什麼是宇宙暴脹？了解早期宇宙（內含中文視頻）

來自專欄 天文在線 https://www.zhihu.com/video/952121539857047552

視頻版權：Fraser Cain ；

字幕翻譯：天文志願字幕組（有錯誤的地方望各位指出）

翻譯@知弦

審核@從科伊伯帶隧穿到奧爾特雲

解說詞

（字幕翻譯：天文志願字幕組，若有錯誤，歡迎指出）N【視頻版權：Fraser Cain 】

宇宙大爆炸NThe Big Bang.

宇宙至今已膨脹幾十億年的發現是NThe discovery that the Universe has been expandingNfor billions of years is one of the biggest

科學發展史中最大的啟示之一Nrevelations in the history of science.

在短短一瞬間 整個宇宙突然出現 並且從那以後開始擴張至今NIn a single moment, the entire Universe poppedNinto existence, and has been expanding ever since.

我們通過多重證據發現：宇宙微波背景輻射NWe know this because of multiple lines ofNevidence: the cosmic microwave background

宇宙中的元素比例等Nradiation, the ratio of elements in the Universe, etc.

但最引人注目的只是一切事物都在彼此遠離的簡單事實NBut the most compelling one is just the simpleNfact that everything is expanding away from everything else.

那意味著 如果你向前撥轉時鐘 宇宙最初是個極端熾熱稠密的區域NWhich means, that if you run the clock backwards, the Universe was once an extremely hot dense region

讓我們返回十億年前NLet』s go backwards in time, billions of years.

你越接近大爆炸 你離一切物質就越近 你也會感覺越熱NThe closer you get to the Big Bang, the closerNeverything was, and the hotter it was.

當你回到大爆炸的38萬年後時 整個宇宙的熱度NWhen you reach about 380,000 years after theNBig Bang, the entire Universe was so hot that

使一切物質處於電離狀態 只有原子核和繞其旋轉的電子Nall matter was ionized, with atomic nucleiNand electrons buzzing around each other.

繼續向前 整個宇宙的溫度和密度相當於一顆恆星的NKeep going backwards, and the entire UniverseNwas the temperature and density of a star,

它那時產生了最初熔合成的氦核和其他我們今天所見到的元素Nwhich fused together the primordial heliumNand other elements that we see to this day.

繼續向前 回到時間之初 會發現一個NContinue to the beginning of time, and thereNwas a point where everything was so hot that

熾熱到原子無法保持穩定 繼續分裂成質子和中子的時期Natoms themselves couldn』t hold together,breaking into their constituent protons and neutrons.

若再往前 甚至原子都會分解成夸克NFurther back still and even atoms break apartNinto quarks.

而在那之前 就是一個巨大的迷題NAnd before that, it』s just a big question mark.

那就是被宇宙學家稱為奇點的無限緻密的宇宙NAn infinitely dense Universe cosmologistsNcalled the singularity.

當你從四面觀察宇宙時 你會看到宇宙微波背景輻射NWhen you look out into the Universe in allNdirections, you see the cosmic microwave background radiation.

這就是宇宙冷卻下了 光線可以自由地穿梭的時期NThat』s that point when the Universe cooled down so that light could travel freely through space.

這個輻射的溫度在你所看的所有的方向上幾乎都是一樣的NAnd the temperature of this radiation is almostNexactly the same in all directions that you look.

只有最敏感的儀器才能可以檢測到極其細微的變化NThere are tiny tiny variations, detectableNonly by the most sensitive instruments.

當兩種物質的溫度相同時 就像你的咖啡里的勺子 它意味著NWhen two things are the same temperature,Nlike a spoon in your coffee, it means that

這兩件事物有機會發生聯繫Nthose two things have had an opportunity to interact.

咖啡把熱傳遞給勺子 現在它們的溫度已經相等了。NThe coffee transferred heat to the spoon,Nand now their temperatures have equalized.

當我們在宇宙的另一邊看到這個 這意味著在某個時刻NWhen we see this in opposite sides of theNUniverse, that means that at some point, in

在古老的過去 這兩個地區是接觸的Nthe ancient past, those two regions were touching.

你的左邊被光在138億年前拋在身後的地方 曾經直接接觸NThat spot where the light left 13.8 billionNyears ago on your left, was once directly

你右邊的在138億年前發射了它的光的地方Ntouching that spot on your right that alsoNemitted its light 13.8 billion years ago.

這是一個出色的理論 但有一個問題NThis is a great theory, but there』s a problem.

宇宙沒有時間使那些相對的地區相接觸NThe Universe never had time for those opposite regions to touch.

宇宙為了有我們今天看的到均衡的溫度 需要花費NFor the Universe to have the uniform temperatureNwe see today, it would have needed to spend

足夠的時間來「混合」Nenough time mixing together.

但是事實上 它沒有足夠的時間 宇宙沒有任何時間去交換溫度NBut it didn』t have enough time, in fact,Nthe Universe didn』t have any time to exchange temperature.

想像一下 你把勺子舀進咖啡里N然後在在溫度可以轉移之前的把它取出來NImagine you dipped that spoon into the coffeeNand then pulled it out moments later before

然而 咖啡和勺子的溫度是一樣的Nthe heat could transfer, and yet the coffeeNand spoon are exactly the same temperature.

發生了什麼？NWhat』s going on?

為了解決這個問題 在1980年宇宙學家Alan Guth提出了宇宙暴漲的想法NTo address this problem, the cosmologist AlanNGuth proposed the idea of cosmic inflation in 1980.

在大爆炸之後的那個瞬間 整個宇宙急劇擴大NThat moments after the Big Bang, the entireNUniverse expanded dramatically.

所謂的「瞬間」 指的是暴漲發生在宇宙誕生之後的NAnd by 「moments」, I mean that the inflationary period started when the Universe was only

10的－36次方秒到10 的－32次方秒之間N10^-36 seconds old, and ended when the UniverseNwas 10^-32 seconds old.

通過"急劇擴張" 我的意思是它的大小擴大了10的26次方倍NAnd by 「expanded dramatically」, I mean that it got 10^26 times larger.

那是1後面跟26個0NThat』s a 1 followed by 26 zeroes.

在暴漲之前 可觀測的宇宙比原子還小NBefore inflation, the observable UniverseNwas smaller than an atom.

在暴漲之後 它大概是0.88毫米長NAfter inflation, it was about 0.88 millimeters.

今天 這些地區已經被拉長了930億光年NToday, those regions have been stretched 93Nbillion light-years apart.

宇宙暴漲的概念由宇宙學家安德烈·林德 保羅·斯泰恩哈特NThis concept of inflation was further developedNby cosmologists Andrei Linde, Paul Steinhardt,

安迪·阿爾卑車特和其他人進一步發展NAndy Albrecht and others.

宇宙暴漲解決了一些大爆炸理論的漏洞NInflation resolved some of the shortcomingsNof the Big Bang Theory.

第一個是作為平坦度問題而為人所知NThe first is known as the flatness problem.

我們今天擁有的最敏感的衛星測量到宇宙是平的NThe most sensitive satellites we have todayNmeasure the Universe as flat.

不像一張紙那樣平 而是在此意義上的平坦：NNot like a piece-of-paper-flat, but flat inNthe sense that parallel lines will remain

當平行線在宇宙中穿行時 它們會一直保持平行Nparallel forever as they travel through the Universe.

在最初的宇宙大爆炸理論中 你會認為宇宙的曲率NUnder the original Big Bang cosmology, youNwould expect the curvature of the Universe

會隨著時間而變大Nto grow with time.

第二個是地平問題NThe second is the horizon problem.

這是我在上面提及的問題——兩個地區的宇宙不可能相互接觸Nthat two regions of the Universe shouldn』t And this is the problem I mentioned above,

並有足夠長的時間達到熱平衡Nhave been able to see each other and interactNlong enough to be the same temperature.

第三個是磁極問題NThe third is the monopole problem.

根據最初的大爆炸理論 應該有大量的重的 穩定的單極子NAccording to the original Big Bang theory,Nthere should be a vast number of heavy, stable

或者是在一極只有一個有磁性的質點N「monopoles」, or a magnetic particle with only a single pole.

宇宙暴漲稀釋了單極子在宇宙中的數量 所以今天我們不能探測到它們Nin the Universe so we just don』t detect them today. Inflation diluted the number of monopoles

過一會兒 我將談談宇宙學家是如何通過N研究宇宙來發掘宇宙暴漲的證據的NIn a moment, I』m going to talk about how astronomers are searching the Universe for

但首先我感謝斯科特·卡萊爾 托馬斯·斯彭德Nevidence of cosmic inflation, but first I』d like to thank Scott Carlisle, Thomas Spenader,

布萊恩 和剩下的734位贊助者的慷慨支持NBryan, and the rest of our 734 patrons forNtheir generous support.

如果你喜歡我們正在做的事情並且想要幫助我們 請登錄 http://patreon.com/universetodayNIf you love what we』re doing and want to help out, head over to http://patreon.com/universetoday

儘管宇宙微波背景輻射幾乎出現在整個天空NAlthough the cosmic microwave background radiation appears mostly even across the sky, there

仍然有證據表明暴漲時期已經過去了Ncould still be evidence of that inflationaryNperiod baked into it.

為了證明這些 天文學家已經聚焦於研究原初引力波NIn order to do this, astronomers have beenNfocusing on searching for primordial gravitational waves.

這些是不同於由大型物體的坍縮而產生的引力波NThese are different from the gravitationalNwaves generated through the collision of massive objects.

原初引力波是宇宙暴漲時期的回聲N從理論上可以在宇宙微波背景輻射的光中NPrimordial gravitational waves are the echoesNfrom that inflationary period which should

通過偏振或定向觀測被探測到Nbe theoretically detectable through the polarization, or orientation, of light in the cosmic microwaveNbackground radiation.

科學家團體用被稱為宇宙銀河系外的偏振的背景成像儀器(BICEP2）NA collaboration of scientists used an instrumentNknown as the Background Imaging of Cosmic

來尋找這種極化NExtragalactic Polarization (or BICEP2) toNsearch for this polarization, and in 2014,

在2014年 他們宣布那可能 只是可能已經用儀器檢測到了Nthey announced that maybe, just maybe, theyNhad detected it, proving the theory of cosmic

從而證明宇宙暴漲理論是正確的Ninflation was correct.

不幸的是 另一個團隊在普朗克空間望遠鏡觀測到的證據NUnfortunately, another team working with theNspace-based Planck telescope posted evidence

表明這種他們看見的波動可以N完全通過銀河系中介於中間的的塵埃來解釋Nthat the fluctuations they saw could be fullyNexplained by intervening dust in the Milky Way.

問題是 BICEP2和普朗克旨在尋找不同的頻率NThe problem is that BICEP2 and Planck areNdesigned to search for different frequencies.

為了真正查明這個問題 需要做更多的搜索N掃描一系列重疊的頻率NIn order to really get to the bottom of this question, more searches need to be done, scanning 95Na series of overlapping frequencies.

這是現在正在進行的工作NAnd that』s in the works now.

BICEP2 普朗克 新開發的南極望遠鏡和一些在智利的天文台NBICEP2 and Planck and the newly developedNSouth Pole Telescope as well as some observatories

都在在同時掃描天空中的不同頻率Nin Chile are all scanning the skies at differentNfrequencies at the same time.

各種前景物體所帶來的失真NDistortion from various types of foregroundNobjects, like dust or radiation should be

比如灰塵或輻射在不同的頻率會變得更亮或者更暗Nbrighter or dimmer in the different frequencies,Nwhile the light from the cosmic microwave

而宇宙微波背景輻射的光則大體保持不變Nbackground radiation should remain constant throughout.

有更多的望遠鏡在搜索更多波長的光NThere are more telescopes, searching moreNwavelengths of light, searching more of the

不斷地探索天空Nsky.

在不久我們將可以更確切的知道這個問題的答案NWe could know the answer to this questionNwith more certainty shortly.

而最有趣的宇宙暴漲的結果之一 如果被證實NOne of the most interesting implications ofNcosmic inflation, if proven, is that our Universe

就是我們的宇宙其實只是許多平行宇宙中的一個Nis actually just one in a vast multiverse.

當宇宙在進行急劇的膨脹 可能會產生NWhile the Universe was undergoing that dramaticNexpansion, it could have created bubbles of

有不同的物理規則的宇宙的時空Nspacetime that spawned other universes, withNdifferent laws of physics.

「事實上」 暴漲理論之父阿蘭· 古斯說Nsaid, 「It』s hard to build models of inflation In fact, the father of inflation, Alan Guth,

「想要建立一個不導致平行宇宙的暴漲模型是困難的」Nthat don』t lead to a multiverse.」

因此 如果宇宙暴漲理論最終得到確認Nthen we』ll have a whole multiverse to search And so, if inflation does eventually get confirmed,

我們將會在宇宙微波背景輻射中去搜尋一個完整的平行宇宙Nfor in the cosmic microwave background radiation.

大爆炸是在科學史上最偉大的理論之一NThe Big Bang was one of the greatest theoriesNin the history of science.

儘管它確實有一些問題 宇宙暴漲理論就是為了解決這些問題而建立的NAlthough it did have a few problems, cosmicNinflation was developed to address them.

儘管開始時有一些錯誤 天文學家現在正在進行嚴謹的研究NAlthough there have been a few false starts,Nastronomers are now performing a sensitive

來找到這個驚人的暴漲時期的證據Nenough search that they might find evidenceNof this amazing inflationary period.

然後或許會因此獲得諾貝爾獎NAnd then it』ll be Nobel Prizes all around.

沒有撒謊 我覺得我僅僅只是觸及了這個理論的皮毛NNot going to lie, I feel like I barely scratchedNthe surface of this concept.

還想要更深入地了解？NWant me to go deeper?

你想在下期節目中了解什麼？NWhat would you like to hear about next?

讓我在評論中了解你們的想法NLet me know your thoughts in the comments.

當我們的步伐推進太陽系時 我們需要思考Nwe』re going to need to think about whatNAs we push forward into the Solar System,

「擁有」宇宙意味著什麼Nit means to 「own」 space.

誰擁有月亮?NWho owns the Moon?

你能在火星上買到地產嗎?NCan you buy property on Mars?

下一期 空間所有權NSpace ownership, next episode.

宇宙暴漲是一個非常複雜的話題NInflation is a really really complicated topic,Nand I recommend you just bathe yourself in

我建議你認真觀看視頻來了解它的要點Nvideos to help you get the gist of it.

我已經為你們創建了一個視頻播放列表NI』ve created a playlist of videos just for you.

我們從一段較老的關於大爆炸的證據視頻開始NWe start with one of our older videos aboutNthe evidence for the Big Bang.

PBS SpaceTime會解釋宇宙暴漲理論N而PhysicsGirl會講講為什麼時空是平坦的NThen PBS SpaceTime tackles Inflation, thenNPhysicsGirl talks about why spacetime is flat,

阿蘭·古斯會解釋宇宙暴漲NAlan Guth explains Inflation.

最後的視頻由勞倫斯·克勞斯所作 是我最愛之一NThe last video, from Lawrence Krauss is oneNof my favorites, why the Universe adds up

為什麼宇宙總計相當於沒有什麼Nto nothing.

那取決你的權利N... that spot on your right.

如果他們在看視頻 那是後退嗎?NIs that backwards if theyre watching the video?N（觀看更多中文天文視頻歡迎關注weibo天文在線）N【也歡迎您加入我們字幕組，私信koukou零度星系（南充）】

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