了解宇宙是如何运行的（2010）

How the Universe Works S05E06

Part 4 April 18, 2021, 7:47 p.m.

发射这道银河宇宙射线
toward our solar system
看看它会对我们的宇宙飞船造成什么影响
and see what it does to our spacecraft.
当子弹击中金属时
As the bullet hits the metal,
弹片像冰雹一样散开
it shatters into a hail of shrapnel
并击中了气球
that spreads out, hitting the balloons.
宇宙射线也是如此
It's the same with cosmic rays.
这些小粒子会撞击金属
These little particles will hit the metal,
它们会从金属原子中
and they will basically free a bunch of electrons
释放出一堆电子
from the atoms in the metal,
而这些电子会穿透你身体
and those electrons will then shoot through you.
现在，已经不是被一个粒子击中
And so now, instead of getting hit by one particle,
而是被千万个粒子击中
you're being hit by a bazillion particles,
这非常糟糕
and that's bad.
德尔达: 那么，如果这是你身体内的细胞
Durda: So, if those were the cells of your body,
那你就极其麻烦了
you'd be in severe trouble
因为当这银河宇宙射线
because when this galactic cosmic ray
穿过航♥天♥器的保护层
blasted through the wall of the spacecraft,
并在原子水平不剥离保护层
it spalled out of there, and at an atomic level,
这已经不仅仅只是一条宇宙射线
it's not just the damage from that one cosmic ray
对一个细胞的破坏了
bursting one cell.
所有这些原子的弹片会炸穿很多细胞
All of this atomic shrapnel blasted through many cells.
所以这些人类细胞的替代品
So these stand-ins for human cells
的确代表了未来太空旅行者
really represent the severe challenge
在太空中面临的严峻挑战
that future space travelers have out there in space.
你如何保护自己
How do you protect yourself
免受这些高能银河宇宙射线的伤害呢？
from these high-energy galactic cosmic rays?
你不希望这种情况发生在DNA上
You don't want that happening to the DNA,
发生在你体内的细胞上
to the cells in your body.
银河系中心是禁区
The center of the galaxy is off-limits ...
一个度假的禁区
a vacation no-go area.
我们很幸运地住在远离银河系中心的地方
We're lucky to live far away from the center
并且受到太阳的保护
and protected by our sun.
我们在银河系的“郊区”
It may seem kind of unfortunate
看起来似乎有点不幸
that we're sort of in the suburbs of the galaxy.
我们距离银河系中心近3万光年
We're almost 30,000 light-years away from the center.
但这里可能是最适合生命生存的地方
But this may be the best place for life.
接下来
Next in our tour
我们来看看宇宙中最糟糕的地方……
of the worst places to visit in the universe ...
一个宇宙托儿所
a cosmic nursery,
恒星和行星的诞生地
the birthplace of stars and planets.
你是不会在这里哼唱摇篮曲的
But you won't be humming any lullabies here,
因为这也是一把装满宇宙铅弹的猎枪
because it's also a shotgun loaded with cosmic buckshot.
现在我们见证了一个行星系统的诞生
Now we witness the birth of a planetary system,
一个由气体和尘埃组成的
a beautifully orchestrated family of planets
美丽的行星家族
somehow coming together out of gas and dust.
谁不想近距离地目睹这样的事情发生呢？
Who wouldn't want to witness such a thing up-close?
不，你不会的，你不会想待在
You, if you don't want to be
这个宇宙中最致命的地方之一的
in one of the most deadly places in the universe,
因为事实证明，行星的诞生是致命的
because, as it turns out, planet birth can be lethal.
这是 lkca 15
This is lkca 15.
它是一颗距离我们450光年的恒星
It's a star 450 light-years away,
质量与我们的太阳相似
similar in mass to our sun.
一个由尘埃和气体组成的原行星圆盘围绕着它
A protoplanetary disk of dust and gas surrounds it.
在那里，新的行星正在诞生
And in it, new planets are being born.
行星刚形成的时候
When planets are first forming,
恒星还非常年轻，此时恒星周围有一个
there's a disk of material around the star
由物质组成的圆盘
when it's very young.
行星基本上就是由这些碎片形成的
And the planets basically form from all this debris.
物质会碰撞和粘在一起
Stuff hits and sticks together.
它会变得越来越大，越来越大
And it grows bigger and bigger and bigger,
然后它的重力把更多的物质吸进来
and then its gravity draws material in.
行星的形成就像一场毁灭竞赛
Planet formation is like a demolition derby.
他们有很多相似之处
There are a lot of similarities.
在比赛中，汽车在赛道上
In a derby, the cars are racing around a track,
以不同的速度绕圈
going around in circles at different speeds.
行星也一样
Well, it's the same thing with planets.
物质绕太阳运行到处都是
The material is orbiting the sun. It's going around.
它们有不同的速度
And they're all going at different speeds,
不同的角度以及不同的轨迹
at different angles, different trajectories.
有时这些物质会碰撞
Sometimes this material collides.
你会得到一个更大的物体
And you get a bigger object left over.
行星就是这样生长的这是它们形成的方式
And that's how planets grow. It's how they form.
它从远处看很美，但如果太近了
It looks beautiful from afar, but venture too close,
你就会被那些超快速度的物质包围
and you'll be surrounded by speeding material.
他们是……灰尘，沙粒
The material ... the dust, the grains of sand,
甚至更大的岩石……
even the bigger rocks ...
以轨道的方式迅速绕着原恒星运动
are moving at orbital speeds around this protostar.
所以我们说的是每秒10、15、20英里的速度
So we're talking about 10, 15, 20 miles per second.
你可能认为大石头
You might think that the large rocks
是最危险的
are the most dangerous.
但在太空中，情况就不一定了
But in space, that's not necessarily the case.
更大的岩石可以看到，可以追踪
The bigger rocks can be seen, can be tracked.
这么大的物体可以在太空中追踪到
Things this big can be tracked in space.
但是任何这么大的东西在太空中都很难发现
But anything that's about this big is hard to find in space.
你不知道它要来了
You don't know it's coming.
所以在太空中我们
So while we're all fearing the big rock,
与其害怕大石头，还不如小心
if you're out in space, you better watch out
移♥动♥得很快的小石头
for the small rock that's moving fast.
如果一块石头大小的石头以每小时四万英里的速度
If a bb-sized rock going at 40,000 miles an hour
击中我们的碰撞测试假人，
hits our crash-test dummy,
就会直接刺穿他
it's gonna cut right through him.
你知道，棒球界有规定
You know, there are rules in baseball
击球手必须戴头盔
that a batter has to wear a helmet
因为有个棒球以每小时100英里的速度
because there's a baseball moving at him
朝他飞过来
at 100 miles an hour,
如果球打到他的头，他可能会没命
and if that hits him in the head, it could kill him.
现在想象一下这个棒球
Now imagine that that baseball
扔出去的速度是原来的1000倍，对吧？
is being thrown 1,000 times faster, right?
会把击球手的头打穿
That would put a hole right through a batter's head.
它甚至不会减速
It wouldn't even slow down.
这些东西就是这么危险
That's how dangerous these things are.
恒星周围的空间
The space around the star
充满了各种大小的碎片
is jammed full of every size of debris.
汤普森: 岩石会旋转
Thompson: Rocks are gonna be spinning around,
互相弹开，或碰撞并粘在一起
ricocheting off each other, colliding and sticking.
这对恰克来说是个可怕的、充满敌意的环境
It's a horrible, hostile environment for Chuck.
他经常会被打得惨不忍♥睹
He's gonna be hit often and hard.
你将会看到他被炸成碎片
You're just gonna see him get blown to bits.
把恰克放在这样的原行星圆盘里
Putting Chuck into a protoplanetary disk like that
基本上就像是在他面前拿一把猎枪对着他
is like, basically, sticking a shotgun in front of him
然后扣动扳机
and pulling the trigger.
有大量的物质
There's just a huge amount of material
以惊人的速度移♥动♥
moving at tremendous speeds,
这些物质会击中他并把他撕成碎片
and it would hit him and just rip him to pieces.
所以，如果你想获得一些平静
So, what if you decide to get a little peace
前往宇宙中最安静的地方
and head to one of the quietest places in the universe,
远离危险的碎片，会怎么样呢？
far from dangerous debris?
嗯，外表会欺骗性你
Well, looks can be deceptive.
因为即使是拜访宇宙中最空旷的地方之一
Because visiting even one of the emptiest places in the cosmos
也可能是一场噩梦
can be a nightmare,
在那里，比原子还薄
where something thinner than an atom
有好几光年长的东西会把你切成碎片
and light-years long can cut you to ribbons.
当我们仰望天空时
When we look out at the heavens,
我们可以看到数十亿个星系和数万亿颗恒星
we can see billions of galaxies and trillions of stars.
它们通常看起来是均匀间隔的
They generally look evenly spaced out.
但在2015年，科学家发现了一些奇怪的现象
But in 2015, scientists spotted something strange.
我们时不时地会发现一些无法解释的现象
But every now and then, we find something we can't explain.
有一个巨大的区域
There is a giant area
比想象中更冷更空旷
that's colder and emptier than it possibly could be.
那里没有多少物质
There's not very much matter in there.