恒星七纪（2012）

shining a rancid red in the inky sky.
大角星就是一颗红巨星 很容易找到
Arcturus is a Red Giant star, very easy to find.
就在大熊座北斗七星的末端
The tail of the Plough, the tail of the Big Bear,
沿着那里看去 就可以找到大角星
you follow that and you reach the star Arcturus,
追随大熊 正符合"Arcturus"原来的意思
so it is in a way following the Big Bear, as a bear-taker,
巨熊的守护者
which is what Arcturus means.
奇特的是
Surprisingly,
大角星引人注目的颜色并非因为它温度高
Arcturus's striking colour is not because it's hotter
反而是因为它温度较低
but because it's cooler.
当重力和核聚变的力量
As the balance between the opposing forces
无法再维持平衡时
of gravity and nuclear fusion breaks down,
恒星的大小就会发生改变
the size of the star changes.
红巨星会逐渐膨胀
Red Giants expand,
它们狂暴的能量扩散开来
their fiery energy spreading over a larger area,
导致它们温度下降
which makes their temperature drop.
从蓝色或白色恒星
They fall from blue or white hot
变为红色恒星
to red hot,
但因为它们体型巨大
but because they are so large,
它们此时还是天空中最耀眼的恒星之一
these stars are still some of the brightest in the sky.
那是大角星
That's Arcturus.
大角星 由弗朗西斯科拍摄
对于像大角星这样明亮的恒星
When we see bright stars like Arcturus in the sky,
在古代 无疑有不少人类文明
no doubt in many, many civilisations in the past,
把某些事件的发生
they have some associations with these stars
与之联♥系♥起来
and something that happens.
"每颗恒星都有着独特的个性
"Each star has its own distinct personality.
《自然博物志》
老普林尼 公元前一世纪
"它们造成的影响也正符合个性
"And it creates effects according to its character.
"大角星的升起一定会伴随着
"When Arcturus rises, it is nearly always accompanied
"一场猛烈的冰雹"
"by a terrible hailstorm."
但其实大角星所预示的灾难
Actually, Arcturus is an omen
可比恶劣天气要糟糕的多
of something far worse than bad weather.
它预示的恐怖场景
A portent of a drama more intense
好莱坞根本不能望其项背
than any Hollywood could imagine.
当太阳在五十亿年后
When our own Sun eventually becomes a Red Giant,
最终变成红巨星时
in five billion years' time,
它将由守护者
it will turn into a destroyer,
演变为这个世界的毁灭者
rather than a protector, of worlds.
罗宾·卡其普尔博士多年以来
Dr. Robin Catchpole has devoted his middle years
致力于研究这些夜空的饕餮巨兽
to studying these devouring beasts of the night.
这要从它们内核中 氢耗尽的那天说起
Their story starts the day the hydrogen in their core runs out.
恒星一生大部分时间
Most of the star's life
都在把氢聚变成氦
it spends fusing hydrogen into helium,
而这一过程提供了
and this, of course, provides the pressure
用以抵抗引力的压力
that resists the force of gravity.
当内核的氢耗尽
When the hydrogen runs out in the core
仅剩下纯氦时
and we've just got pure helium,
就没有了能量来源
then there's no source of energy,
所以内核开始塌缩
so the core starts to collapse.
罗宾·卡其普尔博士
剑桥大学 天文学家
而在塌缩的过程中
And as it collapses,
温度在引力的作用下上升
under the force of gravity, it heats up.
然后温度升高到
And the temperature becomes high enough
足以使核心外♥围♥的壳层发生核聚变
to start nuclear fusion reactions in the shell around the core.
我们称之为壳层氢燃烧
So we have what we call shell hydrogen burning.
核心已经停止了聚变
Fusion has stopped in the core.
它仍然很热 但已经死了
It's still hot, but it's dead.
这颗恒星和我们的太阳
The star is now fundamentally different
已经完全不同了
from our twinkling Sun.
核聚变仍在继续
The light we're seeing
发出我们所看见的光
is still being generated by nuclear fusion,
但它却发生在外♥围♥含氢的壳层
but it's happening in a ring of hydrogen
而不是在内核中
that surrounds the core instead.
这是新的能量来源
This is our new source of energy
这一过程当然也会抵抗其自身的引力
and this, of course, resists the force of gravity
并且实际上导致了恒星外层大气的膨胀
and, in fact, causes the outer atmosphere of the star to expand.
这颗恒星就开始其华丽的变身
The star has begun its dramatic transformation
成为红巨星
into a Red Giant.
对于我们的太阳来说
For our own Sun,
这个变化将是令人畏惧的
the change will be awe-inspiring,
因为在它的晚年
as in its final years,
它会毁掉它之前所照顾的行星
it turns against the planets in its care.
首先 它会不断膨胀
The first thing that happens is it expands up
一直膨胀到水星轨道 然后吞没水星
as far as Mercury's orbit here and swallows Mercury.
到那个时候
At this stage,
它将比现在的太阳亮一千倍
it's about 1,000 times more luminous than the Sun is today.
然后它继续膨胀 大约再过几百万年
It continues to expand and, within another million years or so,
它将膨胀到金星轨道
it gets as far as Venus,
金星也就完了 被吞没了
and that's the end of Venus, Venus is swallowed up.
然后太阳继续膨胀 朝着地球而来
And then the Sun continues out towards the Earth.
要是我们能看到的话 我们会看见它
If we could see it, we would see something
比现在的太阳亮三千倍
nearly 3,000 times brighter than the Sun is today.
它比现在要大260倍
It would be 260 times bigger than it is today,
但是却没有
but it would not have that
现在太阳的完美外形
beautiful tight compactness of the Sun today.
气体从表面涌出
Gas would be streaming off the surface,
它将是红色的 无比狂暴 略微有点透明
it would be red and turbulent, slightly transparent.
看起来就像要从裂缝处炸开了一样
It would almost seem to be coming apart at the seams.
我们唯一的存活希望
Our only chance of survival
就是在灾难降临前远远逃离
would be to flee long before this crisis,
并寻找一个新的太阳系来安家
and go in search of another solar system to call home.
到了它狂暴的晚年
In its angry old age,
即使是面对它最心爱的孩子
the Sun will show no mercy,
太阳也会毫不留情
even to its favoured child.
地球将消失在太阳中
And the Earth disappears into the Sun,
恐怕那时就是地球的末日了
and I'm afraid that's curtains for the Earth.
我们的星球将被炽热的气体球吞没
Our planet will be engulfed by a ball of fiery gases,
彻底被抹掉
never to be seen again.
创造并哺育了我们的恒星
The star that created and nurtured us
最终将会在它膨胀的晚年
will ultimately, in its bloated old age,
毁灭我们
destroy us.
当红巨星带来了毁灭时
But while Red Giants bring annihilation,
科学家们却在其中发现了
scientists have uncovered in them
另一段故事的开始
the beginning of another story.
一个创造的故事 和我们有关
A story of creation that is about us,
也与恒星有关
as well as about the stars.
科学家发现 在引力与核聚变
They discovered that in the last stages of the battle
对抗的最后阶段
between gravity and nuclear fusion,
红巨星产生了
Red Giants generate
宇宙中最丰富的两种基本元素
two of the most abundant building blocks of the universe.
这些重要的元素
And these vital elements
是在红巨星的核心处产生的
are being built in the heart of the Red Giant.
在太阳吞没了可怜的地球
About half a million years after the poor old Earth
大约五十万年后
has disappeared into the Sun,
其温度升高到了
we get the temperature rising to the point
足以开始进行氦聚变
where we can suddenly start helium fusion.
这是恒星一生中的一个新阶段
And this is the next phase of the life of the star,
此时 氦元素在恒星的内核中聚变
is a stage where helium is being fused in the core
并产生碳和氧
to produce carbon and oxygen.
科学家们发现恒星
Stars, scientists discovered,
不仅能发出摇曳的星光
aren't just twinkling points of light.
它们还是炼金术士
They're alchemists,
创造出组成宇宙的物质
creating the materials the cosmos is made of.
你身体中大多数的碳
Most of the carbon in your body
都来自于红巨星废弃的包层
comes from the discarded envelope of a Red Giant.
当引力与核聚变的战争
As the war between gravity and nuclear fusion
终于要分出胜负时
reaches its conclusion,
恒星巨大的外层包层
the vast outer layers of the star
就与高温的核心分离开来
detach from the hot core,
将碳和氧返还至宇宙中
recycling carbon and oxygen into the universe.
这一绚丽的过程之后剩下的
What's left after this remarkable process