了解宇宙是如何运行的（2010）

How the Universe Works S08E04

Part 7 Jan. 30, 2022, 2:58 p.m.

They can access all
the hydrogen they want.
普莱特:在低质量恒星中
Plait: In low-mass stars,
outside of the core,
在核心之外，外层是完全对流的
this outer layer
is fully convective.
这意味着,核心附近的东西上升到表面
What that means is, stuff near
the core rises to the surface
然后下降回落到核心
and then drops back down
all the way to the core,
这意味着，如果你在核心之外的某个地方
and that means if you have
hydrogen somewhere
有氢燃料，最终，它们都会进入核心
outside of the core,
eventually, it's going to make
并可以被用作燃料
its way down there,
and it can be used for fuel.
霍普金斯:红矮星在自助餐上
Hopkins: The red dwarf has
access to everything
可以吃到所有的东西
at the all-you-can-eat buffet.
它可以从恒星表面的遥远区域
It can grab stuff from
the distant regions
捕获物质，并将其一路带到恒星的食道
at the surface of the star
and bring it all the way
到达恒星的核心
down the gullet
to the heart of the star.
这个吃到饱的自助餐
Narrator: This all-you-can-eat
hydrogen buffet
把红矮星的寿命延长到了难以置信的长度
extends the life span of red
dwarfs to incredible lengths.
宇宙已经有130亿年的历史了
The universe is over 13 billion
years old,
但这个年龄的红矮星还只是个蹒跚学步的孩子
but any red dwarf
that age is a toddler.
红矮星，即使它诞生于
A red dwarf, even if it was born
宇宙形成之初
at the very beginning
of the universe
那时红矮星才刚刚形成
when red dwarfs
could first form,
那么直到今天，也只是它寿命的一小部分
even today, it's just
a tiny fraction of its lifespan.
它们可以持续上万亿年
They can last for trillions
of years,
是宇宙当前年龄的数千倍
thousands of times
the current age of the universe.
萨特:130亿岁——
Sutter:
Thirteen billion years old --
这似乎很长时间了
that seems like a long time,
但对于一颗小红矮星来说
but a small red dwarf,
尿布还没换完呢
it's barely out of diapers.
♪
红矮星在10万亿年
narrator:
Red dwarf stars will not die out
或更长时间内不会消亡……
for 10 trillion years or more...
我们发现它们还有另一张王牌
And we're discovering
they have another trump card
这对生命来说是个好消息
that's good news for life.
♪
2017年2月
February 2017.
美国国家航♥空♥航♥天♥局宣布，在宝瓶座星座
Nasa announced
the discovery of a system
发现了一个名为特拉普斯特-1的恒星系
in the aquarius constellation
called trappist-1
有7颗地球大小的行星围绕着一颗红矮星运行
where seven earth-sized
planets orbit a red dwarf star.
普里特:事实证明，红矮星显然
Plait: It turns out that red
dwarfs, apparently,
非常擅长制♥造♥行星
are really good
at making planets,
包括那些和地球差不多大小的行星
including planets that are
roughly the size of the earth.
这真的很酷，因为这些恒星持续了很长时间
That's really cool because
these stars last a long time.
如果它们周围有存在生命的行星
If they have planets
orbiting them with life,
它们的寿命可能比我们的太阳系长上万亿年
they could outlast our solar
system by trillions of years.
听起来很有希望，但是红矮星也有丑陋的一面
Narrator: Sounds promising, but
red dwarfs have an ugly side.
2018年10月
In October 2018,
天文学家将哈勃太空望远镜
astronomers turned
the hubble space telescope
对准了 tucana-horologium 星团的
to a series of young
red dwarf stars
一系列年轻红矮星
in the tucana-horologium
association.
他们看到这些“婴儿”每天都在发脾气
They witnessed these infants
throwing daily stellar tantrums.
泰勒:尽管它们是最小的恒星
Thaller: Even though they're
the smallest stars,
但它们实际上有一些最强的耀斑
they actually have
some of the strongest flares
和星风暴
and storms on them.
红矮星可以发出
Narrator:
Red dwarfs can emit flares
比太阳强一万倍的耀斑
10,000 times more powerful
than the sun.
这些耀斑会把附近的行星烤焦
These flares would cook
any nearby planets.
奥卢塞伊:当红矮星形成时
Oluseyi:
When a red dwarf star forms,
它们旋转得非常快
they're rotating very rapidly,
这就产生了大量的磁场活动
and this creates
a lot of magnetic activity
从而产生耀斑和质量抛射
which creates flares
and mass ejections.
生命的存在
Narrator:
For life to exist,
必须要等到小红矮星长大
it would have to wait for infant
red dwarfs to grow up.
奥卢塞伊:随着红矮星年龄的增长
Oluseyi:
As a red dwarf gets older,
在它旋转的过程中，空间磁场之间
there's drag between
the magnetic fields
会产生阻力
in space as it rotates,
and that has the effect
这就减缓了它的旋转速率
of slowing down
its rate of rotation.
所以这意味着活动稳定下来
And so this means
the activity settles down.
所以也许以后，在红矮星的生命中
So maybe later, in this life
of a red dwarf star,
它们可以支持有生命的行星
they can support
planets with life.
红矮星将主宰未来的宇宙
Narrator: Red dwarf stars will
dominate the future universe
也许会给生命一个生存的机会
and may give life
a chance to survive.
这些小红星寿命极长
These small red stars
are extremely long-lived,
但没有一颗恒星是不朽的
but no star is immortal.
即使他们非常缓慢地消耗他们的核燃料
Even though they're really going
through their nuclear fuel
也没有足够的燃料可以永远使用
very slowly, there's just not
enough fuel to last forever.
这些小星星最终也会消亡
Narrator: These little stars
will die out eventually.
与它们的大恒星兄弟姐妹不同，它们会悄无声息地消失
Unlike their larger stellar
siblings, they'll go quietly.
实际上，恒星会变得更热
Well, it actually just gets
hotter,
恒星的颜色取决于它的温度
and the color of a star
depends on its temperature.
所以当红矮星变热时，它会变蓝
So as the red dwarf gets hotter,
it turns bluer.
所以在遥远的将来
So sometime
in the very distant future,
有些红矮星
some of these red dwarfs
会变成蓝矮星
are actually going
to become blue dwarfs.
宇宙的年龄还不足以让蓝矮星存在
Narrator:
The universe isn't old enough
for blue dwarfs to exist yet.
但数万亿年后
But trillions of years from now,
一束暗淡的蓝♥光♥将完成恒星末日
a dim blue glow will
complete the star apocalypse.
还会有最后一颗恒星，最后一颗红矮星
There will be a last star,
one last red dwarf,
随着温度升高，可能会变成蓝色
maybe now turning blue
as it warms up,
但它最终也会冷却，消失
but it too will eventually
cool off, fade away.
宇宙中就不会再有星星了
And there will be no more stars
in the universe.
这是不可避免的
It is inevitable.
♪
在这个黑暗，没有星星的宇宙中
narrator:
In this dark, starless universe,
生命的前景似乎是不可能的
prospects for life
seem impossible.
但是会有别的东西取代恒星吗？
But will something else