冰层下的外星人——流浪行星上的生命：英语精读讲义

Rogue planets are planets that travel through the universe alone.

流浪行星是在宇宙中独自穿行的行星。

They inhabit the dark and vast space between the stars.

它们栖身于恒星之间黑暗而广阔的空间。

Drifting alone through eternal darkness,

在无尽的黑暗中独自漂泊，

no light warms their surfaces

没有光能温暖它们的表面，

and they're exposed to the freezing cold of outer space.

且它们暴露在外太空极度的严寒之中。

They know no seasons,

它们没有四季，

no days, and no nights

也没有昼夜

which could give away the passing of time. 短語動詞

能用来揭示时间的流逝。

And yet, 表達脈絡

然而，

rogue planets might carry alien life to all corners of the galaxy.

流浪行星可能会将外星生命带到银河系的各个角落。

How would that work?

这是怎么做到的？

And how does a planet become a rogue anyway?

又或者，行星到底是如何变成流浪行星的？

There are several very different things

有几种截然不同的天体

that get called rogue planets.

都被称为流浪行星。

For example,

例如，

sub-brown dwarfs,

次棕矮星、

gas giants

气态巨行星，

that form from collapsing gas clouds

由坍缩的气体云形成的

and are the boring little brothers of brown dwarfs.

它们是棕矮星无趣的小兄弟。

They're a sort of failed star 短語搭配

它们算是某种失败的恒星，

and we'll now stop talking about them.

现在我们不再谈论它们了。

A far more interesting sort of rogue

更让人感兴趣的一类流浪者，

are terrestrial planets

是类地行星，

similar to Earth

也就是与地球相似

that got kicked out of their planetary system. 短語動詞

但被踢出其行星系统的行星。

Young star systems are dangerous places

年轻的星系是危险的地方，

where protoplanets are battling for the available mass,

原行星在那里争夺可用的质量，

guzzling up as much material as possible. 用詞

贪婪地吞噬着尽可能多的物质。

In this fight for dominance,

在这场争夺主导权的战斗中，

they collide with each other

它们会相互碰撞，

or get dangerously close to each other's orbits.

或者危险地靠近彼此的轨道。

If a very massive planet

如果一颗质量很大的行星

moves its orbit closer to the star,

将轨道移向恒星，

it can kick smaller planets

它就能把较小的行星

out of the system.

踢出该系统。

But just because a planet has survived the growing pains of formation, 語法

但是，就算一颗行星熬过了形成期的阵痛，

doesn't mean it's safe.

也并不意味着它就安全了。

Planetary systems can be disrupted by flybys from stars or black holes at any point. 用詞

行星系统随时都可能被飞掠而过的恒星或黑洞扰乱。

Up to half of all planets born

所有诞生的行星中，多达一半

could end up as rogues. 短語動詞

可能最终会沦为流浪者。

Scientists don't agree on the numbers,

科学家们在具体数字上存在分歧，

but it's likely that at the very least, 短語搭配

但很可能，至少，

there are billions of rogue planets

有数十亿颗流浪行星

in the Milky Way alone.

单单存在于银河系中。

Most rogues will share the same depressing fate.

大多数流浪行星都会面临同样令人沮丧的命运。

As their star becomes smaller day by day,

随着它们的恒星一天天变得渺小，

the planet's surface quickly cools down to minus 270 degrees Celsius.

行星表面的温度会迅速下降到零下270摄氏度。

If they have oceans,

如果它们有海洋，

they'll freeze and become as hard as bedrock.

海洋就会冻结，变得像基岩一样坚硬。

Their atmospheres will sink down to the surface

它们的大气层会沉降到表面，

and eventually freeze too.

并最终也会冻结。

But weirdly enough, 短語搭配

但不可思议的是，

some of these frozen dark deserts

这些冰冻黑暗的荒漠中，有些

could harbor life. 用詞

却可能孕育生命。

To understand how,

为了理解其中的原因，

let's imagine a planet similar to Earth

让我们想象一颗类似地球的行星，

in the same order of magnitude 用詞

在同一个数量级上，

in terms of mass and composition. 短語搭配

无论是在质量还是成分方面。

If we put it into deep space,

如果把它放入深空，

how could it still support life?

它怎么还能维持生命呢？

As far as we understand the nature of life, 表達脈絡

就我们对生命本质的理解而言，

there is one indispensable ingredient it needs,

生命需要一种不可或缺的成分：

liquid water.

液态水。

Water is important because it mixes things,

水之所以重要，是因为它能混合事物，

both matter and energy,

包括物质和能量，

which lets interesting chemistry happen, 語法

从而发生有趣的化学反应，

like life.

比如生命。

So our planet needs enough energy

所以，我们的这颗行星需要足够的能量，

to keep at least a part of our oceans warm

来保持至少一部分海洋足够温暖

enough to sustain liquid water. 語法

以维持液态水。

Annoyingly, about 99.97% of Earth's energy

让人头疼的是，地球大约99.97%的能量

budget comes from the sun.

收支来自太阳。

So our imaginary rogue Earth

所以我们假想的流浪地球

needs to work with the 0.03% of energy it has left, 短語動詞

必须利用它仅存的0.03%的能量运作，

which almost exclusively

这些能量几乎完全

comes from its hot center.

来自它滚烫的中心。

Earth's inner core is a giant metal ball

地球的内核是一个巨大的金属球，

about as hot as the surface of the sun

温度几乎和太阳表面一样高，

that's surrounded by the outer core

它被外核包裹着，

made up of liquid metals 短語動詞

外核由液态金属组成，

that are very, very slowly solidifying,

这些金属正非常、非常缓慢地凝固，

releasing a lot of heat in the process. 短語搭配

在此过程中会释放大量热量。

As long as this process is ongoing, 語法

只要这个过程还在继续，

our planet will be geologically active,

我们的行星就会保持地质活跃，

with solid and liquid material

固态和液态物质

moving around

会四处流动，

and transporting energy to the surface

并将能量输送到表面，

where it can be harnessed

在那里它可以被利用

as geothermal energy.

作为地热能。

While the hot core of every planet

虽然每颗行星炙热的核心

will cool off eventually,

最终都会冷却，

this process takes billions of years,

但这过程需要数十亿年，

enough time

有足够的时间

for life to come into existence and thrive. 短語搭配

让生命诞生和繁衍。

There's even one scenario that could allow an Earth-like planet

甚至有一种情况能让类地行星

to have oceans

拥有海洋

that are not frozen over. 短語動詞

且不会被完全冻结。

If the planet had an extremely dense and high pressure hydrogen atmosphere,

如果这颗行星拥有密度极大、压力极高的氢气大气层，

the gas would not freeze and could trap enough of the heat trying to escape the planet

这种气体不会冻结，并且能困住试图逃逸出星体的足够热量，

to enable oceans

从而让海洋

that extend all the way to the surface. 短語搭配

一直延伸到表面。

And there's another possible way to stay warm, 表達脈絡

还有另一种可能保暖的方法：

moons.

卫星。

If a rogue planet

如果一颗流浪行星

brings a moon or more along with them,

携带着一颗或多颗卫星，

a large enough moon

那么足够大的卫星

could inject additional energy

就可以注入额外的能量

into the system via tidal forces. 用詞

通过潮汐力进入该系统。

These forces

这些力量

stretch and squeeze the planet

会拉伸和挤压行星，

a little bit every day,

每天稍微来一点，

like kneading dough, 表達脈絡

就像揉面团一样，

keeping it warm.

让它保持温暖。

But the most likely scenario

但对于一颗孕育生命的流浪行星而言，

for a rogue bearing life 用詞

最有可能的情况

is one with subglacial oceans

是拥有冰下海洋，

under a kilometer thick layer

隐藏在厚达一公里的

of mostly water ice.

主要由水冰构成的冰层之下。

These are not completely absurd, 表達脈絡

这并非完全荒唐，

since we already have a few of them in the solar system.

因为在太阳系中我们就已经有几个这样的例子了。

So how could life

那么生命如何能够

sustain itself at the bottom

在深处维持自身呢？

of a completely dark,

在完全黑暗、

cold ocean?

冰冷的海洋底部？

On Earth,

在地球上，

deep down in our oceans

在我们海洋深处

in complete darkness,

完全黑暗的地方，

in volcanically active areas,

在火山活动活跃的区域，

there are hydrothermal vents called black smokers. 用詞

有一种叫做黑烟囱的热液喷口。

They spew out a cloud 短語動詞

它们喷出一团团

of black material and hot water,

黑色物质和热水，

providing a constant flow

提供了持续不断的

of minerals from Earth's mantle.

来自地幔的矿物水流。

Bacteria feed on the minerals 短語動詞

细菌以这些矿物质为食，

and produce organic materials,

并产生有机物质，

which attracts crustaceans,

这吸引了甲壳类、

bivalves,

双壳类、

snails,

蜗牛、

fish, octopus, and tube worms

鱼类、章鱼以及管蠕虫，

up to 2 m long.

长度可达2米。

Not only are hydrothermal vents 語法

热液喷口不仅是

home to an incredibly diverse 短語搭配

种类极其多样的

group of living beings,

生物群落的家园，

but also a contender

而且还是一个有力的竞争者，

for the place where life

可能就是生命

could have begun on Earth

在地球上开始的地方

billions of years ago.

在数十亿年前。

In the dark ocean

在幽暗的海洋中，

of a rogue planet,

属于一颗流浪行星，

similar vents

类似的喷口

or volcanic activity could be the starting point

或火山活动可能是起点，

and basis for complex ecosystems

并且是复杂生态系统的基础，

we can only imagine right now.

我们现在只能去想象它。

One upside an ecosystem

一个流浪行星海洋中

in a rogue planet ocean

生态系统的一大优势

has is that the environment

是这里的环境

is extremely stable.

极其稳定。

The thick ice sheet protects it from all sorts

厚厚的冰层保护它免受各种

of extinction events,

灭绝事件的影响，

and as long as the energy

只要能量

from the core keeps on coming,

持续不断地从核心涌出，

things stay pretty much the same.

情况就几乎不会改变。

The most likely forms

最有可能的生命形式

of life are bacteria

是细菌

and other microorganisms,

和其他微生物，

but given enough time, 語法

但只要有足够的时间，

more complex alien animals

更复杂的外星动物

could feed on the smaller beings

可能会以更小的生物为食

and thrive.

并繁荣发展。

It's not impossible that intelligent 語法

在这种环境下出现智慧生命

life could emerge in such an environment.

也不是不可能的。

If it did,

如果真的出现了，

it would find itself

它会发现自己

in a pretty weird world.

置身于一个非常怪异的世界里。

Constricted by an impassable

被上方不可逾越的

wall of rock hard ice at the top

坚如岩石的冰墙

and bedrock at the bottom.

和下方的基岩所限制。

Without any plants

没有植物

to store star energy,

来储存恒星的能量，

there would be no wood, oil, or coal.

就不会有木材、石油或煤炭。

Even if there were,

即便有，

it's not like you'd discover fire 語氣意圖

你也不可能在海洋底部

at the bottom of an ocean.

发现火。

Without this energy,

没有这种能量，

metals may never be forged

金属可能永远无法被锻造

into useful things.

成有用的工具。

Our intelligent alien

我们聪明的外星

friends might never break through the ice. 短語動詞

朋友可能永远无法破冰而出。

They might never realize

他们可能永远不会意识到

that there is such a thing as outside 短語搭配

有外面这回事，

and assume that their small world

并假设他们微小的世界

is all there is. 語法

就是宇宙的全部。

Millions of generations

数以百万计的世代

might live and die in these dark oceans,

可能在这些黑暗的海洋中生与死，

ignorant of the unbelievably big universe 用詞

对大得不可思议的宇宙一无所知

above the ice,

在那冰层之上，

until the core of their planet

直到他们行星的内核

cools off and all life vanishes.

彻底冷却，所有生命消失殆尽。

As the oceans completely freeze,

随着海洋完全冻结，

the remnants

文化和生态系统的

of cultures and ecosystems

遗迹

will be trapped

将被永远困在

in an icy grave forever. 習語

一个冰冷的坟墓里。

If you think about it, 表達脈絡

想想看，

it might be better

也许不知道这些

not to be aware of all that.

反而更好。

But the concept is disturbing

但这概念让人不安，

and exciting.

又令人兴奋。

The universe

宇宙

might be teeming with life 短語搭配

可能到处都是生命，

trapped on planets

被困在行星上，

that are basically impossible

基本上不可能

to leave. Worlds

离开。诸如此类的世界

like this could frequently pass

可能会频繁掠过

the solar system

太阳系，

without us even knowing. 語法

而我们甚至一无所知。

Maybe one day,

也许有一天，

in the far future,

在遥远的未来，

humans

人类

will set foot on one 習語

将涉足这些冰冻世界中的

of these frozen worlds

一个，

and try to say hello.

试着去说声你好。