了解宇宙是如何运行的（2010）

How the Universe Works S08E04

Part 4 Jan. 30, 2022, 2:58 p.m.

from ever being born.
泰勒:恒星的形成正在消亡
Thaller:
Star formation is dying.
事实上，消亡的速度很快
And in fact,
it's dying rather quickly.
我们眼前的宇宙
The universe,
right before our eyes,
正变得越来越黑暗
is becoming
a darker place.
它的燃料快用完了
It's running out of fuel.
最终，再也不会有恒星产生了
And eventually, no more stars
will be made at all.
♪
♪
地球上的生命遵循着一系列的规律
narrator: Life on earth follows
a series of regular patterns.
一天又一天，太阳升起……
Day after day,
the sun rises...
又落下
And sets,
星星照亮了黑暗的夜空
and stars light up the darkness
of the night sky.
我开始接触天文学的原因是
The reason I got into astronomy
to begin with
我在农村长大
was because I grew up
in a rural part of the country,
天空是美丽和黑暗的
and the sky
was beautiful and dark.
晚上你走到外面，抬头看
You go outside at night,
and you look up,
你可以看到成千上万的星星
and you could see
thousands of stars.
但情况不会永远如此
But it won't be
that way forever.
2016年，世界各地的望远镜网络
Narrator: 2016, a network
of telescopes across the world
测量了超过20万个星系的能量输出
measured the energy outputs
of over 200,000 galaxies.
♪
他们发现，在过去的20亿年里
they discovered that
in the past 2 billion years,
宇宙失去了一半的亮度
the universe has lost
half its brightness.
夜空越来越暗
The night sky is getting darker
星星闪烁着消失了
as stars flicker
out of existence.
大约100亿年前
About 10 billion years ago,
宇宙达到了顶峰
the universe
kind of hit its peak,
很多恒星都在发光
and lots of stars were shining.
这是一个非常明亮的地方
It was an incredibly
bright place,
但在过去的几十亿年里
but in the last
couple billion years,
它真的，整体上，变得不那么明亮了
it's really, overall,
become a less bright place.
黑暗的宇宙不仅仅是
The darkening universe
isn't just a sign
恒星死亡的标志
that stars are dying.
似乎恒星的诞生也有一个问题
It seems there's a problem
with star birth as well.
明加雷利:当我们研究宇宙的过去时
Mingarelli: When we look
into the universe's past,
我们发现很久以前
what we find is that long ago,
恒星的形成速度要快得多
stars were forming
at a much higher rate.
现在我们看到的是
Right now what we see is
that really,
恒星消亡的速度比它们诞生的速度要快
stars are dying off faster
than they're being born.
一个银河系型的星系，今天
A milky way-type galaxy, today,
每年产生大约七颗恒星
produces about
seven stars per year.
然而，110亿年前
However, 11 billion years ago,
像我们这样的星系每天会产生10倍多的恒星
a galaxy like our own would've
produced 10 times more stars.
在早期的宇宙中，古老的恒星消亡了
Narrator: In the early universe,
old stars died,
新的恒星在它们的位置上
and new ones formed
in their place
由剩下的物质形成
from the material left over.
这是一个循环，让宇宙保持明亮
It was a cycle that kept
the cosmos bright.
但不再是了
Not anymore.
普莱特:这对我们来说很糟糕我们喜欢明亮的宇宙
Plait: It kind of sucks for us.
We like a bright universe.
我们喜欢宇宙中
We like all this energy and life
振动的能量和生命
that's vibrating
through the universe,
但情况并非总是如此
but that's just not always
going to be the case.
宇宙已经趋于平静
The universe is already
winding down.
♪
斯特劳恩:星系演化中最大的谜团之一是
straughn: One of the biggest
mysteries in galaxy evolution
弄清星系是如何停止形成恒星的
is figuring out how galaxies
stop forming their stars.
我们现在还不知道答案
And we really don't know
the answer yet,
找出其中的原因对我们来说非常重要
and it's really important
for us to figure out why
因为最后，恒星真的等于生命
because in the end,
stars really equal life.
♪
为了找出是什么关闭了恒星
narrator: To find out what is
shutting off the stars,
我们研究了星系团
we study galaxy clusters.
♪
这些巨大的空间区域
these giant regions of space
包含了数以百计的星系，它们被引力联♥系♥在一起
contain hundreds of galaxies
bound together by gravity.
慢慢地，星系团将新的星系拉入其中
Slowly, the clusters
pull new galaxies into them,
导致一些奇怪的事情发生
causing something
strange to happen.
当一个星系落入星团时
What we see happening when
a galaxy falls into a cluster
我们所看到的是它的恒星形成过程被终止了
is that its star formation
is quenched.
关闭了
It's shut off.
这种熄灭效应的原因
Narrator: The cause of this
quenching effect
已经困扰了科学家几十年
has baffled scientists
for decades.
然后在2018年10月
Then in October of 2018,
一个国际天文学家团队
an international team
of astronomers
研究了这个长♥期♥存在的谜团
investigated this
long-standing mystery.
♪
他们跟踪了14个星系团的
they tracked variations
in quenching
猝灭变化
across 14 galaxy clusters
并找到了一个可能的解释
and found
a possible explanation.
泰勒:一个星系制♥造♥新恒星的能力
Thaller: The ability a galaxy
has to make new stars
与它所处的更大环境有关
is related to the larger
environment it finds itself in.
在星系团中，许多星系
In clusters of galaxies
where many galaxies
相互环绕
are orbiting around each other,
我们看到相互作用将气体和尘埃带离星系
we see interactions that strip
gas and dust away from galaxies.
构成恒星的物质
The stuff that makes up stars
被拉到太空中
literally just thrown off
into space.
恒星是由稠密的冷气体包裹而成的
Narrator: Stars formed from
dense parcels of cold gas,
星系里充满了这些东西
something galaxies
are filled with.
但当一个星系被拖入星团时
But when a galaxy is dragged
into a cluster,
一切都变了
everything changes.
星系团包含大量的热气体
Clusters of galaxies contain
a lot of hot gas,
而星系内部需要冷气体
whereas you need cold gas
inside of a galaxy
才能形成恒星
in order to form stars,
当星系穿过这些热气体时
and when a galaxy is moving
through this hot gas,
里面的冷气体就会被剥离
then the cold gas inside
is stripped away.
如果这项新研究是正确的
Narrator:
If this new study is right,
星系团正在剥离恒星形成的气体
and galaxy clusters are
stripping away star-forming gas,
新的星光将变得稀少
new starlight will become rare.
回顾宇宙的历史