了解宇宙是如何运行的（2010）

How the Universe Works S08E01

Part 10 Jan. 30, 2022, 2:57 p.m.

an array of little impacts
一系列的小碰撞，而不是单一的大碰撞
instead of one big
single impact.
♪
但是，如果这些影响发生在海上，会发生什么呢？
narrator: But what would happen
if these impacts occur at sea?
我们的海洋是会拯救我们
Will our oceans save us,
还是会来一场巨大的海啸并毁灭我们？
or will a giant tsunami
wipe us out?
2019年
Narrator: 2019,
美国研究人员发现化石沉积
u.S. Researchers
discover deposits of fossils.
其中既有陆地生物的遗骸，也有海洋生物的遗骸
They contain both the remains
of land and sea creatures.
你看到的东西都混在一起
You see things that
are all jumbled together,
所以你会看到海洋生物的化石
so you'll have fossils
of sea creatures.
你会发现海洋沉积物与海岸沉积物
You'll have ocean deposits
that are mixed up
和陆地沉积物混合在一起
with coastal deposits
and onshore deposits,
你会看到这些沉积物
and you see those deposits
in places
位于离你期望的地方
that are very, very far away
非常非常远的位置
from where you would
expect them to be.
所以这些物质显然被扔到了
And so this material was
obviously thrown
很远的内陆
very far inland.
混杂的沉积物表明
Narrator: The jumbled deposits
这些生物是在一次巨大而猛烈的事件中
suggest that the creatures
were killed at the same time
同时死亡的
in a huge and violent event,
这种事件的威力
something powerful enough
足以将海洋生物席卷到遥远的内陆
to sweep ocean-dwelling
creatures far inland.
海啸
A tsunami.
海啸通常是在海底
Tsunamis are usually created
突然移♥动♥时产生的
when the ocean floor
moves suddenly.
海底带起整个海洋
The ground picks up
the entire ocean
上下摇晃
and shakes it up and down,
就像拿着一根绳子摇晃它
and it's sort of like
taking a rope and shaking it,
它在整个海底和海洋表面移♥动♥
and it moves all across
the ocean floor
直到到达陆地
and ocean surface
until it reaches land.
最近一次最大的海啸
The biggest recent tsunami
was caused by the earth's crust
是由海底地壳轻微隆起引起的
at the bottom of the ocean
lifting slightly,
这就意味着整个地壳的抬升位移
so this means that
that entire length of crust
传递给了在它上面的水
that lifted displaced
the water above it,
所以产生海浪、海啸
so the waves,
the tsunamis that result,
结果真的是又长又宽
are really long and wide,
它可以以惊人的速度在海洋中传播
and it can travel
across the ocean
并传播到陆地上
at tremendous speeds
and up on land.
这就是化石生物的遭遇吗？
Narrator: Is this what happened
to the fossilized creatures?
他们是死于一场巨大的海啸吗？
Were they killed
by a huge tsunami?
线索来自于保存下来的遗骸的确定年代
Clues come from dating
the preserved remains.
它们有6600万年的历史
They're 66 million years old.
与此同时，一颗六英里（约9.6公里）宽的小行星
From the same time
a six-mile-wide asteroid
坠入了墨西哥尤卡坦半岛附近的海域
crashed into the sea off
the Yucatán peninsula in mexico.
这两个事件有联♥系♥吗？
Are the two events connected?
撞击海洋的小行星会引发海啸吗？
Do ocean-impacting asteroids
trigger tsunamis?
我们曾经认为一颗巨大的小行星
We used to think
that a big asteroid
撞击海洋会引发一场巨大的海啸
impacting in the ocean would
drive a tremendous tsunami,
一面巨大的水墙以非常快的速度冲出
a huge wall of water
out at very rapid speeds,
基本上会冲刷干净一切
which would basically
scour clean everything.
现在，2018年的一项新研究
Narrator: Now new research
from 2018 suggests
提出了一个非常不同的情景
a very different scenario.
科学家们使用超级计算机
Scientists use super computers
to model asteroids
来模拟撞击深海的小行星
hitting the deep ocean
to work out how much of
并计算出需要多少小行星的动能才会转化成海啸
the asteroid's kinetic energy
is converted into a tsunami.
在模拟中，一颗1600英尺（约488米）高的小行星
In the simulations,
a 1,600-foot asteroid
以每小时2万英里（约3.2万公里）的速度撞击海洋
hits the ocean at
20,000 miles an hour
然后潜入水中
and dives into the water.
当它潜得更深的时候，当然会遇到很多阻力
As it goes deeper in,
of course it's meeting a lot
它会减慢速度，并被压缩
of resistance and it slows down
and it compresses up.
它不断地压缩，最后
It compresses and compresses
and compresses, and then finally
它耗尽了动量
it runs out of momentum,
在一个非常高的压强下
and it's at an extremely
high pressure.
巨大的压力使小行星蒸发了
Narrator: The huge pressure
causes the asteroid to vaporize.
比太阳表面还要高的温度
Temperatures hotter than
the surface of the sun
将数万亿加仑的水转化为蒸汽
turn trillions
of gallons of water into steam.
爆♥炸♥在水面上形成了
The blast creates a huge
short lived cavity
一个巨大短暂的空洞
in the water's surface
并形成了一个飞溅的帷幕
and a splash curtain,
a wall of water,
一堵水墙，跃起数英里高
that leaps up several miles.
然后帘子折叠
This curtain then collapses
and water falls
水落入洞中并喷出水柱
back into the cavity,
shooting a column of water
有五英里（8公里）高
five miles up.
普列斯科:这个很高的柱子无法支撑自己的重量
Plesko: This very tall column
can't support its own weight
然后就倒了下来
and collapses back down.
如此多的水的崩塌引发了
Narrator: The collapse of
so much water triggers
1200英尺（366米）高的海浪
a wave 1,200 feet high.
这会成为一场巨大的海啸吗？
Could this become
a huge tsunami?
如果我们想象一颗流星撞击海洋
If we think about a meteor
striking the ocean,
我们想要知道海浪
we want to understand
how far the waves
可能会传播多远的距离
might propagate from the site.
我们可以用一块石头把它扔到池塘里
We could actually just use a
stone and throw it into a pond,
你可能会想，“好吧，这是一块大石头”
and you might think,
"okay, well, it's a big stone,
“它会溅起很大的水花”
it's going to make
a really big splash,
“它会延伸很远的距离”
and that's just going to
extend out a long distance."
但事实证明，在撞击的地方
but it turns out the splash
stays the biggest really close
飞溅最大
to where it impacts.
然后涟漪就消失了
And then the ripples
die down after that.
我们来试试
So let's try that.
中间有个大水花
Big splash in the middle.
我们看到了向外的波纹
And we see the ripples
going outward,
但与最初的大♥波♥纹相比
but they're really
pretty small compared
它们真的非常小
with that initial big splash.
小行星撞击海洋也是如此
Narrator: It's the same with
an ocean impacting asteroid.
撞击产生的表面波很快就会消失
The impact creates surface
waves that die away quickly
因为只有少量小行星的动能
because only a small amount