了解宇宙是如何运行的（2010）

How the Universe Works S10E05

Part 3 Aug. 5, 2022, 5:05 p.m.

13.3 billion years old,
和通过宇宙微波背景辐射
not too far away from
the figure of
给出的138.2亿年的年龄
13.82 billion years
相差并不远
given by the cosmic
microwave background,
相差了大约6%
a difference of around 6%.
这听起来微不足道，但这相当于
That sounds trivial, but that
equates to hundreds of millions
有数亿年的宇宙历史，要么发生过
of years of cosmic history
that either happened
要么没有发生
or didn't happen.
普莱特:50年前，当我们还不太擅长
PLAIT: 50 years ago,
when we weren't quite as good
测量宇宙中的一切时
at measuring everything about
the universe,
我们会为我们的数字
we would have been
thrilled to
达到这个精度水平而兴奋不已
have our numbers
agreeing to this level.
但现在，有这样的差异
But nowadays, having
a difference like this,
是不可接受的
it's unacceptable.
显然，这两种技术并不一致
Clearly, the two
techniques do not agree.
宇宙学家分成两个阵营
Cosmologists split into
two camps.
我们希望这两种方法就像
We had hoped that these two
methods were like building
从两边建一座桥，然后在中间会合
a bridge from either side
and then meeting in the middle.
但他们没有
But they're not.
现在我们知道正在发生一些
Now we know that something is
going on
我们不理解的事情
we don't understand.
布洛克:尽管这些测量结果
BULLOCK: Even though
these measurements
大致相同
are roughly the same,
但仅仅接受它们并假设一切正常
it's really dangerous to just
accept them and assume that
是非常危险的，因为在科学中
everything's fine,
because in science,
通常，最初真正重大的发现
usually, the initial really big
discoveries start off
都是从微小的差异开始的
as small differences,
but then you pull
但当你理出这条线索，奇妙的东西就出现了
on that thread,
and something wonderful emerges.
所以一个简单的问题
So does a simple question,
宇宙的年龄，能解开一切吗？
how old is the universe,
unravel everything?
宇宙正在向外膨胀
The universe
is expanding outwards.
它的增长速度被称为哈勃常数
The rate it's growing is
called the Hubble constant,
它是计算宇宙年龄的关键
and it's the key to working out
the age of the universe.
所以哈勃常数可能看起来
So the Hubble constant might
just seem
只是一个没有任何意义的学术数字
like some academic number that
doesn't mean anything,
但这个数字包含了
but that number contains
information about
宇宙的组成
the composition,
演化和命运的信息
the evolution, and the fate
of the universe.
这个数字很重要
It's an important number,
但有个问题
but there's a problem.
我们最好的测量方法并不匹配
Our best measurement methods
don't match.
不知道宇宙的年龄
It's incredibly frustrating
to not
是非常令人沮丧的
know how old the universe is.
更令人沮丧的是
It's even more frustrating
to know that
有两个实验，是我们坚信的
there's two experiments,
which are excellent experiments
优秀实验
that we firmly believe in,
但却完全不一致
that completely disagree
with each other.
我的头发很久以前就因为这些东西掉光了
My hair fell out a long time
ago over this kind of stuff.
这是五年来的
This has been
the number-one question
头号♥问题
for over half a decade.
一定是其中一种方法出了问题
There must be something
wrong with one of the methods.
庞岑:在天文届有一种明确的感觉
PONTZEN: There's a definite
sense in the community
不管你碰巧属于哪个阵营
that whichever camp
you happen to fall into,
问题都在“栅栏”的另一边
the problems lie on the other
side of the fence.
所以如果你主要研究宇宙微波背景
So if you're mainly working
with the cosmic
你可能会认为
microwave background,
you probably think
距离阶梯上有什么东西不对劲
something is up
with the distance ladder.
如果距离阶梯有问题
If there's a problem
with the distance ladder,
那么主要问题就是
there's a prime suspect.
这个梯子依靠的是亮度来对恒星进行测距
The ladder relies on stars
that have a predictable
即标准蜡烛
brightness called
standard candles.
但有证据表明，这些恒星的亮度
But there's evidence that
these stars are not always
并不总是相同的
the same brightness.
如果你期望一个物体有特定的亮度
So if you expect an object to
have a particular brightness,
但它却有不同的亮度
and it has
a different brightness,
那么你基于该物体的亮度得出的结论
then whatever conclusion
you draw that relies on
无论如何
the brightness
of that object is
都会有些偏差
gonna be off somewhat.
当把星星想象成街灯
Think of the stars
like streetlights.
如果有一盏灯坏了，而且比其他灯都暗
If one light is broken
and dimmer than the others,
你可能会认为它离你很远
you might think
it's farther away.
庞岑:关于距离阶梯的问题是
PONTZEN: The concern with
the distance ladder is that
如果任何一个梯级出现不完美
if any of the single rungs
is not perfect,
那么当你到达顶端的时候
then the entire ladder might
be out of whack
整个梯子都可能不正常
by the time you get
to the top.
我们需要的是一种
What we need is
a fresh approach
测量宇宙年龄的新方法
to measuring the age of
the universe.
萨特:我们希望我们可以引入一个打破僵局的人
SUTTER: We're hoping we could
bring in a tie breaker,
一个裁判，一个全新的方法
a referee,
a brand new method
不依赖于任何这个或任何那个
that didn't care about
any of this or any
并告诉我们什么是哈勃常数
of that, and tell us what is
the Hubble constant.
我们可能刚刚找到了一个
We may have just found one.
这个天文台没有望远镜
This observatory
doesn't have a telescope.
它在寻找一种看不见的波
It's hunting
for an invisible wave,
一种由大质量物体加速并碰撞
a disturbance in spacetime
itself, caused
引起的时空的扰动
by massive objects
accelerating or colliding.
就是我们所知的 LIGO
It's known as LIGO.
明加雷利: LIGO 是激光干涉仪
MINGARELLI:
LIGO stands for the Laser
引力波天文台的缩写
Interferometer Gravitational
Wave Observatory,
是一种地面引力波探测器
and it is a ground-based
gravitational wave detector.
一束完美稳定的激光束
A perfectly stabilized
beam of laser light bounces
在一个5英里（约8公里）长的 L 形隧♥道♥中反弹
in a five-mile-long,
L-shaped tunnel.
当引力波通过探测器时
As a gravitational wave passes
through the detector,
空间会延伸
space stretches,