人类大历史（2013）

Big History S01E06

Part 2 March 29, 2021, 2:02 p.m.

But the structure must be light enough to get airborne...
推力以支撑发动机和飞行员
yet strong enough to support the weight of the engine...
的重量
and the pilot.
什么样的金属可以做到这一点
What material can do all this?
再一次地这个星球提供他们所需要的
Once again, the planet supplies what they need.
大历史观回溯到
Big history connects back...
史前超大♥陆♥
to a prehistoric supercontinent.
三亿年前
300 million years ago...
地球上的大多数土地
most of the land on Earth...
都是一体的超级盘♥古♥大♥陆♥
clusters into the supercontinent Pangaea.
盘♥古♥大♥陆♥广阔的内陆
The vast interior of Pangaea...
充斥着从数百英里外的边缘吹来的冷风
is hundreds of miles from the cool breezes of the shore.
土地变干
The land dries out.
没有足够的水份许多树枯死了
Without enough moisture, many trees die...
但有些适应了
but some adapt.
它们发展了锥形结构来保护种子
They develop cones to protect their seeds.
这些树存活下来了
These trees survive-
比如云杉
trees like spruce.
在盘♥古♥大♥陆♥分离瓦解之后
After Pangaea breaks apart...
云杉就被带往了世界各地
spruce trees are carried all over the world.
它们的木质具有独特的品质
Their wood has a unique quality.
沉重而旺盛的木质比如橡树
Heavier, heartier woods like your oaks and all of that-
它们太重了
They're just too heavy.
轻一点的木材又太脆弱它们太容易折断
Lighter woods are too weak. They're too brittle.
杉树却是刚刚好
Spruce kind of falls in the middle.
它具有足够强度的延展性
They have just the right amount of high tensile strength.
使它非常适合用来造飞机
Makes it ideal for making aircraft out of.
大历史观云集了坚固而轻巧的云杉
Big history brings together the strength and lightness of spruce...
和铝
and aluminum...
以及汽油发起动机
with the power of the gasoline engine...
在理想的时刻
at the ideal moment...
抵抗了地球引力
to defy gravity-
将一个人送上了天空
And lift a man into the air.
地球给了人类升空的钥匙
Earth gives humanity the Keys to the sky.
一架飞机
One airplane...
进入了
transforms...
飞行的世界
into a world of flight.
现在每天都有
Now, in a single day...
超过九万架飞机在世界各地飞行
more than 90,000 planes take flight around the world.
若非地球在大历史
If it wasn't for that big history moment...
经历了一段时间的干旱
of the Earth drying out, effectively...
我们就没有办法飞行
we wouldn't have that powered flight.
当这个星球干旱着而一棵树说道
It was the planet drying out and this one tree going...
嘿我能存活下来
“Hey, I can live here now.”
大历史把这些拼凑到了一起
Big history allows us to piece that all together.
如今飞行稀松平常
Today, we take flying for granted.
但地球上曾经有一段时间根本不存在飞行这回事
But there was a time on Earth when flight didn't exist at all.
所以谁才是这世上第一个飞行者
So who were the world's first fliers?
他们什么时候开了第一次飞行
And when did they first take to the sky?
大历史观回溯到史前森林
Big history links back to a prehistoric forest...
3.25亿年前
more than 325 million years ago...
第一种展翅的生物
when the first creature on Earth ever to take wing...
并非鸟类
isn't a bird.
而是一种原始的昆虫
It's a primitive insect.
有可能在它从树上落下的时候
Possibly, as it falls from a tree...
它振动背上的凸起
it vibrates nubs on its back...
滑行到安全地带
and glides to safety.
几代以后
Over generations...
这种凸起物就进化成了翅膀
the nubs evolve into wings.
飞行是周游这个星球的最好途径
flight is the best way to get around this planet.
你可以用来旅行也可以用来交♥配♥
You can use it to travel. You can use it to mate.
你可以用来寻找食物躲避天敌
You can use it to hunt for food, escape predators.
飞行是一种生存策略
flight is a strategy for survival...
这一策略为人们铺平了道路
a strategy that paves the way for humans.
大历史观回溯2.6亿年
Big history connects forward 260 million years...
到行星碰撞的时刻
to a moment of impact.
一颗珠穆朗玛峰大小的小行星
An asteroid the size of Mount Everest...
撞击了地球
is on a collision course with Earth.
恐龙灭绝了
The dinosaurs are doomed.
除了一小部分
Except for one group that manages to escape-
那就是进化成今天的鸟类的恐龙
the dinosaurs that evolved into today's birds.
鸟类在白垩纪末期
One of the reasons that birds survived...
得以生存的原因之一
the extinction at the end of the Cretaceous...
大概是因为它们会飞
is probably flight.
如果你可以飞就可以从燃烧的丛林上方
If you can fly away, get up above the burning forest...
尝试去寻找一片未被火焰波及到的净土
try to find small little areas that weren't burning...
如果你找到一个被湖水环绕的岛屿
maybe an island in a great lake type situation...
你大概可以存活下来
you can survive.
飞行使得它们幸存下来
flight got them out of there.
它们的存活与我们息息相关
Their survival is linked to ours.
我们需要鸟类和飞虫来为粮食
We need birds and flying insects to spread and pollinate...
传播授粉
the plants we rely on for food.
我们完全可以认为如果世上不存在飞行
One could certainly argue that if there had been no flight...
那么人类也不会存活
there would be no humans.
我们依赖于飞行
So we depend on flight.
然而飞行依存于地球上特有的物质
But flight depends on something special about the Earth.
在一场有名的灾难中我们得到了一条线索
There's a clue in a famous catastrophe-
一次剧烈的冲撞
a fiery crash...
揭示了飞行在这个星球上的可行性
that reveals how the planet makes flight possible.
大历史观将飞行故事回溯到
Big history connects the story of flight...
宇宙的诞生
to the birth of the universe...
揭示了在大爆♥炸♥发生的瞬间
revealing how gravity emerges within
重力是如何产生的
an instant of the big bang...
又是如何成为了飞行的敌人
and becomes the enemy of flight.
大自然是如何还击
How nature fights back...
人类对轻巧而坚韧材料的开♥发♥
combining lightness and strength.
人类又是如何利用百万年才成型的元素
And how humanity cracks the code by harnessing elements...
来挖掘真♥相♥
millions of years in the making.
大历史揭示了在飞行中还有另一股力量
But big history reveals there's another player at work in flight.
大历史不会单单只看
Big history is not satisfied...
人类历史上的飞行篇章
by simply looking at the human history of flight.
在实现飞行这一活动中
Does the planet play
我们的星球是否起到了作用
any role in enabling flight?
大历史在著名空难
Big history looks for answers...
德国兴登堡号♥飞艇事件中
in history's most famous flight disaster-
寻找答案
the German zeppelin Hindenburg.
驱动四架柴油发动机需要
Four diesel engines power
飞艇中充满七百万立方英尺的瓦斯
an airship filled with seven million cubic feet of gas.
当从柏林起飞到4600英里外时
In the final feet of its 4,600-mile journey from Berlin-..
兴登堡号♥燃烧成了火花
The Hindenburg bursts into flames.
理解兴登堡号♥坠毁的原因
But understanding why the Hindenburg falls...
是为了解释它能飞行起来的先提条件
is to reveal what first made it take flight.
大历史连接了了兴登堡号♥的消亡
Big history links the death of the Hindenburg...
和大气的产生
to the birth of our atmosphere.
首先它是二氧化碳和甲烷的组合毒气
At first, it is a poisonous mix of carbon dioxide and methane.
然后其他气体代替了它们
Then other gases take over...
大部分是氮
mostly nitrogen...
最终形成了我们今天呼吸的气体
and eventually the gas we will one day breathe.
氧气原本是由细菌作为废弃物
Oxygen, originally, was put into the atmosphere...
带入大气的
by bacteria, as a waste product.
虽然我们无法看到大气
Even though we can't see gases...
它们是一种由有重量的原子
they're a form of matter made up of atoms...
所组成的形态
that have weight.
有些气体比其他的更轻
Some gases are lighter than others.
所以那些比地球大气更轻的气体
So any gas lighter than Earth's atmosphere...
就会上浮
will float.
有六种气体比大气轻
Six gases are lighter than our atmosphere...
包括填充在兴登堡号♥飞艇中的氢气
including the one that fills the Hindenburg-
一种宇宙中常见的元素
hydrogen, the most common element in the universe.
但是它也非常易燃
But it's also highly flammable.
由于气体在大气中可携带电子