Three ways the universe could end - Venus Keus

譯者: Lilian Chiu 審譯者: Helen Chang

We know about our universe’s past:

我們知道宇宙的過去：

the Big Bang theory predicts that all matter, time, and space

根據大爆炸理論的預測， 所有的物質、時間、空間

began in an incredibly tiny, compact state about 14 billion years ago.

都開始於一個極小、 極緊實的狀態，

時間是大約一百四十億年前。

And we know about the present:

我們也知道現在：

scientists’ observations of the movement of galaxies

根據科學家對於銀河運動的觀察，

tell us that the universe is expanding at an accelerated rate.

宇宙正在擴張，且速度越來越快。

But what about the future?

但，未來呢？

Do we know how our universe is going to end?

我們是否知道宇宙會如何結束？

Cosmologists have three possible answers for this question,

宇宙學家針對這個問題 有三個可能的答案：

called the Big Freeze,

大凍結、

the Big Rip and the Big Crunch.

大撕裂，和大擠壓。

To understand these three scenarios,

若要了解這三種情境，

imagine two objects representing galaxies.

先想像一下，用兩個物體 來代表兩個銀河。

A short, tight rubber band is holding them together—

有一條很短、很緊的橡膠帶 將它們連結在一起——

that’s the attractive force of gravity.

那就是重力造成的引力。

Meanwhile, two hooks are pulling them apart—

同時，有兩個勾子 在將它們拉開——

that’s the repulsive force expanding the universe.

那就是讓宇宙擴張的排斥力。

Copy this system over and over again,

將這個系統不斷複製，

and you have something approximating the real universe.

得到的結果就會 很接近真實的宇宙。

The outcome of the battle between these two opposing forces

這兩種相反力量之間的對抗

determines how the end of the universe will play out.

會決定宇宙最後的結局是什麼。

The Big Freeze scenario is what happens if the force pulling the objects apart

大凍結的情境是預期 將物體拉開的力量

is just strong enough to stretch the rubber band until it loses its elasticity.

強大到足以將橡膠帶延伸開來， 到失去彈性的程度。

The expansion wouldn’t be able to accelerate anymore,

此時擴張無法再加速了，

but the universe would keep getting bigger.

但宇宙會持續變得更大。

Clusters of galaxies would separate.

一群一群的銀河會分離開來。

The objects within the galaxies–

在銀河中的物體——

suns, planets, and solar systems

太陽、行星，和太陽系，

would move away from each other,

會彼此遠離，

until galaxies dissolved into lonely objects

直到銀河瓦解成單獨的物體，

floating separately in the vast space.

在浩瀚的太空中各自漂浮。

The light they emit would be redshifted to long wavelengths

它們發散的光會發生紅移， 成為長的波長，

with very low, faint energies,

能量則非常低、非常微弱，

and the gas emanating from them would be too thin to create new stars.

它們散發出來的氣體 會太稀薄而無法創造出新星。

The universe would become darker and colder,

宇宙會變得更黑暗、更寒冷，

approaching a frozen state

接近一種冰凍的狀態， 也就是所謂的大冰凍，

also known as the Big Chill,

or the Heat Death of the Universe.

或是宇宙的「熱寂」。

But what if the repulsive force is so strong

但，如果排斥力很強，

that it stretches the rubber band past its elastic limit,

強到讓橡膠帶的延伸 超出它的彈性極限，

真的將它撕裂了，會如何？

and actually tears it?

If the expansion of the universe continues to accelerate,

如果宇宙的擴張持續加速，

it will eventually overcome not only the gravitational force –

最後，它不僅會戰勝重力引力——

tearing apart galaxies and solar systems–

將銀河和太陽系給扯開——

but also the electromagnetic, weak, and strong nuclear forces

同時也會戰勝電磁的、 弱的、強的核力，

which hold atoms and nuclei together.

也就是讓原子和核子 結合在一起的力量。

As a result,

結果就是，形成天體的 物質會破成碎片。

the matter that makes up stars breaks into tiny pieces.

Even atoms and subatomic particles will be destroyed.

就連原子和亞原子粒子 都會被摧毀。

That’s the Big Rip.

那就是大撕裂。

What about the third scenario,

那麼，第三個情境，

where the rubber band wins out?

也就是橡膠帶獲勝的情境呢？

That corresponds to a possible future

在這個情境所對應的可能未來，

in which the force of gravity brings the universe’s expansion to a halt—

重力引力會讓宇宙的 擴張停下來——

and then reverses it.

接著將它逆轉。

Galaxies would start rushing towards each other,

銀河會開始衝向彼此，

and as they clumped together

它們會結成一團，

their gravitational pull would get even stronger.

它們的重力引力就會變得更強。

Stars too would hurtle together and collide.

天體也會衝向彼此並相撞。

Temperatures would rise as space would get tighter and tighter.

隨著空間變得越來越 緊密，溫度會上升。

The size of the universe would plummet

宇宙的大小會極劇縮小，

until everything compressed into such a small space

直到一切都壓縮成 這麼一個小空間，

that even atoms and subatomic particles would have to crunch together.

就連原子和亞原子粒子 也會擠在一起。

The result would be an incredibly dense, hot, compact universe —

結果就會造成一個非常高密度、 高溫、緊密的宇宙——

a lot like the state that preceded the Big Bang.

很像是大爆炸之前的狀態。

This is the Big Crunch.

這就是大擠壓。

Could this tiny point of matter explode in another Big Bang?

這個物質小圓點有沒有可能會爆炸， 發生另一次的大爆炸？

Could the universe expand and contract over and over again,

宇宙有沒有可能會擴張又收縮， 一而再，再而三，

repeating its entire history?

不斷重覆它的整段歷史？

The theory describing such a universe is known as the Big Bounce.

描述這種宇宙的理論叫做大反彈。

In fact, there’s no way to tell how many bounces could’ve already happened—

事實上，無法知道目前 已經發生過多少次反彈——

or how many might happen in the future.

或是未來還會發生多少次。

Each bounce would wipe away any record of the universe’s previous history.

每一次反彈都會將 宇宙的先前歷史紀錄給抹除。

Which one of those scenarios will be the real one?

這些情境中， 哪一個比較可能是真的？

The answer depends on the exact shape of the universe,

答案會依宇宙的形狀而定，

the amount of dark energy it holds,

要看它所保有的暗能量有多少，

and changes in its expansion rate.

以及它擴張速度的改變。

As of now, our observations suggest that we’re heading for a Big Freeze.

目前為止，根據我們的觀察， 我們正在朝大冰凍前進。

But the good news is that we’ve probably got about 10 to the 100th power years

但，好消息是，我們可能 還要等「十的一百次方」年，

before the chill sets in —

才會開始感到寒冷——

so don’t start stocking up on mittens just yet.

所以，還不用開始儲備長手套啦。