But what if there's no dark matter at all?

但是，如果根本沒有暗物質呢？

The idea of dark matter was first proposed by Henri Poincaré in 1906.

昂利．龐加萊於 1906 年首度提出暗物質的概念。

Then in 1933, evidence of dark matter was found by Fritz Zwicky while studying galaxy clusters...

接著 1933 年，弗里茨．茲威基在研究星系團時，發現暗物質的證據。

And then more evidence of dark matter was found based on the calculations of rotational velocities in galaxies made by Vera Rubin in 1978.

根據薇拉．魯賓於 1978 年計算出的星系自轉速度，又發現更多暗物質的證據。

Our universe is made up of less than 5% of visible matter---like stars, planets, galaxies you, me, everything we can see.

我們的宇宙由不到 5％ 的可見物質構成 —— 像是：恆星、行星、星系、你、我，以及看到的每樣東西。

Everything else, is stuff we can't see which we call dark matter.

其他我們看不見的東西，稱之為暗物質。

And scientists think 95% of the matter in our universe is dark matter.

科學家認為，我們宇宙 95% 的物質都是暗物質。

Right now, Dark Matter is used to explain a few pesky things in astrophysics.

現在，暗物質用於解釋天體物理學中不少麻煩事。

Like…

像是......

Why hot galaxy clusters don't blow themselves apart.

為什麼星系團裡的熱氣體不會讓它們爆炸？

Why stars don't get flung out into space because of galaxy rotation.

為什麼恆星不會因星系旋轉而拋入太空？

And also, the temperature fluctuations of the CMB -- or cosmic microwave background radiation.

以及宇宙微波背景 (cosmic microwave background radiation) 的溫度波動。

That said, there are theories that are trying to explain all this without assuming it's dark matte. These are: scale invariance and emergent gravity.

也就是說，有些理論在假設沒有暗物質的情況下解釋一切。包括：尺度不變性和熵引力。

The empty space scale invariance theory says that properties of empty space should not change based on scale.

空間尺度不變性理論認為，空間的特性不應基於尺度而改變。

An astrophysicist looked back at the early equations of Einstein, and Newtonian Dynamics, and modified an acceleration term in Newton's law.

天體物理學家回顧愛因斯坦和牛頓力學的早期方程式，並修改牛頓定律中的加速項。

With this change, the law could explain a new force.

有了這個改變，這個定律可以解釋新的力。

This force can explain things that were explained by dark matter… such as holding a galaxy together that's spinning at high rotational velocities.

這種力可以說明由暗物質所解釋的事物... 像是將整個星系連在一起，就會以高轉速旋轉。

The only problem is, on Earth, this force can be up to billion times smaller than the force of gravity--making it difficult to measure.

唯一的問題是，這種力在地球上可能比重力小十億倍 —— 使其難以測量。

It doesn't explain gravitational lensing, --which is the bending of light-- or the temperature fluctuations of the CMB.

這解釋不了重力透鏡效應 —— 即光的彎曲，或宇宙微波背景的溫度波動。

The craziest, but to me the most interesting, is the holographic principle, which says that

最瘋狂，但對我來說是最有趣的是「全像原理」，

our entire universe can be described on an imaginary sphere that surrounds ordinary matter.

其理論將我們整個宇宙描述為，一個環繞正常物質的虛構天體。

It lead to the theory of emergent gravity.

這帶出了熵引力理論。

That is the idea that gravity arises (or emerges) through the presence of matter.

這就是重力透過物質存在而產生 (或出現) 的想法。

This suggests this happens the same way temperature arises from the movement microscopic particles of matter.

暗示這情況與物質微觀粒子運動所產生溫度的方式一樣。

So, if gravity is formed this way then it can be used to explain gravitational phenomena again!

因此，如果以這種方式形成重力，那麼就可以用來再次解釋重力現象！

Because something is keeping galaxies gravitationally bound.

因為星系受到某些東西的重力束縛。

It's possible that the force created in the emergent gravity theory does this!

在熵引力理論中，力可能就是這樣所引起！

But it still doesn't explain the CMB temperatures...

但仍無法解釋宇宙微波背景的溫度......

Scientists are still developing theories, like these, so they can explain things like the reason our universe hasn't completely blown apart because of invisible matter.

科學家仍在發展像這樣的理論，因為就可以解釋一些事情，像是我們宇宙沒有徹底爆炸的原因，就是因為有暗物質。

And they think it might be because of a gravitational field that developed through the movement of visible matter in our universe.

而他們認為或許因為重力場是透過宇宙中可見物質的運動才產生。

It's all very complicated, and yet, epic.

這一切非常複雜，但卻是史詩般的。

For the moment, arguments for dark matter still stand tall above many of these other theories, but hey, maybe not forever.

就目前來說，暗物質的論點仍高於許多其他理論，但是，嘿，可能不是永遠都這樣。

Hey peeps, take a sec to subscribe for more videos.

嘿，朋友，花點時間訂閱來看看其他影片。

Plus, check out Trace's video about a new form of matter excitonium!

此外，來看看 Trace 的影片，關於一種叫「excitonium」的新物質

And one last fun fact: the holographic principle says we've always looked at life as 3 dimensions,

最後一個有趣的事情：全像原理表示，我們總是將生活視為立體的，

but if we looked at it as 2 dimensions then MAYBE the universe is just a holographic projection of ourselves.

但如果我們視為平面的話，也許宇宙只是我們自身的全像投射。

Thanks for watching!

謝謝觀看！