宇宙时空之旅（2014）

Cosmos: A SpaceTime Odyssey S01E09

Part 4 April 25, 2021, 12:40 p.m.

就像有五十架大型喷气式客机压在你身上
is like having 50 jumbo jets stacked on top of you.
然而即使在这里也有生命存在
Yet even here, life has taken hold.
阳光无法穿透这么深的海
The fact that sunlight can't penetrate the deep ocean
不代表这里没有光
doesn't mean there isn't light down here.
许多水下的物种都会在黑暗中发光
Many underwater species glow in the dark,
通过一种叫做生物发光的过程
through a process called bioluminescence.
我们作为陆生哺乳动物
Our long history as land mammals,
长♥期♥生活在阳光下
denizens of the sunlit world,
使得我们没有想到进化
hasn't prepared us for the amazing variety of life
在深海中能创造出如此多样的生命
that evolution has crafted in the deep oceans.
因为这里没有阳光
Since there's no sunlight down here,
所以没有光合作用
there's no photosynthesis.
那就意味着没有植物供给养分
That means there are no plants to feed on,
然而在这个漆黑的世界里
and yet, even here, in a world of permanent midnight,
却有一条欣欣向荣的食物链
there's a thriving food chain.
它开始于一个叫化能合成的过程
It begins with a process called chemosynthesis.
这些微小的生物学会了
These microscopic creatures have learned to eat
食用从热泉喷出的东西
what's pouring out of that vent...
一种叫做硫化氢的有毒化合物
a noxious compound called hydrogen sulfide.
那些厚重的黑烟提供了
That thick black smoke provides the chemical energy
使生命存在的化学能
that makes life possible here.
小的甲壳纲动物食用细菌
Tiny crustaceans eat the bacteria,
而大一点的动物食用甲壳纲动物
and the larger animals eat the crustaceans.
总有一天在未来的地球
One day, on some future Earth,
这些山会浮出水面
these mountains could very well end up above the water.
构造力仍然在塑造我们的行星
Tectonic forces continue to shape our planet.
未来的地球也会与现在不同
The future is also another planet.
就是这样的一个火山
It was a volcano like this one
在数百万年前创造了夏威夷群岛
that created the Hawaiian islands millions of years ago.
我们生活在地壳上面
We live on the crust of
地壳内部如同沸腾的大锅
a seething cauldron.
在我们的行星中心有一个铁核
At the center of our planet, there's an iron core.
处在液态铁壳中
It's nested inside of a larger, liquid iron shell.
被叫做地幔的部分覆盖
Wrapped over this is the part called the mantle.
它由岩石组成但又热又粘
It's rocky but hot and viscous.
就像火炉上炖着的一盆汤
Like a pot of soup cooking on a stove,
地幔一直在不停翻滚
the mantle is churning.
是什么让它一直运动
What keeps it moving?
两个原因地球形成时剩余的热量
Two things... the heat left over from Earth's formation,
和地核的放射性元素的衰变
and the decay of radioactive elements in the core.
而我们每个人熟知
And this outer layer-- the crust,
并生活的地壳
where you and me and everyone we know lives--
仅仅像苹果皮一样薄
is only as thick as the skin on an apple.
地幔拖着它上面覆盖的地壳
The mantle drags the solid overlying crust along with it.
地壳能够承受是因为它又冷又硬
The crust resists because it's cool and rigid.
有时候它会到强度极限
From time to time, it reaches the breaking point.
这种情况发生的时候地震就来了
When that happens, the Earth quakes.
这并不是因为有人行为不端
It's not because somebody misbehaved
被惩罚
and is being punished.
它起因于随机的力量
It's due to random forces
这种力量取决于自然法则
that are governed by the laws of nature.
我们认为地球很稳定的感觉是一种错觉
Our sense of the stability of the Earth is an illusion
因为我们的生命太短暂了
due to the shortness of our lives.
如果我们能在地球的时间尺度上看看地球
If we could watch our planet on its own timescale,
在数百万年间发生的巨大变化
in which big changes take millions of years to play out,
我们会把它看成一个动态的有机体
we would see it as the dynamic organism it really is.
这是大概两亿年前
This is the world of the late Triassic period
三叠纪后期的世界
about 200 million years ago.
那个小家伙
That little guy?
那是我们遥远祖先中的一个
It's one of our distant ancestors.
他就生活在新泽西州的纽瓦克市
He lived in Newark, New Jersey.
无论你走到地球的哪里
Wherever you walk on Earth...
消失的世界都埋葬在你脚下
lost worlds lie buried beneath your feet.
五千万或一亿年以前
50 or 100 million years ago,
即使是地表上最普通的地方
even the most seemingly ordinary places
都发生了史诗般的变化
have been the scene of epic change.
这些岩壁就是
These Palisades are
盘♥古♥大♥陆♥解体的纪念碑
a monument to the breakup of the supercontinent Pangaea.
火山连续喷发创造了这些悬崖
The sequence of volcanic eruptions that made these cliffs
也导致了下一个大灭绝
also led to the next mass extinction--
也就是结束三叠纪的大灭绝
the one that ended the Triassic world.
但是一个物种的灾难性灭绝
But a catastrophic extinction event for one species
是另一个物种的绝佳机会
is a golden opportunity for another.
三叠纪的灭绝给一个
The Triassic extinctions offered one group
已经出现一段时间的物种
that had been around for a while
提供了登上中♥央♥舞台的机会
the chance to take center stage.
恐龙称霸了
The dinosaurs had a good, long run
长达一亿七千万年
for 170 million years.
那时候印度还是个岛
Back then, India was an island.
它以每年十厘米的速度慢慢往北移♥动♥
It crept northward at the pace of a few inches per year
虽然很慢但最终与亚洲会合
on its slow but inexorable rendezvous with Asia.
然后地球表面下的熔岩再一次喷发
Then, once again, the molten rock beneath Earth's surface
淹没了印度西部的大部分地区
burst forth and flooded a huge area of western India.
但致命一击
The knockout punch
完全没有预兆地出现了
literally came out of the blue.
很少有体重大于45千克的动物
Few animals larger than a hundred pounds
在晚白垩纪的这场大灾难中存活了下来
survived the catastrophes of the late Cretaceous.
尘雾使地球在几个月内都处于黑暗寒冷中
The dust cloud brought night and cold to the surface for months.
恐龙被冻死饿死了
The dinosaurs froze and starved to death.
但是一些小的生物
But there were small creatures
存活了下来
who took shelter in the Earth.
当它们出现时
And when they emerged...
它们发现原来猎食它们的
they found that the monsters who had hunted
恐怖怪兽不见了
and terrorized them were gone.
地球变成了哺乳动物的世界
The Earth was becoming the Planet of the Mammals.
地球继续不断变化着
And the Earth continued its ceaseless changing.
这里曾是寸草不生的沙漠
This was once a desert where nothing could grow.
有着260万平方千米的沙子和盐
It was a million square miles of sand and salt,
比地球上现在任何环境都恶劣
far more hostile than any environment on Earth today.
白天的温度高的可以烤面包
Daytime temperatures were hot enough to bake bread.
而且处在海平面1.5千米以下
And it was more than a mile below sea level,
所以大气压
so the atmospheric pressure
比现在高50%
was about 50% higher than what we're used to.
难以想象
It would be hard to think
这个行星上还有过更糟的环境
of a more unpromising environment on this planet.
但是五百五十万年以前
Yet this was the basin of the Mediterranean
这里是地中海盆地
five and a half million years ago,
然后它就变成了大海
before it became a sea.
地球从来没有停止过移♥动♥
The Earth never stops moving for long.
深盆地西部的
The natural dam at the western end
天然水坝倒塌了
of the deep basin gave way,
可能是因为地震
probably due to earthquakes.
洪水也开始泛滥
And the deluge began.
汹涌的洪水在一年以内
The torrential waters rushed in at a rate 40,000 times greater
以尼亚加拉瀑布四万倍的速度涌来
than Niagara Falls, turning a vast desert
把大♥片♥沙漠
into the Mediterranean Sea...
变成了地中海
in less than a year.
那时没有人
There were as yet no humans
见证这场巨大的洪水
to witness this enormous flood,
也没人感叹它创造出的美丽
nor to admire the beauty it created.
同时在地球的另一端
Meanwhile, half a world away,
一条广阔的海峡把北美和南美分割开来
a broad channel separated North and South America...
使得海流能从大西洋
allowing ocean currents to flow
流进太平洋
from the Atlantic into the Pacific Ocean.
构造力渐渐地
Tectonic forces gradually brought
把这两块大♥陆♥合并到一起封闭了海峡
these two continents together, closing the channel
创造了了巴拿马地峡
and creating the Isthmus of Panama.
这重组了世界的洋流循环
This reorganized the worldwide pattern of ocean currents,
也影响了全球气候
which, in turn, affected the global climate.
在非洲曾经的绿色森林
In Africa, the lush green forest canopy