了解宇宙是如何运行的（2010）

How the Universe Works S01E06

Part 6 April 18, 2021, 7:57 p.m.

数以百万计的带水彗星与小行星
Millions of these watery
comets and asteroids
飞进内太阳系
came flying into the inner solar system.
部分撞落地球
And some of them smashed into Earth.
千秋万载, 地球接收了小行星的水
Over the aeons, the Earth acquired the
water that had been a part of the asteroids,
陆续聚成今天几近覆盖地球的水量
and that indeed makes up the mass of
water that nearly covers the Earth today.
至于外来水的多寡
But the amount of water
that was delivered?
则全看运气
That was the luck of the draw.
有没有可能…
Couldn't it have been the case
当初地球接收的水量少了一半?
that the Earth would have acquired,
maybe, half as much water as it did?
那地表纵不是完全干涸也差不多
If so, the Earth would be nearly dry
on its surface, if not completely dry,
水都给地球核心吸了下去
the sponge of the interior
soaking up the rest of the water.
表面没水, 生机免谈
No surface water would
have meant no life.
但换了水量过多又如何?
And what about too much water?
地球会变成水世界, 深海更深
We would be a water world,
the oceans much deeper,
淹没所有大♥陆♥, 甚至额菲尔士峰
covering the continents,
even Mt. Everest.
你不妨问: 假设地球被水覆没
And so you can ask, then, "If
the Earth were covered by water,
水量只要比现在多一倍
only having twice as
much as it currently has,
那地球还适宜发展科技吗?
would we have had a planet that was
suitable for technological life?"
科技需要陆地
Technology requires dry land.
所以极有可能…
And it's quite likely
是地球刚好拥有的水量
that the precise amount of water
that the Earth just happens to have
催生了我们智人这种好科技的人种
has allowed a technological species
like we Homo sapiens to spring forth.
我们熟悉的世界之所以存在
The world as we know it exists
乃40亿年前受彗星与小行星的轰炸
because a blizzard of
comets and asteroids
给地球带来分量刚好的水
delivered just the right amount of
water about four billion years ago.
也许此时此刻, 宇宙间其它角落
And just maybe the same
thing is happening right now
正在发生同样情况
somewhere else in the universe.
肯定的一点, 太空里有许多水
One thing's for sure, there
is plenty of water out there.
氢是宇宙间最普遍的原子
Hydrogen, the most common
atom in the universe,
氧是宇宙间第二普遍的原子
and oxygen, one of the next most
common atoms in the universe.
水H2O肯定是最常见的分子
H20 is certainly going to
be a very popular molecule.
而我们的宇宙中也确实如此
And indeed it is, within our universe.
宇宙间无处不是水
So water is everywhere in the universe,
我们还发现宇宙间无处不是行星
and we're discovering
that planets are, too.
但依然未见第二个有液态水的行星
But we still haven't found
another planet with liquid water.
科学家新发现了四百多颗行星
Scientists have discovered
more than 400 new planets.
没有一颗与地球面貌相似
None of them look like our world.
始终未找到一颗系外行星…
What we have not yet found is a planet
that is about the same size and mass
大小、质量与化学成分跟地球相约
and chemical composition as the
Earth, orbiting another star.
所以始终是人类的终极追寻
So it remains an extraordinary
holy grail for humanity
找一片让我们想起家园的新居地
to find other abodes
that remind us of home.
但我们会继续努力
But we'll keep looking.
我们银河系中已有二千亿颗恒星
We know that there are around 200
billion stars in our galaxy alone.
当中四百亿颗有机会有行星
And as many as 40 billion
of them could have planets.
我们希望发现类似地球的行星后
We're still hopeful that when we
discover terrestrial-style planets
能帮助我们知得更多更深
that will help us
tremendously in understanding
穷究我们系内行星与地球的演变
how our own inner solar system
planets and the Earth evolved
与系外行星的演变有何异同
in comparison to the
outer solar system planets.
我们的行星探索正迈进…
We are entering into what is
gonna be thought of in the future
将为后世奉为黄金盛世的时代
as the Golden Age of
planetary discovery.
我们第一次实实在在了解到…
We will really, for the first
time, begin to truly understand
太空里果真是千姿百态
the actual diversity
that lies out there.
我认为这是一个让人兴奋的盛世
I think it's gonna be a
fantastically exciting time.
行星按物理与化学定律诞生
Planets form according to the
laws of physics and chemistry.
但往后的变化则要看造化
What they become, that has
a lot more to do with luck.
不少科学家相信…
Many scientists believe
我们迟早找到一个类似地球的行星
it's only a matter of time before
we find another planet like Earth,
它在合适地方以相同材料形成
one that formed from the same
ingredients, in the right place,
拥有分量怡好的水
with just the right amount of water.
有一点毋庸置疑
One thing's for sure,
太空里尚有数以十亿计的行星
there are billions of planets out there.
有待发掘
waiting to be discovered.