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我们能阻止小行星的撞击吗?

Could We Stop An Asteroid? Feat. Bill Nye

我们都曾目睹过流星之美,但是
We’ve all witnessed the beauty of a shooting star, but what would happen if
如果小行星撞击了地球那会怎样?
an asteroid was on a collision course for earth?
我们在此之前能检测到吗?更重要的是,我们能阻止它的发生吗? 我相信
Could we detect it ahead of time? And more importantly could we stop it? I believe
我已有答案,你们都明白,小行星撞击
I have an answer, now you see, asteroid impacts
是十分严重的事,我读二年级的时候,McGonigalnv女士告诉我们
are serious business, when I was in second grade Ms. McGonigal told us
关于恐龙的事,她说恐龙灭绝是因为它们的脑子很小
that the dinosaurs the ancient dinosaurs died out because they had small brains
可能就像
may be like
我以前的老板。但她也知道这种理论是站不住脚的
my old boss. But even she knew that was kind a lame that theory was
也毫无根据
nothing.
结果是,在我有生之年人们发现了这个陨石坑—
It turns out in my lifetime people found this crater,
墨西哥的奇虚乐陨石坑。这个坑很大,到底有多大?反正就是很大
off Chicxulub mexico. This crator was so big, how big was it, it was so big
大到有小行星(或撞击器)撞击地球那么大
that an asteroid hit the earth (or impactors hit the earth).
通过撞击地球,它向地球上空丢弃许多垃圾,这致使地球的直径
Hit the earth,it threw so much stuff into the Earth’s sky, it was bigger in diameter
比原来大很多,在那时地球被炽热的岩石
than the earth itself so the earth was surrounded by red hot rock for weeks at
包裹了数周
a time,
一切东西都被加热,动物们居住在洞穴里,
it cooked everything. And just the animals that lived in burrows and caves,
就像我们的祖先一样,你可能会回想起,2013年
our ancestors lead to us ,so ,serious business you may recall ,Valentine’s Day
情人节事件
2013?
俄罗斯的雅宾斯克(爆炸声)的空中爆炸
Chelyabinsk Russia (boom) air burst.
所以勒,假设你是个小行星,以10或20千米每秒的速度飞行
So,if you are an asteroid, and you are going 10 km /s or 20 km /s
然后撞到大气层上,大气层就像水泥
And you hit the Earth’s atmosphere, the atmosphere is like concrete.
你通不过,所以,就在上空爆炸了
you can’t get out of the way ,so ,the asteroid just explodes in air burst.
所以,这些小行星非常危险,它们大多是
So these asteroids are serious, most of them
很小的。如果你的直径小于十米,你撞击到大气层,燃烧起来,就产生了大大的
are very small. If you’re under 10 meters, in diameter, you hit the Earth’s atmosphere you burn up all Big
蓝色的尾巴,绿色的尾巴
Blue streak, green streak
白色的尾巴,然后人们就对着这些尾巴许愿啰。
white streak and then humans make wishes upon you.
我不知道许的愿灵不灵,但人们都这样做,好了
I don’t know how efficacious those wishes are but people do that, alright
所以
so,
如果小行星变得更大了,流星的直径就会达到25米
if ther asteroid starts to get bigger, starts to get into the twenty-five meters and the
至45米之间的长度,结果就产生了亚利桑那州陨石坑(威猛)那样巨大的
45 meters in diameter ,then you get Meteor Crater Arizona (wham) huge
东西
thing.
这就可能摧毁一座城,或者灭掉一个县
That would be like a city killer, or a county killer.
如果直径达到了100至140米,就足以摧毁一个国家
And then when they get to be a 100 meters / 140 meters, now you’re into a country killer,
如果继续变大,就足以灭掉整片大洲,比这还大的话,
and then they get bigger than that and it’s a continent killer, much bigger than that
你就摧毁了
and you’re taking out
所有的古物种族群了
whole races of ancient species.
所以,如果我们发现了冲向地球的行星,我们如何发现它?
So, what if we found an asteroid that was headed our way, how would we find it?
如何发现它是撞向我们的那个?这个问题真棒,好吧,
How would we find an asteroid headed our way? That’s a good question, well
你可以使用望远镜,有经验的人知道,把相机对准天空,然后
you can use telescopes. Skilled people can point the cameras at the sky and
去找快速移动的物体。
look for fast-moving objects.
这些物体会穿过地球的轨道,但也有可能我们会错过
Objects that are crossing the Earth’s orbit, but we’re missing perhaps a
成百上千
hundred thousand
的撞击行星——它们毁县,屠城,甚至摧毁整个国家。
of these things, of these county killers, city killers and country killers.
所以勒,我们想要造一架名为“哨兵”的飞行器,
So, what we want to do is build a spacecraft called The Sentinel,
正如俗话所说;黑夜找碳团
and as we say ‘it’s like looking for a charcoal briquette
这些行星难以发现。它们与广阔的宇宙比起来
in the dark’, these things are hard to find. They are tiny compared to the vastness
太小了
of space.
但他们会放射出红外线辐射,所以勒,你会怎么做
But infrared light / heat bounces off them, so ,what you will do –
假如你是一个卫星,是个测量型航天器
you are a satellite, you are a surveying spacecraft,
你跑到太阳的屁股后面,
you get your back to the Sun and look out
在金星的轨道上东张西望。努力找到
from about the orbit of Venus. And try to find
所有的行星。然后找到了一个,你会怎么做?你会扭着圈圈
all these asteroids. And then you find one, what do you do? Do you run in circles
惊声尖叫?
screaming?
啊!不,不,不,我们得让它走偏一点,只要
‘AH’ No, No No, we’ve got to deflect it, just
一丁点,一丁点就行。行星可能会以一万米每秒的速度运行
a little, just a tiny amount. Asteroid might be going 10 km/s
我们想要改变它的速度
we want to change its speed
只要两毫米每秒的改变就行。
about 2 mm/s.
所以勒, 十千米就是十乘一千米,也就是一万米。
So ten kilometers, that’s ten times a thousand meters, that’s 10,000 meters.
一毫米是千分之一米
A millimeter that’s a thousandth of
所以勒,你选取一千分之一,它就是一千乘(本身速度)一万
a meter so that you take the one over the thousand its a thousand times ten

thousand,
等于一百万,这就是你所改变的比例——
that’s 10 million. You want to change its speed a 10 millionth
总速度的一百万分之一,这真的不多
of its total. That’s not very much,
但是,如果你是一个
but if you’re an asteroid that comes in at
万至十万吨重的小行星
10,000 tons / 100,000 tonnes,
改变速度的百万分之一就需要费一点力了。
it does take quite a bit force to change it a 10 millionth of its speed.
好的,
Okay,
怎么办呢?嗯,最快捷的方法
how do we do that? Well, the easiest way
是有个火箭,够大就好了,只要从这头到
is to get a rocket, just a big rocket, just go out there and
那头,因为在外太空,所有就(安静)
smack into it. Except as an outer space so it just goes (silence)
像这样了。好,这会致使它的速度有一点点的改变,现在注意了,
like that. Okay, that would change its speed a little, now notice everybody,
如果它不是一个完整的石头?只是一堆松散的石块
what if it’s not just a rock? What if its a pile of rocks just
被原引力所聚集起来了而已?
loosely held together by primordial gravity?
这样,如果你击中了它们,它们就会飞的到处都是,你就会享受到
And so if you hit them they will just spread out and you will have a shower of
石块淋浴了
rocks.
这糟糕的很。所以勒,这咋办勒?
That would be bad. So, how about this?
我们放出大宇宙飞船这个大招,宇宙飞船到达这里
We will get a big space craft that is massive, a massive spacecraft will go out there
慢慢靠近小行星
and just get nearer to the asteroid.
靠近之后,然后相互之间的引力——
Just get near it, and then the mutual gravity
你和我——小行星与宇宙飞船,
of the you the asteroid and me the spacecraft
就会把小行星稍微拉动一点
will tug the asteroids just a little bit
只是一点点,可能拉向这边,也可能拉向另一边
just a tiny amounth or maybe get on the other side and tug
这种做法或许有用,但是这里有两个问题。
this way. That might work but here’s the problem.
我们需要大量的燃料,或许是几天用的
We need a huge amount of fuel, for days
也可能是几周,几月,甚至几年用的。
and weeks and months and years.
如果(飞行器)停止工作,你也不能到那里修理它。好吧,
And what if it stops working, you can’t go out there and fix it. Okay,
这样做怎么样?使用激光小蜜蜂?
how about this? The Laser Bees?
一大群
A swarm
太阳能激光器发射激光
of sunlight powered lasers,
射到小行星的表面
that are zapping the surface of the asteroid,
几天,几周,几月,几年
for days, and weeks, and months,and years
咝咝咝,这样,一些小行星,一些岩石就会汽化
ZAP ZAP ZAP, so some asteroids, some rock is vaporized
这样,排出的废物,以及喷射出的东西就成为动力
so the ejecta, or the stuff ejected has momentum
就像我们的火箭燃料一样,就像站在溜冰板上
just like rocket fuel, just like just like standing on a skateboard and playing
还一边玩着保龄球接球游戏…
catch with a bowling ball…
你这样做。然后就会
the way you do. And so it would then
致使小行星改变它的速度。所以,你发射了一大群这样的激光
cause the asteroid to change its speed. And so you send a swarm of these laser
航天器,这样
spacecraft, so that
如果有一个挂了,你就能使用另外一个。你还能
if one of them stops working you can use the other one. And you can
让它们从不同的角度发射。如果小行星
have them come in from all different angles. And what if the asteroid is
的形状不规则(就像这样)
irregularly shaped (like this)
你可以等到它变得光滑时再发射
you could beam it when the thing is smooth
以及,当它有一个凹陷或难以照射完全的地方时,你可以
and then when there’s a pit or an inefficient place to be beaming you turn
关掉
off,
等到小行星转个身,又把激光航天器打开。你们明白了吧,
you wait for the asteroid to turn, then you turn it back on. You see everybody,
几率小不意味着不重要。
just because it’s unlikely, doesn’t mean it’s not a big deal.
你懂的,如果这事千年一遇,它又
You know if it only happens once every few thousand years, well if it happens
刚好在我活着的时候发生了
on my watch
就像小孩子那样说吧;“傻客”。好吧,惹不起
it would as the kids say ‘suck’. Okay, so we don’t want that to happen, we want to
躲得起。
avoid that.
小行星蛮危险的,但是这是还挺让人激动滴。
Asteroids are serious business, but they’re exciting.
(飞船噪声)我们不在太空上
(Spaceship noise) Except we are in space so its (silence).
这个选题好吗?欢迎订阅asapscience,请在
Got a burning question? Well be sure to subscribe asapscience, follow us
Facebook或者Twitter上找到我们,像你的小伙伴们那样
on Twitter and Facebook, that’s what all the kids are doing.
小行星这个话题虽不劲爆,但它
And if it’s an asteroid it may not be a burning question, it might be
是一个有力度的问题,甚至
an impacting question, or even
是一个有深度的话题。
and ablating question.

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