我们能阻止小行星撞击地球吗？（比尔·奈客串）：英语精读讲义

We've all witnessed the beauty of a shooting star,

我们都曾见识过流星之美，

but what would happen if an asteroid was on a collision course for Earth? 短語搭配

但如果一颗小行星正沿着撞向地球的轨道飞来，会发生什么？

Could we detect it ahead of time? 短語搭配

我们能提前探测到它吗？

And more importantly, 表達脈絡

更重要的是，

could we stop it?

我们能阻止它吗？

I believe I have an answer.

我想我有答案。

Now, you see,

你看，

asteroid impacts are serious business. 習語

小行星撞击可不是闹着玩的。

When I was in second grade,

我上二年级时，

Ms. McGonigal told us that the dinosaurs,

McGonigal老师告诉我们，恐龙，

the ancient dinosaurs,

那些远古的恐龙，

died out because they had small brains, 短語動詞

是因为脑子太小才灭绝的，

maybe like my old boss.

也许就像我的前老板一样。

But even she knew that was kind of lame,

但就连她也知道，这种说法有点站不住脚，

with that theory was nothing.

那套理论根本毫无根据。

It turns out in my lifetime people found this crater 表達脈絡

后来，在我有生之年，人们发现了这个陨石坑，

off Chicxulub, Mexico.

位于墨西哥希克苏鲁伯附近。

This crater was so big.

这个陨石坑大得惊人。

How big was it?

到底有多大？

It was so big

它大到这种程度：

that an asteroid hit the Earth or impactors

一颗小行星撞上了地球，或者说多个撞击体

hit the Earth,

撞上地球后，

threw so much stuff into the Earth's sky.

把大量物质抛进了地球上空。

It was bigger in diameter than the Earth itself.

它的直径比地球本身还大。

So the Earth was surrounded by red-hot rock for weeks at a time. 短語搭配

于是，地球连续数周被炽热的岩石包围。

Cooked everything.

一切都被烤熟了。

And just the animals that lived in burrows and caves,

只有那些住在地洞和洞穴里的动物活了下来，

our ancestors led to us.

它们成了我们的祖先，最终演化出了我们。

So,

所以，

serious business.

这绝不是小事。

You may recall Valentine's Day 2013,

你可能还记得2013年的情人节，

Chelyabinsk, Russia air burst. 文化背景

俄罗斯车里雅宾斯克发生了空爆。

See, if you're an asteroid and you're going 10 km a second,

你想，如果你是一颗以每秒10公里飞行的小行星，

20 km a second,

甚至每秒20公里，

and you hit the Earth's atmosphere,

当你撞上地球大气层时，

the atmosphere is like concrete. 表達脈絡

大气层就像混凝土一样坚硬。

Then it can't get out of the way. 習語

它根本来不及让开。

So the asteroid just explodes in air burst. 用詞

于是小行星就在空中爆炸了。

So these asteroids are serious.

所以，这些小行星真不能小看。

Most of them are very small.

它们大多非常小。

If you're under 10 m in diameter,

如果你的直径不到10米，

you hit the Earth's atmosphere,

撞上地球大气层后，

you burn up 短語動詞

你会燃烧殆尽，

big blue streak,

划出一道巨大的蓝色光芒，

bl- green streak,

蓝——绿色光芒，

white streak,

或白色光芒，

and then humans make wishes upon you. 文化背景

然后人类会对着你许愿。

I don't know how efficacious those wishes are, 用詞

我不知道这些愿望有多灵验，

but people do that.

但人们就是会这么做。

All right.

好吧。

So,

那么，

if the asteroid starts to get bigger,

如果小行星开始变大，

starts to get into the 25 m and the 45 m in diameter,

直径达到25米乃至45米，

then you get Meteor Crater, Arizona.

就会形成亚利桑那州的陨石坑那样的景象。

Wham, a huge thing.

轰！一个巨大的坑。

That would be like a s- city killer or a county killer.

它足以摧毁一座城市，甚至一个县。

And then when they get to be 100 m,

等它们的直径达到100米，

140 m,

140米时，

now you're into a country killer.

就足以摧毁一个国家了。

And then they get bigger than that,

如果比这还大，

it's a continent killer.

就足以摧毁一整片大陆。

Much bigger than that and you're taking out whole races of ancient species.

再大得多，就会灭绝整个远古物种族群。

So,

那么，

what if we found an asteroid that was headed our way? 短語搭配

如果我们发现一颗正朝我们飞来的小行星呢？

How would we find it?

我们要怎么找到它？

How would we find an asteroid headed our way?

我们要怎么找到一颗正朝我们飞来的小行星？

That's a good question.

这个问题问得好。

Well,

嗯，

you can use telescopes,

可以使用望远镜，

skilled people can point their cameras at the sky and look for fast-moving objects,

让训练有素的人员把相机对准天空，寻找快速移动的天体，

objects that are crossing the Earth's orbit.

也就是那些正在穿越地球轨道的天体。

But we're missing perhaps a 100,000 of these things, 用詞

但我们可能还漏掉了约10万个这样的天体，

of these county killers, 用詞

其中有能摧毁一个县的，

city killers,

能摧毁一座城市的，

country killers.

还有能摧毁一个国家的。

So what we want to do is build a spacecraft called the Sentinel. 語法

所以，我们想建造一艘名为“哨兵号”的航天器。

And as we say,

正如我们常说的，

it's like looking for a charcoal briquette in the dark. 表達脈絡

这就像在黑暗中寻找一块木炭。

These things are hard to find.

这些东西很难找到。

They're tiny compared to the vastness of space.

与浩瀚的太空相比，它们实在太小了。

But infrared light bounces off of them. 短語動詞

不过，红外线会从它们表面反射回来。

So what you'll do,

所以，你要做的是——

you're a satellite,

假设你是一颗卫星，

you're a surveying spacecraft,

一艘巡天航天器，

you'll get your back to the Sun

你要背对太阳，

and look out from about the orbit of Venus

从大约金星轨道的位置向外观测，

and try to find all these asteroids.

设法找出所有这些小行星。

And then you find one, what do you do?

找到一颗之后，该怎么办？

Do you run in circles screaming? 習語

绕着圈尖叫吗？

No, no, no.

不，不，不。

We've got to deflect it 語法

我们得让它偏转，

just a little, 表達脈絡

只偏一点点，

just a tiny amount.

极其微小的一点。

Asteroid might be going 10 km a second,

小行星的速度可能是每秒10公里，

we want to change its speed about 2 mm a second.

我们只想让它的速度改变约每秒2毫米。

So 10 km,

那么，10公里，

that's 10 times a 1,000 m,

就是10乘以1000米，

that's 10,000 m.

也就是10000米。

A millimeter,

1毫米，

that's a thousandth of a meter.

是1米的千分之一。

So that you take the one over the thousandth,

所以，你用这个千分之一来算，

it's a thousand times 10,000,

1000乘以10000，

that's 10 million.

就是1000万。

You want to change its speed a 10 millionth of its total.

我们只要让它的速度改变到总速度的千万分之一。

That's not very much.

这并不算多。

But if you're an asteroid that comes in at 10,000 tons,

但如果你是一颗重达10000吨的小行星，

100,000 tons,

甚至100000吨，

it does take quite a bit of force to change it a 10 millionth of its speed.

要让速度改变千万分之一，仍然需要相当大的力。

Okay,

好，

how do we do that?

怎么做到呢？

Well, the b- easiest way is to get a rocket,

嗯，最——最简单的方法是找一枚火箭，

a big rocket.

一枚大火箭。

Just go out there and just smack into it. 用詞

直接飞过去，狠狠撞上它。

Except it's in outer space,

只不过这是在外太空，

so it just goes like that.

所以它只会这样动一下。

Okay,

好，

and that would change its speed a little.

这会让它的速度稍微改变。

Now, notice everybody,

现在，大家注意，

what if it's not just a rock? 語法

如果它不只是一整块岩石呢？

What if it's what if it's a pile of rocks?

如果它……如果它是一堆岩石呢？

just loosely held together by primordial gravity. 短語動詞

只是靠原始引力松散地聚在一起。

And so if you hit them,

那么，如果你撞上它们，

they'll just spread out and you'll have a shower of rocks.

它们只会四散开来，变成一场岩石雨。

That would be bad.

那可就糟了。

So,

所以，

how about this? 語氣意圖

这个办法怎么样？

We'll get a big spacecraft that's massive,

我们造一艘体量很大的航天器，

a massive spacecraft,

一艘质量巨大的航天器，

and we'll go out there and just get near the asteroid,

然后飞到那里，只靠近小行星，

just get near it.

就只是靠近它。

And then the mutual gravity of you,

接着，彼此之间的引力——你，

the asteroid,

也就是小行星，

and me, the spacecraft,

和我，也就是航天器——

will tug the asteroid speed just a little bit,

会把小行星的速度稍微拉动一点，

just a tiny bit.

只改变极小的一点。

Or maybe get on the other side and tug this way.

或者飞到另一侧，朝这个方向拉它。

That might work, but here's the problem. 表達脈絡

这也许可行，但问题来了。

I need a huge amount of fuel

我需要大量燃料，

for days and weeks and months and years. 表達脈絡

连续维持几天、几周、几个月甚至几年。

And what if it stops working?

要是它停止工作了呢？

You can't go out there and fix it.

你不可能飞过去修理它。

Okay,

好，

how about this?

那这个办法呢？

The laser bees, 習語

“激光蜜蜂”，

a swarm of sunlight-powered lasers

一群以阳光为能源的激光器，

that are zapping the surface of the asteroid 用詞

持续照射小行星表面，

for days and weeks and months and years.

一照就是几天、几周、几个月甚至几年。

So some asteroid, some rock is vaporized

这样，小行星上的一部分岩石就会汽化，

and the ejecta, 用詞

而喷出物，

the stuff ejected,

也就是被喷射出去的物质，

has momentum just like rocket fuel,

会像火箭燃料一样带有动量，

just like just like standing on a skateboard and playing catch with a bowling ball, 表達脈絡

就像……就像你站在滑板上和别人互抛保龄球一样，

the way you do. 語氣意圖

就像你平时会做的那样。

And so it would then cause the asteroid to change its speed. 語法

这样一来，小行星的速度就会改变。

And so you send a swarm of these laser spacecraft

因此，可以派出一群这样的激光航天器，

so that if one of them stops working, 語法

这样即便其中一艘停止工作，

you can use the other one.

你也可以使用另一艘。

Or and you can you can have them come in from all different angles.

而且，还可以让它们从各个不同角度飞来。

And what if the asteroid is irregularly shaped like this?

如果小行星像这样，形状很不规则呢？

You could beam it when the thing is smooth 用詞

可以在它表面平滑时发射激光，

and then when there's a pit or an inefficient place to be beaming,

等转到凹坑或不适合照射的位置时，

you turn off,

就关掉激光，

you wait for the asteroid to turn,

等小行星继续转动，

then you turn it back on.

然后再把激光打开。

See, everybody,

大家明白了吧，

just 'cause it's unlikely doesn't mean it's not a big deal. 講解

一件事发生的概率低，并不代表它不严重。

You know,

要知道，

if it only happens once every few thousand years.

哪怕它每几千年才发生一次。

Well, if it happens during on my watch, 習語

可如果偏偏在我任内发生，

it would, as the kids say, suck. 語氣意圖

用孩子们的话说，那就“糟透了”。

Okay,

好，

so we don't want that to happen.

所以，我们不希望这种事发生。

We want to avoid that.

我们要避免它。

Asteroids are serious business,

小行星是件严肃的事，

but they're exciting.

但也让人兴奋。

Except we're in space,

只不过我们身处太空，

so it's just

所以就只能……

Got a burning question?

有什么火烧眉毛的问题吗？

Well, be sure to subscribe to AsapSCIENCE.

那就一定要订阅AsapSCIENCE。

Follow us on Twitter and Facebook.

还要在Twitter和Facebook上关注我们。

That's what all the kids are doing.

年轻人现在都这么做。

And if it's an asteroid,

如果问题是一颗小行星，

it may not be a burning question, 表達脈絡

它可能就不是一个“火烧眉毛”的问题，

it might be an impacting question

而是一个“撞击性”的问题，

or even an ablating question.

甚至是一个“烧蚀性”的问题。