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  • The city sky is, frankly, rather boring.

    說實話,城市的天空,還滿無聊的。

  • If you look up at the patches of murk between buildings,

    如果你抬頭看看建築物間的小塊夜空,

  • you might be able to pick out The Big Dipper,

    你或許能找出北斗七星,

  • or perhaps, Orion's Belt.

    或者是獵戶座腰帶。

  • But hold on.

    不過等等,

  • Look at that murky patch again and hold out your thumb.

    再仔細看看那片黑夜, 伸出你的大拇指,

  • How many stars do you think are behind it?

    你覺得你蓋住了多少恆星?

  • Ten, twenty? Guess again.

    十顆?二十顆?再猜一猜。

  • If you looked at that thumbnail-sized patch of sky

    如果你用哈勃天文望遠鏡

  • with the Hubble Space Telescope,

    去看那片拇指大小的天空,

  • instead of points of light, you'd see smudges.

    你不會看到許多小亮點, 而是看到一團團光暈。

  • These aren't stars.

    而這些光暈不是恆星,

  • They're galaxies, just like our Milky Way.

    它們是星系,就像我們的銀河系一樣,

  • Cities of billions of stars,

    每個都是好幾十億恆星的群落,

  • and more than 1,000 of them are hidden behind your thumb.

    在你大拇指底下,就有超過一千個星系。

  • The universe is bigger than you can see from the city,

    宇宙的規模比你從城市裡所見的還要巨大,

  • and even bigger than the starry sky you can see from the countryside.

    甚至比你從鄉間所望見的星空還要浩瀚。

  • This is the universe as astrophysicists see it,

    這就是天文物理學家眼中的宇宙,

  • with more stars than all the grains of sand on Earth.

    裡面的恆星比地球上的沙粒還要多。

  • By staring up at the stars at night,

    每當你在夜晚仰望星空時,

  • you've taken part in the oldest science in human history.

    你實際上是在參與人類史上最古老的科學活動。

  • The study of the heavens is older than

    天文研究在人類史上

  • navigation, agriculture, perhaps even language itself.

    比航海、農業、可能比語言的存在還要古老。

  • Yet unlike other sciences, astronomy is purely observational.

    但不像其他科學,天文學的基礎完全只憑觀測。

  • We cannot control the parameters of our experiments from lab benches.

    我們無法在實驗室控制任何變因或參數。

  • Our best technology can send man to the moon,

    用最尖端的科技,我們可以送人類上月球

  • and probes to the edge of the solar system.

    並探勘太陽系的邊界,

  • But these distances are vanishingly small

    但比起星辰間的無垠地帶,

  • compared to the yawning gulfs between stars.

    人類所能探觸的距離簡直微不足道。

  • So how can we know so much about other galaxies,

    所以我們怎麼獲得大量其他星系的知識呢?

  • what they're made of, how many there are, or that they're even there at all?

    我們怎麼知道它們的成分、數量, 甚至確定它們存在?

  • Well, we can start with the first thing we see when we look up at night: the stars.

    好吧,我們可以先從仰望天空 最先看到的東西開始:星星。

  • What we are trying to learn is their properties.

    我們試著了解它們的特質。

  • What are they made of? How hot are they? How massive? How old?

    它們的成分是甚麼?溫度多高? 規模多大?存在了多久?

  • How far are they from Earth?

    它們離地球的距離有多遠?

  • And believe it or not,

    信不信由你,

  • we can learn all of these things simply from the light shining in the sky.

    這些答案都可以從星星發出的光芒推算出來。

  • We can decipher one kind of stellar message by turning starlight into rainbows.

    我們將這些星光轉換為彩虹光譜, 就可以破解這些星辰背後的秘密。

  • When you look at a rainbow on Earth,

    當你在地球上看到彩虹的時候,

  • you're really looking at light from our Sun

    其實你看到的是太陽所發出的光,

  • being scattered through water droplets in the atmosphere

    被大氣層的水珠折射後所散發的光譜,

  • into all the different wavelengths that make it up.

    水珠將光線分散成不同的波長,形成彩虹。

  • And we study the light from other stars,

    所以當我們分析其他星球的光芒時,

  • we can create rainbows on demand using not water droplets,

    我們可以自己將它變成彩虹,但不是用水珠,

  • but other specific instruments that disperse light.

    是用其他分散光譜的儀器。

  • When we look at the scattered light from our sun,

    當我們仔細觀察太陽光的彩虹光譜時,

  • we see something strange: dark lines in our rainbow.

    有個奇怪的現象:彩虹光裡有一些黑線。

  • These lines are the characteristic fingerprints of atoms.

    這些黑線就像指紋一樣,是原子的特有的波紋。

  • Each type of atom in the solar atmosphere soaks up light at specific wavelengths,

    在大氣層中, 每一種原子只會吸收某段特定波長的光,

  • and the amount of absorption depends on how many of these atoms there are.

    這些波長的光被吸收的量, 取決於該原子數量的多寡。

  • So by observing how much light is missing at these characteristic wavelengths,

    所以如果我們觀察在這個特定波長裡, 有多少光不見了,

  • we can tell not only what elements are in the Sun's atmosphere,

    我們不只可以推斷出 太陽系大氣層裡有哪些元素,

  • but even their concentrations.

    甚至還可以推算出元素所占的比例。

  • And the same idea can be applied to study other stars.

    同樣的方法也可運用於其他恆星:

  • Make a spectral rainbow, see what's missing,

    將恆星的彩虹光譜分析出來, 看看裡面缺少那些波段,

  • and figure out which elements are present.

    就可推算出有那些元素的存在。

  • Bingo. Now you know what stars are made of.

    太好了,現在你知道恆星的成分了。

  • But we aren't restricted to just the wavelengths that our eyes perceive.

    儘管我們眼睛的可見光有限, 我們並不會被此限制,

  • Consider radio waves.

    試想,還有無線電波呢。

  • Yes, they can bring the Billboard Top 100 to your car,

    是的,無線電波可以讓你 在車上聽廣播金曲排行榜,

  • but they can also travel almost unimpeded through space.

    但這種波也可以在太空中自由傳遞,

  • Because they've come so far,

    而因為它們是從太空中非常遠的地方傳來,

  • radio waves can tell us the very early history of the universe,

    無線電波可以告訴我們宇宙非常早期的歷史,

  • from just a few thousand years after The Big Bang.

    甚至可以追朔到 宇宙大爆炸後僅幾千年的時間。

  • We can also study the infrared light, emitted by colder objects,

    我們也可以研究其他比較冷的物體 所發出來的遠紅外線,

  • like the gas and dust clouds in space,

    像是太空中的氣體和塵雲,

  • and the ultraviolet light from the hot stars recently born from those clouds.

    也可以觀察剛誕生的、 比較熱的恆星所發出來的紫外線光。

  • Studying different wavelengths not only gives us

    研究不同的波長,不但可以讓我們

  • a more complete picture of any single object

    對一個物體有更全面的了解,

  • but also different views of the universe.

    也可以讓我們對宇宙有不同的認識。

  • For this reason, astrophysicists use several different kinds of telescopes

    因此,天文物理學家運用了幾種不同的望遠鏡,

  • covering the spectrum from the infrared to the ultraviolet to the X-ray,

    好讓他們可以完整觀察各種光線, 包含遠紅外線、紫外線和X光射線,

  • from giant radio dishes to giant silver mirrors to space satellites,

    接收的媒介包含巨型的無線電接收器、 反射鏡和人造衛星,

  • detecting light that would be otherwise blocked by the Earth's atmosphere.

    這些可以偵測到 原本地球大氣層收不到的東西。

  • Astrophysicists don't just see

    天文物理學家不只可以看見

  • the billions of stars among the billions of galaxies in the universe.

    宇宙中好幾十億的星系中好幾十億的恆星,

  • They hear, feel and sense them through many channels,

    他們也可以透過各種媒介聽見、 觸及、感覺到這些星球的存在。

  • each revealing a different story.

    每一個恆星都訴說著不同的故事。

  • But it all begins with light, the kind we can see and the kind we can't.

    但這一切都是從光開始的, 有些光我們看得見,有些我們看不見。

  • Want to know the secrets of the Universe?

    想知道宇宙的祕密嗎?

  • Just follow the light.

    就追隨光吧。

The city sky is, frankly, rather boring.

說實話,城市的天空,還滿無聊的。

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B1 中級 中文 美國腔 TED-Ed 恆星 彩虹 天文 波長 光譜

【TED-Ed】我們如何判讀星辰 - (How do we study the stars? - Yuan-Sen Ting)

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    稲葉白兎 發佈於 2015 年 03 月 10 日
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