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  • The ancient Greeks had a great idea:

    古代希臘人有一個偉大的想法:

  • The universe is simple.

    宇宙是簡單的。

  • In their minds,

    在他們心中,

  • all you needed to make it were four elements:

    要建構宇宙只須要四種元素:

  • earth,

    土、

  • air,

    空氣、

  • fire,

    火、

  • and water.

    還有水。

  • As theories go, it's a beautiful one.

    就像它的理論一樣, 這是美麗的。

  • It has simplicity and elegance.

    既簡單、又優雅。

  • It says that by combining

    理論中認為

  • the four basic elements in different ways,

    藉由四種元素的不同組合,

  • you could produce all the wonderful diversity of the universe.

    可以產生宇宙萬物。

  • Earth and fire, for example,

    比如說土加火,

  • give you things that are dry.

    就會有一些乾的東西。

  • Air and water, things that are wet.

    而空氣加水,就會得到濕的東西。

  • But as theories go, it had a problem.

    但依照這理論, 會有一個問題。

  • It didn't predict anything that could be measured,

    它沒辦法預測出任何 可以測量的事物,

  • and measurement is the basis of experimental science.

    而測量又是實驗科學的基礎。

  • Worse still, the theory was wrong.

    更糟的是,這理論是錯的。

  • But the Greeks were great scientists of the mind

    但希臘人仍是 思想上偉大的科學家,

  • and in the 5th century B.C.,

    在西元前 5 世紀,

  • Leucippus of Miletus came up

    米勒都的留基伯(Leucippus of Miletus)

  • with one of the most enduring scientific ideas ever.

    提出有史以來 最經得起考驗的科學思想之一。

  • Everything we see is made up

    我們看到的每樣東西

  • of tiny, indivisible bits of stuff called atoms.

    都由微小、看不見的東西組成, 這東西稱作原子。

  • This theory is simple and elegant,

    這個理論既簡單又優雅,

  • and it has the advantage

    而它超越 土、空氣、水、火的理論

  • over the earth, air, fire, and water theory

    而它超越 土、空氣、水、火的理論

  • of being right.

    更接近事實。

  • Centuries of scientific thought and experimentation

    幾世紀以來的 科學思想及實驗

  • have established that the real elements,

    證實了實體的物質,

  • things like hydrogen,

    像是氫氣、

  • carbon,

    碳、

  • and iron,

    還有鐵,

  • can be broken down into atoms.

    都可以分解成原子。

  • In Leucippus's theory, the atom is the smallest,

    在留基伯的理論中,原子是最小的、

  • indivisible bit of stuff that's still recognizable

    看不見的物質, 但仍然可以作區分,

  • as hydrogen,

    像是氫原子、

  • carbon,

    碳原子、

  • or iron.

    鐵原子。

  • The only thing wrong with Leucippus's idea

    留基伯的想法裡, 唯一有問題的是

  • is that atoms are, in fact, divisible.

    事實上原子也還可以再細分。

  • Furthermore, his atoms idea turns out

    而且,他的原子說最終

  • to explain just a small part

    只解釋了宇宙組成 的一小部份。

  • of what the universe is made of.

    只解釋了宇宙組成 的一小部份。

  • What appears to be the ordinary stuff of the universe

    平常所見到的物質, 實際上在宇宙中

  • is, in fact, quite rare.

    非常稀少。

  • Leucippus's atoms, and the things they're made of,

    留基伯討論的原子、 還有它們組成的物質,

  • actually make up only about 5%

    事實上只佔了 我們知道的物質

  • of what we know to be there.

    的大約 5%。

  • Physicists know the rest of the universe,

    物理學家認為其餘的宇宙,

  • 95% of it,

    就是那 95%,

  • as the dark universe,

    是暗宇宙,

  • made of dark matter and dark energy.

    由暗物質和暗能量組成。

  • How do we know this?

    我們怎麼知道?

  • Well, we know because we look at things

    嗯,我們會知道是因為

  • and we see them.

    我們有觀察到。

  • That might seem rather simplistic,

    這聽起來蠻簡單的,

  • but it's actually quite profound.

    但實際上有點複雜。

  • All the stuff that's made of atoms is visible.

    所有原子組成的物質 是看得見的。

  • Light bounces off it, and we can see it.

    它會反射光線, 然後我們就看得到。

  • When we look out into space,

    當我們觀察宇宙時,

  • we see stars and galaxies.

    我們會看到星星和銀河。

  • Some of them, like the one we live in,

    有些就像我們居住的地方一樣,

  • are beautiful, spiral shapes, spinning gracefully through space.

    很美麗、有螺旋的結構、 優雅地在太空中旋轉。

  • When scientists first measured the motion

    當科學家在 1930 年代 第一次

  • of groups of galaxies in the 1930's

    觀測一群星系時,

  • and weighed the amount of matter they contained,

    並同時估算它們的質量,

  • they were in for a surprise.

    科學家們大為震驚。

  • They found that there's not enough visible stuff

    他們發現 並沒有足夠的可見物質

  • in those groups to hold them together.

    讓這些星系群 靠在一起。

  • Later measurements of individual galaxies

    之後對單獨星系的觀察

  • confirmed this puzzling result.

    證實了這個謎樣的結果。

  • There's simply not enough visible stuff in galaxies

    星系裡就是沒有足夠的 可見物質

  • to provide enough gravity to hold them together.

    來提供足夠的重力 讓它們靠在一起。

  • From what we can see,

    從我們的觀測之中,

  • they ought to fly apart, but they don't.

    它們應該向外飛走, 但並沒有。

  • So there must be stuff there

    所以一定有什麼東西

  • that we can't see.

    是我們看不到的。

  • We call that stuff dark matter.

    我們把這東西稱作 暗物質。

  • The best evidence for dark matter today

    現今關於暗物質 最有力的證據

  • comes from measurements of something

    來自於對於一種叫作

  • called the cosmic microwave background,

    宇宙背景微波輻射的觀測,

  • the afterglow of the Big Bang,

    也就是大爆炸後 留下的餘光,

  • but that's another story.

    但這是另一段故事了。

  • All of the evidence we have

    所有我們掌握的證據

  • says that dark matter is there

    都說明了暗物質的存在,

  • and it accounts for much of the stuff

    而在天空中

  • in those beautiful spiral galaxies

    那些美麗的螺旋星系中

  • that fill the heavens.

    它佔據了大部份的質量。

  • So where does that leave us?

    這告訴我們什麼?

  • We've long known that the heavens

    長久以來我們知道

  • do not revolve around us

    天空並不是繞著我們旋轉,

  • and that we're residents of a fairly ordinary planet,

    而我們只是 一顆平凡行星上的居民,

  • orbiting a fairly ordinary star,

    繞著一顆平凡的恆星、

  • in the spiral arm of a fairly ordinary galaxy.

    座落在一個平凡星系的螺旋臂上。

  • The discovery of dark matter took us

    暗物質的發現 帶領我們

  • one step further away from the center of things.

    更進一步了解 物質的本質。

  • It told us that the stuff we're made of

    這告訴我們 組成我們的物質

  • is only a small fraction of what makes up the universe.

    只是組成宇宙的物質 其中的一小部份。

  • But there was more to come.

    但是不只這樣。

  • Early this century,

    在這世紀初,

  • scientists studying the outer reaches of the universe

    研究宇宙外部的科學家

  • confirmed that not only is everything moving apart

    證實了不只是

  • from everything else,

    物質與物質之間不斷遠離,

  • as you would expect in a universe

    就如同你想像

  • that began in hot, dense big bang,

    宇宙誕生於 高溫、高密度的大爆炸一樣,

  • but that the universe's expansion

    這宇宙向外的擴張

  • also seems to be accelerating.

    似乎正在加速。

  • What's that about?

    這代表什麼?

  • Either there is some kind of energy

    要不就是有某種能量

  • pushing this acceleration,

    促成這樣的加速,

  • just like you provide energy to accelerate a car,

    就像是你提供能量 讓一輛車加速一樣;

  • or gravity does not behave exactly as we think.

    要不就是重力 和我們想的不完全一樣。

  • Most scientists think it's the former,

    大多數科學家相信 前者是對的,

  • that there's some kind of energy driving the acceleration,

    也就是有某種能量 促成這種加速,

  • and they called it dark energy.

    他們把它叫作 暗物質。

  • Today's best measurements allow us to work out

    現今最好的觀測 讓我們可以計算

  • just how much of the universe is dark.

    宇宙有多少部份 是屬於暗的。

  • It looks as if dark energy makes up

    看似暗能量佔了

  • about 68% of the universe

    大約 68% 的宇宙,

  • and dark matter about 27%,

    而暗物質佔了 27%,

  • leaving just 5% for us

    剩的 5% 才是

  • and everything else we can actually see.

    所有其它我們看得到的東西。

  • So what's the dark stuff made of?

    所以這些黑暗的東西 是由什麼組成的?

  • We don't know,

    我們並不知道,

  • but there's one theory, called supersymmetry,

    但有一個理論, 叫作「超對稱理論」,

  • that could explain some of it.

    可以解釋一些。

  • Supersymmetry, or SUSY for short,

    超對稱(supersymmetry), 或簡稱 SUSY,

  • predicts a whole range of new particles,

    預測了一系列新的粒子,

  • some of which could make up the dark matter.

    其中的一些 可以組成暗物質。

  • If we found evidence for SUSY,

    如果我們找到 超對稱的證據,

  • we could go from understanding 5% of our universe,

    我們就可以從 對宇宙那 5% 的認識,

  • the things we can actually see,

    也就是我們看得到的那些,

  • to around a third.

    進展到 大約 1/3。

  • Not bad for a day's work.

    還算不錯。

  • Dark energy would probably be harder to understand,

    暗能量可能 更難去了解,

  • but there are some speculative theories out there

    但有些猜測的理論

  • that might point the way.

    也許指出了方向。

  • Among them are theories that go back

    其中有些 可以追溯到

  • to that first great idea of the ancient Greeks,

    古希臘人那第一個偉大的想法,

  • the idea that we began with several minutes ago,

    也就是幾分鐘前 我們起頭的想法,

  • the idea that the universe must be simple.

    這想法說明宇宙必須是簡單的。

  • These theories predict that there is just a single element

    這些理論 預測所有的宇宙萬物

  • from which all the universe's wonderful diversity stems,

    只由單一一種東西組成,

  • a vibrating string.

    一條振動的絃。

  • The idea is that all the particles we know today

    這想法是說 我們今天知道的所有粒子

  • are just different harmonics on the string.

    只是這條絃上不同的波。

  • Unfortunately, string theories today

    不幸的是,絃論現今

  • are, as yet, untestable.

    還沒辦法證實。

  • But, with so much of the universe waiting to be explored,

    然而,宇宙中還有 這麼多事物等著去探索,

  • the stakes are high.

    這賭注太大了。

  • Does all of this make you feel small?

    這所有的東西 讓你覺得藐小嗎?

  • It shouldn't.

    不應該這樣。

  • Instead, you should marvel

    相反地, 你應該讚嘆

  • in the fact that, as far as we know,

    ──至少到目前為止──

  • you are a member of the only species in the universe

    你是這宇宙中 唯一一個開始了解

  • able even to begin to grasp its wonders,

    宇宙奧秘的物種 其中的一員,

  • and you're living at the right time

    而且你生對時代

  • to see our understanding explode.

    來見證這知識的爆炸。

The ancient Greeks had a great idea:

古代希臘人有一個偉大的想法:

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B1 中級 中文 TED-Ed 物質 宇宙 理論 原子 星系

【TED-Ed】看不見不代表不存在:暗物質 Dark matter: The matter we can't see - James Gillies

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