Why is our universe fine-tuned for life? | Brian Greene

4,612,420 views ・ 2012-04-23

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00:00
Translator: Jenny Zurawell
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譯者: Dennis Guo 審譯者: Anny Chung
00:15
A few months ago
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幾個月前,
00:17
the Nobel Prize in physics
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兩個天文學家的團隊,
00:19
was awarded to two teams of astronomers
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因為他們所作出的一個
00:21
for a discovery that has been hailed
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被稱為天文觀測史上
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as one of the most important
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最重要的觀察之一,
00:26
astronomical observations ever.
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而獲得了諾貝爾物理學獎。
00:28
And today, after briefly describing what they found,
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而今天,在簡短的描述他們的發現之後,
00:30
I'm going to tell you about a highly controversial framework
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我將告訴你們一個可以解釋他們的發現,
00:33
for explaining their discovery,
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但卻非常有爭議的理論架構。
00:36
namely the possibility
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那就是,
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that way beyond the Earth,
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在超出地球,
00:40
the Milky Way and other distant galaxies,
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超出銀河系和一切遙遠的星系以上,
00:43
we may find that our universe
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我們可能會明白我們的宇宙
00:45
is not the only universe,
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并不是唯一的宇宙,
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but is instead
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而只是一個極度龐大的宇宙群,
00:49
part of a vast complex of universes
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我們所謂的多元宇宙,
00:51
that we call the multiverse.
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其中的一個。
00:53
Now the idea of a multiverse is a strange one.
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多元宇宙的想法有些奇怪。
00:56
I mean, most of us were raised to believe
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我們大多數人在成長中都被教予
00:58
that the word "universe" means everything.
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“宇宙”這個詞代表著所有的一切。
01:01
And I say most of us with forethought,
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我說“我們大多數”是經過考慮的,
01:04
as my four-year-old daughter has heard me speak of these ideas since she was born.
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因為我的四歲的女兒從出生便開始聽我說這些想法,
01:07
And last year I was holding her
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而去年當我抱住她
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and I said, "Sophia,
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然後我對她說: “索菲亞,
01:11
I love you more than anything in the universe."
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我愛你超過宇宙中所有的一切。”
01:14
And she turned to me and said, "Daddy,
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然後她轉過來對我說, “爸爸,
01:16
universe or multiverse?"
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是宇宙還是多元宇宙?”
01:18
(Laughter)
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(笑聲)
01:21
But barring such an anomalous upbringing,
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但在這反常的教育以外,
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it is strange to imagine
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設想和我們的世界
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other realms separate from ours,
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分離的領域還是很奇怪,
01:28
most with fundamentally different features,
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它們或許有著從根本上完全不同的特徵,
01:30
that would rightly be called universes of their own.
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并各自可以被稱作宇宙。
01:33
And yet,
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但是,雖然
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speculative though the idea surely is,
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這個設想只是推測,
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I aim to convince you
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我的目標是說服你們
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that there's reason for taking it seriously,
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的確有理由來認真的考慮它,
01:41
as it just might be right.
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因為它有可能就是真的。
01:43
I'm going to tell the story of the multiverse in three parts.
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我將把多元宇宙的故事分成三部份。
01:46
In part one,
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在第一部份,
01:48
I'm going to describe those Nobel Prize-winning results
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我將描述那獲得諾貝爾獎的研究結果,
01:50
and to highlight a profound mystery
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以及這些結果揭發的
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which those results revealed.
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一個意義深遠的謎團。
01:54
In part two,
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在第二部份,
01:56
I'll offer a solution to that mystery.
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我將為那個謎團提出一個解釋。
01:58
It's based on an approach called string theory,
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它基於一個叫做弦理論的方法,
02:00
and that's where the idea of the multiverse
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並會將多元宇宙的概念
02:02
will come into the story.
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來引進這個故事中。
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Finally, in part three,
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最終,在第三部份,
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I'm going to describe a cosmological theory
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我將描述一個叫做“暴脹”的
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called inflation,
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宇宙論,
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which will pull all the pieces of the story together.
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而它將把故事所有的片段聯繫在一起。
02:13
Okay, part one starts back in 1929
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好的。 第一部份從1929年開始。
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when the great astronomer Edwin Hubble
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著名的天文學家愛德文.哈伯
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realized that the distant galaxies
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發現遠處的星系
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were all rushing away from us,
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都在迅速的離我們遠去,
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establishing that space itself is stretching,
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說明了空間本身正在伸展,
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it's expanding.
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在擴張。
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Now this was revolutionary.
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而這是突破性的。
02:31
The prevailing wisdom was that on the largest of scales
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當時普遍的認知是,在最大的範圍內,
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the universe was static.
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宇宙是靜止的。
02:36
But even so,
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但即使如此,
02:38
there was one thing that everyone was certain of:
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有一件事情是所有人都確信的:
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The expansion must be slowing down.
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擴張必定在逐漸緩慢下來。
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That, much as the gravitational pull of the Earth
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就像地球上的萬有引力
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slows the ascent of an apple tossed upward,
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將往上拋的蘋果的速度慢下來,
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the gravitational pull
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每一個星系對對方的
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of each galaxy on every other
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萬有引力
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must be slowing
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必定也在將空間的擴張
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the expansion of space.
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緩慢下來。
02:58
Now let's fast-forward to the 1990s
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現在讓我們快轉到90年代,
03:01
when those two teams of astronomers
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當我在一開始講到的
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I mentioned at the outset
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那兩個天文學家的團隊
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were inspired by this reasoning
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受到了這個推理的啟迪,
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to measure the rate
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來測量宇宙擴張
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at which the expansion has been slowing.
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減慢的速度。
03:11
And they did this
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他們
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by painstaking observations
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對很多個遠處星系
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of numerous distant galaxies,
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做出的縝密的觀察
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allowing them to chart
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允許他們記錄下來
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how the expansion rate has changed over time.
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宇宙隨著時間過去,擴張速度的變化
03:22
Here's the surprise:
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而令人吃驚的事情發生了:
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They found that the expansion is not slowing down.
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他們發現擴張并沒有緩緩減速。
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Instead they found that it's speeding up,
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相反,他們發現它正在加速,
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going faster and faster.
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越來越快。
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That's like tossing an apple upward
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這就像將一個蘋果拋上空中,
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and it goes up faster and faster.
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然後它往上的速度越來越快。
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Now if you saw an apple do that,
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如果你看到一個蘋果那樣表現的話,
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you'd want to know why.
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你會想知道這是爲什麽。
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What's pushing on it?
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是什麽東西在推動著它?
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Similarly, the astronomers' results
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同樣的,這些天文學家的結果
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are surely well-deserving of the Nobel Prize,
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肯定應該獲得諾貝爾獎,
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but they raised an analogous question.
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但它們也提起了一個相似的問題。
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What force is driving all galaxies
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是什麽力量在將
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to rush away from every other
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所有的星系往外
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at an ever-quickening speed?
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以越來越快的速度推動?
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Well the most promising answer
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最好的答案
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comes from an old idea of Einstein's.
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源於愛因斯坦的一個老想法。
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You see, we are all used to gravity
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你看,我們都習慣於萬有引力
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being a force that does one thing,
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只做一件事情,
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pulls objects together.
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那就是將事物拉到一起。
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But in Einstein's theory of gravity,
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但在愛因斯坦的萬有引力理論,
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his general theory of relativity,
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它的廣義相對論中,
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gravity can also push things apart.
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萬有引力也可以將事物推開。
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How? Well according to Einstein's math,
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這是如何做到的?根據愛因斯坦的計算,
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if space is uniformly filled
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如果空間被一種
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with an invisible energy,
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無形的能量均勻的佔據,
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sort of like a uniform, invisible mist,
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就像一個均勻的,無形的迷霧,
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then the gravity generated by that mist
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那麼這個迷霧產生的引力
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would be repulsive,
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將會是相斥的,
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repulsive gravity,
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而相斥的引力
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which is just what we need to explain the observations.
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恰恰可以提我們解釋這些觀察結果。
04:38
Because the repulsive gravity
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因為空間中一種無形的能量
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of an invisible energy in space --
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產生的相斥的引力 -
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we now call it dark energy,
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我們現在叫它暗能量,
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but I've made it smokey white here so you can see it --
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但我在這裡將它變成煙霧般的白色讓你能看到 -
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its repulsive gravity
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它的相斥的引力
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would cause each galaxy to push against every other,
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會導致每一個星系互相推動,
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driving expansion to speed up,
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將擴張速度變快,
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not slow down.
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而不是變慢。
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And this explanation
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而這個解釋
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represents great progress.
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代表著很大的進展。
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But I promised you a mystery
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但我答應了你在第一部份
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here in part one.
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有一個謎團。
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Here it is.
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謎題是如此的:
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When the astronomers worked out
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當這些天文學家計算出
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how much of this dark energy
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空間中需要
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must be infusing space
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多少暗能量
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to account for the cosmic speed up,
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才能導致現在的宇宙擴張加速,
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look at what they found.
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看看他們所發現的。
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This number is small.
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這個數字很小。
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Expressed in the relevant unit,
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以相應的單位时表示,
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it is spectacularly small.
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它令人吃驚地小。
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And the mystery is to explain this peculiar number.
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而謎團便是如何解釋這個古怪的數字。
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We want this number
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我們想讓這個數字
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to emerge from the laws of physics,
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從物理定律中自然的浮現,
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but so far no one has found a way to do that.
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但目前為止沒有人知道如何做。
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Now you might wonder,
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現在你可能在想,
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should you care?
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這是你應該關心的嗎?
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Maybe explaining this number
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或許解釋這個數字
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is just a technical issue,
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只是一個技術上的問題,
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a technical detail of interest to experts,
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一個專家對之有興趣的技術細節,
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but of no relevance to anybody else.
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但對其他人來說沒有任何意義。
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Well it surely is a technical detail,
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它的確是一個技術細節,
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but some details really matter.
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但有些細節真的狠重要。
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Some details provide
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有些細節可以為
06:01
windows into uncharted realms of reality,
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探索未知的現實提供一扇窗。
06:03
and this peculiar number may be doing just that,
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而這個特殊的數字很有可能就是這扇窗,
06:06
as the only approach that's so far made headway to explain it
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因為到目前為止,唯一一個可以解釋它的方法
06:09
invokes the possibility of other universes --
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包括了其他宇宙的存在的可能 -
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an idea that naturally emerges from string theory,
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一個從弦理論中自然而然浮現的理念,
06:15
which takes me to part two: string theory.
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而從這裡我開始講第二部份: 弦理論。
06:18
So hold the mystery of the dark energy
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請將神秘的暗能量
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in the back of your mind
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暫時放在腦後,
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as I now go on to tell you
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因為我將告訴你
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three key things about string theory.
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關於弦理論的三個關鍵的事情。
06:29
First off, what is it?
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首先,弦理論是什麽?
06:31
Well it's an approach to realize Einstein's dream
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它是一個可以完成愛因斯坦的夢想,
06:34
of a unified theory of physics,
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一個統一的物理理論的方法,
06:37
a single overarching framework
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一個可以形容
06:39
that would be able to describe
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宇宙中所有運行的力的
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all the forces at work in the universe.
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全面的思想架構。
06:43
And the central idea of string theory
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而弦理論的中心思想
06:45
is quite straightforward.
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很直接明瞭。
06:47
It says that if you examine
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它說,如果你近乎無限仔細的考察
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any piece of matter ever more finely,
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任何一個物質,
06:51
at first you'll find molecules
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一開始你會發現分子,
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and then you'll find atoms and subatomic particles.
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然後你會發現原子和次原子微粒。
06:56
But the theory says that if you could probe smaller,
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但弦理論說,如果你能夠在探查的更細微一些,
06:58
much smaller than we can with existing technology,
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比任何我們現在擁有的科技可以做到的都細微,
07:01
you'd find something else inside these particles --
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你會發現在這些微粒中還有東西 --
07:04
a little tiny vibrating filament of energy,
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一個很小的,振動的能量絲,
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a little tiny vibrating string.
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一個很小的,振動的弦。
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And just like the strings on a violin,
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而就像一個小提琴的琴弦一樣,
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they can vibrate in different patterns
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它們可以以不同的頻率振動,
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producing different musical notes.
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產生不同的音調。
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These little fundamental strings,
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這些小的基礎的弦們,
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when they vibrate in different patterns,
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當它們以不同的頻率振動的時候,
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they produce different kinds of particles --
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它們會產生不同的微粒,
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so electrons, quarks, neutrinos, photons,
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比如電子,夸克,中微子,光子,
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all other particles
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以及所有的其他的微粒
07:26
would be united into a single framework,
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都會被統一在一個體系之下,
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as they would all arise from vibrating strings.
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因為他們都由振動的弦構成。
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It's a compelling picture,
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這是一個非常扣人心弦的構想,
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a kind of cosmic symphony,
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一種星雲交響曲,
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where all the richness
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我們所看到周圍的
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that we see in the world around us
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這個世界上的富饒的一切,
07:40
emerges from the music
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都在這些細小的弦的
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that these little, tiny strings can play.
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演奏中形成。
07:45
But there's a cost
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但這個優美的統一理論
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to this elegant unification,
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有著一個代價,
07:49
because years of research
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因為多年的研究
07:51
have shown that the math of string theory doesn't quite work.
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表明了弦理論的數學不怎麼貫通。
07:54
It has internal inconsistencies,
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它有著內在的矛盾,
07:56
unless we allow
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除非我們考慮
07:58
for something wholly unfamiliar --
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一個我們完全不熟悉的東西 --
08:01
extra dimensions of space.
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額外的空間維度。
08:04
That is, we all know about the usual three dimensions of space.
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我們每個人都知道常見的三個空間維度。
08:07
And you can think about those
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而你也可以將它們想成
08:09
as height, width and depth.
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高度,寬度,和長度。
08:12
But string theory says that, on fantastically small scales,
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但弦理論說,在極度小的比例上,
08:15
there are additional dimensions
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存在著額外的維度,
08:17
crumpled to a tiny size so small
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縮小到了我們還無法
08:19
that we have not detected them.
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測試到的地步。
08:21
But even though the dimensions are hidden,
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但雖然那些維度被隱藏著,
08:23
they would have an impact on things that we can observe
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它們對於我們可以觀察的東西有著一定的影響,
08:26
because the shape of the extra dimensions
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因為這些額外的維度的形狀
08:29
constrains how the strings can vibrate.
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決定了弦們如何振動。
08:32
And in string theory,
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而在弦理論中,
08:34
vibration determines everything.
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振動決定一切。
08:37
So particle masses, the strengths of forces,
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所以微粒質量,力的力度,
08:39
and most importantly, the amount of dark energy
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以及最重要的,暗能量的數量
08:42
would be determined
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都會由這些額外的維度的
08:44
by the shape of the extra dimensions.
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形狀決定。
08:46
So if we knew the shape of the extra dimensions,
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而如果我們知道了這些額外維度的形狀,
08:49
we should be able to calculate these features,
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我們應該可以計算這些特徵,
08:52
calculate the amount of dark energy.
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計算暗能量的數量。
08:55
The challenge
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我們的挑戰是,
08:57
is we don't know
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我們并不知道
08:59
the shape of the extra dimensions.
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這些額外維度的形狀。
09:02
All we have
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我們只知道
09:04
is a list of candidate shapes
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一些數學允許的
09:06
allowed by the math.
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候選形狀。
09:09
Now when these ideas were first developed,
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當這些想法第一次被發展出來的時候,
09:11
there were only about five different candidate shapes,
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候選的形狀只有五個左右,
09:13
so you can imagine
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所以你會覺得
09:15
analyzing them one-by-one
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將它們一個一個的分析
09:17
to determine if any yield
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來決定是否有一個可以產生
09:19
the physical features we observe.
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我們觀察到的物理特徵。
09:21
But over time the list grew
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但隨著研究人員不斷的找到其他的候選形狀
09:23
as researchers found other candidate shapes.
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數量不斷的在增加。
09:25
From five, the number grew into the hundreds and then the thousands --
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它的數字從五個增長到幾百個甚至幾千個 --
09:28
A large, but still manageable, collection to analyze,
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一個雖然龐大,但仍然可以處理和分析的數字,
09:31
since after all,
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因為不管如何,
09:33
graduate students need something to do.
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研究博士生們總需要些事情做。
09:36
But then the list continued to grow
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但這個清單繼續增長
09:38
into the millions and the billions, until today.
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到了百萬甚至今天的數十億。直到今天,
09:41
The list of candidate shapes
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候選形狀的清單
09:43
has soared to about 10 to the 500.
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百億從猛增到了萬億。
09:48
So, what to do?
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現在該怎麼辦?
09:51
Well some researchers lost heart,
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有一些研究人員失去了信心,
09:54
concluding that was so many candidate shapes for the extra dimensions,
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覺得因為額外維度有著如此之多的候選形狀,
09:57
each giving rise to different physical features,
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每一個又可能產生不同的物理特徵,
10:00
string theory would never make
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弦理論永遠也不可能做出
10:02
definitive, testable predictions.
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確定的,可測試的預測。
10:04
But others turned this issue on its head,
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但其他人決定從問題的源頭開始,
10:08
taking us to the possibility of a multiverse.
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回到一個多元宇宙的可能。
10:10
Here's the idea.
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想法是這樣的。
10:12
Maybe each of these shapes is on an equal footing with every other.
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或許這些形狀的每一個都是與其他的形狀平等的。
10:15
Each is as real as every other,
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每一個都是真實的,
10:17
in the sense
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這意味著
10:19
that there are many universes,
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有著很多的宇宙,
10:21
each with a different shape, for the extra dimensions.
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每一個都有著不同形狀的額外維度。
10:24
And this radical proposal
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這一個重大的提論
10:26
has a profound impact on this mystery:
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對於這個謎題有著深遠的影響:
10:29
the amount of dark energy revealed by the Nobel Prize-winning results.
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關於著那得了諾貝爾獎的暗能量的數量。
10:32
Because you see,
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因為
10:34
if there are other universes,
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如果有著其他的宇宙,
10:37
and if those universes
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以及如果那些宇宙每一個的額外維度
10:39
each have, say, a different shape for the extra dimensions,
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都有一個不同的形狀
10:43
then the physical features of each universe will be different,
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那麼每一個宇宙的物理特徵就會不同,
10:45
and in particular,
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而特別的,
10:47
the amount of dark energy in each universe
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每一個宇宙的暗能量的數量
10:49
will be different.
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就會不一樣。
10:51
Which means that the mystery
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這意味著解釋
10:53
of explaining the amount of dark energy we've now measured
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我們測量的暗能量的古怪數量
10:55
would take on a wholly different character.
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會有著一個完全不同的意義。
10:58
In this context,
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在這種情況下,
11:00
the laws of physics can't explain one number for the dark energy
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物理定律不會能解釋暗能量的一個數字,
11:03
because there isn't just one number,
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因為不止有一個數字,
11:06
there are many numbers.
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反而有很多。
11:08
Which means
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這意味著
11:10
we have been asking the wrong question.
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我們一路以來都問錯了問題。
11:13
It's that the right question to ask is,
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對的問題應該是,
11:15
why do we humans find ourselves in a universe
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爲什麽我們人類會在
11:18
with a particular amount of dark energy we've measured
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一個有著特定的數量的暗能量的宇宙,
11:21
instead of any of the other possibilities
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而不再外面存在的無數的
11:24
that are out there?
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其他可能之中?
11:26
And that's a question on which we can make headway.
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而這個問題我們可以嘗試解決。
11:29
Because those universes
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因為在那些有著
11:31
that have much more dark energy than ours,
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比我們更多的暗能量的宇宙中,
11:33
whenever matter tries to clump into galaxies,
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每當物質試圖凝聚成星系的時候,
11:36
the repulsive push of the dark energy is so strong
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暗能量所產生的相斥力量會強大到
11:39
that it blows the clump apart
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將凝聚的物質爆開,
11:41
and galaxies don't form.
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以致星系無法形成。
11:43
And in those universes that have much less dark energy,
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而在那些有著比我們少的暗能量的宇宙中,
11:46
well they collapse back on themselves so quickly
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他們的崩塌的速度會快到
11:48
that, again, galaxies don't form.
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使星系無法形成。
11:51
And without galaxies, there are no stars, no planets
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而沒有星系的話,恒星和行星也不會形成,
11:54
and no chance
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也不可能會有
11:56
for our form of life
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像我們這樣的生命
11:58
to exist in those other universes.
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存在於那些宇宙當中。
12:00
So we find ourselves in a universe
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所以我們所在的宇宙有一個
12:02
with the particular amount of dark energy we've measured
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特定數量的暗能量
12:05
simply because our universe has conditions
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僅僅因為我們的宇宙有著可以讓
12:08
hospitable to our form of life.
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我們這種生命發展的條件。
12:12
And that would be that.
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就是這樣。
12:14
Mystery solved,
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秘密被揭開了。
12:16
multiverse found.
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多元宇宙也找到了。
12:18
Now some find this explanation unsatisfying.
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有些人對這種解釋很不滿意。
12:23
We're used to physics
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我們都習慣于物理
12:25
giving us definitive explanations for the features we observe.
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為我們觀察到的東西給予確定的解釋。
12:28
But the point is,
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但其實
12:30
if the feature you're observing
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如果一個你觀察到的特性
12:33
can and does take on
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可以或者的確
12:35
a wide variety of different values
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在不同的現實中有著
12:37
across the wider landscape of reality,
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很多不同的數值,
12:40
then thinking one explanation
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那麼只想著給予其中一個數值
12:42
for a particular value
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一種解釋
12:44
is simply misguided.
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未免誤入歧途了。
12:47
An early example
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一個早期的例子
12:49
comes from the great astronomer Johannes Kepler
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來自于偉大的天文學家約翰內斯。開普勒。
12:52
who was obsessed with understanding
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他癡迷于試圖瞭解
12:54
a different number --
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一個不同的數字 --
12:56
why the Sun is 93 million miles away from the Earth.
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爲什麽太陽離地球有九千三百萬英里?
13:00
And he worked for decades trying to explain this number,
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他花了幾十年來解釋這個數字,
13:03
but he never succeeded, and we know why.
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但他從未成功,而我們知道爲什麽。
13:06
Kepler was asking
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開普勒問了
13:08
the wrong question.
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一個錯的問題。
13:10
We now know that there are many planets
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我們現在知道宇宙中有很多行星
13:13
at a wide variety of different distances from their host stars.
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和他們的恒星有著完全不同的距離。
13:16
So hoping that the laws of physics
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所以希望物理定律
13:19
will explain one particular number, 93 million miles,
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能解釋一個特別的數字,九千三百萬英里,
13:22
well that is simply wrongheaded.
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也是誤入了歧途。
13:25
Instead the right question to ask is,
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反而,正確的問題應該是,
13:27
why do we humans find ourselves on a planet
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爲什麽我們人類存在在一個離恒星
13:30
at this particular distance,
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剛好這麼遠的一個距離上的行星中,
13:32
instead of any of the other possibilities?
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而不在任何其他一個可能中?
13:35
And again, that's a question we can answer.
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再一次,這個問題我們可以回答。
13:38
Those planets which are much closer to a star like the Sun
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那些離像太陽一樣的恒星太近的行星
13:41
would be so hot
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會熱的
13:43
that our form of life wouldn't exist.
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讓我們這種生命無法生存。
13:45
And those planets that are much farther away from the star,
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而那些離恒星太遠的行星
13:48
well they're so cold
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又冷到
13:50
that, again, our form of life would not take hold.
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讓我們這種生命無法形成。
13:52
So we find ourselves
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所以我們才會在一個
13:54
on a planet at this particular distance
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離恒星有著特定的距離的行星上,
13:56
simply because it yields conditions
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僅僅因為它製造出
13:58
vital to our form of life.
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對於我們這種生命必須的環境。
14:01
And when it comes to planets and their distances,
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而對於行星和距離來說,
14:04
this clearly is the right kind of reasoning.
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這明顯是一個對的邏輯。
14:08
The point is,
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我的意思是,
14:10
when it comes to universes and the dark energy that they contain,
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當說到宇宙和它所包含的暗能量,
14:13
it may also be the right kind of reasoning.
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這也有可能是對的邏輯。
14:17
One key difference, of course,
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當然,最重要的不同點在於
14:20
is we know that there are other planets out there,
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我們知道外面有著其他的星球,
14:22
but so far I've only speculated on the possibility
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但到目前為止我們只能猜測
14:25
that there might be other universes.
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有其他宇宙的可能性。
14:27
So to pull it all together,
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所以讓它合理化的話,
14:29
we need a mechanism
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我們需要一個
14:31
that can actually generate other universes.
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可以產生其他宇宙的機制。
14:34
And that takes me to my final part, part three.
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而這帶我們來到了第三也是最後一部份。
14:37
Because such a mechanism has been found
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因為這個機制被研究大爆炸的
14:40
by cosmologists trying to understand the Big Bang.
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宇宙學家發現了。
14:43
You see, when we speak of the Big Bang,
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你看,當我們講大爆炸的時候,
14:45
we often have an image
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我們經常會想到
14:47
of a kind of cosmic explosion
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一種類似于星雲爆裂
14:49
that created our universe
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而造成空間不停的擴張的
14:51
and set space rushing outward.
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產生宇宙的方法。
14:54
But there's a little secret.
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但這裡面哪有一個小小的秘密。
14:56
The Big Bang leaves out something pretty important,
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大爆炸理論沒有包括一個非常重要的東西,
14:59
the Bang.
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那就是爆炸的時候。
15:01
It tells us how the universe evolved after the Bang,
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它告訴我們宇宙是如何在爆炸以後產生的,
15:04
but gives us no insight
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但不告訴我們
15:06
into what would have powered the Bang itself.
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什麽東西產生了爆炸。
15:10
And this gap was finally filled
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而這個缺口終於被一個
15:12
by an enhanced version of the Big Bang theory.
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升級了的大爆炸理論填補了。
15:14
It's called inflationary cosmology,
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它叫暴脹宇宙論。
15:17
which identified a particular kind of fuel
369
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它識別了一種特別的能量,
15:21
that would naturally generate
370
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可以自然產生爆炸時的
15:23
an outward rush of space.
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快速空間膨脹。
15:25
The fuel is based on something called a quantum field,
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那個能量基於一種叫做量子場的東西,
15:28
but the only detail that matters for us
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但對於我們而言唯一重要的細節就是
15:31
is that this fuel proves to be so efficient
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這種能量的效率高到
15:34
that it's virtually impossible
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不可能一次性
15:36
to use it all up,
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將它全部用完,
15:38
which means in the inflationary theory,
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而這意味著在暴脹理論中,
15:40
the Big Bang giving rise to our universe
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產生了我們的宇宙的大爆炸
15:43
is likely not a one-time event.
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很有可能不是一個一次性的事件。
15:46
Instead the fuel not only generated our Big Bang,
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反之,這個能量不僅僅造成了我們的大爆炸,
15:49
but it would also generate countless other Big Bangs,
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也會造成無數個其他的大爆炸,
15:55
each giving rise to its own separate universe
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每一個都會產生一個不同的宇宙,
15:58
with our universe becoming but one bubble
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而我們的宇宙只是一個巨大的星雲泡沫中的
16:00
in a grand cosmic bubble bath of universes.
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一個泡泡。
16:03
And now, when we meld this with string theory,
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而現在,當我們將它和弦理論融合一起的時候,
16:05
here's the picture we're led to.
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我們被領到一個特定的畫面。
16:07
Each of these universes has extra dimensions.
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每一個宇宙都有額外的維度。
16:09
The extra dimensions take on a wide variety of different shapes.
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這些額外的維度有著很多不同的形狀。
16:12
The different shapes yield different physical features.
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不同的形狀產生不同的物理特性。
16:15
And we find ourselves in one universe instead of another
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而我們發現我們存在於這一個宇宙而不在另外一個
16:18
simply because it's only in our universe
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僅僅因為這是唯一一個宇宙
16:21
that the physical features, like the amount of dark energy,
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有著可以讓我們這種生命形成的物理特性,
16:24
are right for our form of life to take hold.
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比如說暗能量的數量。
16:28
And this is the compelling but highly controversial picture
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這是一個很有說服力但又非常有爭議的
16:31
of the wider cosmos
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宇宙的畫面,
16:33
that cutting-edge observation and theory
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而最先進的觀察和理論正在指引我們
16:35
have now led us to seriously consider.
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嚴肅的去考慮它。
16:39
One big remaining question, of course, is,
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當然,一個剩下的很大的問題便是
16:43
could we ever confirm
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我們是否能證明
16:46
the existence of other universes?
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其他宇宙的存在?
16:49
Well let me describe
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讓我描述一種
16:51
one way that might one day happen.
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這有一天可能發生的方式。
16:54
The inflationary theory
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暴脹理論
16:56
already has strong observational support.
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已經有了很強大的觀測結果支持。
16:58
Because the theory predicts
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因為這個理論預測了
17:00
that the Big Bang would have been so intense
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大爆炸會強烈到
17:02
that as space rapidly expanded,
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當空間快速的膨脹的時候,
17:05
tiny quantum jitters from the micro world
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在微型世界中細小的量子暴動
17:07
would have been stretched out to the macro world,
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也會被拉扯到整個宏觀世界,
17:10
yielding a distinctive fingerprint,
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而產生一種特殊的印記 --
17:13
a pattern of slightly hotter spots and slightly colder spots,
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一種在空間中有著稍微熱些的地方
17:15
across space,
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和稍微冷些的地方的規律,
17:17
which powerful telescopes have now observed.
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而強大的望遠鏡可以觀察到它。
17:20
Going further, if there are other universes,
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更進一步,如果其他的宇宙的確存在,
17:23
the theory predicts that every so often
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那理論預測這些宇宙有些時候
17:25
those universes can collide.
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會和對方相撞,
17:27
And if our universe got hit by another,
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而如果我們的宇宙和另外一個相撞,
17:29
that collision
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撞擊的能量
17:31
would generate an additional subtle pattern
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會在空間中產生一種額外的
17:33
of temperature variations across space
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細微的溫差規律,
17:35
that we might one day
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而我們有一天可能可以
17:37
be able to detect.
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觀察到它。
17:39
And so exotic as this picture is,
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而無論這個理論是如何的奇異,
17:42
it may one day be grounded
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有一天它有可能會被
17:44
in observations,
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觀察證實
17:46
establishing the existence of other universes.
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其他宇宙的存在。
17:49
I'll conclude
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讓我以由這些
17:51
with a striking implication
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想法產生的一個在遙遠的未來有著
17:54
of all these ideas
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驚人的後果
17:56
for the very far future.
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來結尾。
17:58
You see, we learned
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你看,我們學到了
18:00
that our universe is not static,
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我們的宇宙并不是靜止的,
18:02
that space is expanding,
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空間正在擴張,
18:04
that that expansion is speeding up
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而擴張的速度也在加快,
18:06
and that there might be other universes
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還有其他的宇宙的確有可能存在。
18:08
all by carefully examining
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這些都是由小心的調查
18:10
faint pinpoints of starlight
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由遙遠的星系傳來的
18:12
coming to us from distant galaxies.
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微弱的星光。
18:15
But because the expansion is speeding up,
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但因為擴張的速度在加快,
18:18
in the very far future,
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在很遙遠的未來,
18:20
those galaxies will rush away so far and so fast
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那些星系便會加速遠離到
18:23
that we won't be able to see them --
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我們再也無法看到它們 --
18:26
not because of technological limitations,
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不是因為技術上的限制,
18:28
but because of the laws of physics.
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而是因為物理定律。
18:30
The light those galaxies emit,
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那些星系發射的光線,
18:32
even traveling at the fastest speed, the speed of light,
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就算以最快的速度,光速來移動,
18:35
will not be able to overcome
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也不能比超越我們之間的
18:37
the ever-widening gulf between us.
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不停的在加大的距離。
18:40
So astronomers in the far future
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所以當未來的天文學家
18:42
looking out into deep space
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往太空深處查看的時候,
18:44
will see nothing but an endless stretch
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除了無盡的靜止的漆黑,
18:47
of static, inky, black stillness.
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什麽也看不到。
18:51
And they will conclude
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而他們會認為
18:53
that the universe is static and unchanging
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宇宙是靜止和不變的,
18:55
and populated by a single central oasis of matter
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而其中只有一個他們居住的
18:58
that they inhabit --
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中心的樂土 --
19:00
a picture of the cosmos
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一個我們確定的知道是錯誤的
19:02
that we definitively know to be wrong.
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宇宙觀。
19:05
Now maybe those future astronomers will have records
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或許這些未來的天文學家會有從前一個紀元
19:08
handed down from an earlier era,
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留下的記錄,
19:10
like ours,
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像我們的一樣,
19:12
attesting to an expanding cosmos
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陳述著一個有無數的星雲點綴的
19:14
teeming with galaxies.
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不停的擴張的宇宙。
19:16
But would those future astronomers
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但這些未來的天文學家們
19:18
believe such ancient knowledge?
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會否相信這些古老的知識?
19:21
Or would they believe
466
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又或者他們會相信
19:23
in the black, static empty universe
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他們自己的先進的觀察帶來的
19:26
that their own state-of-the-art observations reveal?
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那個漆黑,寧靜并空虛的宇宙?
19:30
I suspect the latter.
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我覺得會是後者。
19:32
Which means that we are living
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這意味著我們正活在一個
19:34
through a remarkably privileged era
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有著特殊的榮幸的紀元,
19:37
when certain deep truths about the cosmos
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當宇宙最深奧的真相
19:39
are still within reach
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仍然存在在人類探索精神
19:41
of the human spirit of exploration.
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能夠到達的地方。
19:43
It appears that it may not always be that way.
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但這並不永遠如此。
19:48
Because today's astronomers,
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因為當今天的天文學家
19:50
by turning powerful telescopes to the sky,
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用強大的望遠鏡對準夜空時,
19:53
have captured a handful of starkly informative photons --
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他們發現了一些分明的帶著信息的光子 --
19:56
a kind of cosmic telegram
479
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一種經歷了上億年的
19:59
billions of years in transit.
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宇宙電報。
20:01
and the message echoing across the ages is clear.
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而從亙古傳來的信息很清楚。
20:05
Sometimes nature guards her secrets
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有些時候自然用不可違背的
20:08
with the unbreakable grip
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物理定律來
20:10
of physical law.
484
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守護她的秘密。
20:12
Sometimes the true nature of reality beckons
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有些時候現實真正的面貌就在
20:16
from just beyond the horizon.
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地平線的遠端。
20:19
Thank you very much.
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謝謝。
20:21
(Applause)
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(掌聲)
20:25
Chris Anderson: Brian, thank you.
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Chris Anderson: Brian,謝謝。
20:27
The range of ideas you've just spoken about
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你剛剛所講的思想範圍
20:29
are dizzying, exhilarating, incredible.
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使人有些頭暈但興奮。
20:32
How do you think
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你覺得
20:34
of where cosmology is now,
493
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現在的天文學
20:36
in a sort of historical side?
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在歷史中佔有什麽樣的位置?
20:38
Are we in the middle of something unusual historically in your opinion?
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在你的意見來說,我們是否正在經歷著一個特別的歷史片段?
20:41
BG: Well it's hard to say.
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BG:這有些難說。
20:43
When we learn that astronomers of the far future
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當我們瞭解到未來的天文學家
20:46
may not have enough information to figure things out,
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有可能沒有足夠的信息來瞭解一切,
20:49
the natural question is, maybe we're already in that position
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一個自然的問題便是,我們有可能已經在這樣的一個位置,
20:52
and certain deep, critical features of the universe
500
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而一些深奧的,重要的宇宙特性
20:55
already have escaped our ability to understand
501
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已經逃出了我們可以理解的範圍,
20:58
because of how cosmology evolves.
502
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僅僅因為天文學的發展。
21:00
So from that perspective,
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所以從這個觀點來看,
21:02
maybe we will always be asking questions
504
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可能我們已經處於無法回答
21:04
and never be able to fully answer them.
505
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我們問的問題的局面。
21:06
On the other hand, we now can understand
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但換個角度來說,我們現在可以理解
21:08
how old the universe is.
507
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宇宙到底有多老。
21:10
We can understand
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我們可以理解
21:12
how to understand the data from the microwave background radiation
509
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十四億年前留下的宇宙微波背景輻射
21:15
that was set down 13.72 billion years ago --
510
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所傳達的信息 --
21:18
and yet, we can do calculations today to predict how it will look
511
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甚至於,今天我們可以計算以及預測它的樣貌
21:20
and it matches.
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并與觀察符合。
21:22
Holy cow! That's just amazing.
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天啊!這太棒了。
21:24
So on the one hand, it's just incredible where we've gotten,
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所以換個角度來說的話,我們到達今天已經很不可思議,
21:27
but who knows what sort of blocks we may find in the future.
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但誰知道我們將來會遇到什麽樣的障礙。
21:31
CA: You're going to be around for the next few days.
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CA:你會停留幾天。
21:34
Maybe some of these conversations can continue.
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或許可以繼續討論這些話題。
21:36
Thank you. Thank you, Brian. (BG: My pleasure.)
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謝謝你。謝謝你,Brian。(BG:我的榮幸。)
21:38
(Applause)
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(掌聲)
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