Name: 為什麼外星生命會是我們的末日--大過濾器。 (Why Alien Life Would be our Doom - The Great Filter)
Uploaded: 2021-01-14T07:45:36.000Z
Duration: 9 min 36 s

Imagine NASA announced today
that they found aliens.

想像一下如果NASA今天宣布發現了外星人。

Bacteria on Mars, weird alien fish
in the oceans of Europa,

以及泰坦(土衛六)上古老的異星遺跡。

恩~~錯，這是個壞消息，或許還會是一場災難。

It could mean that the end of humanity
is almost certain

這可能表示人類注定要滅亡了，

Why would the most exciting
discovery of our lifetime

為什麼這個也許是一生中最新奇的新聞會很糟？

00:00:40,320 --> 00:00:44,740
讓我們想像生命從一開始到今日的發展

第一層是無生命的化合物，必須自行組合

成能複製的結構，具穩定性和可修復性，

The first step is dead chemistry
that needs to assemble itself

into self-replicating patterns,
stable and resilient,

第二層的生命形式變得更複雜，

The second step is for our early life to
become more complex,

able to build more complicated structures,

再來，這些細胞組合成多細胞生物，

and use the available energy
much more efficiently.

使其發展出不可思議的多樣性和更高的複雜性。

On the next step, these cells combine
to become multicellular beings,

最上層則是該物種演化出巨大的腦，

enabling unbelievable variety
and further complexity.

讓他們能使用工具、產生文化並傳播知識，

The step above sees the species
evolve big brains,

enabling the use of tools, culture
and shared knowledge,

The species can now become the
dominant lifeform on its planet,

現階段正在畏畏縮縮地試著離開行星，

First shy attempts to leave its
planet are happening.

我們知道生命的天性是去每個適合生活的地方，

但由於每個行星的承載量和它的壽命皆為有限，

若ㄧ物種要長存，必定要尋找更多容身之處。

to reach out, to cover every
niche it can.

And since planets have a limited
carrying capacity and lifespan,

it will look for more places
to spread to.

理論上，其最終將是橫跨整個星系的文明。

So the steps above the current
ones seem logical:

這很可能是全宇宙文明的通則，

then spread further to reach
other stars,

如果一個物種有足夠的競爭力和動機，
而能宰制其所在的行星，

to the possible final step:
becoming a galaxy-wide civilization.

It's very likely that this is a universal
principle for civilizations,

我們已知銀河系中行星可多達五千億顆星球，

其中類似地球的至少一百億顆，

If a species is competitive and driven
enough to take control over its planet,

很多星球比地球年長數十億年。

但目前觀測到的星系文明數量是零。

We know that there are up to 500 billion
planets in the Milky Way,

我們應該能看到些什麼，但沒有─

不論從何觀之，虛無的太空一片死寂。

Many have been around billions
of years longer than Earth.

But we're observing zero
galactic civilizations.

爬上比我們如今所在更高的階梯，

它使星系文明成為難如登天，甚至是永不可能的目標。

這就是大過濾，一種挑戰或危機，

危險得足以摧毀幾乎所有遭遇它的物種。

This means something is preventing living
things from climbing the staircase,

...Something that makes becoming
a galactic civilization

其二，我們大難臨頭且必死無疑。

這取決於「濾網」位於我們目前階段的前面或後面。

情況一：大過濾已過去。我們獨占鰲頭。

...A challenge or danger so
hard to overcome,

如果濾網在我們後方，表示我們經歷過的某個步驟

that it eliminates almost every
species that encounters it.

One means we are incredibly
special and lucky,

the other one means we are doomed
and practically already dead.

目前很難預測生命有多少機率從非生命中起源，

It depends on where the filter
is on our staircase:

某些科學家認為只要環境具備，生命能源自任何一處，

其他人則主張地球可能為宇宙中唯一有生命之處。

另一個選項是複雜的動物細胞是非常特殊的，

這個階段發生了一件極特殊之事件，

that means that one of the steps we passed

一個原始的獵食細胞吞噬了另一個細胞，

處理與外部環境的交互作用並提供資源，

It's very hard to make predictions
about how likely it is

專住於提供大量多餘能量給宿主。

擁有了更多能量，宿主細胞長得比以前更大，

Some scientists think it develops everywhere
where the conditions are right;

產生更高成本的新結構以增進其生存，

而房客成為細胞的發電廠(粒線體)。

這種細胞組成了地球上所有動物。

Another candidate is the step
of complex animal cells.

也許銀河中有億萬顆覆滿細菌的行星，

A very specific thing happened
on this step,

卻沒有半個能達到地球生命的複雜度。

and as far as we know, it happened
exactly once.

A primitive hunter cell
swallowed another cell,

創造填字遊戲和言情小說的人類似乎相當聰明，

but instead of devouring it,
the two cells formed a union.

但巨大的腦本身就是非常昂貴的演化投資。

它如此脆弱，無法在和熊搏鬥時成為助力，

took care of interacting with the
environment and providing resources,

while the smaller one used its
new home and free stuff,

即使如此，現代智人也花上二十萬年

to focus on providing a lot of extra
energy for its host.

With the abundant energy, the host cell
could grow more than before

and build new and expensive things
to improve itself,

也許智慧本身其實不合適宜，只是我們僥倖成功。

while the guest became the
powerhouse of the cell.

These cells make up every
animal on the planet.

Maybe there are billions of bacteria-covered planets in the Milky Way,

比我們歷經的任何災難都艱險無數倍，

即使一次大災難殺死多數人，或讓文明倒退數千年，

We humans feel very smart and
sophisticated

只要我們能再起，哪怕需要數百萬年，

with our crossword puzzles and romantic novels.

這也不是個大過濾，只是邁向星系文明的普通障礙。

以宇宙尺度而言，幾百萬年不過眨眼之間而已。

a very expensive evolutionary investment.

它必然是如此艱難、絕望且強大

they don't help in a fistfight with a bear,

足以摧毀星系中數十億年來大多數(若非全部)先進文明。

一個令人膽寒且沮喪的假設是，

字幕列表影片播放

為什麼外星生命會是我們的末日--大過濾器。 (Why Alien Life Would be our Doom - The Great Filter)

scenario

extremely

eliminate

devastating