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They might use chemicals in their skin to generate their own light,
它們可能用其外表的化學物質自己發光
as many deep-sea creatures do back home.
就像地球上的很多深海生物一樣
They might even swim in school-like colonies,
它們甚至可能像魚群一樣群居
just as aquatic animals do on earth.
就像地球上的水生物一樣
But even if advanced animals do live inside Europa,
但是即使木衛二內部真有高等動物存在
I think they're unlikely to be trying to make contact with us anytime soon.
我認為它們在短期內不會嘗試與我們聯系
They'd exist cocooned in an icy shell 15 miles thick,
它們被緊緊包裹在15英里厚的冰層下
so they'd be blissfully unaware of the universe beyond.
所以它們意識不到宇宙的存在，無憂無慮
To find them, we'd need to send a mission here,
要找到它們，我們得派遣飛船來這里
which would be even more risky and expensive than visiting Mars.
這將比訪問火星更加冒險而昂貴
I hope one day we will discover Europa's secrets.
我希望有一天我們能夠揭開木衛二的秘密
But before then, it's worth continuing our journey
但在那之前，我們仍值得繼續
to search for aliens with a wider outlook.
以更寬的視野探索外星生命
I think we need to leave our solar system and
我認為我們需要離開太陽系
voyage into the vastness that lies beyond.
探索在那之外的廣袤星空
Stars surround us in the universe, but until recently,
宇宙中有無數顆恒星在我們周圍，但直到現在
no one knew how many had planets in orbit around them,
也沒人知道究竟有多少恒星擁有行星
let alone if any of those planets could support alien life.
更不用說有多少行星上面可能存在生命
Finding out is tough, because stars are big and blindingly bright.
弄清這些很困難，因為恒星很大很耀眼
Planets are tiny and dark.
而行星很小很暗淡
Spotting them requires technology on an enormous scale.
觀測它們需要巨大倍數的望遠鏡技術
The binocular keck telescope in Hawaii,
夏威夷的Keck雙筒望遠鏡
with its twin 30-foot mirrors,
每個鏡頭有30英尺長
is one of the most powerful land-based telescopes ever built.
這是迄今為止陸地上最強大的望遠鏡之一
But even this vast machine can't see distant planets.
但即使是這個強大的家伙也看不到遙遠的行星
Instead, it looks for stars that wobble
然而，它可以觀測到一些飄搖不定的恒星
-- the telltale sign of an unseen planet in orbit.
這種跡象標明有顆看不見的行星圍繞著它
A hammer thrower demonstrates the principle.
鏈球運動員就能解釋這個原理
As he spins, the hammer pulls on his body
當他旋轉時，鏈球拽著他的身體
and he wobbles from side to side.
他從一側搖晃到另一側
The same thing happens as a planet swings 'round its star.
同樣事情也會發生在被行星圍繞著的恒星上
Planets also reveal themselves if they pass between their star and us.
行星如果運行到其恒星與地球之間，也會現身
The planet causes regular dimming,
行星可導致恒星規律的變暗
and from the timing, we can even determine
通過計時 我們甚至可以計算出
if it's inside the star's "goldilocks" zone.
它是否在恒星的"金發姑娘"地帶內
