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  • A few months ago

    幾個月前,

  • the Nobel Prize in physics

    兩個天文學家的團隊,

  • was awarded to two teams of astronomers

    因為他們所作出的一個

  • for a discovery that has been hailed

    被稱為天文觀測史上

  • as one of the most important

    最重要的觀察之一,

  • astronomical observations ever.

    而獲得了諾貝爾物理學獎。

  • And today, after briefly describing what they found,

    而今天,在簡短的描述他們的發現之後,

  • I'm going to tell you about a highly controversial framework

    我將告訴你們一個可以解釋他們的發現,

  • for explaining their discovery,

    但卻非常有爭議的理論架構。

  • namely the possibility

    那就是,

  • that way beyond the Earth,

    在超出地球,

  • the Milky Way and other distant galaxies,

    超出銀河系和一切遙遠的星系以上,

  • we may find that our universe

    我們可能會明白我們的宇宙

  • is not the only universe,

    并不是唯一的宇宙,

  • but is instead

    而只是一個極度龐大的宇宙群,

  • part of a vast complex of universes

    我們所謂的多元宇宙,

  • that we call the multiverse.

    其中的一個。

  • Now the idea of a multiverse is a strange one.

    多元宇宙的想法有些奇怪。

  • I mean, most of us were raised to believe

    我們大多數人在成長中都被教予

  • that the word "universe" means everything.

    “宇宙”這個詞代表著所有的一切。

  • And I say most of us with forethought,

    我說“我們大多數”是經過考慮的,

  • as my four-year-old daughter has heard me speak of these ideas since she was born.

    因為我的四歲的女兒從出生便開始聽我說這些想法,

  • And last year I was holding her

    而去年當我抱住她

  • and I said, "Sophia,

    然後我對她說: “索菲亞,

  • I love you more than anything in the universe."

    我愛你超過宇宙中所有的一切。”

  • And she turned to me and said, "Daddy,

    然後她轉過來對我說, “爸爸,

  • universe or multiverse?"

    是宇宙還是多元宇宙?”

  • (Laughter)

    (笑聲)

  • But barring such an anomalous upbringing,

    但在這反常的教育以外,

  • it is strange to imagine

    設想和我們的世界

  • other realms separate from ours,

    分離的領域還是很奇怪,

  • most with fundamentally different features,

    它們或許有著從根本上完全不同的特徵,

  • that would rightly be called universes of their own.

    并各自可以被稱作宇宙。

  • And yet,

    但是,雖然

  • speculative though the idea surely is,

    這個設想只是推測,

  • I aim to convince you

    我的目標是說服你們

  • that there's reason for taking it seriously,

    的確有理由來認真的考慮它,

  • as it just might be right.

    因為它有可能就是真的。

  • I'm going to tell the story of the multiverse in three parts.

    我將把多元宇宙的故事分成三部份。

  • In part one,

    在第一部份,

  • I'm going to describe those Nobel Prize-winning results

    我將描述那獲得諾貝爾獎的研究結果,

  • and to highlight a profound mystery

    以及這些結果揭發的

  • which those results revealed.

    一個意義深遠的謎團。

  • In part two,

    在第二部份,

  • I'll offer a solution to that mystery.

    我將為那個謎團提出一個解釋。

  • It's based on an approach called string theory,

    它基於一個叫做弦理論的方法,

  • and that's where the idea of the multiverse

    並會將多元宇宙的概念

  • will come into the story.

    來引進這個故事中。

  • Finally, in part three,

    最終,在第三部份,

  • I'm going to describe a cosmological theory

    我將描述一個叫做“暴脹”的

  • called inflation,

    宇宙論,

  • which will pull all the pieces of the story together.

    而它將把故事所有的片段聯繫在一起。

  • Okay, part one starts back in 1929

    好的。 第一部份從1929年開始。

  • when the great astronomer Edwin Hubble

    著名的天文學家愛德文.哈伯

  • realized that the distant galaxies

    發現遠處的星系

  • were all rushing away from us,

    都在迅速的離我們遠去,

  • establishing that space itself is stretching,

    說明了空間本身正在伸展,

  • it's expanding.

    在擴張。

  • Now this was revolutionary.

    而這是突破性的。

  • The prevailing wisdom was that on the largest of scales

    當時普遍的認知是,在最大的範圍內,

  • the universe was static.

    宇宙是靜止的。

  • But even so,

    但即使如此,

  • there was one thing that everyone was certain of:

    有一件事情是所有人都確信的:

  • The expansion must be slowing down.

    擴張必定在逐漸緩慢下來。

  • That, much as the gravitational pull of the Earth

    就像地球上的萬有引力

  • slows the ascent of an apple tossed upward,

    將往上拋的蘋果的速度慢下來,

  • the gravitational pull

    每一個星系對對方的

  • of each galaxy on every other

    萬有引力

  • must be slowing

    必定也在將空間的擴張

  • the expansion of space.

    緩慢下來。

  • Now let's fast-forward to the 1990s

    現在讓我們快轉到90年代,

  • when those two teams of astronomers

    當我在一開始講到的

  • I mentioned at the outset

    那兩個天文學家的團隊

  • were inspired by this reasoning

    受到了這個推理的啟迪,

  • to measure the rate

    來測量宇宙擴張

  • at which the expansion has been slowing.

    減慢的速度。

  • And they did this

    他們

  • by painstaking observations

    對很多個遠處星系

  • of numerous distant galaxies,

    做出的縝密的觀察

  • allowing them to chart

    允許他們記錄下來

  • how the expansion rate has changed over time.

    宇宙隨著時間過去,擴張速度的變化

  • Here's the surprise:

    而令人吃驚的事情發生了:

  • They found that the expansion is not slowing down.

    他們發現擴張并沒有緩緩減速。

  • Instead they found that it's speeding up,

    相反,他們發現它正在加速,

  • going faster and faster.

    越來越快。

  • That's like tossing an apple upward

    這就像將一個蘋果拋上空中,

  • and it goes up faster and faster.

    然後它往上的速度越來越快。

  • Now if you saw an apple do that,

    如果你看到一個蘋果那樣表現的話,

  • you'd want to know why.

    你會想知道這是爲什麽。

  • What's pushing on it?

    是什麽東西在推動著它?

  • Similarly, the astronomers' results

    同樣的,這些天文學家的結果

  • are surely well-deserving of the Nobel Prize,

    肯定應該獲得諾貝爾獎,

  • but they raised an analogous question.

    但它們也提起了一個相似的問題。

  • What force is driving all galaxies

    是什麽力量在將

  • to rush away from every other

    所有的星系往外

  • at an ever-quickening speed?

    以越來越快的速度推動?

  • Well the most promising answer

    最好的答案

  • comes from an old idea of Einstein's.

    源於愛因斯坦的一個老想法。

  • You see, we are all used to gravity

    你看,我們都習慣於萬有引力

  • being a force that does one thing,

    只做一件事情,

  • pulls objects together.

    那就是將事物拉到一起。

  • But in Einstein's theory of gravity,

    但在愛因斯坦的萬有引力理論,

  • his general theory of relativity,

    它的廣義相對論中,

  • gravity can also push things apart.

    萬有引力也可以將事物推開。

  • How? Well according to Einstein's math,

    這是如何做到的?根據愛因斯坦的計算,

  • if space is uniformly filled

    如果空間被一種

  • with an invisible energy,

    無形的能量均勻的佔據,

  • sort of like a uniform, invisible mist,

    就像一個均勻的,無形的迷霧,

  • then the gravity generated by that mist

    那麼這個迷霧產生的引力

  • would be repulsive,

    將會是相斥的,

  • repulsive gravity,

    而相斥的引力

  • which is just what we need to explain the observations.

    恰恰可以提我們解釋這些觀察結果。

  • Because the repulsive gravity

    因為空間中一種無形的能量

  • of an invisible energy in space --

    產生的相斥的引力 -

  • we now call it dark energy,

    我們現在叫它暗能量,

  • but I've made it smokey white here so you can see it --

    但我在這裡將它變成煙霧般的白色讓你能看到 -

  • its repulsive gravity

    它的相斥的引力

  • would cause each galaxy to push against every other,

    會導致每一個星系互相推動,

  • driving expansion to speed up,

    將擴張速度變快,

  • not slow down.

    而不是變慢。

  • And this explanation

    而這個解釋

  • represents great progress.

    代表著很大的進展。

  • But I promised you a mystery

    但我答應了你在第一部份

  • here in part one.

    有一個謎團。

  • Here it is.

    謎題是如此的:

  • When the astronomers worked out

    當這些天文學家計算出

  • how much of this dark energy

    空間中需要

  • must be infusing space

    多少暗能量

  • to account for the cosmic speed up,

    才能導致現在的宇宙擴張加速,

  • look at what they found.

    看看他們所發現的。

  • This number is small.

    這個數字很小。

  • Expressed in the relevant unit,

    以相應的單位时表示,

  • it is spectacularly small.

    它令人吃驚地小。

  • And the mystery is to explain this peculiar number.

    而謎團便是如何解釋這個古怪的數字。

  • We want this number

    我們想讓這個數字

  • to emerge from the laws of physics,

    從物理定律中自然的浮現,

  • but so far no one has found a way to do that.

    但目前為止沒有人知道如何做。

  • Now you might wonder,

    現在你可能在想,

  • should you care?

    這是你應該關心的嗎?

  • Maybe explaining this number

    或許解釋這個數字

  • is just a technical issue,

    只是一個技術上的問題,

  • a technical detail of interest to experts,

    一個專家對之有興趣的技術細節,

  • but of no relevance to anybody else.

    但對其他人來說沒有任何意義。

  • Well it surely is a technical detail,

    它的確是一個技術細節,

  • but some details really matter.

    但有些細節真的狠重要。

  • Some details provide

    有些細節可以為

  • windows into uncharted realms of reality,

    探索未知的現實提供一扇窗。

  • and this peculiar number may be doing just that,

    而這個特殊的數字很有可能就是這扇窗,

  • as the only approach that's so far made headway to explain it

    因為到目前為止,唯一一個可以解釋它的方法

  • invokes the possibility of other universes --

    包括了其他宇宙的存在的可能 -

  • an idea that naturally emerges from string theory,

    一個從弦理論中自然而然浮現的理念,

  • which takes me to part two: string theory.

    而從這裡我開始講第二部份: 弦理論。

  • So hold the mystery of the dark energy

    請將神秘的暗能量

  • in the back of your mind

    暫時放在腦後,

  • as I now go on to tell you

    因為我將告訴你

  • three key things about string theory.

    關於弦理論的三個關鍵的事情。

  • First off, what is it?

    首先,弦理論是什麽?

  • Well it's an approach to realize Einstein's dream

    它是一個可以完成愛因斯坦的夢想,

  • of a unified theory of physics,

    一個統一的物理理論的方法,

  • a single overarching framework

    一個可以形容

  • that would be able to describe

    宇宙中所有運行的力的

  • all the forces at work in the universe.

    全面的思想架構。

  • And the central idea of string theory

    而弦理論的中心思想

  • is quite straightforward.

    很直接明瞭。

  • It says that if you examine

    它說,如果你近乎無限仔細的考察

  • any piece of matter ever more finely,

    任何一個物質,

  • at first you'll find molecules

    一開始你會發現分子,

  • and then you'll find atoms and subatomic particles.

    然後你會發現原子和次原子微粒。

  • But the theory says that if you could probe smaller,

    但弦理論說,如果你能夠在探查的更細微一些,

  • much smaller than we can with existing technology,

    比任何我們現在擁有的科技可以做到的都細微,

  • you'd find something else inside these particles --

    你會發現在這些微粒中還有東西 --

  • a little tiny vibrating filament of energy,

    一個很小的,振動的能量絲,

  • a little tiny vibrating string.

    一個很小的,振動的弦。

  • And just like the strings on a violin,

    而就像一個小提琴的琴弦一樣,

  • they can vibrate in different patterns

    它們可以以不同的頻率振動,

  • producing different musical notes.

    產生不同的音調。

  • These little fundamental strings,

    這些小的基礎的弦們,

  • when they vibrate in different patterns,

    當它們以不同的頻率振動的時候,

  • they produce different kinds of particles --

    它們會產生不同的微粒,

  • so electrons, quarks, neutrinos, photons,

    比如電子,夸克,中微子,光子,

  • all other particles

    以及所有的其他的微粒

  • would be united into a single framework,

    都會被統一在一個體系之下,

  • as they would all arise from vibrating strings.

    因為他們都由振動的弦構成。

  • It's a compelling picture,

    這是一個非常扣人心弦的構想,

  • a kind of cosmic symphony,

    一種星雲交響曲,

  • where all the richness

    我們所看到周圍的

  • that we see in the world around us

    這個世界上的富饒的一切,

  • emerges from the music

    都在這些細小的弦的

  • that these little, tiny strings can play.

    演奏中形成。

  • But there's a cost

    但這個優美的統一理論

  • to this elegant unification,

    有著一個代價,

  • because years of research

    因為多年的研究

  • have shown that the math of string theory doesn't quite work.

    表明了弦理論的數學不怎麼貫通。

  • It has internal inconsistencies,

    它有著內在的矛盾,

  • unless we allow

    除非我們考慮

  • for something wholly unfamiliar --

    一個我們完全不熟悉的東西 --

  • extra dimensions of space.

    額外的空間維度。

  • That is, we all know about the usual three dimensions of space.

    我們每個人都知道常見的三個空間維度。

  • And you can think about those

    而你也可以將它們想成

  • as height, width and depth.

    高度,寬度,和長度。

  • But string theory says that, on fantastically small scales,

    但弦理論說,在極度小的比例上,

  • there are additional dimensions

    存在著額外的維度,

  • crumpled to a tiny size so small

    縮小到了我們還無法

  • that we have not detected them.

    測試到的地步。

  • But even though the dimensions are hidden,

    但雖然那些維度被隱藏著,

  • they would have an impact on things that we can observe

    它們對於我們可以觀察的東西有著一定的影響,

  • because the shape of the extra dimensions

    因為這些額外的維度的形狀

  • constrains how the strings can vibrate.

    決定了弦們如何振動。

  • And in string theory,

    而在弦理論中,

  • vibration determines everything.

    振動決定一切。

  • So particle masses, the strengths of forces,

    所以微粒質量,力的力度,

  • and most importantly, the amount of dark energy

    以及最重要的,暗能量的數量

  • would be determined

    都會由這些額外的維度的

  • by the shape of the extra dimensions.

    形狀決定。

  • So if we knew the shape of the extra dimensions,

    而如果我們知道了這些額外維度的形狀,

  • we should be able to calculate these features,

    我們應該可以計算這些特徵,

  • calculate the amount of dark energy.

    計算暗能量的數量。

  • The challenge

    我們的挑戰是,

  • is we don't know

    我們并不知道

  • the shape of the extra dimensions.

    這些額外維度的形狀。

  • All we have

    我們只知道

  • is a list of candidate shapes

    一些數學允許的

  • allowed by the math.

    候選形狀。

  • Now when these ideas were first developed,

    當這些想法第一次被發展出來的時候,

  • there were only about five different candidate shapes,

    候選的形狀只有五個左右,

  • so you can imagine

    所以你會覺得

  • analyzing them one-by-one

    將它們一個一個的分析

  • to determine if any yield

    來決定是否有一個可以產生

  • the physical features we observe.

    我們觀察到的物理特徵。

  • But over time the list grew

    但隨著研究人員不斷的找到其他的候選形狀

  • as researchers found other candidate shapes.

    數量不斷的在增加。

  • From five, the number grew into the hundreds and then the thousands --

    它的數字從五個增長到幾百個甚至幾千個 --

  • A large, but still manageable, collection to analyze,

    一個雖然龐大,但仍然可以處理和分析的數字,

  • since after all,

    因為不管如何,

  • graduate students need something to do.

    研究博士生們總需要些事情做。

  • But then the list continued to grow

    但這個清單繼續增長

  • into the millions and the billions, until today.

    到了百萬甚至今天的數十億。直到今天,

  • The list of candidate shapes

    候選形狀的清單

  • has soared to about 10 to the 500.

    百億從猛增到了萬億。

  • So, what to do?

    現在該怎麼辦?

  • Well some researchers lost heart,

    有一些研究人員失去了信心,

  • concluding that was so many candidate shapes for the extra dimensions,

    覺得因為額外維度有著如此之多的候選形狀,

  • each giving rise to different physical features,

    每一個又可能產生不同的物理特徵,

  • string theory would never make

    弦理論永遠也不可能做出

  • definitive, testable predictions.

    確定的,可測試的預測。

  • But others turned this issue on its head,

    但其他人決定從問題的源頭開始,

  • taking us to the possibility of a multiverse.

    回到一個多元宇宙的可能。

  • Here's the idea.

    想法是這樣的。

  • Maybe each of these shapes is on an equal footing with every other.

    或許這些形狀的每一個都是與其他的形狀平等的。

  • Each is as real as every other,

    每一個都是真實的,

  • in the sense

    這意味著

  • that there are many universes,

    有著很多的宇宙,

  • each with a different shape, for the extra dimensions.

    每一個都有著不同形狀的額外維度。

  • And this radical proposal

    這一個重大的提論

  • has a profound impact on this mystery:

    對於這個謎題有著深遠的影響:

  • the amount of dark energy revealed by the Nobel Prize-winning results.

    關於著那得了諾貝爾獎的暗能量的數量。