TED英语演讲视频：宇宙暗物质，我们看不见的物质
TED英语演讲视频：宇宙暗物质，我们看不见的物质
https://v.qq.com/txp/iframe/player.html?width=500&height=375&auto=0&vid=v0837scyx2i
TED演讲稿The ancient Greeks had a great idea:
古代希腊人有一个伟大的想法：
The universe is simple.
宇宙是简单的。
In their minds,
在他们心中，
all you needed to make it were four elements:
要建构宇宙只须要四种元素：
earth,
土、
air,
空气、
fire,
火、
and water.
还有水。
As theories go, it’s a beautiful one.
就像它的理论一样， 这是美丽的。
It has simplicity and elegance.
既简单、又优雅。
It says that by combining
理论中认為
the four basic elements in different ways,
藉由四种元素的不同组合，
you could produce all the wonderful diversity of the universe.
可以產生宇宙万物。
Earth and fire, for example,
比如说土加火，
give you things that are dry.
就会有一些乾的东西。
Air and water, things that are wet.
而空气加水，就会得到湿的东西。
But as theories go, it had a problem.
但依照这理论， 会有一个问题。
It didn’t predict anything that could be measured,
它没办法预测出任何 可以测量的事物，
and measurement is the basis of experimental science.
而测量又是实验科学的基础。
Worse still, the theory was wrong.
更糟的是，这理论是错的。
But the Greeks were great scientists of the mind
但希腊人仍是 思想上伟大的科学家，
and in the 5th century B.C.,
在西元前 5 世纪，
Leucippus of Miletus came up
米勒都的留基伯（Leucippus of Miletus）
with>提出有史以来 最经得起考验的科学思想之一。
Everything we see is made up
我们看到的每样东西
of tiny, indivisible bits of stuff called atoms.
都由微小、看不见的东西组成， 这东西称作原子。
This theory is simple and elegant,
这个理论既简单又优雅，
and it has the advantage
而它超越 土、空气、水、火的理论
over the earth, air, fire, and water theory
而它超越 土、空气、水、火的理论
of being right.
更接近事实。
Centuries of scientific thought and experimentation
几世纪以来的 科学思想及实验
have established that the real elements,
证实了实体的物质，
things like hydrogen,
像是氢气、
carbon,
碳、
and iron,
还有铁，
can be broken down into atoms.
都可以分解成原子。
In Leucippus’s theory, the atom is the smallest,
在留基伯的理论中，原子是最小的、
indivisible bit of stuff that’s still recognizable
看不见的物质， 但仍然可以作区分，
as hydrogen,
像是氢原子、
carbon,
碳原子、
or iron.
铁原子。
The>留基伯的想法裡， 唯一有问题的是
is that atoms are, in fact, divisible.
事实上原子也还可以再细分。
Furthermore, his atoms idea turns out
而且，他的原子说最终
to explain just a small part
只解释了宇宙组成 的一小部份。
of what the universe is made of.
只解释了宇宙组成 的一小部份。
What appears to be the ordinary stuff of the universe
平常所见到的物质， 实际上在宇宙中
is, in fact, quite rare.
非常稀少。
Leucippus’s atoms, and the things they’re made of,
留基伯讨论的原子、 还有它们组成的物质，
actually make up only about 5%
事实上只佔了 我们知道的物质
of what we know to be there.
的大约 5%。
Physicists know the rest of the universe,
物理学家认為其餘的宇宙，
95% of it,
就是那 95%，
as the dark universe,
是暗宇宙，
made of dark matter and dark energy.
由暗物质和暗能量组成。
How do we know this?
我们怎麼知道？
Well, we know because we look at things
嗯，我们会知道是因為
and we see them.
我们有观察到。
That might seem rather simplistic,
这听起来蛮简单的，
but it’s actually quite profound.
但实际上有点复杂。
All the stuff that’s made of atoms is visible.
所有原子组成的物质 是看得见的。
Light bounces off it, and we can see it.
它会反射光线， 然后我们就看得到。
When we look out into space,
当我们观察宇宙时，
we see stars and galaxies.
我们会看到星星和银河。
Some of them, like the one we live in,
有些就像我们居住的地方一样，
are beautiful, spiral shapes, spinning gracefully through space.
很美丽、有螺旋的结构、 优雅地在太空中旋转。
When scientists first measured the motion
当科学家在 1930 年代 第一次
of groups of galaxies in the 1930’s
观测一群星系时，
and weighed the amount of matter they contained,
并同时估算它们的质量，
they were in for a surprise.
科学家们大為震惊。
They found that there’s not enough visible stuff
他们发现 并没有足够的可见物质
in those groups to hold them together.
让这些星系群 靠在一起。
Later measurements of individual galaxies
之后对单独星系的观察
confirmed this puzzling result.
证实了这个谜样的结果。
There’s simply not enough visible stuff in galaxies
星系裡就是没有足够的 可见物质
to provide enough gravity to hold them together.
来提供足够的重力 让它们靠在一起。
From what we can see,
从我们的观测之中，
they ought to fly apart, but they don’t.
它们应该向外飞走， 但并没有。
So there must be stuff there
所以一定有什麼东西
that we can’t see.
是我们看不到的。
We call that stuff dark matter.
我们把这东西称作 暗物质。
The best evidence for dark matter today
现今关於暗物质 最有力的证据
comes from measurements of something
来自於对於一种叫作
called the cosmic microwave background,
宇宙背景微波辐射的观测，
the afterglow of the Big Bang,
也就是大爆炸后 留下的餘光，
but that’s another story.
但这是另一段故事了。
All of the evidence we have
所有我们掌握的证据
says that dark matter is there
都说明了暗物质的存在，
and it accounts for much of the stuff
而在天空中
in those beautiful spiral galaxies
那些美丽的螺旋星系中
that fill the heavens.
它佔据了大部份的质量。
So where does that leave us?
这告诉我们什麼？
We’ve long known that the heavens
长久以来我们知道
do not revolve around us
天空并不是绕著我们旋转，
and that we’re residents of a fairly ordinary planet,
而我们只是 一颗平凡行星上的居民，
orbiting a fairly ordinary star,
绕著一颗平凡的恆星、
in the spiral arm of a fairly ordinary galaxy.
座落在一个平凡星系的螺旋臂上。
The discovery of dark matter took us
暗物质的发现 带领我们
one step further away from the center of things.
更进一步了解 物质的本质。
It told us that the stuff we’re made of
这告诉我们 组成我们的物质
is>只是组成宇宙的物质 其中的一小部份。
But there was more to come.
但是不只这样。
Early this century,
在这世纪初，
scientists studying the outer reaches of the universe
研究宇宙外部的科学家
confirmed that not>证实了不只是
from everything else,
物质与物质之间不断远离，
as you would expect in a universe
就如同你想像
that began in hot, dense big bang,
宇宙诞生於 高温、高密度的大爆炸一样，
but that the universe’s expansion
这宇宙向外的扩张
also seems to be accelerating.
似乎正在加速。
What’s that about?
这代表什麼？
Either there is some kind of energy
要不就是有某种能量
pushing this acceleration,
促成这样的加速，
just like you provide energy to accelerate a car,
就像是你提供能量 让一辆车加速一样；
or gravity does not behave exactly as we think.
要不就是重力 和我们想的不完全一样。
Most scientists think it’s the former,
大多数科学家相信 前者是对的，
that there’s some kind of energy driving the acceleration,
也就是有某种能量 促成这种加速，
and they called it “dark energy”.
他们把它叫作 暗物质。
Today’s best measurements allow us to work out
现今最好的观测 让我们可以计算
just how much of the universe is dark.
宇宙有多少部份 是属於暗的。
It looks as if dark energy makes up
看似暗能量佔了
about 68% of the universe
大约 68% 的宇宙，
and dark matter about 27%,
而暗物质佔了 27%，
leaving just 5% for us
剩的 5% 才是
and everything else we can actually see.
所有其它我们看得到的东西。
So what’s the dark stuff made of?
所以这些黑暗的东西 是由什麼组成的？
We don’t know,
我们并不知道，
but there’s one theory, called 「supersymmetry」,
但有一个理论， 叫作「超对称理论」，
that could explain some of it.
可以解释一些。
Supersymmetry, or SUSY for short,
超对称（supersymmetry）， 或简称 SUSY，
predicts a whole range of new particles,
预测了一系列新的粒子，
some of which could make up the dark matter.
其中的一些 可以组成暗物质。
If we found evidence for SUSY,
如果我们找到 超对称的证据，
we could go from understanding 5% of our universe,
我们就可以从 对宇宙那 5% 的认识，
the things we can actually see,
也就是我们看得到的那些，
to around a third.
进展到 大约 1/3。
Not bad for a day’s work.
还算不错。
Dark energy would probably be harder to understand,
暗能量可能 更难去了解，
but there are some speculative theories out there
但有些猜测的理论
that might point the way.
也许指出了方向。
Among them are theories that go back
其中有些 可以追溯到
to that first great idea of the ancient Greeks,
古希腊人那第一个伟大的想法，
the idea that we began with several minutes ago,
也就是几分鐘前 我们起头的想法，
the idea that the universe must be simple.
这想法说明宇宙必须是简单的。
These theories predict that there is just a single element
这些理论 预测所有的宇宙万物
from which all the universe’s wonderful diversity stems,
只由单一一种东西组成，
a vibrating string.
一条振动的絃。
The idea is that all the particles we know today
这想法是说 我们今天知道的所有粒子
are just different harmonics on the string.
只是这条絃上不同的波。
Unfortunately, string theories today
不幸的是，絃论现今
are, as yet, untestable.
还没办法证实。
But, with so much of the universe waiting to be explored,
然而，宇宙中还有 这麼多事物等著去探索，
the stakes are high.
这赌注太大了。
Does all of this make you feel small?
这所有的东西 让你觉得藐小吗？
It shouldn’t.
不应该这样。
Instead, you should marvel
相反地， 你应该讚嘆
in the fact that, as far as we know,
──至少到目前為止──
you are a member of the only species in the universe
你是这宇宙中 唯一一个开始了解
able even to begin to grasp its wonders,
宇宙奥秘的物种 其中的一员，
and you’re living at the right time
而且你生对时代
to see our understanding explode.
来见证这知识的爆炸。
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