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They might use chemicals in their skin to generate their own light,
它们可能用其外表的化学物质自己发光
as many deep-sea creatures do back home.
就像地球上的很多深海生物一样
They might even swim in school-like colonies,
它们甚至可能像鱼群一样群居
just as aquatic animals do on earth.
就像地球上的水生物一样
But even if advanced animals do live inside Europa,
但是即使木卫二内部真有高等动物存在
I think they're unlikely to be trying to make contact with us anytime soon.
我认为它们在短期内不会尝试与我们联系
They'd exist cocooned in an icy shell 15 miles thick,
它们被紧紧包裹在15英里厚的冰层下
so they'd be blissfully unaware of the universe beyond.
所以它们意识不到宇宙的存在，无忧无虑
To find them, we'd need to send a mission here,
要找到它们，我们得派遣飞船来这里
which would be even more risky and expensive than visiting Mars.
这将比访问火星更加冒险而昂贵
I hope one day we will discover Europa's secrets.
我希望有一天我们能够揭开木卫二的秘密
But before then, it's worth continuing our journey
但在那之前，我们仍值得继续
to search for aliens with a wider outlook.
以更宽的视野探索外星生命
I think we need to leave our solar system and
我认为我们需要离开太阳系
voyage into the vastness that lies beyond.
探索在那之外的广袤星空
Stars surround us in the universe, but until recently,
宇宙中有无数颗恒星在我们周围，但直到现在
no one knew how many had planets in orbit around them,
也没人知道究竟有多少恒星拥有行星
let alone if any of those planets could support alien life.
更不用说有多少行星上面可能存在生命
Finding out is tough, because stars are big and blindingly bright.
弄清这些很困难，因为恒星很大很耀眼
Planets are tiny and dark.
而行星很小很暗淡
Spotting them requires technology on an enormous scale.
观测它们需要巨大倍数的望远镜技术
The binocular keck telescope in Hawaii,
夏威夷的Keck双筒望远镜
with its twin 30-foot mirrors,
每个镜头有30英尺长
is one of the most powerful land-based telescopes ever built.
这是迄今为止陆地上最强大的望远镜之一
But even this vast machine can't see distant planets.
但即使是这个强大的家伙也看不到遥远的行星
Instead, it looks for stars that wobble
然而，它可以观测到一些飘摇不定的恒星
-- the telltale sign of an unseen planet in orbit.
这种迹象标明有颗看不见的行星围绕着它
A hammer thrower demonstrates the principle.
链球运动员就能解释这个原理
As he spins, the hammer pulls on his body
当他旋转时，链球拽着他的身体
and he wobbles from side to side.
他从一侧摇晃到另一侧
The same thing happens as a planet swings 'round its star.
同样事情也会发生在被行星围绕着的恒星上
Planets also reveal themselves if they pass between their star and us.
行星如果运行到其恒星与地球之间，也会现身
The planet causes regular dimming,
行星可导致恒星规律的变暗
and from the timing, we can even determine
通过计时 我们甚至可以计算出
if it's inside the star's "goldilocks" zone.
它是否在恒星的"金发姑娘"地带内
