宇宙（2007）

The Universe S05E06

Part 4 April 22, 2021, 1:50 p.m.

There would have been tons and tons of soot
将会有成千上万吨♥的浓烟
up in the atmosphere.
上升至大气层中
And so that is something that we really
这也是我们非常
would not want to see happen.
不愿意见到的
For the primitive life on earth at the time,
在地球处于原始生物时代时
it was a major extinction event,
由于地球受到撞击导致大多物种灭绝
with a crater more than 1 1/2 times larger than
撞击中出现的陨石坑的大小
the one that wiped out the dinosaurs.
是使恐龙灭绝的陨石坑的一点五倍
The South African crater wasn't discovered
南非陨石坑直到二十世纪九十年代
until the 1990s,
才被发现
since most of its features had eroded
在过去的二十亿年里
in the last two billion years.
陨石坑的面貌大部分都被侵蚀了
But photos from space revealed its existence.
但是太空中所拍的照片揭示了它的存在
A hilly region in the center of the deep crater initially
在陨石坑中♥央♥突起的山丘在最初
had scientists thinking that there'd been
被科学家认为是
volcanic activity in the area.
火山活动区域
But it's actually
事实上
what's known as a central rebound peak,
这被称作中♥央♥反弹峰
a distinctive feature for craters
其主要特征是
about 100 miles wide or larger.
宽度为一百英里以上
As you get to larger sizes,
正如你接到一个从高空坠落下来的
the energy of the impactor is so high,
大体积的物体
that when it comes in,
当它到达之时
the rock essentially acts like it has no strength.
事实上石头本身是没有力度可言的
Then what you get is something very much like
而你所得到的是譬如
when you drop a pebble in water,
当你把石子扔进水中
and you see that rebound peak
你会看到四周扩散的波纹
as the water fills in,
当水重新填补之后
comes back up.
水面又恢复平静
But since it is rock,
但是这是岩石
it then solidifies.
产生波纹时的状态凝固了下来
And we see lots of these central peaks
我们将会在月球或者太阳系的其他地方
on the moon and elsewhere in the solar system.
看到很多这样的中♥央♥峰
But there are other large asteroids that have hit
很多大型小行星撞击过地球
much more recently, even more recently than
甚至比六千五百万年前
the dinosaur-killing asteroid from
那颗将恐龙灭绝的
65 million years ago.
小行星撞击还要近
30 million years later,
三千万年之后
another massive asteroid
另一颗大型小行星
pummeled the east coast of America,
撞击到美国东海岸
and helped form, what is now Chesapeake bay.
也因此形成了现在的切萨皮克湾
We see evidence of debris from that impact
我们可以看到在整个东海岸
all the way up and down the eastern seaboard.
都还有那次撞击残留下来的碎片
All the way up to new Jersey and New York,
一路沿着新泽西和纽约
and comparable on the south end of it.
一直到最南端
The 55-mile-wide crater was
一个宽达五十五英里的
hidden from view underwater,
陨石坑深藏在了水下
until oil exploration confirmed
直到上世纪九十年代
its existence in the 1990s.
在勘探石油的时候才被证实存在
And since the asteroid hit just offshore,
若小行星撞击离岸不远的海域
it created a massive Tsunami.
这将引发巨大的海啸
Some say that the waves could have been
一些人觉得这些海浪可能高达
10, 20, maybe even 30 miles high.
十或者二十甚至三十英里
That's a big wave.
这是非常巨大的海浪
The Appalachian mountains are
阿巴拉契亚山脉也就只有
only a few thousand feet high.
几千英尺高而已
So even though a lot of the wave was diminished
所以尽管水浪在涌入内陆时
as it went inland, that's a lot of water.
水量已经减少了但仍不可小视
And it could well have flooded over
这些水能够越过
the Appalachians and into
阿巴拉契亚山脉
what we now think of as the Ohio river valley.
然后进入俄亥俄河谷地区
And if that same impact happened today,
如果那样的撞击发生在今天
the east coast would never be the same again.
那么东海岸将从此改变
An asteroid attack has
一颗小行星撞击所产生的
the power to instantly kill
力量足以瞬间结束
millions of people.
数百万人的生命
The largest impacts can also cause global catastrophes,
最强的冲击波还能造成全球性的大灾难
threatening the very existence of mankind.
危机人类的生存
That's why the study of asteroids is one of science's
那就是为什么小行星的研究是科学家们
highest priorities.
最优先的课题之一
35 million years ago, an enormous asteroid slammed
三千五百万年前一个巨大的小行星撞击了
into America's east coast.
美国的东海岸
The 55-mile-wide crater was hidden until recently,
五十五英里宽的陨石坑直到不久前才
under Chesapeake bay.
在切萨皮克湾的水底被发现
Its effects were devastating.
撞击的结果是毁灭性的
But what if that same impact happened today?
但如果同样的撞击发生在今天会怎么样呢
It would wipe out the east coast essentially through
它会通过引起一系列的海啸冲击波和热效应
a combination of tsunamis, blast waves, thermal effects,
从而将东海岸彻底毁灭
and it would also throw out huge amounts of ejecta
它还会抛出大量的喷射物
that would spread to great distances,
它们会传播到很远的地方
igniting additional forest fires.
引起森林火灾
It would be millions of people instantaneously killed
数百万的人会在撞击时马上死亡
or shortly after the impact.
或者在撞击后不久死去
But it would have farther-reaching consequences too,
但它还会引起更进一步的后果
because of the overriding disruption
因为整个地区的
throughout the entire region:
生态平衡都被打破了
Farming, communications,
农业通信业
certainly our center of our government
当然我们的中♥央♥政♥府♥
is on the east coast.
也在东海岸
But according to recently uncovered fossil records,
但最近发现的古生物遗迹表明
the one-mile-wide Chesapeake bay asteroid
一英里宽的切萨皮克湾小行星
didn't seem to have the same global effects
对地球造成的影响
as the massive extinctions triggered
比不上那颗六英里宽
by the 6-mile asteroid that killed the dinosaurs.
导致恐龙大范围灭绝的小行星
The impact that created
三千多万年前
the Chesapeake bay structure
造成切萨皮克湾的撞击
more than 30 million years ago was enormous,
威力非常强大
but it was still only a small fraction of the energy
但它仅仅只是六千五百万年前
that was released during the impact in the Yucatan,
在尤卡坦半岛撞击释放的能量的
65 million years ago.
一小部分
The impact was right on the threshold of
撞击刚好提供了引起
providing truly global effects,
全球性影响的能量
right on the threshold of
刚好可以造成
what's required to make a mass extinction occur.
一次大范围的生物灭绝
Because of that destructive power,
由于这种毁灭性的力量
it's crucial to know exactly what we're dealing with.
了解我们要面对的问题很重要
And that means getting up close and personal.
那就意味着近距离和亲身观察小行星
In 2001, the NASA mission named "Near"
2001年美国宇航局名为"接近"的任务
was supposed to just orbit the asteroid, Eros.
预定目标是在小行星伊洛斯上空盘旋
But once it had got there
但当它一到达那里
and it completed its mission objectives,
并完成任务时
the decision was made,
我们决定
let's try to land this thing.
着陆到小行星上
Which is really, really fun.
那真是太有意思了
It's kind of old-fashioned exploration.
有点像老一套的探索方式
"Hey, go ahead and give it a try."
"嘿过去试试吧"
So, they did.
于是他们这么做了
The images from the approach and the landing
从接近到着陆的图像
gave scientists a much more detailed look
给了科学家们
at the surface of an asteroid
一些关于小行星
than they'd ever had before,
从未有过的详细信息
with some unexpected results.
还带来了一些意外收获
One of the surprises looking at these small bodies
从这些小行星得到的其中一个惊喜
is that they have geology.
就是它们也有地质构造
It had tectonic features, and looks like
它有地壳构造而且看起来
it had landslides and erosion happening on its surface,
它的表面有山崩和侵蚀发生
and impact craters all over it and boulders everywhere.
到处都是撞击的陨石坑和巨石
And one imagines the scenario where a little asteroid
有人想象那种场景当一颗小的小行星
comes along and hits a bigger asteroid, crashes into it,
运行并撞到一颗大点的小行星后碎裂了
digs up a whole bunch of debris,
引出了一大堆残骸