《星际穿越》中的科学

并同意它应该刚刚足够大…
…and agreed that it should be just barely big enough…
基普·索恩 加州理工学院
它应该能够从地球上看到…
…that it could be seen from Earth…
通过虫洞周围光的弯曲…
…through the bending of light around the Wormhole…
通过虫洞扭曲的空间
…by the wormhole’s warped space.
基普·索恩为《星际穿越》的虫洞
Kip Thorne worked out just the right gravity
算出了合适的引力…
for lnterstellar’s Wormhole…
使用基于爱因斯坦 广义相对论的方程式
…using equations based on Einstein’s theory of general relativity.
众所周知 该理论指出
As we’ve learned, that theory states
物体弯曲时空 产生引力
that objects warp space-time, creating gravity.
它还预测 当物体移♥动♥时 它们会产生脉冲…
It also predicts that when objects move, they generate a pulse…
通过时空传播 有点像波浪过水
…that propagates through space-time, a bit like waves through water.
这些引力波从未被直接观测到过
These gravitational waves have never been directly observed.
它们很小 难以探测…
They would be small and hard to detect…
除非它们由大规模强烈运动生成
…unless they were generated by a massively violent motion.
就像宇宙诞生一样
Like the birth of the universe.
物理学家在某种程度上 发展了他们的大爆♥炸♥理论…
Physicists developed their big bang theory…
通过观测 发现今天宇宙正在膨胀
…in part by observing that today the universe is expanding.
银河系正在互相分离
Galaxies are moving away from each other
就像正发起面包里面的葡萄干…
like raisins in a rising loaf of bread…
这表明在遥远的过去
…which suggests that in the distant past,
宇宙一定是小得多
the universe must have been much smaller.
如果你把电影倒回去
If you wind the movie backwards, in the past,
在过去 一切都靠得比较近…
everything was closer together…
肖恩·卡罗尔 加州理工学院
你把该概念引入 爱因斯坦给我们的方程式
…and you plug that idea into the equations that Einstein gives us.
有一个时段 现在我们知道
And there’s a moment, which we now know was
大约是在140亿年前…
about 14 billion years ago…
那时一切都紧挨着彼此…
…when everything was on top of everything else…
那时宇宙中物质的密度显然极其大
…when the density of stuff in the universe was apparently infinitely big.
那时一股强大的力量 触发了太空自身的膨胀
Then a powerful force triggered an expansion of space itself.
比光速还要快 一种理论称作宇宙膨胀说
Faster than the speed of light, a theory called cosmic inflation.
该理论指出这种膨胀
And the theory said
应已在太空形状上引起了波动…
that this inflation should’ve taken fluctuations in the shape of space…
并放大了它们 因此它们变得更加强大
…and amplified them so they got much stronger.
它们变成了引力波…
And they become gravitational waves…
在时空的结构上产生了涟波
…producing ripples in the fabric of space and time.
如果今天我们能够探测这些涟波…
If we could detect those ripples today…
它会帮助我们了解 大爆♥炸♥爆♥炸♥有多大
…it would help us understand how the big bang banged.
一直棘手的问题是 我们要如何测量这样一种东西
The trick was always how were we going to measure such a thing.
这引导我们提出并发展…
And that led us to propose and develop…
杰米·博克 加州理工学院
这个非常专业的实验…
…this very specialized experiment, um…
我的一位同事高兴地称作野鹅追逐
…which one of my colleagues referred to gleefully as a wild-goose chase.
加州理工学院物理学家 杰米·博克致力于实验宇宙学
Caltech physicist Jamie Bock works in experimental cosmology.
实验宇宙学就是构建实验…
Experimental cosmology is building experiments…
试图回到时间的开端
…trying to get back to the dawn of time.
你需要帮忙吗
You need a hand with that?
他最新实验关注的…
The focus of his latest experiment…
就是宇宙中最古老的光
…was the oldest light in the universe.
大爆♥炸♥的微弱余辉
The faint afterglow of the big bang.
物理学家已经绘制出了 穿越宇宙的…
Physicists have mapped this cosmic microwave background…
这种宇宙微波背景
…across the universe.
如果宇宙的诞生产生了引力波…
If the birth of the universe produced gravitational waves…
它们会已经扭曲了这原始光…
…they would’ve warped this primordial light. ..
并致使它被极化 或在一个特定方向卷曲
…and caused it to be polarized or curled in a specific direction.
如果人能够测量极化…
If one could measure the polarization…
而且不仅测量它 而且观察它的形状…
…and then not only measure it but look at its pattern…
可能会有一种漩涡形的形状…
…there might be kind of a swirly pattern…
这会是引力波的一个指标
…that would be an indicator of gravitational waves.
杰米和他的团队设计了一系列
Jamie and his team designed a series
小型超灵敏望远镜…
of small super-sensitive telescopes…
他们安装在天空澄澈的地方
…that they installed where the skies are crystal clear.
安装在南极
At the South Pole.
南极是我们可以接触外太空
The South Pole is the closest we can get to outer space…
以进行我们的测量最近的地方
…to make our measurements.
八年以来 团队的望远镜扫描了天空的一片…
For eight years, the team’s telescopes scanned a patch in the sky…
测量了宇宙微波背景…
…measuring minute differences in the temperature…
和出现的形状…
…of the cosmic microwave background…
在温度上的微小差异
…and a pattern emerged.
我们的研究结果指出
Our results reported that we see
我们看到这个极化的涡旋形状…
this swirly pattern of polarization…
与你对引力波所预期的一致
…that’s consistent with, uh, what you expect from gravitational waves.
因此他们没真正 从早期宇宙看到引力波…
So they didn’t really see the gravitational waves from the early universe…
但他们看到了这个极化形状
…but they saw this polarization pattern
正是所预测的…
that was precisely what was predicted…
除了它比预测的更强
…except that it was stronger than expected.
告诉我们 紧接大爆♥炸♥之后发生了什么…
Tells us what went on immediately after the big bang…
当时宇宙刚刚诞生
…when the universe was a trillionth of a trillionth of a trillionth of a second old.
所以这几乎看到了宇宙的诞生
So it’s seeing almost the creation of the universe.
该发现必须由其他实验确证
The finding must be confirmed by other experiments.
如果证明属实
If it holds up,
引力波探测的这第一个证据…
this first evidence for the detection of gravitational waves…
将会加深我们对宇宙诞生的理解
…will deepen our understanding of the birth of the universe.
甚至于可能会帮我们 回答一个旷久的问题
And that, by extension, may help us answer an enduring question:
我们能穿梭时间吗
Can we time travel?
在时间里穿梭非常简单
You know, it’s very easy to travel in time.
昨天 我已向前推进了24小时 而现在我来到了现在
Yesterday, I’ve moved forward 24 hours and here I am.
但这是唯一简单的途径 跨入未来很容易
But that’s the only way that it’s easy. It’s easy to go into the future.
其实不只是容易 这是必然的
In fact, it’s not just easy, it’s inevitable.
随着时间推移 我们都会跨入未来
We all move into the future over time.
但穿越到过去就是另一♥码♥事了…
But traveling to the past is a different story…
因为时间和空间具有完全不同的特性
…because space and time have profoundly different properties.
在空间里 你可以上下 左右 前后移♥动♥
In space, you can go up, down, left, right, forward, backward.
我们在三维空间自♥由♥穿梭
We move freely through the three dimensions of space.
而在时间里 我们体验它的一维 而且自♥由♥度少了很多
In time, we experience its one dimension and a lot less freedom.
因为时间有一个方向 而空间没有
Because time has a direction and space does not.
在时间里 在一个方向未来…
In time, there’s a huge difference…
和另一方向过去之间有巨大不同
…between one direction, the future, and the other direction, the past.
比如说 你记得过去 但你不记得未来
For example, you remember the past, but you don’t remember the future.
你在过去比较年轻 我们在过去都比较年轻
You were younger in the past, we were all younger in the past.
我们都会变老 对我们来说都通用
We will all be older. It’s all universal to us.
这个时间箭头有点神秘
This arrow of time is a little bit mysterious.
我们了解基本的理论基础…
We understand the basic underpinnings…
用一种概念叫嫡 即宇宙的混乱程度
…in a concept called entropy, the disorderliness of the universe.
嫡是系统中的混乱衡量
Entropy is the measure of the disorder in a system.
系统越有序 它的嫡值就越低
The more ordered a system, the lower its entropy.
系统越混乱 它的嫡值就越高
The more disordered a system, the higher its entropy.
嫡值增加的经典例子 就是把奶油混进咖啡
A classic example of entropy increasing is just mixing cream into coffee.
当奶油和咖啡分开时 嫡值就低
When the cream and the coffee are separate, that’s low entropy.
它们组织有序 这是奶油 咖啡
They’re organized. There’s the cream, the coffee.
你把它们倒在一起 你让它们混合起来
You pour them together, you let them mix together.
嫡值就升高了 物质变得越来越无序
Entropy just goes up. Things become more and more disorderly.
而这要一直往回追溯140亿年 追溯到大爆♥炸♥时期
And this goes all the way back 14 billion years to the big bang.
那个时候 宇宙中所有物质都紧挨着
Back then, all the matter in the universe would have been on top of itself.
密度极其大
Density would have been infinite.
那是低嫡值的典型
It was the epitome of low entropy.
但嫡值从大爆♥炸♥时起一直在上升
But entropy has been on the rise ever since the big bang.
我们认为 但我们还没完全证明…
We think, but we haven’t absolutely established…
从有序到无序的这个总趋势…
…that this general tendency to go from order to disorder…
就是过去为何不同于未来的单一原因
…is the single reason why the past is different from the future.
基本上我们无法低估 回到过去的可能性…
We can’t discount in principle the possibility of visiting the past…
但所有这些奇怪的谜题 一定程度上惹恼了我们…
…but all of these weird puzzles that sort of rub us the wrong way…
关于我是否能回到过去
…about if I go back into the past
并给了我自己一个很好的想法…
and I give myself a really good idea…
后来我长大 并因这想法变得富有
…and then I grow up and become rich off that idea,
这个想法来自哪里呢
where did the idea come from?
这些谜题会在我们 禁锢自己的情况下会消失…
These kinds of puzzles would evaporate…
如果我们说
…if we just said,
物理定律不允许你回到过去”
“Well, the laws of physics don’t allow you to visit the past.”
所以这可能是真的
So that’s probably true.
深思空间 时间和宇宙的奥秘…