国家地理：科学新发现 宇宙之死（2008）

It just might be on to
太空的关键成分之一
one of the key ingredients of space
一种看不见的成分
An invisible ingredient
可以让暗能量的作用放缓
that could put the brakes on dark energy's effect
还能导致大寒时代
and cause a Big Chill.
那就是暗物质
That's dark matter.
科学家们说的暗物质
Scientists talk about dark matter
是指能让宇宙结合在一起
as the substance that holds the universe together
能阻止大裂缝的物质
and could prevent a Big Rip.
在哈勃对附近星系的照片中
Evidence that dark matter exists
发现了暗物质存在的证据
is seen in some of Hubble's images of nearby galaxies.
有时它就像
It sometimes appears
是有其他星系在周围
as though other galaxies surround them.
其实周围根本就没有星系
The other galaxies are not really there at all.
更准确的说 它们是
Rather, they are reflections
后面更深处星系的镜像
of more distant galaxies coming from behind.
天文学家怀疑
Astronomers suspect
这种视觉错觉是暗物质导致的
this optical illusion is dark matter
对光的怪异扭曲
causing a weird distortion of light
称为引力透镜效应
called gravitational lensing.
更遥远星系的光
The light from the more distant galaxies
被传播路线上的恒星和暗物质
is literally bent by the curvature of space
所引起的空间曲率所扭曲
caused by stars and dark matter in its path
地球和遥远星系之间
The more dark matter there is
暗物质越多
between Earth and the distant galaxy
光被扭曲的程度越高
the more the light will be bent
导致大寒时代的力量就越大
and the greater the force to cause a Big Chill.
引力透镜效应
The gravitational lensing
是天文学家的绝妙工具
is a tremendous tool for the astronomer
因为我们能计算背后星系的
because we can measure the distortion
扭曲程度
in background galaxies
用它来描绘
and use it to trace
在不同区域 暗物质的分布
the distribution of dark matter on various scales.
我们在寻找天空中
We're looking at a distribution of
理想化的星系分布
idealized galaxies here along the sky
这些遥远星系的光
And the light from these distant galaxies
被复♥制♥后穿过成簇的暗物质
is patterning through clumps of dark matter
眼见不为实
What you look at is not really what's happening.
像是你戴了眼镜
It's a bit like wearing spectacles
但不知道自己戴了
and not knowing that you're wearing them.
如果能知道扭曲程度
And if you can tell how much that bending is occurring,
你就能画出暗物质分布图
you can map the dark matter
还能清楚看到
and you can also see well,
是否真的有暗物质
if there's dark matter there,
暗物质附近的宇宙
is the universe around that dark matter
是否按常理 有重力
behaving the way it should given the gravity or not?
确定哪个能量更占优势
Identifying which energy force dominates
暗物质还是暗能量
dark matter or dark energy,
能让科学家们对于我们的命运
will give scientists more confidence
是大寒时代还是大裂缝
about whether a Big Chill or a Big Rip
有更多信心
will be our fate.
最厉害的证据表明 暗能量
The best evidence shows dark energy
是驱动力
as the driving force.
但到底是多少
But by how much?
解决这个谜题要取决于天文学家
Solving this mystery depends on astronomers
找到测量
finding ways to measure
宇宙运动速度的方法
how fast the universe is moving.
在地球上 要确定
On Earth it's simple to determine
物体运动速度很容易
how fast something moves.
比如一架飞机 比较接近
An airplane, for example, is relatively close.
我们观察它 估计飞行距离
We can look at it and calculate its speed
两地之间的
by estimating the distance it travels
飞行时间
and timing how long it takes
就能算出速度
to get from one point to another.
但恒星的光
But a star's light
在到达地球前
can travel for millions or billions of years
可能传播了几百万或几十亿年
before it can be seen on Earth.
在到达地球时
By the time its light gets here,
光就会永远消失
the star will be long gone.
而且太遥远了 不可能准确地
And it's too far away to gauge its speed
计算速度和距离
or distance traveled with any certainty.
宇宙在膨胀
The universe is expanding.
只是科学家们不知道
Only scientists cannot give
是以怎样的速度
precise answers about how fast.
以更高的精度设想宇宙
The mystery moves closer to being solved
使得离揭开谜底更近了
by imaging the cosmos with greater precision.
在哈勃太空望远镜升空前
You couldn't even observe the galaxies
你甚至都无法
that are in this image
观察这张照片中的星系
before Hubble Space Telescope was launched.
我们的技术能力近来得到
So the increase in our capability with technology
惊人地发展
recently has been astounding.
让我们有能力做事
It has enabled us to do things,
用从未想像过的方式
to chart the evolution of the universe
描绘宇宙的演变
in a way that we never could have imagined
来自太空的清晰照片
Clearer images from space
让膨胀速度的确定更轻松
make it easier to estimate the rate of expansion.
如果随着时间 宇宙继续膨胀
If the universe continues to expand with time,
最终所有的能源
then ultimately all of the energy sources,
核反应堆和恒星会精尽而亡
the nuclear furnaces and stars would run out and die
宇宙也会变得寒冷
and the universe would actually get very cold.
会出现大寒时代
And there would be something called the Big Chill.
在大寒时代的设想中
In the Big Chill scenario
随着宇宙膨胀 地球将是
Earth could become a lonely cold planet
寒冷孤寂的行星
as the universe expands.
恒星之间的距离变得如此之大
Distances between stars grow so vast
以致于从视野中消失
that they nearly disappear from view.
终有一日会燃烧殆尽
Over time they burn out.
最终 整个宇宙将
And eventually the entire universe
以冻结态告终
ends in a frozen state.
这些观点
These are ideas
都来源于爱因斯坦和哈勃
that sprang from the work of Einstein and Hubble.
只是他们都没能
Only neither of them lived
活着看到结果
long enough to see these results.
试想如果埃德温·哈勃
Imagine what Edwin Hubble
和阿尔伯特·爱因斯坦
and Albert Einstein would think
活到今天
if they were alive today
看到课题进展会怎么想
watching the progress in the subject.
爱因斯坦
You know, Einstein thinking
思考宇宙膨胀
about the expanding universe
是他方程式的天然解决方案
as a natural solution to his equations,
但也很困惑
but puzzled you know,
宇宙看起来一点都没变
that the universe didn't appear to be changing.
埃德温·哈勃 迫切想要
Edwin Hubble, desperate to measure
测量宇宙的膨胀
whether the universe
是否减速了
was slowing down in its expansion.
事实上 他们都错了
In fact, you know, they were both wrong.
它正在加速
It's speeding up.
爱因斯坦提出一般相对论时
The time that Einstein developed the general theory,
我们还不知道在银河系之外
we didn't know that there were other galaxies
还有其他星系
outside of our own Milky Way galaxy.
不知道宇宙正在膨胀
And we didn't know that the universe was expanding.
其实爱因斯坦自己
And in fact Einstein himself,
除了他的等式
despite the fact that
冲他喊 宇宙在进化
his equations were screaming at him
其实他自己
that the universe had to be evolving,
对这个结果 没有足够信心
didn't have enough confidence in that result
不敢说宇宙一定在膨胀
to say the universe must be expanding
或是宇宙一定在收缩
or the universe must be contracting.
但 他的工作导致了科学突破
Still, his work led to the scientific breakthroughs
使得能够判别暗物质和暗能量
that would identify dark matter and dark energy;
这些能导致大寒时代的能力