宇宙时空之旅（2014）

Cosmos: A SpaceTime Odyssey S01E06

Part 2 April 25, 2021, 12:40 p.m.

这只是日间进行的活动
And that's just the day shift
当光照提供能量来源的时候
when sunlight supplies the incoming stream of energy
还有一项工作是全天进行的
There's a second shift that works day and night
利用储备的太阳能
using the solar energy kept in reserve.
自♥由♥电子的能量用于
The energy of the free electrons is put to work,
结合二氧化碳和水中的氢原子
combining carbon dioxide with hydrogen from the water.
最终产品是糖类它将太阳能储存起来
The end product is sugar, which stores the solar energy.
叶绿体是存在三十亿年之久的太阳能收集器
The chloroplast is a three-billion-year-old solar energy collector.
这个亚微观的太阳能电池
This sub-microscopic solar battery
为所有森林绿野
is what drives all the forests and the fields
海中的浮游生物
and the plankton of the seas.
和动物供能
And the animals.
其中也包括我们
Including us.
这种太阳能细胞器
The solar-powered biosphere
可收集加工的能量
collects and processes six times more power
比整个人类文明多六倍
than our entire civilization.
我们知道光合作用的化学机制
We understand on a chemical level how photosynthesis works.
我们可以在实验室中再现这个过程
We can recreate the process in a laboratory.
但我们远没有植物那么娴熟
But we're not as good at it as plants are.
这不足为奇
And it's not surprising,
毕竟大自然已是几十亿年的老手
considering nature has been at this for billions of years,
而我们还是菜鸟
and we've only just started.
但如果我们能揭开光合作用的奥秘
But if we could figure out the trade secrets of photosynthesis,
如今我们所依赖的所有其他能源
every of other source of energy we depend on today...
煤炭石油天然气
coal, oil, natural gas...
都将被淘汰
would become obsolete.
光合作用是终极绿色能源
Photosynthesis is the ultimate green power.
不会污染空气
It doesn't pollute the air
而且可实现碳中和
and is, in fact, carbon neutral.
将人工光合作用扩大到一定规模
Artificial photosynthesis on a big enough scale
可减小温室效应
could reduce the greenhouse effect
避免气候恶化
that's driving climate change in a dangerous direction.
不好此处正在蒸发
Uh-oh, place is evaporating.
该离开这里了
Time to get out of here.
一滴露珠的生命是如此转瞬即逝
How fleeting is the life of a dewdrop.
在凉爽的夜间从空气中凝结而来
It condenses from thin air in the cool of the night,
只为在温暖的日间蒸发消失
only to vanish with the heat of the day.
而它的居民们水熊虫去哪了呢
And what of its inhabitants, the tardigrades?
它们不会有事的
They'll be fine.
它们可以几年不沾水
They can go without water for years.
很难想象
It's hard to imagine,
植物遍布地球
but plants covered the surface of the Earth
几亿年之久
for hundreds of millions of years
才开出第一朵花
before they put forth their first flower.
这是大概一亿年以前的事
That was about a hundred million years ago,
在恐龙灭绝不久之前
shortly before the dinosaurs were wiped out.
那时的地球一定看起来色彩单调
Our world must've been a relatively drab-looking place back then,
到处都是绿色和褐色
dominated by shades of green and brown.
是的那时有大树蕨类及其他植物
Yeah, there were giant trees and ferns and other plant life,
却不见紫色的鸢尾花
but not the purple of an iris
深红色的玫瑰
or the crimson of a red, red rose.
兰花是地球上最早的开花植物之一
Orchids were among the first flowering species to appear on Earth,
也是种类最繁多的
and they're the most diverse.
达尔文曾对
Darwin was particularly fascinated
马达加斯加的彗星兰格外着迷
by the comet orchid of Madagascar,
它的花粉藏在
a flower whose pollen is hidden
细长的花距底部
at the bottom of a very long, thin spur.
一个想法的预测能力是对自身最好的检验
There can be no stronger test of an idea than its predictive power.
基于自然选择的进化论
On the basis of his theory of evolution through natural selection,
达尔文推断在马达加斯加岛某处
Darwin speculated that somewhere on the island of Madagascar,
一定存在有超长舌头的飞行昆虫
there must live flying insects with extraordinarily lengthy tongues,
舌长足以取到花粉
ones long enough to reach the pollen.
没有人见过这种生物
No one had ever seen such a beast there,
但达尔文坚持认为
but Darwin insisted
符合此描述的动物一定存在
that an animal fitting this description must exist.
当时很少有人相信他
Few people at the time believed him.
直到五十年以后
It wasn't until more than 50 years later
达尔文的预测才被证实
that Darwin was proven right.
在1903年名为马岛长喙天蛾的巨大天蛾
In 1903, a huge hawk moth, called the Morgan's sphinx
在马达加斯加被发现
was discovered in Madagascar.
这种蛾子被彗星兰的气味吸引
Attracted by the Comet Orchid's scent,
用它三十厘米长的舌头吸取花粉
the moth slurps its pollen with its foot-long tongue,
正如达尔文预测的那样
exactly as Darwin expected it would.
更神奇的是人们找到了马岛长喙天蛾
It's even more amazing that the Morgan's sphinx was discovered
尽管马达加斯加90%的热带雨林
when you consider that more than 90% of Madagascar's rain forest
都已被破坏
had been destroyed.
达尔文♥做♥出著名预测的几年后
In the years since Darwin's famous prediction,
此种飞蛾本来很可能同其他物种
this moth species could have easily become extinct
一起灭绝
with all the others...
每个物种都是一段独特的生命之诗
every one of them a unique phrase of life's poetry,
由亿万年的进化中用原子书写而成
written in the atoms by eons of evolution.
紫丁香的芬芳
Ah, the fragrance of lilacs.
是那种可以触发
It's one of those scents that
一系列联想的气味
triggers a whole constellation of associations,
那些久远的六月
all those Junes of long ago.
它的原理是什么呢
But how does that happen?
一种气味怎么能在你脑海中形成画面
How does a smell prompt a movie to start running in your head?
气味是不可见的
It's not something we can see.
会是某种能量波吗像光波一样
Could it be a wave of energy, like light?
还是某种微观粒子
Or is it some kind of microscopic particle?
事实上它是一个分子
It's actually a molecule.
我们能闻到的气味无论是烧焦面包
Every odor we can sense, whether it comes from burnt toast,
汽油还是遍野的紫丁香
gasoline, or a field of lilacs,
都是一团分子
is a cloud of molecules.
这些分子有特定形状
These molecules have particular shapes.
当我将它们吸入
When I inhale them,
它们会刺♥激♥鼻子内特定的受体细胞
they stimulate a particular set of receptor cells in my nose.
一个电♥信♥♥号♥♥传递到我的大脑
An electrical signal then travels to my brain,
大脑识别出紫丁香的气味
which identifies the scent as lilac.
其他气味由其他形状各异的分子传送
Other scents are carried by different molecules with different shapes.
但当我闻到花香或篝火的烟味
But when I smell a flower or the smoke from a campfire
或汽车齿轮的油味
or the grease from a motor gear,
我脑中会充满记忆
I'm often flooded with memories.
为什么像花香这么简单的东西
Why is it that a simple thing such as the scent of a flower
可以触发强烈的回忆呢
can trigger powerful memories?
这与人脑的进化有关
It has to do with the way our brains have evolved.
当大脑中的嗅觉神经受到刺♥激♥
Our sense of smell kicks in
就产生了嗅觉
when the olfactory nerve in our brain is stimulated.
嗅觉神经距离杏仁体♥位♥置很近
That nerve is located very close to the amygdala,
杏仁体是使我们体验情感的重要结构
a structure that is integral to our experience of emotion.
嗅觉神经与海马体也很近
It's also very close to the Hippocampus,
海马体帮助我们形成记忆
which helps us form memories.
将气味信♥号♥♥
The network of neurons
从鼻子运送到大脑的神经元网络
that carry the scent signal from my nose to my brain
已被数亿年的进化调整得很好
has been fine-tuned over hundreds of millions of years of evolution.
这是一种
It's a survival mechanism
可以预警并引领我们脱险的生存机制
that can alert us to danger or guide us to safety.
如果你能在捕食者靠近并出击前探测到它
If you you can detect the predator before he's near enough to strike,
或在被困森林前得知着火了
or the fire before it traps you in the forest,
你幸存的几率就更大
you have a much better chance to survive
继续向下一代传递基因
and pass on your genes to the next generation.
这片花海散发出的馥郁
That lovely scent from this field of flowers
触发一系列独特的神经信♥号♥♥
sets off a unique combination of nerve signals.
只有这种正确的密♥码♥可以打开
Only that exact combination can crack the safe
我大脑中储存紫丁香记忆的保险柜
where the memory of lilacs is stored inside my brain.
好想知道会送给谁
Wonder who they're for.
或许稍后我们能知晓
Maybe we'll find out later.
但首先另一个隐藏宇宙在等我们
But first, there's another hidden cosmos waiting for us.
植物在轻轻地呼吸
The plants are softly breathing,
吸入二氧化碳分子
inhaling molecules of carbon dioxide