Atoms, stars and galaxies, planets and trees, rocks and us.

這些物質佔整個宇宙不到５%。

This matter accounts for less than 5% of the known universe.

在整個宇宙中， 大約２５%是暗物質，７０%是暗能量。

About 25% is dark matter; and 70% is dark energy.

暗物質與暗能量都無法被觀測到。

Both of which are invisible.

這聽起來有點奇怪， 這表示我們所接觸到的世界只佔了極其微小的部分。

This is kind of strange because it suggests that everything we experience is

更糟糕的是， 我們對暗物質與暗能量究竟是什麼、如何運作毫無頭緒

really only a tiny fraction of reality.

更糟糕的是， 我們對暗物質與暗能量究竟是什麼、如何運作毫無頭緒

But it gets worse.

我們非常確定它們是存在的。 至於，為什麼我們知道它們存在呢？

We really have no clue what dark matter and energy are, or how they work.

暗物質使星系穩定存在

We are pretty sure they exist though.

我們開始分析宇宙的結構時，發現能被觀測的"普通物質"並不足以令宇宙維持穩定存在。

So, what do we know?

來自"普通物質"的重力不足以形成星系這樣的複雜結構，恆星間會更為鬆散，並四處散佈，

Dark matter is the stuff that makes it possible for galaxies to exist.

這將導致星系無法形成。 因此，我們確信一定有某種東西在維繫星系的結構。

When we calculated why the universe is structured the way it is,

某種東西，它不發射光，也不反射光

it quickly became clear that there's just not enough normal matter.

所以稱作「暗」。

The gravity of the visible matter is not strong enough to form

除了能計算到暗物質的存在以外，

galaxies and complex structures.

我們還能看到它的微小跡象。 高濃度暗物質的地方會使經過它的光線扭曲。

The stars would more likely be scattered all over the place and not form galaxies.

因此我們確信有東西在那兒，並且會與重力作用。

So, we know there is something else inside and around them.

現在， 對於暗物質(旁白口誤成暗能量)是什麼有進一步認識， 那麼它究竟是什麼？

Something that doesn't emit or reflect light.

我們知道暗物質並非一團無光源的普通物質， 因為普通物質會放射出我們能觀測到的粒子。

Something dark...

暗物質也不是"反"物質， 因為反物質會與普通物質反應，並放出特殊的γ射線。

but besides being able to calculate the existence of dark matter,

暗物質也不是由黑洞所構成。

we can see it... kind of.

黑洞是種緊密的物體，且會劇烈影響周圍環境， 但是暗物質似乎是零星散布在整個宇宙。

Places with a high concentration of dark matter bend light passing near by.

基本上，我們目前對於暗物質只能確定三件事：

So we know there's something there that interacts with gravity.

一、有東西就在那裡。

Right now, we have more ideas about what dark energy is not, than what it is!

二、它會與重力作用。

We know dark matter is not just clouds of normal matter without stars,

三、它們有很多很多。

because it would emit particles we could detect.

暗物質有可能是由某種複雜又特殊的粒子組成， 這種粒子不會與光、普通物質反應

Dark matter is not anti-matter,

但目前我們真的不瞭解它到底是什麼。

because anti-matter produces unique gamma rays when it reacts with normal matter.

暗能量又更奇怪與神祕：

Dark matter is also not made up of black holes,

我們無法檢測它、無法測量它、無法觸碰它。

very compact objects that violently affect their surroundings,

帶我們卻能非常清晰地看到它造成的影響：

while dark matter seems to be scattered all over the place.

1929年，愛德溫·哈伯透過研究遙遠星系發出的光的波長，

Basically, we only know 3 things for sure;

發現光經過宇宙後出現紅移現象。

1. Something is out there.

哈伯發現較黯淡、較遙遠的星系會出現較大的紅移。

2. It interacts with gravity.

距離近些的星系則出現紅移的幅度則小些。

3. There is a lot of it.

哈伯肯定地認為會出現紅移現象是因為宇宙正在膨脹，

Dark matter is probably made up of a complicated exotic particle

紅移的出現，是因為光的波長隨宇宙膨脹而被拉伸。

that doesn't interact with light and matter in a way we expect,

近幾年的研究報告顯示宇宙的膨脹正在加速。

but right now, we just don't know.

在此之前， 人們認為重力將使宇宙膨脹減緩，甚至塌縮回一個點。

Dark energy is even more strange and mysterious.

空間並沒有因為膨脹而改變它的性質。

We can't detect it, we can't measure it and we can't taste it.

宇宙膨脹就只是讓空間變更多！

But we do see its effects very clearly.

年輕的新空間一直在宇宙所有地方新生。

In 1929, Edward Hubble examined how the wavelength of light

星系是一種透過重力緊密集群的東西。

emitted by distant galaxies, shifts towards the red end

因此身處星系中的我們不會感受到宇宙膨脹， 但我們仍能在任何地方看到膨脹的影響。

of the electromagnetic spectrum as it travels through the space.

無論何處，宇宙中隨時都有新的空間(空白空間)在形成

He found that fainter, more distant galaxies showed a large degree of red shift;

因此，暗能量似乎是某種空白空間裡固有的能量。

closer galaxies, not so much.

暗能量，比任何東西都要強大而且日益增強。

Hubble determined that this was because the universe itself is expanding.

空白空間中的能量比起宇宙其他所有東西的總和還要多

The red shift occurs, because the wavelengths of light

我們對於暗能量可能是什麼有多種猜測。

are stretched as the universe expands.

一種猜測是暗能量並非某種事物，它只是空間的特性。

More recent discoveries have shown that, the expansion of the universe is accelerating.

空白空間並非"虛無"，它擁有自己的能量。

Before that, it was thougth that the pull of gravity would cause the expansion to

空白空間可以產生更多空間，而且相當活躍。

either slow down or even retract and collapse in on itself at some point.

因此當宇宙在膨脹時，空白空間使更多空間出現並填補缺口，造成宇宙加速膨脹。

Space doesn't change its properties as it expands; there's just more of it.

這個猜測接近愛因斯坦在1917年對宇宙常數概念的想法。

New space is constantly created everywhere,

有一種力與重力對抗著。

galaxies are tight bound clusters of stuff held together by gravity

唯一的問題是，當我們嘗試這樣計算暗能量的多寡時， 會出現詭異的結果，留下更多困惑與謎題。

so we don't experience this expansion in our daily lives.

另一種猜測是空白空間充斥著一種暫時且虛無飄渺的粒子，它會不斷從一無所有形成，然後再消失回一無所有。

But we see it everywhere around us.

這些粒子的能量可能就是暗能量。

Wherever there is empty space in the universe, more is forming every second.

或是另一種猜測：暗能量是種未知的動態能量流體或是力場，它滲入了整個宇宙。

So, dark energy seems to be some kind of energy intrinsic to empty space.

但不知何故，它有與普通物質、普通能量相反的效果。

Energy that is stronger than anything else we know

如果真是如此，我們並不知道怎麼、在哪探測到它。

and it keeps getting stronger as time passes by.

所以目前還有許多問題待解決。

Empty space has more energy than everything else in the universe combined.

我們關於暗物質、暗能量的理論仍處於理論階段。

We have multiple ideas about what dark energy might be.

一方面而言，這挺令人洩氣的； 另一方面，因為這是最前端的科學，因此使人興奮，

One idea is, the dark energy is not a thing, but just a property of space.

這代表著無論我們多麼認為自己是萬物之王，但其實只是活在宇宙中脆弱小島並使用智慧型手機的猿人。 因此，去仰望這片天空吧！去追尋宇宙運行的真理！

Empty space is not nothing, it has its own energy.

有太多東西等著我們去知道並學習。 而且這些東西令人驚嘆！

It can generate more space and is quite active.

本影片由澳洲科學院(AAS)支援合作。 AAS是一推廣支持卓越科學研究的機構。

So, as the universe expands, it could be that just more and more space

想瞭解更多關於本主題及其他類似內容請上"nova.org.au"

appears to fill the gaps and this leads to a faster expanding universe.

與NOVA.org一起工作超讚的，所以快去看他們網站吧！

This idea is close to an idea that Einstein had back in 1917,

本影片也因為你在"patreon.com"的贊助而成為可能。

of the concept of a cosmological constant,

若你想贊助我們並成為Kurzgesagt鳥大軍的成員之一，快去patreon的網頁吧！

a force that counteracted the force of gravity.

The only problem is, that when we tried to calculate the amount of this energy

the result was so wrong and weird, that it only added to the confusion.

Another idea is, that empty space is actually full of

temporary, virtual particles that spontaneously and continually

form from nothing and then dissapear into nothing again.

The energy form those particles could be dark energy.

Or maybe dark energy is an unknown kind of dynamic energy fluid or field

which permeates the entire universe, but somehow has the opposite effect

on the universe than normal energy and matter.

But if it exists, we don't know how and where or how we could detect it.

So there are still a lot of questions to answer.

Our theories about dark matter and dark energy are still just that;

theories.

On one hand, this is kind of frustrating, on the other hand this is frontier science

making it very exciting.

It shows us that no matter how much we feel we're on top of things,

we are still very much apes with smartphones, on a tiny

fragile island in space looking into the sky wondering how our universe works

There is so much left to learn, and that is awesome.

This video is supported by the Australian Academy of Science,

which promotes and supports excellence in science.

Learn more about this topic and others like it at nova.org.au.

It was a blast of work with them so go check out their site.

Our videos are also made possible by your support on patreon.com,

if you want to support us and become part of the Kurzgesagt Bird Army,

check out our patreon page.

Subtitles by the Amara.org community