How will the universe end？
Science has outlined four ways that our universe could meet its doom. They're called the Big Freeze, the Big Crunch, the Big Change and the Big Rip.
科學家已經勾勒出了宇宙最終結束的四種方式：“大凍結”、“大塌縮”， “大轉變”（“終極生態災難”）， “大撕裂”（“幽靈暗能量”）。
Don't panic, but our planet is doomed. It's just going to take a while. Roughly 6 billion years from now, the Earth will probably be vaporized when the dying Sun expands into a red giant and engulfs our planet.
請保持鎮定：我們的地球註定將會毀滅。 但如果你幸災樂禍， 那麼還有一個消息， 那就是你可能還需要等上一段時間， 比如60億年——在那之後， 膨脹為紅巨星的太陽將吞噬整個地球。
But the Earth is just one planet in the solar system, the Sun is just one of hundreds of billions of stars in the galaxy, and there are hundreds of billions of galaxies in the observable universe. What's in store for all of that? How does the universe end?
然而地球也僅僅是太陽系中的行星之一， 太陽也只是銀河系中數千億顆恒星之一， 而在我們可以觀測的宇宙之中， 還有著數以千億計的其他星系。 所有這一切的命運將會是什麼？宇宙會終結嗎？
1 “熱寂就要降臨”The science is much less settled on how that will happen. We're not even sure if the universe will come to a firm, defined end, or just slowly tail off. Our best understanding of physics suggests there are several options for the universal apocalypse. It also offers some hints on how we might, just maybe, survive it.
依照我們目前的科學認識水準甚至還無力去探討這一切為何會如此，
自誕生以來， 我們的宇宙便處於不停的膨脹之中
Our first clue to the end of the universe comes from thermodynamics, the study of heat. Thermodynamics is the wild-eyed street preacher of physics, bearing a cardboard placard with a simple warning: "THE HEAT DEATH IS COMING".
我們對於宇宙終結的第一個線索來自熱力學， 也就是對熱的研究。 熱力學就像是個一臉猙獰的物理學傳道士， 沿著街道行走， 手上拿著一張大大的海報， 上面寫著：“熱寂就要降臨”(THE HEAT DEATH IS COMING)。
Despite the name, the heat death of the universe isn't a fiery inferno. Instead, it's the death of all differences in heat.
但儘管從名字上聽起來非常恐怖，
但它的實際意義並非是說我們將會被活活燒死，
這裡的“熱寂”更多指代的是熱力差的消亡。
This may not sound scary, but the heat death is far worse than being burnt to a crisp. That's because nearly everything in everyday life requires some kind of temperature difference, either directly or indirectly.
這聽上去似乎並沒有什麼大不了的， 但實際上這樣的前景甚至要比將我們直接燒死更加糟糕。 這是因為我們生活中的幾乎任何事物都需要仰賴於某種程度溫差的存在，
For instance, your car runs because it's hotter inside its engine than outside. Your computer runs on electricity from the local power plant, which probably works by heating water and using that to power a turbine. And you run on food, which exists thanks to the enormous temperature difference between the Sun and the rest of the universe.
舉例來說，
你的小汽車之所以能夠在路上開動，
這是因為你的車子的引擎內部溫度要比外部更高。
你使用的家用電腦需要依賴你家附近的發電廠提供能源，
而那座電 廠的工作基礎可能是燒水使之沸騰並用水蒸氣驅動發電機組。
另外，
你需要吃東西來維持生命，
而你之所以會有食物可吃，
還要感謝太陽與宇宙其他區域之間存在的溫度差。
目前認為， 宇宙有4種可能的最終命運， 但它們的共同點都是毀滅
However, once the universe reaches heat death, everything everywhere will be the same temperature. That means nothing interesting will ever happen again.
然而， 一旦宇宙抵達熱寂狀態， 宇宙中任何區域， 一切事物都將是同一個溫度。 這就意味著宇宙中任何“有趣”的事物都將不復存在。
Every star will die, nearly all matter will decay, and eventually all that will be left is a sparse soup of particles and radiation. Even the energy of that soup will be sapped away over time by the expansion of the universe, leaving everything just a fraction of a degree above absolute zero.
In this "Big Freeze", the universe ends up uniformly cold, dead and empty.
所有的恒星都將死亡， 幾乎所有的物質都已經衰變分解， 最終整個宇宙中將只剩下稀疏分佈的均勻的粒子與輻射“湯”。 甚至連這“宇宙湯”中的能量也將最終隨著宇宙的膨脹而被徹底稀釋掉， 使其溫度降到只比絕對零度超出一點點的水準上——就在這“大凍結”(Big Freeze)中， 整個宇宙陷入一片死寂：均勻而徹底的寒冷，
After the development of thermodynamics in the early 1800s, heat death looked like the only possible way the universe could end. But 100 years ago, Albert Einstein's theory of general relativity suggested that the universe had a far more dramatic fate.
實際上， 在19世紀初物理學家們最初發展出熱力學理論時， 人們曾經一度認為這樣的“熱寂”理論似乎就是我們的宇宙唯一確定的宿命。 但在大約100年前， 愛因斯坦提出的廣義相對論卻指出， 宇宙將面臨遠比這更加狂暴的命運。
M47星系，所有的星系都在遠離我們，宇宙正在加速膨脹
2 “大凍結”還是“大塌縮”？General relativity says that matter and energy warp space and time. This relationship between space-time and matter-energy (stuff) — between the stage and the actors on it — extends to the entire universe. The stuff in the universe, according to Einstein, determines the ultimate fate of the universe itself.
相對論指出物質和能量會彎曲時空。這種“時空”與“質能”之間的關係就像是舞臺與在它上面表演的演員，只是在這裡舞臺延伸到了整個宇宙。而根據愛因斯坦的想法，宇宙中的物質將決定宇宙本身的最終命運。
The theory predicted that the universe as a whole must either be expanding or contracting. It could not stay the same size. Einstein realized this in 1917, and was so reluctant to believe it that he fudged his own theory.
相對論預言，作為一個整體，宇宙必定正處於膨脹或收縮的狀態下，而不可能保持相同大小。愛因斯坦是在1917年意識到這一點的，在當時他完全無法接受這樣的結果，以至於認為一定是自己的理論哪裡出錯了。
Then in 1929, the American astronomer Edwin Hubble found hard evidence that the universe was expanding. Einstein changed his mind, calling his previous insistence on a static universe the "greatest blunder" of his career.
隨後在1929年，美國天文學家愛德溫·哈勃發現了宇宙的確正在膨脹的證據。獲悉這一情況之後，愛因斯坦改變了自己的觀點，並將自己此前對靜態宇宙理論的堅持稱為“我職業生涯中最大的錯誤”。
If the universe is expanding, it must once have been much smaller than it is now. This realization led to the Big Bang theory: the idea that the universe began as something incredibly small, and then expanded incredibly quickly. We can see the "afterglow" of the Big Bang even today, in the cosmic microwave background radiation – a constant stream of radio waves, coming from all directions in the sky.
那麼如果宇宙的確正處於膨脹之中，那麼在此之前宇宙一定要比現在更小。這一想法催生了宇宙大爆炸學說的出現。該理論認為宇宙最初是從某種極端微小的開端肇始 的，隨後發生了難以置信的快速膨脹。甚至在今天我們仍然能夠在微波波段的背景輻射中目睹宇宙大爆炸留下的“餘暉”，這是一種均勻的電磁波信號，分佈在宇宙 的所有方向上。
宇宙微波背景輻射(CMB)。這是宇宙大爆炸的餘暉
The fate of the universe, then, hinges on a very simple question: will the universe continue to expand, and how quickly?
於是，我們所在宇宙的命運完全取決於一個非常簡單的問題的答案：宇宙將會繼續膨脹嗎？這種膨脹有多快？
For a universe containing normal "stuff", such as matter and light, the answer to this question depends on how much stuff there is. More stuff means more gravity, which pulls everything back together and slows the expansion.
對於一個包含大量常規“充填物”的宇宙，如物質和光，那麼這個問題的答案就取決於這些“充填物”的量有多少。更多的“充填物”就意味著更加強大的引力，而這會將一切“往回拉”，從而導致宇宙的膨脹減速。
As long as the amount of stuff doesn't go over a critical threshold, the universe will continue to expand forever, and eventually suffer heat death, freezing out.
只要這些“充填物”的量沒有多到超過某個臨界點，那麼我們宇宙將會繼續膨脹，並最終抵達熱寂狀態，在“大凍結”(Big Freeze)中迎來死亡。
But if there's too much stuff, the expansion of the universe will slow down and stop. Then the universe will begin to contract. A contracting universe will shrink smaller and smaller, getting hotter and denser, eventually ending in a fabulously compact inferno, a sort of reverse Big Bang known as the Big Crunch.
但如果宇宙中“充填物”的數量超過了臨界值水準，那麼宇宙的膨脹就將不斷減速並最後停滯。隨後，宇宙開始出現收縮，變得越來越小，溫度不斷上升，密度不斷加大。最終，宇宙迎來終極壓縮的命運——與大爆炸的情景相反，這種情況被人們稱作“大塌縮”(Big Crunch)。
宇宙可能在“大塌縮”中自行塌縮
For most of the 20th century, astrophysicists weren't sure which of these scenarios would play out. Would it be the Big Freeze or the Big Crunch? Ice or fire?
在20世紀的大部分時間裡，天體物理學家們無法判斷這兩種可能情景中究竟哪一種才是真實情況。我們究竟將迎來何種終極命運？“大凍結”還是“大塌縮”？冰還是火？
They tried to perform a cosmic census, adding up how much stuff there is in our universe. It turned out that we're strangely close to the critical threshold, leaving our fate uncertain.
於是他們決定開展一次宇宙大調查，目的是查明宇宙中究竟含有多少“充填物”。這項研究的結果卻發現我們宇宙中“充填物”的量奇怪的恰好位於臨界點的附近，這就讓我們宇宙的未來命運變得捉摸不定。
3 “大轉變”與“終極生態災難”That all changed at the end of the 20th century. In 1998, two competing teams of astrophysicists made an astonishing announcement: the expansion of the universe is speeding up.
然而這一切都在20世紀末的一天被徹底改變了。在1998年，兩個相互競爭的獨立研究小組先後宣佈了一項驚人結果：宇宙的膨脹正在加速。
Normal matter and energy can't make the universe behave this way. This was the first evidence of a fundamentally new kind of energy, dubbed "dark energy", which didn't behave like anything else in the cosmos.
這種現象是難以解釋的。正常的物質和能量不可能造成這種情況的出現。這是人類首次接觸到一類全新的能量形式——被稱為“暗能量”(dark energy)存在的線索，其行為特徵與宇宙中任何其他東西都完全不同。
Dark energy pulls the universe apart. We still don't understand what it is, but roughly 70% of the energy in the universe is dark energy, and that number is growing every day.
暗能量正在撕裂整個宇宙。科學家們到目前為止仍然未能理解暗能量究竟是什麼東西，但他們已經可以判定，整個宇宙中大約70%的能量屬於暗能量，並且這一數字每天都在增加。
“大塌縮”導致宇宙走向過熱的毀滅
The existence of dark energy means that the amount of stuff in the universe doesn't get to determine its ultimate fate.
Instead, dark energy controls the cosmos, accelerating the expansion of the universe for all time. This makes the Big Crunch much less likely.
But that doesn't mean that the Big Freeze is inevitable. There are other possibilities.
One of them originated, not in the study of the cosmos, but in the world of subatomic particles. This is perhaps the strangest fate for the universe. It sounds like something out of science fiction, and in a way, it is.
暗能量的存在意味著宇宙的終極命運並非由其內部所含的“充填物”來決定。相反，暗能量控制了宇宙的前途，它讓宇宙不斷加速膨脹。面對這樣的情況，“大塌縮” 的前景已經變得非常不可能。但這也並不意味著“大凍結”是無法避免的。這其中還存在著其他的可能性。其中的一項理論並非源自宇宙學研究領域，而是來自亞原子粒子研究領域。
在特定的條件下，液態水可以在低於冷凝點的情況下不發生凍結
In Kurt Vonnegut's classic sci-fi novel Cat's Cradle, ice-nine is a new form of water ice with a remarkable property: it freezes at 46 °C, not at 0 °C. When a crystal of ice-nine is dropped into a glass of water, all the water around it immediately patterns itself after the crystal, since it has lower energy than liquid water.
< p="">美國作家庫爾特·馮內古特(Kurt Vonnegut)在其經典科幻小說《貓的搖籃》(Cat's Cradle)一書中設想了一種新的水冰形式，叫做“冰-9”(ice-nine)，它的凝結溫度不是0攝氏度，而是46攝氏度。當一顆“冰-9”晶體被丟進一杯水裡，這顆晶體周圍的水分子便立即開始轉變為與“冰-9”相同的結構，因為前者的結構擁有更低的能級。The new crystals of ice-nine do the same thing to the water around them, and in the blink of an eye, the chain reaction turns all the water in the glass — or (spoiler alert!) all of Earth's oceans — into solid ice-nine.
隨後這些新形成的“冰-9”分子又開始對其周圍的其他水分子產生同樣的作用——在一瞬間，失控的鏈式反應已經將整杯水全部變為“冰-9”成分——它也可以瞬間將整個地球上所有海洋中的水體全部變成“冰-9”。
The same thing can happen in real life with normal ice and normal water. If you put very pure water into a very clean glass, and cool it just below 0°C, the water will become supercooled: it stays liquid below its natural freezing point. There are no impurities in the water and no rough patches on the glass, so there's nowhere for the ice to start forming. But if you drop a crystal of ice into the glass, the water will freeze rapidly, just like ice-nine.
同樣的情況在現實中使用正常的冰和正常的水也會發生。如果你使用非常純淨的水，將其倒入一隻非常乾淨的玻璃杯中，然後將其降溫到剛好低於零度的水準。此時杯中的水體將處於過冷卻狀態：儘管水溫已經跌破凝結溫度，但水體依舊保持液態。這是由於水體非常純淨，杯子內壁也非常光滑，完全沒有瑕疵，冰無法找到開始凝結的地點。但如果此時你將一顆小冰粒扔進杯子裡，這杯水就將迅速凝固——就像“冰-9”產生的效應那樣。
Ice-nine and supercooled water may not seem relevant to the fate of the universe. But something similar could happen to space itself.
這裡討論的“冰-9”和過冷卻水當然不會對宇宙的命運產生什麼影響。但空間之中可能會上演相似的情形。
或許存在一種能級更低的新形式的“真空”。如果這樣的情況的確存在，那麼對於我們絕對不是什麼好消息
Quantum physics dictates that even in a totally empty vacuum, there is a small amount of energy. But there might also be some other kind of vacuum, which holds less energy.
If that's true, then the entire universe is like a glass of supercooled water. It will only last until a "bubble" of lower-energy vacuum shows up.
量子物理學原理指出，即便在完全的真空之中實際上也存在非常少量的能量。但可能還存在另外一種類型的真空，其所包含的能量更低。如果這一想法正確，那麼我們的整個宇宙就像是那一杯處於過冷卻狀態的水。它一直存在著，直到有一顆能級更低的“小冰晶”出現。
Fortunately, there are no such bubbles that we're aware of. Unfortunately, quantum physics also dictates that if a lower-energy vacuum is possible, then a bubble of that vacuum will inevitably dart into existence somewhere in the universe.
幸運的是，我們目前還尚未觀測到這類“小冰晶”存在的跡象。但同時不幸的是，量子物理學同時也指出，如果一種更低能級的真空狀態是可能的，那麼這種真空將無法避免的在某個時刻於宇宙的某處出現。
When that happens, just like ice-nine, the new vacuum will "convert" the old vacuum around it. The bubble would expand at nearly the speed of light, so we'd never see it coming.
Inside the bubble, things would be radically different, and not terribly hospitable.
如果發生了這種情況，就像一顆“冰-9” 被丟進了宇宙這杯水裡——新的，能級更低的真空將會把其周圍“舊的真空”轉變為與它一樣的“新的真空”。這顆“小冰晶”造成的影響將以接近光速的速度擴散 開來，因此我們將永遠無法預見到它的到來(有沒有讓你想到大劉《三體》裡的二維化？)。一旦轉變完成，一切都將變得極為不同。
量子物理學原理指出，即便是“完全的”真空中也存在著能量
The properties of fundamental particles like electrons and quarks could be entirely different, radically rewriting the rules of chemistry and perhaps preventing atoms from forming.
Humans, planets and even the stars themselves would be destroyed in this Big Change. In a 1980 paper, Physicists Sidney Coleman and Frank de Luccia called it "the ultimate ecological catastrophe".
一些基本粒子，如電子與誇克的性質將變得完全不同，從而徹底改寫化學定律，甚至可能導致原子無法形成。在這一“大轉變”中，人類，行星，甚至是恒星本身都將被徹底摧毀。在一篇發表於1980年的論文中，物理學家悉尼·科爾曼(Sidney Coleman)和弗蘭克·盧西亞(Frank de Luccia)將這一前景稱為“終極生態災難”(the ultimate ecological catastrophe)。
Adding insult to injury, dark energy would probably behave differently after the Big Change. Rather than driving the universe to expand faster, dark energy might instead pull the universe in on itself, collapsing into a Big Crunch.
更為雪上加霜的是，在“大轉變”之後，暗能量的表現形式可能將變得有所不同。與此前導致宇宙不斷加速膨脹不同，此時的暗能量可能將轉而導致宇宙不斷收縮，並最終迎來“大塌縮”。
幽靈暗能量將撕裂並毀滅宇宙中的一切
4 “大撕裂”與“幽靈暗能量”There is a fourth possibility, and once again dark energy is at centre stage. This idea is very speculative and unlikely, but it can't yet be ruled out. Dark energy might be even more powerful than we thought, and might be enough to end the universe on its own, without any intervening Big Change, Freeze, or Crunch.
另外還有第四可能的情形，在這種情形中暗能量仍然居於中心位置。不過這一理論給出的前景是高度揣測性的，因而可能性非常低，但即便如此仍然不能予以完全的排 除。該理論的中心思想是：暗能量很有可能比我們目前所想像的更加強大，它甚至可以憑藉一己之力直接造成宇宙的終結，而根本不需要經過什麼“大轉變”、“大凍結”或是“大塌縮”。
Dark energy has a peculiar property. As the universe expands, its density remains constant. That means more of it pops into existence over time, to keep pace with the increasing volume of the universe. This is unusual, but doesn't break any laws of physics.
暗能量具有一種非常奇特的性質。隨著宇宙膨脹，它的密度不會發生變化。這就意味著隨著時間推移，宇宙中正在產生越來越多的暗能量，從而能夠跟上宇宙不斷膨脹的空間並保持其密度的不變。這種情況非常不同尋常，但並未打破任何的物理學定律。
However, it could get weirder. What if the density of dark energy increases as the universe expands? In other words, what if the amount of dark energy in the universe increases more quickly than the expansion of the universe itself?
然而情況還可以變得更加詭異——如果暗能量的密度隨著宇宙的膨脹而增加，情況將會如何？換句話說，如果宇宙中暗能量的增加速度超過了宇宙本身的膨脹速度，那將會如何？
This idea was put forward by Robert Caldwell of Dartmouth College in Hanover, New Hampshire. He calls it "phantom dark energy". It leads to a remarkably strange fate for the universe.
這個問題是由美國新罕布什爾州達特茅斯學院的羅伯特·查得威爾(Robert Caldwell)提出來的。他將其稱為“幽靈暗能量”(phantom dark energy)，它將引導宇宙走向一條詭異的命運之路。
幽靈暗能量將開始撕裂星系
If phantom dark energy exists, then the dark side is our ultimate downfall, just like Star Wars warned us it would be.
如果所謂的“幽靈暗能量”真的存在，那麼“黑暗終將勝利”——正如電影《星球大戰》中警告我們的那樣。
Right now, the density of dark energy is very low, far less than the density of matter here on Earth, or even the density of the Milky Way galaxy, which is much less dense than Earth. But as time goes on, the density of phantom dark energy would build up, and tear the universe apart.
目前，宇宙中暗能量的密度還非常低，遠低於地球上物質的密度水準，甚至是銀河系中物質的密度水準。但隨著時間的推移，這種“幽靈暗能量”將會持續累積並最終撕裂宇宙。
In a 2003 paper, Caldwell and his colleagues outlined a scenario they called "cosmic doomsday". Once the phantom dark energy becomes more dense than a particular object, that object gets torn to shreds.
在一篇2003年發表的論文中，查得威爾和他的同事們構建出了一套他們稱之為“宇宙末日”(cosmic doomsday)的理論。其核心內容是：一旦“幽靈暗能量”的密度超過宇宙中的某一個物體，這個物體就將被撕裂。
First, phantom dark energy would pull the Milky Way apart, sending its constituent stars flying. Then the solar system would be unbound, because the pull of dark energy would be stronger than the pull of the Sun on the Earth.
這也就意味著，“幽靈暗能量”將首先撕裂銀河系，其中的恒星將散落各處。隨後密度更高的太陽系將會被撕裂，因為此時暗能量將物質撕裂開的力量已經超過了太陽引力場對地球和其他公轉天體的牽引作用。
Finally, in a few frantic minutes the Earth would explode. Then atoms themselves would shatter, a fraction of a second before the universe itself ripped apart. Caldwell calls this the Big Rip.
緊接著，在短短幾分鐘內，地球將會被撕裂。再然後，原子將被粉碎，最終，整個宇宙將會被撕碎。查得威爾將這種前景稱為“大撕裂”(the Big Rip)。
“大撕裂”將撕碎恒星和行星
The Big Rip is, by Caldwell's own admission, "very outlandish" – and not just because it sounds like something out of an over-the-top superhero comic.
查爾維爾自己也承認，他的“大撕裂”理論看上去非常怪誕離奇，但這並不意味著它完全不可能發生。
Phantom dark energy flies in the face of some fairly basic ideas about the universe, like the assumption that matter and energy can't go faster than the speed of light. There are good reasons not to believe in it.
有關幽靈暗能量的理論與一些基本宇宙理論之間存在存在衝突，比如一項基本的傳統假設，即認為物質與能量的運動速度不可超越光速。因此我們有足夠的理由拒絕相信這一理論。
Based on our observations of the expansion of the universe, and particle physics experiments, it seems much more likely that the ultimate fate of our universe is a Big Freeze, possibly followed by a Big Change and a final Big Crunch.
基於我們對宇宙膨脹的觀測以及粒子物理學的實驗結果，宇宙的最終命運更有可能是“大凍結”，很有可能在那之後還會經歷“大轉變”以及一次終極的“大塌縮”。
5 逃離厄運的希望But this is a remarkably grim portrait of the future — aeons of cold emptiness, finally terminated by a vacuum decay and a final implosion into nothingness. Is there any escape? Or are we doomed to book a table at the Restaurant at the End of the Universe?
這樣的未來一片黑暗——亙古持久的冰冷空曠，隨後在一次真空衰變中被終結，最終迎來終極塌縮，一切全部消失。有沒有可能逃離這樣的噩夢？抑或這是我們命中註定的末日？
All this shall pass, but not for a very long time
There's certainly no reason for us, individually, to worry about the end of the universe. All of these events are trillions of years into the future, with the possible exception of the Big Change, so they're not exactly an imminent problem.
當然對於我們每個單獨的個體而言，根本就沒有必要去擔心這樣的事情。因為除了“大轉變”的時間可能還難以預料之外，以上所討論的這些事都是在億萬年之後才有可能發生的，因此對於我們而言，它們還“尚未成為”某種非常重要的問題。
Also, there's no reason to worry about humanity. If nothing else, genetic drift will have rendered our descendants unrecognizable long before then. But could intelligent feeling creatures of any kind, human or not, survive?
另外，我們似乎也根本不必為人類的命運擔憂。如果沒有發生其他變故，經歷如此久遠的時間，光是遺傳漂變效應就已經足以讓我們的後代變得與今天的我們完全不同。那麼退一萬步說，那時候的某種“智慧生物”將能夠逃離這樣的毀滅命運嗎？
Physicist Freeman Dyson of the Institute for Advanced Studies in Princeton, New Jersey considered this question in a classic paper published in 1979. At the time, he concluded that life could modify itself to survive the Big Freeze, which he thought was less challenging than the inferno of the Big Crunch.
美國普林斯頓高等學術研究所的物理學家弗裡曼·戴森(Freeman Dyson)在1979年發表的一篇經典論文中探討過這個問題。在當時，戴森認為生命體可以通過對自身進行改造，從而在“大凍結”中倖存。戴森認為逃過“大凍結”要比經歷可怕的“大塌縮”容易得多。
But these days, he's much less optimistic, thanks to the discovery of dark energy.
"If the universe is accelerating, that's really bad news," says Dyson. Accelerating expansion means we'll eventually lose contact with all but a handful of galaxies, dramatically limiting the amount of energy available to us. "It's a rather dismal situation in the long run."
然而時至今日，由於暗能量的發現，戴森對於這個問題的樂觀情緒已經幾乎完全消散了。對此他曾經發表過自己的觀點：“如果宇宙正在加速膨脹，那可真是一個壞消息。”加速的膨脹意味著我們將最終失去與絕大部分星系之間的聯繫，從而大大限制我們能夠獲取的能 源數量。戴森表示：“從長遠來看，這是一種非常糟糕的情 況。”
The situation could still change. "We really don't know whether the expansion is going to continue since we don't understand why it's accelerating," says Dyson. "The optimistic view is that the acceleration will slow down as the universe gets bigger." If that happens, "the future is much more promising."
然而情況仍然可能發生變化。戴森指出：“我們目前仍然無法確定這樣的膨脹是否將會一直持續下去，因為我們根本還不理解宇宙為何會加速膨脹。對此較為樂觀的觀點是，隨著宇宙變得越來越大，這樣的加速終將停滯。如果是那樣，那麼我們的未來將會明朗得多。”
But what if the expansion doesn't slow down, or if it becomes clear that the Big Change is coming? Some physicists have proposed a solution that is solidly in mad-scientist territory. To escape the end of the universe, we should build our own universe in a laboratory, and jump in.
可是如果宇宙的膨脹並沒有出現減速呢？或者說，如果有朝一日事情變的明朗，那就是“大轉變”即將來臨，那時候將會如何？對此，一些物理學家們給出了自己的解決方案，但聽上去完全就像是一群瘋子科學家的設想：要想逃離宇宙終結的命運，那就在實驗室裡創建我們自己的黑洞，然後跳進去。
新生的宇宙曾經經歷過極其迅速的膨脹，即所謂的“暴漲”理論
One physicist who has worked on this idea is Alan Guth of MIT in Cambridge, Massachusetts, who is known for his work on the very early universe.
"I can't say that the laws of physics absolutely imply that it's possible," says Guth. "If it is possible, it would require technology vastly beyond anything that we can foresee. It would require huge amounts of energy that one would need to be able to obtain and control."
這些物理學家中的一位是美國麻省理工學院的阿蘭·古斯(Alan Guth)，他是極早期宇宙研究方面的頂尖專家。古斯教授表示：“我無法確認物理學定律是否真的允許這樣做。但如果這是可能的，那麼這也將需要極高的，遠遠超出我們目前能夠預見的技術水準。我們也將需要巨大的能量來創造黑洞並對其進行操控。”
The first step, according to Guth, would be creating an incredibly dense form of matter — so dense that it was on the verge of collapsing into a black hole. By doing that in the right way, and then quickly clearing the matter out of the area, you might be able to force that region of space to start expanding rapidly.
阿蘭表示，作為第一步，我們需要創造出一種密度極高的物質——它的密度需要高到幾乎達到只差一點就會自行塌縮為黑洞的臨界點。如果能夠以恰當的方式實現這一步，並迅速清空該區域周圍的其他物質，那麼我們就有可能迫使這一空間區域發生快速膨脹。
In effect, you would jump-start the creation of an entirely new universe. As the space in the region expanded, the boundary would shrink, creating a bubble of warped space where the inside was bigger than the outside.
事實上，此時你已經開始創造了一個全新的宇宙。隨著該區域空間的膨脹，宇宙的邊界將會收縮，形成一個扭曲的空間“氣泡”，此時的“裡面”要比“外面”更大。
大爆炸：宇宙的開端
That may sound familiar to Doctor Who fans, and according to Guth, the TARDIS is "probably a very accurate analogy" for the kind of warping of space he's talking about.
古斯表示，這樣的情景對於《神秘博士》(Doctor Who)的粉絲們可能並不陌生，這部科幻劇裡面的TARDIS可能是對於他所提到的空間扭曲模式“相當精准的描述”。
Eventually, the outside would shrink to nothingness, and the new baby universe would pinch off from our own, spared from whatever fate our universe may meet.
最終，外部的世界完全收縮並消失，新生的宇宙將讓我們得以逃脫“舊”宇宙中我們將要面臨的所有厄運。
It's far from certain that this scheme would actually work. "I would have to say that it's unclear," says Guth. "We don't really know if it's possible or not."
不過基於我們當前的認識水準，我們還遠遠無法確定這樣做是否真的可行。古斯表示：“我必須指出，對於這一點我們還不甚清楚。我們目前還無法確定這樣做是否真的可行。”
However, Guth also points out that there is another source of hope beyond the end of the universe – well, hope of a sort.
不過，古斯也指出，除此之外我們在面對宇宙的終結時或許還有著另外的一絲希望——對，只有一絲而已。
“多重宇宙”與“宇宙氣泡”
暴漲理論認為我們所處的宇宙僅僅是所謂“多重宇宙”中的一個，並且存在著一個永恆膨脹的“背景”，它在不斷製造出像我們所處的宇宙這樣的新的“宇宙氣泡”
Guth was the first to propose that the very early universe expanded astonishingly fast for a tiny fraction of a second, an idea known as "inflation". Many cosmologists now believe inflation is the most promising approach for explaining the early universe, and Guth's plan for creating a new universe relies on recreating this rapid expansion.
古斯是最早提出早期宇宙曾經在極短的時間內經歷過一次極高速膨脹的科學家之一，這就是所謂的“宇宙暴漲”(inflation)。許多宇宙學家現在都相信暴漲理論是目前解釋早期宇宙中各類現象的最佳理論。而古斯所說的那“一絲希望”正是基於重現這樣的暴漲。
Inflation has an intriguing consequence for the ultimate fate of the universe. The theory dictates that the universe we inhabit is just one small part of a multiverse, with an eternally inflating background continually spawning "pocket universes" like our own.
暴漲對於宇宙的命運有著奇妙的影響。該理論認為我們所處的宇宙僅僅是所謂“多重宇宙”(multiverse)中的一個，並且存在著一個永恆膨脹的“背景”，它在不斷製造出像我們所處的宇宙這樣的新的“宇宙氣泡”。
"If that's the case, even if we're convinced that an individual pocket universe will ultimately die through refrigeration, the multiverse as a whole will go on living forever, with new life being created in each pocket universe as it's created," says Guth. "In this picture, the multiverse as a whole is genuinely eternal, at least eternal into the future, even as individual pocket universes live and die."
古斯表示：“如果情況的確如此，那麼即便我們知道每一個單獨的宇宙‘氣泡’最終將會死亡，但多重宇宙將會永生，在每一個新的‘宇宙氣泡’中都有新的生命被產生出來。在這樣的圖景之中，多重宇宙作為一個整體是永恆的存在，至少在未來是永恆的，儘管單個的宇宙‘氣泡’們不斷的誕生，然後死亡。”
In other words, Franz Kafka may have been right on the money when he said that there is "plenty of hope, an infinite amount of hope—but not for us."
卡夫卡的那句話也許說的很對，他說：“有很多希望，無限多的希望——但不是我們的。”
By Adam Becker
M47星系，所有的星系都在遠離我們，宇宙正在加速膨脹
2 “大凍結”還是“大塌縮”？General relativity says that matter and energy warp space and time. This relationship between space-time and matter-energy (stuff) — between the stage and the actors on it — extends to the entire universe. The stuff in the universe, according to Einstein, determines the ultimate fate of the universe itself.
相對論指出物質和能量會彎曲時空。這種“時空”與“質能”之間的關係就像是舞臺與在它上面表演的演員，只是在這裡舞臺延伸到了整個宇宙。而根據愛因斯坦的想法，宇宙中的物質將決定宇宙本身的最終命運。
The theory predicted that the universe as a whole must either be expanding or contracting. It could not stay the same size. Einstein realized this in 1917, and was so reluctant to believe it that he fudged his own theory.
相對論預言，作為一個整體，宇宙必定正處於膨脹或收縮的狀態下，而不可能保持相同大小。愛因斯坦是在1917年意識到這一點的，在當時他完全無法接受這樣的結果，以至於認為一定是自己的理論哪裡出錯了。
Then in 1929, the American astronomer Edwin Hubble found hard evidence that the universe was expanding. Einstein changed his mind, calling his previous insistence on a static universe the "greatest blunder" of his career.
隨後在1929年，美國天文學家愛德溫·哈勃發現了宇宙的確正在膨脹的證據。獲悉這一情況之後，愛因斯坦改變了自己的觀點，並將自己此前對靜態宇宙理論的堅持稱為“我職業生涯中最大的錯誤”。
If the universe is expanding, it must once have been much smaller than it is now. This realization led to the Big Bang theory: the idea that the universe began as something incredibly small, and then expanded incredibly quickly. We can see the "afterglow" of the Big Bang even today, in the cosmic microwave background radiation – a constant stream of radio waves, coming from all directions in the sky.
那麼如果宇宙的確正處於膨脹之中，那麼在此之前宇宙一定要比現在更小。這一想法催生了宇宙大爆炸學說的出現。該理論認為宇宙最初是從某種極端微小的開端肇始 的，隨後發生了難以置信的快速膨脹。甚至在今天我們仍然能夠在微波波段的背景輻射中目睹宇宙大爆炸留下的“餘暉”，這是一種均勻的電磁波信號，分佈在宇宙 的所有方向上。
宇宙微波背景輻射(CMB)。這是宇宙大爆炸的餘暉
The fate of the universe, then, hinges on a very simple question: will the universe continue to expand, and how quickly?
於是，我們所在宇宙的命運完全取決於一個非常簡單的問題的答案：宇宙將會繼續膨脹嗎？這種膨脹有多快？
For a universe containing normal "stuff", such as matter and light, the answer to this question depends on how much stuff there is. More stuff means more gravity, which pulls everything back together and slows the expansion.
對於一個包含大量常規“充填物”的宇宙，如物質和光，那麼這個問題的答案就取決於這些“充填物”的量有多少。更多的“充填物”就意味著更加強大的引力，而這會將一切“往回拉”，從而導致宇宙的膨脹減速。
As long as the amount of stuff doesn't go over a critical threshold, the universe will continue to expand forever, and eventually suffer heat death, freezing out.
只要這些“充填物”的量沒有多到超過某個臨界點，那麼我們宇宙將會繼續膨脹，並最終抵達熱寂狀態，在“大凍結”(Big Freeze)中迎來死亡。
But if there's too much stuff, the expansion of the universe will slow down and stop. Then the universe will begin to contract. A contracting universe will shrink smaller and smaller, getting hotter and denser, eventually ending in a fabulously compact inferno, a sort of reverse Big Bang known as the Big Crunch.
但如果宇宙中“充填物”的數量超過了臨界值水準，那麼宇宙的膨脹就將不斷減速並最後停滯。隨後，宇宙開始出現收縮，變得越來越小，溫度不斷上升，密度不斷加大。最終，宇宙迎來終極壓縮的命運——與大爆炸的情景相反，這種情況被人們稱作“大塌縮”(Big Crunch)。
宇宙可能在“大塌縮”中自行塌縮
For most of the 20th century, astrophysicists weren't sure which of these scenarios would play out. Would it be the Big Freeze or the Big Crunch? Ice or fire?
在20世紀的大部分時間裡，天體物理學家們無法判斷這兩種可能情景中究竟哪一種才是真實情況。我們究竟將迎來何種終極命運？“大凍結”還是“大塌縮”？冰還是火？
They tried to perform a cosmic census, adding up how much stuff there is in our universe. It turned out that we're strangely close to the critical threshold, leaving our fate uncertain.
於是他們決定開展一次宇宙大調查，目的是查明宇宙中究竟含有多少“充填物”。這項研究的結果卻發現我們宇宙中“充填物”的量奇怪的恰好位於臨界點的附近，這就讓我們宇宙的未來命運變得捉摸不定。
3 “大轉變”與“終極生態災難”That all changed at the end of the 20th century. In 1998, two competing teams of astrophysicists made an astonishing announcement: the expansion of the universe is speeding up.
然而這一切都在20世紀末的一天被徹底改變了。在1998年，兩個相互競爭的獨立研究小組先後宣佈了一項驚人結果：宇宙的膨脹正在加速。
Normal matter and energy can't make the universe behave this way. This was the first evidence of a fundamentally new kind of energy, dubbed "dark energy", which didn't behave like anything else in the cosmos.
這種現象是難以解釋的。正常的物質和能量不可能造成這種情況的出現。這是人類首次接觸到一類全新的能量形式——被稱為“暗能量”(dark energy)存在的線索，其行為特徵與宇宙中任何其他東西都完全不同。
Dark energy pulls the universe apart. We still don't understand what it is, but roughly 70% of the energy in the universe is dark energy, and that number is growing every day.
暗能量正在撕裂整個宇宙。科學家們到目前為止仍然未能理解暗能量究竟是什麼東西，但他們已經可以判定，整個宇宙中大約70%的能量屬於暗能量，並且這一數字每天都在增加。
“大塌縮”導致宇宙走向過熱的毀滅
The existence of dark energy means that the amount of stuff in the universe doesn't get to determine its ultimate fate.
Instead, dark energy controls the cosmos, accelerating the expansion of the universe for all time. This makes the Big Crunch much less likely.
But that doesn't mean that the Big Freeze is inevitable. There are other possibilities.
One of them originated, not in the study of the cosmos, but in the world of subatomic particles. This is perhaps the strangest fate for the universe. It sounds like something out of science fiction, and in a way, it is.
暗能量的存在意味著宇宙的終極命運並非由其內部所含的“充填物”來決定。相反，暗能量控制了宇宙的前途，它讓宇宙不斷加速膨脹。面對這樣的情況，“大塌縮” 的前景已經變得非常不可能。但這也並不意味著“大凍結”是無法避免的。這其中還存在著其他的可能性。其中的一項理論並非源自宇宙學研究領域，而是來自亞原子粒子研究領域。
在特定的條件下，液態水可以在低於冷凝點的情況下不發生凍結
In Kurt Vonnegut's classic sci-fi novel Cat's Cradle, ice-nine is a new form of water ice with a remarkable property: it freezes at 46 °C, not at 0 °C. When a crystal of ice-nine is dropped into a glass of water, all the water around it immediately patterns itself after the crystal, since it has lower energy than liquid water.
< p="">美國作家庫爾特·馮內古特(Kurt Vonnegut)在其經典科幻小說《貓的搖籃》(Cat's Cradle)一書中設想了一種新的水冰形式，叫做“冰-9”(ice-nine)，它的凝結溫度不是0攝氏度，而是46攝氏度。當一顆“冰-9”晶體被丟進一杯水裡，這顆晶體周圍的水分子便立即開始轉變為與“冰-9”相同的結構，因為前者的結構擁有更低的能級。The new crystals of ice-nine do the same thing to the water around them, and in the blink of an eye, the chain reaction turns all the water in the glass — or (spoiler alert!) all of Earth's oceans — into solid ice-nine.
隨後這些新形成的“冰-9”分子又開始對其周圍的其他水分子產生同樣的作用——在一瞬間，失控的鏈式反應已經將整杯水全部變為“冰-9”成分——它也可以瞬間將整個地球上所有海洋中的水體全部變成“冰-9”。
The same thing can happen in real life with normal ice and normal water. If you put very pure water into a very clean glass, and cool it just below 0°C, the water will become supercooled: it stays liquid below its natural freezing point. There are no impurities in the water and no rough patches on the glass, so there's nowhere for the ice to start forming. But if you drop a crystal of ice into the glass, the water will freeze rapidly, just like ice-nine.
同樣的情況在現實中使用正常的冰和正常的水也會發生。如果你使用非常純淨的水，將其倒入一隻非常乾淨的玻璃杯中，然後將其降溫到剛好低於零度的水準。此時杯中的水體將處於過冷卻狀態：儘管水溫已經跌破凝結溫度，但水體依舊保持液態。這是由於水體非常純淨，杯子內壁也非常光滑，完全沒有瑕疵，冰無法找到開始凝結的地點。但如果此時你將一顆小冰粒扔進杯子裡，這杯水就將迅速凝固——就像“冰-9”產生的效應那樣。
Ice-nine and supercooled water may not seem relevant to the fate of the universe. But something similar could happen to space itself.
這裡討論的“冰-9”和過冷卻水當然不會對宇宙的命運產生什麼影響。但空間之中可能會上演相似的情形。
或許存在一種能級更低的新形式的“真空”。如果這樣的情況的確存在，那麼對於我們絕對不是什麼好消息
Quantum physics dictates that even in a totally empty vacuum, there is a small amount of energy. But there might also be some other kind of vacuum, which holds less energy.
If that's true, then the entire universe is like a glass of supercooled water. It will only last until a "bubble" of lower-energy vacuum shows up.
量子物理學原理指出，即便在完全的真空之中實際上也存在非常少量的能量。但可能還存在另外一種類型的真空，其所包含的能量更低。如果這一想法正確，那麼我們的整個宇宙就像是那一杯處於過冷卻狀態的水。它一直存在著，直到有一顆能級更低的“小冰晶”出現。
Fortunately, there are no such bubbles that we're aware of. Unfortunately, quantum physics also dictates that if a lower-energy vacuum is possible, then a bubble of that vacuum will inevitably dart into existence somewhere in the universe.
幸運的是，我們目前還尚未觀測到這類“小冰晶”存在的跡象。但同時不幸的是，量子物理學同時也指出，如果一種更低能級的真空狀態是可能的，那麼這種真空將無法避免的在某個時刻於宇宙的某處出現。
When that happens, just like ice-nine, the new vacuum will "convert" the old vacuum around it. The bubble would expand at nearly the speed of light, so we'd never see it coming.
Inside the bubble, things would be radically different, and not terribly hospitable.
如果發生了這種情況，就像一顆“冰-9” 被丟進了宇宙這杯水裡——新的，能級更低的真空將會把其周圍“舊的真空”轉變為與它一樣的“新的真空”。這顆“小冰晶”造成的影響將以接近光速的速度擴散 開來，因此我們將永遠無法預見到它的到來(有沒有讓你想到大劉《三體》裡的二維化？)。一旦轉變完成，一切都將變得極為不同。
量子物理學原理指出，即便是“完全的”真空中也存在著能量
The properties of fundamental particles like electrons and quarks could be entirely different, radically rewriting the rules of chemistry and perhaps preventing atoms from forming.
Humans, planets and even the stars themselves would be destroyed in this Big Change. In a 1980 paper, Physicists Sidney Coleman and Frank de Luccia called it "the ultimate ecological catastrophe".
一些基本粒子，如電子與誇克的性質將變得完全不同，從而徹底改寫化學定律，甚至可能導致原子無法形成。在這一“大轉變”中，人類，行星，甚至是恒星本身都將被徹底摧毀。在一篇發表於1980年的論文中，物理學家悉尼·科爾曼(Sidney Coleman)和弗蘭克·盧西亞(Frank de Luccia)將這一前景稱為“終極生態災難”(the ultimate ecological catastrophe)。
Adding insult to injury, dark energy would probably behave differently after the Big Change. Rather than driving the universe to expand faster, dark energy might instead pull the universe in on itself, collapsing into a Big Crunch.
更為雪上加霜的是，在“大轉變”之後，暗能量的表現形式可能將變得有所不同。與此前導致宇宙不斷加速膨脹不同，此時的暗能量可能將轉而導致宇宙不斷收縮，並最終迎來“大塌縮”。
幽靈暗能量將撕裂並毀滅宇宙中的一切
4 “大撕裂”與“幽靈暗能量”There is a fourth possibility, and once again dark energy is at centre stage. This idea is very speculative and unlikely, but it can't yet be ruled out. Dark energy might be even more powerful than we thought, and might be enough to end the universe on its own, without any intervening Big Change, Freeze, or Crunch.
另外還有第四可能的情形，在這種情形中暗能量仍然居於中心位置。不過這一理論給出的前景是高度揣測性的，因而可能性非常低，但即便如此仍然不能予以完全的排 除。該理論的中心思想是：暗能量很有可能比我們目前所想像的更加強大，它甚至可以憑藉一己之力直接造成宇宙的終結，而根本不需要經過什麼“大轉變”、“大凍結”或是“大塌縮”。
Dark energy has a peculiar property. As the universe expands, its density remains constant. That means more of it pops into existence over time, to keep pace with the increasing volume of the universe. This is unusual, but doesn't break any laws of physics.
暗能量具有一種非常奇特的性質。隨著宇宙膨脹，它的密度不會發生變化。這就意味著隨著時間推移，宇宙中正在產生越來越多的暗能量，從而能夠跟上宇宙不斷膨脹的空間並保持其密度的不變。這種情況非常不同尋常，但並未打破任何的物理學定律。
However, it could get weirder. What if the density of dark energy increases as the universe expands? In other words, what if the amount of dark energy in the universe increases more quickly than the expansion of the universe itself?
然而情況還可以變得更加詭異——如果暗能量的密度隨著宇宙的膨脹而增加，情況將會如何？換句話說，如果宇宙中暗能量的增加速度超過了宇宙本身的膨脹速度，那將會如何？
This idea was put forward by Robert Caldwell of Dartmouth College in Hanover, New Hampshire. He calls it "phantom dark energy". It leads to a remarkably strange fate for the universe.
這個問題是由美國新罕布什爾州達特茅斯學院的羅伯特·查得威爾(Robert Caldwell)提出來的。他將其稱為“幽靈暗能量”(phantom dark energy)，它將引導宇宙走向一條詭異的命運之路。
幽靈暗能量將開始撕裂星系
If phantom dark energy exists, then the dark side is our ultimate downfall, just like Star Wars warned us it would be.
如果所謂的“幽靈暗能量”真的存在，那麼“黑暗終將勝利”——正如電影《星球大戰》中警告我們的那樣。
Right now, the density of dark energy is very low, far less than the density of matter here on Earth, or even the density of the Milky Way galaxy, which is much less dense than Earth. But as time goes on, the density of phantom dark energy would build up, and tear the universe apart.
目前，宇宙中暗能量的密度還非常低，遠低於地球上物質的密度水準，甚至是銀河系中物質的密度水準。但隨著時間的推移，這種“幽靈暗能量”將會持續累積並最終撕裂宇宙。
In a 2003 paper, Caldwell and his colleagues outlined a scenario they called "cosmic doomsday". Once the phantom dark energy becomes more dense than a particular object, that object gets torn to shreds.
在一篇2003年發表的論文中，查得威爾和他的同事們構建出了一套他們稱之為“宇宙末日”(cosmic doomsday)的理論。其核心內容是：一旦“幽靈暗能量”的密度超過宇宙中的某一個物體，這個物體就將被撕裂。
First, phantom dark energy would pull the Milky Way apart, sending its constituent stars flying. Then the solar system would be unbound, because the pull of dark energy would be stronger than the pull of the Sun on the Earth.
這也就意味著，“幽靈暗能量”將首先撕裂銀河系，其中的恒星將散落各處。隨後密度更高的太陽系將會被撕裂，因為此時暗能量將物質撕裂開的力量已經超過了太陽引力場對地球和其他公轉天體的牽引作用。
Finally, in a few frantic minutes the Earth would explode. Then atoms themselves would shatter, a fraction of a second before the universe itself ripped apart. Caldwell calls this the Big Rip.
緊接著，在短短幾分鐘內，地球將會被撕裂。再然後，原子將被粉碎，最終，整個宇宙將會被撕碎。查得威爾將這種前景稱為“大撕裂”(the Big Rip)。
“大撕裂”將撕碎恒星和行星
The Big Rip is, by Caldwell's own admission, "very outlandish" – and not just because it sounds like something out of an over-the-top superhero comic.
查爾維爾自己也承認，他的“大撕裂”理論看上去非常怪誕離奇，但這並不意味著它完全不可能發生。
Phantom dark energy flies in the face of some fairly basic ideas about the universe, like the assumption that matter and energy can't go faster than the speed of light. There are good reasons not to believe in it.
有關幽靈暗能量的理論與一些基本宇宙理論之間存在存在衝突，比如一項基本的傳統假設，即認為物質與能量的運動速度不可超越光速。因此我們有足夠的理由拒絕相信這一理論。
Based on our observations of the expansion of the universe, and particle physics experiments, it seems much more likely that the ultimate fate of our universe is a Big Freeze, possibly followed by a Big Change and a final Big Crunch.
基於我們對宇宙膨脹的觀測以及粒子物理學的實驗結果，宇宙的最終命運更有可能是“大凍結”，很有可能在那之後還會經歷“大轉變”以及一次終極的“大塌縮”。
5 逃離厄運的希望But this is a remarkably grim portrait of the future — aeons of cold emptiness, finally terminated by a vacuum decay and a final implosion into nothingness. Is there any escape? Or are we doomed to book a table at the Restaurant at the End of the Universe?
這樣的未來一片黑暗——亙古持久的冰冷空曠，隨後在一次真空衰變中被終結，最終迎來終極塌縮，一切全部消失。有沒有可能逃離這樣的噩夢？抑或這是我們命中註定的末日？
All this shall pass, but not for a very long time
There's certainly no reason for us, individually, to worry about the end of the universe. All of these events are trillions of years into the future, with the possible exception of the Big Change, so they're not exactly an imminent problem.
當然對於我們每個單獨的個體而言，根本就沒有必要去擔心這樣的事情。因為除了“大轉變”的時間可能還難以預料之外，以上所討論的這些事都是在億萬年之後才有可能發生的，因此對於我們而言，它們還“尚未成為”某種非常重要的問題。
Also, there's no reason to worry about humanity. If nothing else, genetic drift will have rendered our descendants unrecognizable long before then. But could intelligent feeling creatures of any kind, human or not, survive?
另外，我們似乎也根本不必為人類的命運擔憂。如果沒有發生其他變故，經歷如此久遠的時間，光是遺傳漂變效應就已經足以讓我們的後代變得與今天的我們完全不同。那麼退一萬步說，那時候的某種“智慧生物”將能夠逃離這樣的毀滅命運嗎？
Physicist Freeman Dyson of the Institute for Advanced Studies in Princeton, New Jersey considered this question in a classic paper published in 1979. At the time, he concluded that life could modify itself to survive the Big Freeze, which he thought was less challenging than the inferno of the Big Crunch.
美國普林斯頓高等學術研究所的物理學家弗裡曼·戴森(Freeman Dyson)在1979年發表的一篇經典論文中探討過這個問題。在當時，戴森認為生命體可以通過對自身進行改造，從而在“大凍結”中倖存。戴森認為逃過“大凍結”要比經歷可怕的“大塌縮”容易得多。
But these days, he's much less optimistic, thanks to the discovery of dark energy.
"If the universe is accelerating, that's really bad news," says Dyson. Accelerating expansion means we'll eventually lose contact with all but a handful of galaxies, dramatically limiting the amount of energy available to us. "It's a rather dismal situation in the long run."
然而時至今日，由於暗能量的發現，戴森對於這個問題的樂觀情緒已經幾乎完全消散了。對此他曾經發表過自己的觀點：“如果宇宙正在加速膨脹，那可真是一個壞消息。”加速的膨脹意味著我們將最終失去與絕大部分星系之間的聯繫，從而大大限制我們能夠獲取的能 源數量。戴森表示：“從長遠來看，這是一種非常糟糕的情 況。”
The situation could still change. "We really don't know whether the expansion is going to continue since we don't understand why it's accelerating," says Dyson. "The optimistic view is that the acceleration will slow down as the universe gets bigger." If that happens, "the future is much more promising."
然而情況仍然可能發生變化。戴森指出：“我們目前仍然無法確定這樣的膨脹是否將會一直持續下去，因為我們根本還不理解宇宙為何會加速膨脹。對此較為樂觀的觀點是，隨著宇宙變得越來越大，這樣的加速終將停滯。如果是那樣，那麼我們的未來將會明朗得多。”
But what if the expansion doesn't slow down, or if it becomes clear that the Big Change is coming? Some physicists have proposed a solution that is solidly in mad-scientist territory. To escape the end of the universe, we should build our own universe in a laboratory, and jump in.
可是如果宇宙的膨脹並沒有出現減速呢？或者說，如果有朝一日事情變的明朗，那就是“大轉變”即將來臨，那時候將會如何？對此，一些物理學家們給出了自己的解決方案，但聽上去完全就像是一群瘋子科學家的設想：要想逃離宇宙終結的命運，那就在實驗室裡創建我們自己的黑洞，然後跳進去。
新生的宇宙曾經經歷過極其迅速的膨脹，即所謂的“暴漲”理論
One physicist who has worked on this idea is Alan Guth of MIT in Cambridge, Massachusetts, who is known for his work on the very early universe.
"I can't say that the laws of physics absolutely imply that it's possible," says Guth. "If it is possible, it would require technology vastly beyond anything that we can foresee. It would require huge amounts of energy that one would need to be able to obtain and control."
這些物理學家中的一位是美國麻省理工學院的阿蘭·古斯(Alan Guth)，他是極早期宇宙研究方面的頂尖專家。古斯教授表示：“我無法確認物理學定律是否真的允許這樣做。但如果這是可能的，那麼這也將需要極高的，遠遠超出我們目前能夠預見的技術水準。我們也將需要巨大的能量來創造黑洞並對其進行操控。”
The first step, according to Guth, would be creating an incredibly dense form of matter — so dense that it was on the verge of collapsing into a black hole. By doing that in the right way, and then quickly clearing the matter out of the area, you might be able to force that region of space to start expanding rapidly.
阿蘭表示，作為第一步，我們需要創造出一種密度極高的物質——它的密度需要高到幾乎達到只差一點就會自行塌縮為黑洞的臨界點。如果能夠以恰當的方式實現這一步，並迅速清空該區域周圍的其他物質，那麼我們就有可能迫使這一空間區域發生快速膨脹。
In effect, you would jump-start the creation of an entirely new universe. As the space in the region expanded, the boundary would shrink, creating a bubble of warped space where the inside was bigger than the outside.
事實上，此時你已經開始創造了一個全新的宇宙。隨著該區域空間的膨脹，宇宙的邊界將會收縮，形成一個扭曲的空間“氣泡”，此時的“裡面”要比“外面”更大。
大爆炸：宇宙的開端
That may sound familiar to Doctor Who fans, and according to Guth, the TARDIS is "probably a very accurate analogy" for the kind of warping of space he's talking about.
古斯表示，這樣的情景對於《神秘博士》(Doctor Who)的粉絲們可能並不陌生，這部科幻劇裡面的TARDIS可能是對於他所提到的空間扭曲模式“相當精准的描述”。
Eventually, the outside would shrink to nothingness, and the new baby universe would pinch off from our own, spared from whatever fate our universe may meet.
最終，外部的世界完全收縮並消失，新生的宇宙將讓我們得以逃脫“舊”宇宙中我們將要面臨的所有厄運。
It's far from certain that this scheme would actually work. "I would have to say that it's unclear," says Guth. "We don't really know if it's possible or not."
不過基於我們當前的認識水準，我們還遠遠無法確定這樣做是否真的可行。古斯表示：“我必須指出，對於這一點我們還不甚清楚。我們目前還無法確定這樣做是否真的可行。”
However, Guth also points out that there is another source of hope beyond the end of the universe – well, hope of a sort.
不過，古斯也指出，除此之外我們在面對宇宙的終結時或許還有著另外的一絲希望——對，只有一絲而已。
“多重宇宙”與“宇宙氣泡”
暴漲理論認為我們所處的宇宙僅僅是所謂“多重宇宙”中的一個，並且存在著一個永恆膨脹的“背景”，它在不斷製造出像我們所處的宇宙這樣的新的“宇宙氣泡”
Guth was the first to propose that the very early universe expanded astonishingly fast for a tiny fraction of a second, an idea known as "inflation". Many cosmologists now believe inflation is the most promising approach for explaining the early universe, and Guth's plan for creating a new universe relies on recreating this rapid expansion.
古斯是最早提出早期宇宙曾經在極短的時間內經歷過一次極高速膨脹的科學家之一，這就是所謂的“宇宙暴漲”(inflation)。許多宇宙學家現在都相信暴漲理論是目前解釋早期宇宙中各類現象的最佳理論。而古斯所說的那“一絲希望”正是基於重現這樣的暴漲。
Inflation has an intriguing consequence for the ultimate fate of the universe. The theory dictates that the universe we inhabit is just one small part of a multiverse, with an eternally inflating background continually spawning "pocket universes" like our own.
暴漲對於宇宙的命運有著奇妙的影響。該理論認為我們所處的宇宙僅僅是所謂“多重宇宙”(multiverse)中的一個，並且存在著一個永恆膨脹的“背景”，它在不斷製造出像我們所處的宇宙這樣的新的“宇宙氣泡”。
"If that's the case, even if we're convinced that an individual pocket universe will ultimately die through refrigeration, the multiverse as a whole will go on living forever, with new life being created in each pocket universe as it's created," says Guth. "In this picture, the multiverse as a whole is genuinely eternal, at least eternal into the future, even as individual pocket universes live and die."
古斯表示：“如果情況的確如此，那麼即便我們知道每一個單獨的宇宙‘氣泡’最終將會死亡，但多重宇宙將會永生，在每一個新的‘宇宙氣泡’中都有新的生命被產生出來。在這樣的圖景之中，多重宇宙作為一個整體是永恆的存在，至少在未來是永恆的，儘管單個的宇宙‘氣泡’們不斷的誕生，然後死亡。”
In other words, Franz Kafka may have been right on the money when he said that there is "plenty of hope, an infinite amount of hope—but not for us."
卡夫卡的那句話也許說的很對，他說：“有很多希望，無限多的希望——但不是我們的。”
By Adam Becker