Well, it turns out our cosmic fate will be decided by a fight between two titans.

原來，我們的宇宙命運將由兩個巨人之間的戰鬥來決定。

The two warriors deciding the fate of the universe.

兩位勇士決定著宇宙的命運。

Our universe was born 14 billion years ago in the Big Bang and has been expanding ever since.

我們的宇宙誕生於 140 億年前的宇宙大爆炸，此後一直在不斷膨脹。

For some reason, new empty space is being created out of nothing between galaxies.

出於某種原因，星系之間正在憑空產生新的空白空間。

Space itself is becoming bigger.

空間本身越來越大。

Will it go on forever or will it stop one day?

這種情況會一直持續下去，還是有一天會停止？

Today, we think the universe is at the mercy of two cosmic demigods fighting for dominance.

今天，我們認為宇宙受到兩個宇宙半神爭奪統治權的擺佈。

The first one is all the stuff in the universe.

第一個是宇宙中所有的東西。

Galaxies, gas, dark matter.

星系、氣體、暗物質

While they're very different, they just want to do one thing, get together.

雖然他們性格迥異，但他們只想做一件事，那就是聚在一起。

Matter is attracted by matter, pulled together by gravity.

物質被物質吸引，在萬有引力的牽引下聚集在一起。

And gravity also pulls on the universe as a whole, slowing the expansion that started at the Big Bang.

引力還對整個宇宙產生拉力，減緩了宇宙大爆炸時開始的膨脹。

Our second warrior is empty space.

我們的第二位勇士是虛空。

While it seems, well, empty and powerless, empty space has an intrinsic energy.

雖然看起來空洞無力，但空曠的空間卻蘊含著內在的能量。

We don't really have an idea what this energy is or why it's there.

我們並不清楚這種能量是什麼，也不知道為什麼會有這種能量。

It's really a placeholder that fills a blank in our understanding of reality.

它實際上是一個佔位符，填補了我們對現實理解的空白。

But it's got a cool name, dark energy.

但它有一個很酷的名字，暗能量。

Dark energy pushes things apart, a sort of anti-gravity that accelerates the cosmic expansion.

暗能量會將物體推開，這是一種反引力，會加速宇宙膨脹。

So, we have all the matter in the universe pulling in and empty space infused with dark energy pushing out.

是以，宇宙中的所有物質都被拉進來，而注入暗能量的虛空則被推出去。

Whoever wins will kill the universe in fun ways.

無論誰獲勝，都將以有趣的方式殺死宇宙。

But who will win?

但誰會贏呢？

It all depends on the mysterious dark energy.

這一切都取決於神祕的暗能量。

Will its strength stay the same, a common assumption just because it keeps our model simple?

它的強度會保持不變嗎？這是一個常見的假設，只是因為它能使我們的模型保持簡單？

Or will it get weaker?

還是會越來越弱？

Or will it get more powerful over time?

還是會隨著時間的推移而變得更加強大？

1.

1.

Constant dark energy, heat death.

恆定的暗能量，熱死亡。

If the strength of dark energy stays constant, it will win the war.

如果暗能量的強度保持不變，它將贏得這場戰爭。

Since space is growing, matter is getting more and more diluted, like sugar in a cup being filled with more and more tea.

由於空間在不斷擴大，物質越來越稀釋，就像杯子裡的糖越來越多，茶越來越濃。

But as the universe expands, new empty space is created, which brings more dark energy, which pushes everything apart even more, which creates more empty space, which makes the universe grow even faster.

但是，隨著宇宙的膨脹，新的空洞產生了，這帶來了更多的暗能量，暗能量把萬物推得更開，這又創造了更多的空洞，使宇宙增長得更快。

A feedback loop that will make the universe expand at an exponential rate.

反饋迴路將使宇宙以指數速度膨脹。

Every 12 billion years or so, it will double in diameter forever.

每隔 120 億年左右，它的直徑將永遠翻一番。

But while dark energy is winning the war, matter is winning at least one battle.

不過，在暗能量贏得戰爭的同時，物質至少贏得了一場戰鬥。

At short distances, it can keep things together.

在短距離內，它可以讓東西保持在一起。

Local galaxy bubbles can overcome the push of dark energy.

在地星系氣泡可以克服暗能量的推動。

In a few billion years, our local group of galaxies will merge into a gigantic ball with trillions of stars.

再過幾十億年，我們的本星系群將合併成一個擁有數萬億顆恆星的巨大球體。

It will soon become our last view of the cosmos.

它很快就會成為我們最後的宇宙景觀。

All other galaxies will be pushed away by the expansion.

所有其他星系都會被膨脹推開。

For us, it will look like the rest of the universe is rushing away, until in a few hundred billion years, we won't see other galaxies at all.

對我們來說，宇宙的其他部分看起來正在匆匆遠去，直到幾千億年後，我們根本看不到其他星系。

We'll be alone, surrounded by a seemingly infinite dark void.

我們將孤身一人，周圍是看似無邊無際的黑暗虛空。

In about 100 trillion years, all the stars of our super galaxy will have died out.

大約 100 萬億年後，我們超級星系中的所有恆星都將消亡。

All gas that could create new stars has been consumed, and no new gas can come in.

所有可以產生新恆星的氣體都已消耗殆盡，沒有新的氣體可以進來。

The galaxy will be dark and filled with stellar corpuses.

銀河系將變得漆黑一片，到處都是恆星屍體。

Over quadrillions of years, white dwarfs and neutron stars will slowly cool until becoming truly dark, turning off the last lights of the universe.

經過數萬億年的時間，白矮星和中子星將慢慢冷卻，直到變成真正的黑暗，關閉宇宙中最後的燈光。

All structures, big and small, will slowly dissolve.

所有結構，無論大小，都將慢慢解體。

One by one, all dead stars and planets will leave the super galaxy, which slowly dissolves over sextillions of years.

所有死亡的恆星和行星都會一個接一個地離開超級星系，而超級星系會在六千億年的時間裡慢慢溶解。

Every object will end up on its own, which means that dark energy takes over again, creating more and more empty space between everything.

每個物體最終都會自生自滅，這意味著暗能量再次接管，在萬物之間創造出越來越多的空隙。

Objects will be so far apart, that it will be as if each had a universe for itself.

物體之間將相距甚遠，就好像每個物體都有一個自己的宇宙。

Not much happens anymore, until in a good old years, all black holes will have evaporated.

在若干年後，所有的黑洞都會消失。

In the end, entropy and dark energy won't stop until their job is finished.

歸根結底，熵和暗能量在完成它們的工作之前是不會停止的。

Over time spans you might as well call forever, all remaining structures might even dissolve into single particles that will be pushed away from each other by an ever-growing empty space.

隨著時間的推移，所有殘留的結構甚至會溶解成單個粒子，被不斷擴大的虛空推開。

Imagine a whole universe with just a single lonely particle traveling through nothingness.

想象一下，整個宇宙只有一個孤獨的粒子在虛無中穿梭。

This is the final state, the true end.

這才是最終的狀態，真正的終結。

The big freeze, or heat death.

大冰凍或熱死

A completely featureless, cold and eternally expanding universe.

一個完全沒有特徵、冰冷且永恆膨脹的宇宙。

Nothing will ever be able to happen again. Phew, that was a bummer.

一切都不會再發生了。 呼，真掃興。

What else could happen?

還會發生什麼？

Two, increasing dark energy.

二，暗能量增加。

Big rip.

大撕裂。

What if dark energy gets stronger?

如果暗能量越來越強呢？

In this case, empty space won't just win over matter, it will literally rip it to pieces.

在這種情況下，虛空不僅會戰勝物質，而且會把物質撕成碎片。

In the big freeze scenario, matter lost the war but won some battles.

在大凍結情景中，物質輸掉了戰爭，但贏得了一些戰鬥。

But here, matter wins nothing.

但在這裡，物質什麼也贏不了。

Dark energy is growing stronger over time, overcoming the pull of gravity and creating new empty space at smaller and smaller distances.

隨著時間的推移，暗能量越來越強大，克服了引力的牽引，在越來越小的距離上創造出新的空曠空間。

In this scenario, things will escalate quickly.

在這種情況下，事情會迅速升級。

It could start as early as 20 billion years from now.

最早可能從 200 億年後開始。

First, dark energy will create empty space between individual galaxies.

首先，暗能量會在單個星系之間產生空隙。

Our galaxy will leave its local cluster and begin to drift alone in a rapidly inflating and ever darker cosmos.

我們的星系將離開它的本星系團，開始在一個迅速膨脹、越來越黑暗的宇宙中孤獨地漂流。

Some billion years later, empty space starts to push between individual stars, dissolving the galaxy.

大約十億年後，空曠的空間開始擠入各個恆星之間，銀河系隨之解體。

If you live on a planet in a star system, the night sky will start looking sad and gloomy, as other stars are pushed too far away to be seen.

如果你生活在恆星系統中的一顆行星上，夜空就會開始變得黯淡無光，因為其他恆星都被擠得看不見了。

A few million years after the sky turns dark, dark energy starts to create empty space inside star systems.

在天空變暗的幾百萬年後，暗能量開始在恆星系統內部形成空洞。

Your planet is pushed away from its star and all life in the universe freezes to death.

你的星球被推離恆星，宇宙中的所有生命都會被凍死。

There's not much time left as a few months later, dark energy is creating empty space inside solid objects.

剩下的時間不多了，因為幾個月後，暗能量就會在固體物體內部產生空隙。

Stars, neutron stars, planets, asteroids, everything solid is being ripped into pieces.

恆星、中子星、行星、小行星，一切堅固的東西都被撕成碎片。

If you're on a spaceship, you only have a short time before you are ripped apart.

如果你在飛船上，在你被撕碎之前，你只有很短的時間。

Half an hour later, even atoms are destroyed, as new space is being created so furiously that electrons and nuclei are separated.

半小時後，原子也被摧毀了，因為新的空間被瘋狂地創造出來，電子和原子核分離了。

Now the universe has just a fraction of a second left.

現在，宇宙只剩下幾分之一秒。

In this final moment, only dying black holes remain, drained and defeated by dark energy.

在這最後一刻，只剩下垂死的黑洞，被暗能量耗盡並擊敗。

They're tiny, septillions of times smaller than an atom, and they explode with the power of a trillion supernovae in a trillionth of an octillionth of a second.

它們非常微小，比原子小七千億倍，在萬億分之八億秒內爆發出一萬億個超新星的威力。

Finally, the very fabric of reality is torn to its core, obliterating space-time itself, the Big Rip.

最後，現實的核心結構被撕裂，時空本身湮滅，這就是大裂解。

Space and time have lost their meanings, making it impossible to predict what will happen next. 3.

空間和時間失去了意義，無法預測接下來會發生什麼。3.

Decreasing dark energy, big crunch.

暗能量減少，大緊縮。

Poor matter, but there is one scenario where it wins.

雖然差強人意，但有一種情況是它贏了。

If the strength of dark energy decreases with time, and if this reduction is strong enough, the pull of gravity will win, and all the things in existence will move towards each other, unfortunately making the universe collapse into itself.

如果暗能量的強度隨著時間的推移而減弱，而這種減弱又足夠強大，萬有引力就會獲勝，所有存在的事物就會相互移動，不幸的是，宇宙就會自我坍縮。

No one knows when this might begin, but it could be as soon as a few hundred million years.

沒有人知道這種情況何時會開始，但最快也要幾億年後。

What will it look like?

它會是什麼樣子？

As the universe begins to contract, over billions of years, galaxies and galaxy clusters approach each other until they eventually collide.

隨著宇宙開始收縮，經過數十億年的時間，星系和星系團相互靠近，直至最終相撞。

They're mostly made of empty space, so a collision is like the gentle merger of two clouds.

它們大多是由虛空構成的，是以碰撞就像是兩朵雲的輕柔合併。

At any rate, first galaxies and later individual stars get closer and closer.

無論如何，先是星系，後來是單個恆星越來越近。

As the universe goes on collapsing, you might worry about stars and planets eventually crashing against each other.

隨著宇宙不斷坍縮，你可能會擔心恆星和行星最終會相互撞擊。

This will happen, but it's not your worst problem.

這種情況會發生，但不是最嚴重的問題。

If space itself shrinks, this also concentrates all the radiation emitted in the past by all the stars, supernovae, and quasars that ever existed.

如果空間本身縮小了，那麼過去存在過的所有恆星、超新星和類星體發出的輻射也會是以而集中起來。

Now, empty space is filled with radiation.

現在，虛空中充滿了輻射。

The dark nothing between stars is heating up, making life unpleasant and then impossible, as planets just burn.

恆星之間的黑暗虛無正在升溫，使生命變得不愉快，甚至不可能，因為行星只是在燃燒。

Slowly at first, then rapidly, space gets as hot as it was after the Big Bang.

起初，空間會慢慢變熱，然後迅速變熱，就像宇宙大爆炸後一樣。

Stars are pretty hot, but now the space around them is hotter.

恆星的溫度很高，但現在它們周圍的空間溫度更高。

They're literally boiled from the outside.

簡直就是從外面煮熟的。

As the universe collapses into itself, all galaxies and all stars merge into a single ball of hot plasma.

隨著宇宙的自我坍縮，所有星系和恆星都會合併成一團炙熱的等離子體。

The Big Crunch is complete.

大緊縮已經完成。

From here on, there are two possibilities.

從這裡開始，有兩種可能性。

Either the universe will collapse completely into a singularity, a point of zero size and infinite density, without space and time, the way it might have been before the Big Bang.

宇宙要麼完全坍縮為一個奇點，即一個大小為零、密度無限、沒有空間和時間的點，就像宇宙大爆炸之前的樣子。

Or the universe could bounce back, restarting the cosmic expansion, creating a new baby universe.

或者，宇宙可能會反彈，重新開始宇宙膨脹，創造出一個新的嬰兒宇宙。

Somewhat poetic, really.

真的有點詩意。

Everything died, but everything is reborn.

萬物死而復生。

But to be clear, we have zero evidence that this has happened before or well in the future.

但要說明的是，我們沒有任何證據表明這種情況以前或將來會發生。

So what will happen?

那麼會發生什麼呢？

Most scientists think that dark energy will stay constant, so the likely fate of the universe is heat death, eternal cold, and utter boredom.

大多數科學家認為，暗能量將保持恆定，是以宇宙的命運可能是熱死、永冷和徹底無聊。

Which seems sad, but has a huge upside.

這看似可悲，卻有巨大的好處。

In this scenario, we get to have the universe for the longest.

在這種情況下，我們擁有宇宙的時間最長。

It gives us trillions of years to expand, jump from star to star, maybe even from galaxy to galaxy.

它給了我們數萬億年的時間來擴張，從一顆恆星跳躍到另一顆恆星，甚至從一個星系跳躍到另一個星系。

We might even find a way to keep consciousness around forever.

我們甚至有可能找到一種方法，讓意識永遠存在。

We don't know.

我們不知道。

So we just have to wait and see, and make the most of the amazing universe we have right now.

是以，我們只能拭目以待，充分利用我們現在所擁有的神奇宇宙。

NASA Jet Propulsion Laboratory, California Institute of Technology

美國國家航空航天局噴氣推進實驗室、加州理工學院