.

Cold objects, like comets and asteroids, emit low energy radiation, which is invisible

to the naked eye.

Much of the universe is even colder than this.

The clouds of dust and gas, of which stars are made, are only slightly warmer than absolute

zero.

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To capture images of cold objects, astronomers use radio telescopes.

为ALMA寻觅最完美的落成台址耗费了天文学家数十载光阴。来自遥远深空的毫米波辐射极其微弱，极易被地球大气层中的水蒸气吸收、扭曲失真。为了获得水晶般澄澈的高信噪比观测数据，望远镜必须安置在一处海拔极高、且处于全球最干燥腹地的绝佳区位。阿塔卡马沙漠的查赫南托高原完美契合了所有严苛到极致的苛求标准。

A radio telescope is a device that typically uses a large dish antenna to collect the low

energy radiation emitted by objects in space.

In the 1960s, astronomers started using them to view asteroids, planets, comets and other

objects.

However, it was challenging to get a clear image of those objects using ground-based antennas

because low energy radiation is absorbed and distorted by water vapour in the Earth's atmosphere.

The signal that a dish antenna on the ground finally receives is therefore weak.

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And it can be made even stronger by arranging several antennas in an array, combining their

在海拔5000米的极限环境下作业面临着难以想象的生理极限挑战。这里的空气含氧量仅为海平面的一半，工作人员必须随身携带便携式氧气瓶，并接受极为严格的心肺医学评估。在零下严寒、紫外线暴晒以及安第斯狂风的肆虐下操纵精密仪器，对工程耐久性提出了极致要求。绝大多数天文学家通常在位于较低安全海拔的运行支持基地，通过远程遥控指挥观测。

signals so that they function together as a single, more powerful telescope.

By the 1980s, several small arrays were operating in Japan, Europe and the United States.

Technological advances soon made much larger arrays possible, provided that a high flat

site could be found where the antennas could be set up.

And if the antennas were portable, the distance between them could be adjusted to change the

sensitivity of the telescope.

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Grouping the antennas closer together would have the effect of zooming out, which would

ALMA的运作原理并不像单面反射镜那样简单。它运用了前沿的“干涉测量技术（Interferometry）”。分布在各处的66面天线接收到的微弱无线电信号，被汇总汇聚并传输至一台被称为“ALMA相关器”的定制超级计算机进行毫秒级精准同步。这颗数字大脑每秒可处理高达1.7亿亿次运算，将零散的数据流无缝合成为具备惊人角分辨率的超高清宇宙深空图像。

be useful for capturing images of an object as large as a galaxy.

In the 1990s, astronomers began searching the world for the ideal place to set up a large

array of antennas.

The Perfect Location

One May morning, two small trucks passed through the quiet town of San Pedro in Chile's Atacama

Desert and headed up a mountainside.

It was 1994 and the men inside the trucks were trying to find the highest, driest, flattest

place on Earth.

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Now, guided by a map and a Chilean astronomer named to Hernan Quintana, they were searching

更为叹为观止的是，这些巨型天线并非固定死板，而是具备机动移动能力。依托特制的28轮超重型重载运输车，重达百吨的庞大碟形天线可在整座高平原上自如调配阵型。当天线群紧凑收拢在几百米范围内时，ALMA能捕捉蔓延数十光年的星际尘埃云全景；而当天线分散展开在长达16公里的超大阵列网络中时，它便能如显微镜般高倍聚焦新生太阳系内部的行星吸积盘。

for the Chajnon-Tor plateau.

At 5,000 meters, it is almost as high as the two base camps used by the climbers on Mount

Everest, Chamalungma.

The Atacama Desert is one of the driest places on Earth, with less than 1.2 centimeters

of rain a year on average.

The desert's remoteness and thin dry air make the area ideal for observing the night sky.

Astronomers from several countries were very interested in setting up observatories there.

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using the portion of the light spectrum that the human eye can see.

自全面投入科研运行以来，ALMA彻底颠覆了观测天体物理学。它首次直接拍摄到了原行星盘的真实高清图像——例如环绕幼年恒星金牛座HL周围，新生行星在尘埃盘中清道犁出的一道道清晰同心环暗纹。此外，它还在遥远恒星形成区的原始星云中，探测到了复杂的有机分子，这是生命诞生不可或缺的化学奠基基石。

Quintana and his companions were looking for a location to set up an array of dish antennas

for a large radio telescope.

Quintana felt that the Atacama Desert was likely the best possible place, but it wasn't easy

to get to.

The trip was slower and painful because the tyres kept getting stuck in the sand, remembers

Ricardo Giavenelli of Cornell University, one of the researchers who accompanied Quintana.

When they finally arrived, the group was not disappointed.

The sky was beautiful.

It was the deepest blue one can expect to see, remember Giavenelli.

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There was no doubt that somewhere nearby was the place.

通过凝视深邃虚空中横跨数百亿光年的遥远光芒，ALMA实际上在带领人类穿梭时空，回溯宇宙开天辟地的“宇宙黎明（Cosmic Dawn）”——那是大爆炸后数亿年间，第一缕恒星与星系相继点燃破晓的黄金纪元。潜心研究这些远古天体灯塔，科学家正一步步揭开人类最深邃的终极谜题：宇宙究竟是如何从一片混沌虚无的黑暗中，演化演变为今天我们所栖息的壮美大千世界？

One of the astronomers brought along an instrument to measure water vapour.

It was lower than any other place they had been.

News of the discovery inspired a cooperative effort among astronomers in the United States,

Europe and Japan.

Scientists in these countries began to realise that by working together, they could build

a larger and more powerful array than any one of them could alone.

In 1999, an agreement was signed to cooperate on a telescope project.

Assembling the array, it would take more than ten years to transform one of the world's

💡 审辩式思维 (Critical Thinking: Site Selection & Exploration)

1. What geological and meteorological conditions are required to host world-class astronomical observatories?

为何世界顶尖天文观测站（如ALMA、甚大望远镜VLT、凯克望远镜）无一例外选址于极高海拔的荒芜高原或火山顶端？

思维指引 (Sample Perspective):
• 空气稀薄与水汽微弱：海拔5000米的大气柱水汽含量不到海平面的几十分之一，能极大消除水分子对微弱宇宙微波的吸收与散射。
• 远离光污染与大气湍流：荒漠腹地常年万里无云（年均晴夜超300天），气流平稳，提供了全球无可比拟的超高清天体视宁度（Seeing）。

2. Is allocating billions of dollars to deep-space astronomy justifiable when Earth faces immediate socioeconomic crises?

观点思辨：在地球面临贫困、气候变暖与疾病困扰的当下，斥资数百亿美元建造超级深空望远镜是否合理？

思维指引 (Sample Perspective):
• 科技外溢效应：为了研发ALMA与射电干涉网，人类突破了超导受讯器、原子钟同步、千兆兆次边缘超算与极速WiFi算法（WiFi前身正是射电天文学副产品）；探索宇宙本质更维系着人类作为智慧生命的崇高好奇心与哲学归属感。

📝 课文理解深度练习 (Comprehension & Skills)

Reading Comprehension: Multiple Choice (P.205) Reading Comprehension: ALMA Architecture (P.206) Reading Skill: EHT Black Hole Collaboration (P.207)

预习练习得分: 0 / 19 题

Reading Comprehension Part A: Multiple Choice (P.205)

READING COMPREHENSION · MAIN IDEA

1. What is the main idea of the reading passage?

READING COMPREHENSION · DETAIL

2. Why can ALMA see objects that are completely invisible to conventional optical telescopes?

READING COMPREHENSION · INFERENCE

3. Why was the Chajnantor Plateau in Chile selected as the location for ALMA?

READING COMPREHENSION · DETAIL

4. What is the function of the ALMA Correlator supercomputer?

READING COMPREHENSION · DETAIL

5. Why are the antenna dishes designed to be moved by giant 28-wheel transporter vehicles?

READING COMPREHENSION · DETAIL

6. What major discovery was revealed in the famous ALMA image of the young star HL Tauri?

READING COMPREHENSION · VOCABULARY

7. The term 'Cosmic Dawn' in paragraph H refers to:

Reading Comprehension Part B: ALMA Architecture & Operations (P.206)