TED2015
Sara Seager: The search for planets beyond our solar system
莎拉·西格爾: 尋找太陽系外的行星
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我們看到天空中的每一顆恆星，至少有一顆行星繞著它運轉，天文學家莎拉·西格爾如此說。我們了解這些外行星嗎？要如何發現更多的外行星呢？西格爾介紹一組她最喜歡的外行星，並展示新的技術，能夠幫助我們尋找有生命跡象的外行星。
Sara Seager - Exoplanet expert
Sara Seager’s research led to the first discovery of an atmosphere on a planet outside our solar system. Now she’s on the hunt for a twin Earth. Full bio
Sara Seager’s research led to the first discovery of an atmosphere on a planet outside our solar system. Now she’s on the hunt for a twin Earth. Full bio
Double-click the English transcript below to play the video.
00:12
I'm here to tell you
about the real search for alien life.
about the real search for alien life.
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在這裡我要告訴各位一個有關
探尋外星生命的真實故事。
探尋外星生命的真實故事。
00:16
Not little green humanoids
arriving in shiny UFOs,
arriving in shiny UFOs,
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我所說不是長得像人的綠色小個子
乘坐發光飛碟抵達地球，
乘坐發光飛碟抵達地球，
00:19
although that would be nice.
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儘管那個主題也很好。
00:21
But it's the search for planets
orbiting stars far away.
orbiting stars far away.
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我們在找尋的是
繞行恆星的遠方行星。
繞行恆星的遠方行星。
00:25
Every star in our sky is a sun.
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天空中每一顆恆星都是一個太陽。
00:27
And if our sun has planets --
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如果我們的太陽有行星
00:29
Mercury, Venus, Earth, Mars, etc.,
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如水星、金星、地球、火星等等，
00:31
surely those other stars
should have planets also,
should have planets also,
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當然那些其他恆星也應該有行星，
00:34
and they do.
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它們確實有行星。
00:35
And in the last two decades,
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在過去的二十年，
00:36
astronomers have found
thousands of exoplanets.
thousands of exoplanets.
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天文學家已發現數千顆系外行星。
00:40
Our night sky is literally
teeming with exoplanets.
teeming with exoplanets.
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夜晚的天空幾乎佈滿系外行星。
00:43
We know, statistically speaking,
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依據統計，我們知道，
00:44
that every star has at least one planet.
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每顆恆星至少有一顆行星。
00:47
And in the search for planets,
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在探尋行星中，
00:49
and in the future,
planets that might be like Earth,
planets that might be like Earth,
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未來，行星或許像地球一樣，
00:52
we're able to help address
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我們能夠提出
00:54
some of the most amazing
and mysterious questions
and mysterious questions
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一些令人訝異且神秘的問題
00:57
that have faced humankind for centuries.
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這問題已經圍繞人類數百年之久。
00:59
Why are we here?
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我們為什麼在這裡？
01:01
Why does our universe exist?
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我們的宇宙為什麼存在？
01:03
How did Earth form and evolve?
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地球是如何形成與演變而來的？
01:05
How and why did life originate
and populate our planet?
and populate our planet?
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生命的起源是什麼
我們為何生活在這顆星球上？
我們為何生活在這顆星球上？
01:09
The second question
that we often think about is:
that we often think about is:
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我們經常思考的第二個問題是：
01:12
Are we alone?
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我們獨立存在宇宙中嗎？
01:14
Is there life out there?
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有其他的生物存在嗎？
01:17
Who is out there?
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他們是誰？
01:19
You know, this question has been around
for thousands of years,
for thousands of years,
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你知道，
這個問題已經圍繞人類數千年了，
這個問題已經圍繞人類數千年了，
01:22
since at least the time
of the Greek philosophers.
of the Greek philosophers.
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至少從古希臘哲學家那時候起
就已經有這個問題。
就已經有這個問題。
01:25
But I'm here to tell you
just how close we're getting
just how close we're getting
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但此時我要告訴你
我們有多接近
我們有多接近
01:27
to finding out the answer
to this question.
to this question.
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取得這個問題的答案。
01:30
It's the first time in human history
that this really is within reach for us.
that this really is within reach for us.
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這是人類史上的第一次
01:35
Now when I think about the possibilities
for life out there,
for life out there,
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當我思索其他生物存在的可能性，
01:38
I think of the fact that our sun
is but one of many stars.
is but one of many stars.
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事實上太陽是眾多恆星之一。
01:42
This is a photograph of a real galaxy,
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這是一張真實銀河星系的照片，
01:44
we think our Milky Way
looks like this galaxy.
looks like this galaxy.
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我們認為銀河就像這張照片。
01:47
It's a collection of bound stars.
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是由眾多恆星組成。
01:48
But our [sun] is one
of hundreds of billions of stars
of hundreds of billions of stars
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太陽是千億恆星中的一員
01:53
and our galaxy is one of upwards
of hundreds of billions of galaxies.
of hundreds of billions of galaxies.
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我們的銀河是千億銀河中的一員。
01:58
Knowing that small planets
are very common,
are very common,
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我們知道小行星是非常普遍的，
02:01
you can just do the math.
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可以算得出來。
02:03
And there are just so many stars
and so many planets out there,
and so many planets out there,
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那裡有好多的恆星行星，
02:07
that surely, there must be life
somewhere out there.
somewhere out there.
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必然一定有生物存在。
02:11
Well, the biologists get furious
with me for saying that,
with me for saying that,
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生物學家
對我這樣的說法會非常生氣，
對我這樣的說法會非常生氣，
02:14
because we have absolutely no evidence
for life beyond Earth yet.
for life beyond Earth yet.
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因為我們的確無法證明
地球之外有生物存在。
地球之外有生物存在。
02:18
Well, if we were able to look
at our galaxy from the outside
at our galaxy from the outside
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如果我們能夠從外部觀察銀河系
02:23
and zoom in to where our sun is,
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將太陽的位置放大觀察，
02:26
we see a real map of the stars.
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我們看到一張真實的恆星地圖。
02:28
And the highlighted stars
are those with known exoplanets.
are those with known exoplanets.
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高亮度的恆星
是那些為大家所知的系外行星。
是那些為大家所知的系外行星。
02:31
This is really just
the tip of the iceberg.
the tip of the iceberg.
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這只是冰山的一角。
02:34
Here, this animation is zooming in
onto our solar system.
onto our solar system.
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這個動畫放大太陽系的位置。
02:38
And you'll see here the planets
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你會看到這些行星
02:40
as well as some spacecraft
that are also orbiting our sun.
that are also orbiting our sun.
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和一些太空船一樣繞著太陽轉。
02:44
Now if we can imagine going
to the West Coast of North America,
to the West Coast of North America,
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想像我們到北美的西岸，
02:48
and looking out at the night sky,
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看著那裡的夜空，
02:50
here's what we'd see on a spring night.
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這就是當地春天的夜晚。
02:52
And you can see
the constellations overlaid
the constellations overlaid
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你可以看到佈滿星群
02:54
and again, so many stars with planets.
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同樣的，很多的恆星和行星。
02:57
There's a special patch of the sky
where we have thousands of planets.
where we have thousands of planets.
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天空有一特殊區塊
那裡有數千顆行星。
那裡有數千顆行星。
03:01
This is where the Kepler Space Telescope
focused for many years.
focused for many years.
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這是克卜勒太空望遠鏡
多年來關注的地方。
多年來關注的地方。
03:05
Let's zoom in and look
at one of the favorite exoplanets.
at one of the favorite exoplanets.
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我們放大畫面
觀察其中一顆我們喜愛的系外行星。
觀察其中一顆我們喜愛的系外行星。
03:10
This star is called Kepler-186f.
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這恆星被稱為克卜勒-186f。
03:14
It's a system of about five planets.
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是一個由五個行星組成的系統。
03:16
And by the way, most of these exoplanets,
we don't know too much about.
we don't know too much about.
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順道一提，大部分的系外行星
我們並不太了解。
我們並不太了解。
03:20
We know their size, and their orbit
and things like that.
and things like that.
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我們知道它們的大小，
運行軌道之類的。
運行軌道之類的。
03:23
But there's a very special planet
here called Kepler-186f.
here called Kepler-186f.
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有一個非常特別的行星
被稱為克卜勒-186f。
被稱為克卜勒-186f。
03:27
This planet is in a zone
that is not too far from the star,
that is not too far from the star,
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這顆行星所在區域
距離恆星不遠，
距離恆星不遠，
03:31
so that the temperature
may be just right for life.
may be just right for life.
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其溫度可能適合生物生存。
03:35
Here, the artist's conception
is just zooming in
is just zooming in
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這是藝術家的觀念，將畫面放大
03:38
and showing you what that planet
might be like.
might be like.
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向你們展示那顆行星的樣子。
03:43
So, many people have this
romantic notion of astronomers
romantic notion of astronomers
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因此，
很多人對天文學家有浪漫的想法
很多人對天文學家有浪漫的想法
03:48
going to the telescope
on a lonely mountaintop
on a lonely mountaintop
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在一個孤寂的山頂
對著望遠鏡
對著望遠鏡
03:52
and looking at the spectacular night sky
through a big telescope.
through a big telescope.
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透過大的望遠鏡
觀察壯觀的夜空。
觀察壯觀的夜空。
03:55
But actually, we just work
on our computers like everyone else,
on our computers like everyone else,
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但事實上，我們只是
和其他人一樣在電腦前忙碌，
和其他人一樣在電腦前忙碌，
03:59
and we get our data by email
or downloading from a database.
or downloading from a database.
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透過郵件或從資料庫下載
以取得資料。
以取得資料。
04:03
So instead of coming here to tell you
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我不是跑到這裡來告訴你
04:05
about the somewhat tedious nature
of the data and data analysis
of the data and data analysis
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有點冗長乏味的資料和資料分析
04:08
and the complex computer models we make,
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以及我們做的複雜電腦程式，
04:10
I have a different way
to try to explain to you
to try to explain to you
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我要以不同的方式向你們解說
04:13
some of the things
that we're thinking about exoplanets.
that we're thinking about exoplanets.
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我們對系外行星的一些想法。
04:15
Here's a travel poster:
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這是一張旅行海報：
04:16
"Kepler-186f:
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「克卜勒-186f：
04:19
Where the grass is always redder
on the other side."
on the other side."
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這草的顏色
總是比另一邊的草還要紅。」
總是比另一邊的草還要紅。」
04:22
That's because Kepler-186f
orbits a red star,
orbits a red star,
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那是因為克卜勒-186f
繞著紅恆星運轉，
繞著紅恆星運轉，
04:25
and we're just speculating
that perhaps the plants there,
that perhaps the plants there,
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我們只是推測那裡的行星，
04:28
if there is vegetation
that does photosynthesis,
that does photosynthesis,
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如果有進行光合作用的植物，
04:31
it has different pigments and looks red.
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會有不同的色素
看起來是紅色。
看起來是紅色。
04:34
"Enjoy the gravity on HD 40307g,
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「盡情享受 HD 40307g 的重力，
04:38
a Super-Earth."
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一顆超級地球。」
04:40
This planet is more massive than Earth
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這顆行星遠大於地球
04:42
and has a higher surface gravity.
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而且有較大地表引力。
04:44
"Relax on Kepler-16b,
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「在克卜勒-16b上放輕鬆
04:47
where your shadow always has company."
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影子在那裡成雙成對。」
04:49
(Laughter)
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(笑聲）
04:51
We know of a dozen planets
that orbit two stars,
that orbit two stars,
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我們知道繞著二顆恆星
運轉的十二顆行星，
運轉的十二顆行星，
04:55
and there's likely many more out there.
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那裡可能有更多的行星。
04:57
If we could visit one of those planets,
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如果我們能夠參觀其中一顆行星，
04:59
you literally would see two sunsets
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你幾乎可以看到二個日落
05:01
and have two shadows.
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和二個自己的影子。
05:03
So actually, science fiction
got some things right.
got some things right.
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事實上，
科幻小說的故事有些是正確的。
科幻小說的故事有些是正確的。
05:05
Tatooine from Star Wars.
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星際大戰裡的塔圖因星
05:08
And I have a couple of other
favorite exoplanets
favorite exoplanets
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我還有我喜歡的外行星
05:10
to tell you about.
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要告訴你。
05:11
This one is Kepler-10b,
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這顆是克卜勒-10b，
05:13
it's a hot, hot planet.
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是一顆很熱的行星，
05:15
It orbits over 50 times closer to its star
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繞行就近的恆星超過五十次
05:18
than our Earth does to our sun.
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超過地球繞太陽的次數。
05:20
And actually, it's so hot,
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事實上，它的溫度很高
05:22
we can't visit any
of these planets, but if we could,
of these planets, but if we could,
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我們無法參觀任何這類的行星
如果可以的話，
如果可以的話，
05:25
we would melt long before we got there.
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在我們到達之前就已經融化。
05:27
We think the surface
is hot enough to melt rock
is hot enough to melt rock
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我們認為其表面溫度很高
足以融化岩石
足以融化岩石
05:29
and has liquid lava lakes.
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有液體熔岩湖。
05:31
Gliese 1214b.
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格利澤 1214b。
05:33
This planet, we know the mass and the size
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這顆行星，我們知道它的質量和體積
05:35
and it has a fairly low density.
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其密度極低。
05:36
It's somewhat warm.
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有溫暖的氣候。
05:38
We actually don't know
really anything about this planet,
really anything about this planet,
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事實上我們對這星球一無所知，
05:40
but one possibility
is that it's a water world,
is that it's a water world,
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但有一個可能性是
這顆行星是個水世界，
這顆行星是個水世界，
05:43
like a scaled-up version
of one of Jupiter's icy moons
of one of Jupiter's icy moons
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像一顆放大版的木星冰冷衛星之一
05:46
that might be 50 percent water by mass.
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或許水就佔了質量的一半。
05:49
And in this case, it would have
a thick steam atmosphere
a thick steam atmosphere
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在這種情況下，
它有厚厚的大氣流，
它有厚厚的大氣流，
05:52
overlaying an ocean,
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覆蓋著一片海洋，
05:54
not of liquid water,
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但不是液體形態的水，
05:55
but of an exotic form
of water, a superfluid --
of water, a superfluid --
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而是異質形態的水，一種超級液體，
05:58
not quite a gas, not quite a liquid.
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不完全是氣態，不完全是液態。
06:00
And under that wouldn't be rock,
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在海洋下面並非岩石，
06:02
but a form of high-pressure ice,
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而是一種高壓冰的形態，
06:04
like ice IX.
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如同冰 IX。
06:06
So out of all these planets out there,
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在那些行星範圍之外的地方，
06:08
and the variety
is just simply astonishing,
is just simply astonishing,
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其多樣性也令人驚訝，
06:12
we mostly want to find the planets
that are Goldilocks planets, we call them.
that are Goldilocks planets, we call them.
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我們大部分想找的行星
是金髮星球行星。
是金髮星球行星。
06:17
Not too big, not too small,
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體積不太大，也不太小，
06:19
not too hot, not too cold --
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溫度不太熱，也不太冷，
06:20
but just right for life.
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剛好適合生物生存。
06:22
But to do that,
we'd have to be able to look
we'd have to be able to look
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不過要做到這一點，
我們必須能夠
我們必須能夠
06:24
at the planet's atmosphere,
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觀察到這顆行星的大氣，
06:26
because the atmosphere
acts like a blanket trapping heat --
acts like a blanket trapping heat --
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因為大氣就像一塊保溫地毯
06:28
the greenhouse effect.
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溫室效應。
06:30
We have to be able to assess
the greenhouse gases
the greenhouse gases
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我們必須能夠偵測到其他行星的
06:33
on other planets.
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溫室氣體。
06:35
Well, science fiction
got some things wrong.
got some things wrong.
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這方面，科幻小說的描述有誤。
06:37
The Star Trek Enterprise
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「星艦迷航－企業號」
06:39
had to travel vast distances
at incredible speeds
at incredible speeds
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必須以高速繞行其他行星
06:42
to orbit other planets
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做長距離旅行
06:44
so that First Officer Spock
could analyze the atmosphere
could analyze the atmosphere
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因此副艦長斯波克才能分析大氣
06:48
to see if the planet was habitable
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以看出該行星是否適合生物定居
06:50
or if there were lifeforms there.
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或者是否有生物存在。
06:52
Well, we don't need
to travel at warp speeds
to travel at warp speeds
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我們不需要以極高速度行駛
06:55
to see other planet atmospheres,
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以取得其他其他行星的大氣資料，
06:57
although I don't want to dissuade
any budding engineers
any budding engineers
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雖然我不想去勸阻
新進工程師
新進工程師
07:00
from figuring out how to do that.
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去找到實踐這項工作的方法。
07:02
We actually can and do study
planet atmospheres
planet atmospheres
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實際上我們可以
由地球軌道
由地球軌道
07:04
from here, from Earth orbit.
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去研究那些行星的大氣。
07:06
This is a picture, a photograph
of the Hubble Space Telescope
of the Hubble Space Telescope
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這是哈柏望遠鏡的照片
07:09
taken by the shuttle Atlantis
as it was departing
as it was departing
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由太空梭亞特蘭蒂斯號
返航時所拍攝的照片
返航時所拍攝的照片
07:12
after the last
human space flight to Hubble.
human space flight to Hubble.
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最後一次載人太空船到哈柏之後。
07:14
They installed a new camera, actually,
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他們在太空船上安裝新的照相機，
07:16
that we use for exoplanet atmospheres.
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可以用來收集外行星大氣資料。
07:18
And so far, we've been able to study
dozens of exoplanet atmospheres,
dozens of exoplanet atmospheres,
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目前，我們已經能夠
研究數十個外行星大氣資料，
研究數十個外行星大氣資料，
07:23
about six of them in great detail.
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其中六個有非常詳細的資料。
07:25
But those are not
small planets like Earth.
small planets like Earth.
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這些行星不像地球是個小行星。
07:27
They're big, hot planets
that are easy to see.
that are easy to see.
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它們體積大且溫度高，
是容易觀察到的行星。
是容易觀察到的行星。
07:30
We're not ready,
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我們還沒準備好，
07:31
we don't have the right technology yet
to study small exoplanets.
to study small exoplanets.
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我們沒有相當的技術
以研究小行星。
以研究小行星。
07:36
But nevertheless,
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儘管如此，
07:37
I wanted to try to explain to you
how we study exoplanet atmospheres.
how we study exoplanet atmospheres.
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我仍然想要向大家解釋
我們是如何研究外行星大氣。
我們是如何研究外行星大氣。
07:41
I want you to imagine,
for a moment, a rainbow.
for a moment, a rainbow.
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大家可以想像一下彩虹。
07:44
And if we could look
at this rainbow closely,
at this rainbow closely,
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如果我們可近距離觀察彩虹，
07:47
we would see that some
dark lines are missing.
dark lines are missing.
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可以看到一些暗色線消失了。
07:51
And here's our sun,
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這是我們的太陽。
07:52
the white light of our sun split up,
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白色光分解了。
07:54
not by raindrops, but by a spectrograph.
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不是被雨滴，而是被光譜儀分解了。
07:56
And you can see
all these dark, vertical lines.
all these dark, vertical lines.
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你可以看到這暗色垂直的線。
07:59
Some are very narrow, some are wide,
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有些非常窄，有些寬，
08:00
some are shaded at the edges.
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有些邊緣被遮住了。
08:02
And this is actually how astronomers
have studied objects in the heavens,
have studied objects in the heavens,
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這就是天文學家
如何研究太空物質的方式，
如何研究太空物質的方式，
08:06
literally, for over a century.
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這是過去一百年的研究方式。
08:07
So here, each different atom and molecule
177
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這張圖，每一原子和分子
08:10
has a special set of lines,
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各有特殊的頻譜線，
08:11
a fingerprint, if you will.
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你可以把它當作指紋，
08:13
And that's how we study
exoplanet atmospheres.
exoplanet atmospheres.
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那就是我們利用這訊息
來研究外行星的大氣成份
來研究外行星的大氣成份
08:15
And I'll just never forget
when I started working
when I started working
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我永遠忘不了
二十年前
二十年前
08:18
on exoplanet atmospheres 20 years ago,
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剛開起研究外行星大氣的時候，
08:20
how many people told me,
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多少人告訴我，
08:21
"This will never happen.
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「這行不通。
08:22
We'll never be able to study them.
Why are you bothering?"
Why are you bothering?"
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我們永遠無法做到。
為何費心在這種事上？」
為何費心在這種事上？」
08:25
And that's why I'm pleased to tell you
about all the atmospheres studied now,
about all the atmospheres studied now,
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那就是為什麼我很高興要告訴你們
目前所有有關的大氣研究，
目前所有有關的大氣研究，
08:29
and this is really a field of its own.
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它已成形了。
08:31
So when it comes to
other planets, other Earths,
other planets, other Earths,
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當談及到其他行星，
其他類似地球行星，
其他類似地球行星，
08:33
in the future when we can observe them,
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將來我們可以觀察到，
08:35
what kind of gases
would we be looking for?
would we be looking for?
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什麼是我們要尋找的氣體？
08:38
Well, you know, our own Earth
has oxygen in the atmosphere
has oxygen in the atmosphere
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你知道，地球的大氣
08:41
to 20 percent by volume.
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含有百分之二十的氧氣。
08:43
That's a lot of oxygen.
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含量很高。
08:45
But without plants
and photosynthetic life,
and photosynthetic life,
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但若沒有植物及其光合作用。
08:48
there would be no oxygen,
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大氣中不會有氧氣。
08:49
virtually no oxygen in our atmosphere.
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1841
事實上我們的大氣中沒有氧氣。
08:52
So oxygen is here because of life.
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1923
因為生物的存在才有氧氣。
08:54
And our goal then is to look for gases
in other planet atmospheres,
in other planet atmospheres,
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我們目標就是尋找
其他行星大氣中的氣體，
其他行星大氣中的氣體，
08:58
gases that don't belong,
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氣體原本不存在，
09:00
that we might be able
to attribute to life.
to attribute to life.
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2383
或許我們可以歸功於生物。
09:02
But which molecules should we search for?
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我們在尋找哪些分子呢？
09:04
I actually told you
how diverse exoplanets are.
how diverse exoplanets are.
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我告訴過各位外行星的種類很多。
09:07
We expect that to continue in the future
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535454
1997
未來會陸續發現更多
09:09
when we find other Earths.
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537475
1301
當我們發現其他類似地球的行星。
09:10
And that's one of the main things
I'm working on now,
I'm working on now,
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這是我目前正在從事的最主要工作，
09:13
I have a theory about this.
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我有個自己的理論。
09:14
It reminds me that nearly every day,
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2288
它幾乎每天提醒我，
09:17
I receive an email or emails
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545025
2652
我收到一封或多封郵件
09:19
from someone with a crazy theory
about physics of gravity
about physics of gravity
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3627
是對重力物理學理論
09:23
or cosmology or some such.
210
551352
1832
或是宇宙論
提出瘋狂想法的人所寄來的。
提出瘋狂想法的人所寄來的。
09:25
So, please don't email me
one of your crazy theories.
one of your crazy theories.
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3333
所以請不要再給我發這種郵件了。
09:28
(Laughter)
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1214
（笑聲）
09:29
Well, I had my own crazy theory.
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557803
2178
我有自己瘋狂的理論。
09:32
But, who does the MIT professor go to?
214
560005
1984
麻省理工學院的教授要跟誰探討呢？
09:34
Well, I emailed a Nobel Laureate
in Physiology or Medicine
in Physiology or Medicine
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562703
4211
我向諾貝爾生理及醫學獎得主發信
09:38
and he said, "Sure, come and talk to me."
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566938
1973
他說，「好，我們討論一下。」
09:40
So I brought my two biochemistry friends
217
568935
1999
我帶了二個
我的生物化學領域的朋友
我的生物化學領域的朋友
09:42
and we went to talk to him
about our crazy theory.
about our crazy theory.
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2352
要和他討論我們的瘋狂理論。
09:45
And that theory was that life
produces all small molecules,
produces all small molecules,
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3441
那理論是，生命製造了所有小分子，
09:48
so many molecules.
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576799
1674
許許多多的分子。
09:50
Like, everything I could think of,
but not being a chemist.
but not being a chemist.
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2895
所有我可以想得到的事情，
雖然我不是個化學領域專家。
雖然我不是個化學領域專家。
09:53
Think about it:
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1183
想想看：
09:54
carbon dioxide, carbon monoxide,
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2030
二氧化碳，一氧化碳，
09:56
molecular hydrogen, molecular nitrogen,
224
584677
1859
氫分子，氮分子,
09:58
methane, methyl chloride --
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1366
甲烷，氯甲烷，
09:59
so many gases.
226
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1161
等諸多氣體。
10:01
They also exist for other reasons,
227
589135
1935
它們的存在也有其原因，
10:03
but just life even produces ozone.
228
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1852
生物即可產生臭氧。
10:04
So we go to talk to him about this,
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1758
所以我們和他談論這個主題，
10:06
and immediately, he shot down the theory.
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2142
結果立刻被他否決。
10:09
He found an example that didn't exist.
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2267
他找到一個不存在的氣體的例子。
10:11
So, we went back to the drawing board
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1781
所以我們回去從頭做起
10:13
and we think we have found something
very interesting in another field.
very interesting in another field.
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我們發現在其他領域
非常有趣的東西。
非常有趣的東西。
10:17
But back to exoplanets,
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回到外行星這個話題，
10:18
the point is that life produces
so many different types of gases,
so many different types of gases,
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3279
重點是生物製造各種不同的氣體，
10:21
literally thousands of gases.
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2212
差不多有幾千種。
10:24
And so what we're doing now
is just trying to figure out
is just trying to figure out
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我們現在要做的是試著找出
10:26
on which types of exoplanets,
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外行星上有那些氣體，
10:28
which gases could be attributed to life.
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3220
那些氣體是由生物產生。
10:34
And so when it comes time
when we find gases
when we find gases
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2048
當我們在外行星大氣中
10:36
in exoplanet atmospheres
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1351
所找到的氣體
10:37
that we won't know
if they're being produced
if they're being produced
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2096
不知道這些氣體是由
10:39
by intelligent aliens or by trees,
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3030
外星人製造，或是樹木所產生，
10:42
or a swamp,
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1210
或是由沼澤產生。
10:44
or even just by simple,
single-celled microbial life.
single-celled microbial life.
245
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2861
或是來自單細胞生物。
10:47
So working on the models
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1550
所以有了一些模型
10:49
and thinking about biochemistry,
247
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1651
以生物化學思考，
10:50
it's all well and good.
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1197
會有好的結果。
10:52
But a really big challenge
ahead of us is: how?
ahead of us is: how?
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但面臨最大的挑戰是：
如何做？
如何做？
10:54
How are we going to find these planets?
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2162
要如何找到這些行星？
10:57
There are actually many ways
to find planets,
to find planets,
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2204
其實有許多方法找到行星。
10:59
several different ways.
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1519
許多不同的方法。
11:00
But the one that I'm most focused on
is how can we open a gateway
is how can we open a gateway
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3859
不過我把焦點放在
我們如何何開啟一個通道
我們如何何開啟一個通道
11:04
so that in the future,
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1237
在未來，
11:05
we can find hundreds of Earths.
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1849
我們可以找到數百個地球。
11:07
We have a real shot
at finding signs of life.
at finding signs of life.
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655870
2333
我們確實已著手找尋
有生命跡象的生物。
有生命跡象的生物。
11:10
And actually, I just finished
leading a two-year project
leading a two-year project
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658227
3126
我剛完成一個
由我負責的二年專案
由我負責的二年專案
11:13
in this very special phase
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2088
在這個特殊的專案中
11:15
of a concept we call the starshade.
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2654
有一個我們稱為遮星板的概念。
11:18
And the starshade
is a very specially shaped screen
is a very specially shaped screen
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遮星板是一個形狀非常特殊的螢幕
11:21
and the goal is to fly that starshade
261
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1867
把遮星板送至外太空
11:23
so it blocks out the light of a star
262
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3094
它可遮恆星的光
11:26
so that the telescope
can see the planets directly.
can see the planets directly.
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2939
因此可以透過望遠鏡直接看到行星。
11:29
Here, you can see myself
and two team members
and two team members
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2393
這張圖可以看到我和二位團隊成員
11:31
holding up one small part
of the starshade.
of the starshade.
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2189
拿著遮星板的一小部分。
11:33
It's shaped like a giant flower,
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1580
它的形狀就像朵巨大的花，
11:35
and this is one of the prototype petals.
267
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2483
這是一片花瓣的雛型。
11:38
The concept is that a starshade
and telescope could launch together,
and telescope could launch together,
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4461
這個概念是
遮星板和望遠鏡可以一同送到太空，
遮星板和望遠鏡可以一同送到太空，
11:43
with the petals unfurling
from the stowed position.
from the stowed position.
269
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2594
然後從存放位置打開花瓣
11:46
The central truss would expand,
270
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2056
中心的花束會展開，
11:48
with the petals snapping into place.
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3092
花瓣迅速到達特定位置。
11:52
Now, this has to be made very precisely,
272
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2230
這過程要做到非常準確，
11:54
literally, the petals to microns
273
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1588
這花瓣要達微米的精確度
11:55
and they have to deploy to millimeters.
274
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2715
部署要達毫米精確度。
11:58
And this whole structure would have to fly
275
706697
2055
這整個架構必須送到
12:00
tens of thousands of kilometers
away from the telescope.
away from the telescope.
276
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3359
距離望遠鏡數萬公里的地方。
12:04
It's about tens of meters in diameter.
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712159
2142
它的直徑有幾十公尺。
12:06
And the goal is to block out
the starlight to incredible precision
the starlight to incredible precision
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4953
目的是這個難以置信的精確度
要去遮擋恆星的光線
要去遮擋恆星的光線
12:11
so that we'd be able to see
the planets directly.
the planets directly.
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2738
這樣我們就可以直接觀察行星。
12:15
And it has to be a very special shape,
280
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2229
它的形狀必須很特殊，
12:17
because of the physics of defraction.
281
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1889
因為繞射現象。
12:19
Now this is a real project
that we worked on,
that we worked on,
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2219
這是我們做的一個專案，
12:21
literally, you would not believe how hard.
283
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2468
你無法想像這有多難。
12:24
Just so you believe
it's not just in movie format,
it's not just in movie format,
284
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2662
這不是一個電影情節
12:26
here's a real photograph
285
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1636
這是一張真實的照片
12:28
of a second-generation
starshade deployment test bed in the lab.
starshade deployment test bed in the lab.
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4991
實驗室裡第二代
遮星板測試平台。
遮星板測試平台。
12:33
And in this case,
I just wanted you to know
I just wanted you to know
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在這個專案中，
我只是想讓你們知道
我只是想讓你們知道
12:35
that that central truss
has heritage left over
has heritage left over
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花的中心點
12:38
from large radio deployables in space.
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由太空中大範圍展開的無線電設備
所留下來。
所留下來。
12:41
So after all of that hard work
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經過努力之後
12:43
where we try to think of all the crazy
gases that might be out there,
gases that might be out there,
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我們試想所有有可能出現的瘋狂氣體，
12:46
and we build the very
complicated space telescopes
complicated space telescopes
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我們建造非常複雜的太空望遠鏡
12:49
that might be out there,
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或許就在那裡，
12:51
what are we going to find?
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我們將會發現什麼呢？
12:52
Well, in the best case,
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最好的情況是，
12:54
we will find an image
of another exo-Earth.
of another exo-Earth.
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我們會找到另一張
類地球行星的圖片。
類地球行星的圖片。
12:58
Here is Earth as a pale blue dot.
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這個淡藍色的點就是地球。
13:00
And this is actually
a real photograph of Earth
a real photograph of Earth
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這是一張地球的真實照片
13:03
taken by the Voyager 1 spacecraft,
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是由太空船旅行者一號所拍攝的，
13:05
four billion miles away.
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從四十億英里外的距離拍下的。
13:07
And that red light is just scattered light
in the camera optics.
in the camera optics.
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這紅色光線是相機散射的光。
13:11
But what's so awesome to consider
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思考其中的奧妙
13:13
is that if there are intelligent aliens
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如果存在高智慧外星生物
13:16
orbiting on a planet
around a star near to us
around a star near to us
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靠近我們的行星繞著恆星轉
13:20
and they build complicated
space telescopes
space telescopes
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他們建造複雜的太空望遠鏡
13:22
of the kind that we're trying to build,
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我們正在建造的那種望遠鏡，
13:24
all they'll see is this pale blue dot,
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他們看到的也是一個淡藍色點，
13:27
a pinprick of light.
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一個小小的光點。
13:29
And so sometimes, when I pause to think
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有時候，我停下來思考
13:32
about my professional struggle
and huge ambition,
and huge ambition,
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我所面臨的困難和雄心壯志，
13:36
it's hard to think about that
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與浩瀚宇宙相比
13:38
in contrast to the vastness
of the universe.
of the universe.
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真是無法比擬。
13:42
But nonetheless, I am devoting
the rest of my life
the rest of my life
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儘管如此，我打算奉獻我的一生
13:46
to finding another Earth.
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來找尋另一個地球。
13:48
And I can guarantee
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我可以保證
13:50
that in the next generation
of space telescopes,
of space telescopes,
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下一代的太空望遠鏡，
13:52
in the second generation,
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也就是第二代，
13:54
we will have the capability
to find and identity other Earths.
to find and identity other Earths.
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我們有能力找到
並識別其他類地球行星。
並識別其他類地球行星。
13:59
And the capability
to split up the starlight
to split up the starlight
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有能力分開星光的光線
14:02
so that we can look for gases
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找到那些氣體
14:04
and assess the greenhouse gases
in the atmosphere,
in the atmosphere,
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確認大氣中溫室氣體的成份，
14:07
estimate the surface temperature,
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預估星球的表面溫度，
14:09
and look for signs of life.
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尋找生命的跡象。
14:11
But there's more.
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不過我們有更多的計劃。
14:13
In this case of searching
for other planets like Earth,
for other planets like Earth,
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在尋找類地球行星時，
14:16
we are making a new kind of map
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我們也製作一張圖
14:19
of the nearby stars
and of the planets orbiting them,
and of the planets orbiting them,
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有關於附近恆星及其行星的太空圖，
14:22
including [planets] that actually might be
inhabitable by humans.
inhabitable by humans.
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包括可能適合人類居住的行星。
14:26
And so I envision that our descendants,
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我在想我們的後代子孫，
14:29
hundreds of years from now,
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數百年後，
14:31
will embark on an interstellar
journey to other worlds.
journey to other worlds.
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透過星際旅行到其他的星球。
14:35
And they will look back at all of us
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他們回顧我們這一代
14:37
as the generation who first found
the Earth-like worlds.
the Earth-like worlds.
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是第一個發現類地星球的一代
14:41
Thank you.
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謝謝各位。
14:42
(Applause)
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（掌聲）
14:49
June Cohen: And I give you,
for a question,
for a question,
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吉恩·科恩：你先提問，
14:51
Rosetta Mission Manager Fred Jansen.
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有請羅塞塔任務管理經理
弗雷德·詹森
弗雷德·詹森
14:53
Fred Jansen: You mentioned halfway through
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弗雷德·詹森：
你剛剛有提到
你剛剛有提到
14:55
that the technology
to actually look at the spectrum
to actually look at the spectrum
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那個用來找尋
類地球行星的光譜技術
類地球行星的光譜技術
14:59
of an exoplanet like Earth
is not there yet.
is not there yet.
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尚未找到。
15:02
When do you expect this will be there,
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你認為何時可實現
15:04
and what's needed?
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我們要如何做？
15:05
Actually, what we expect is what we call
our next-generation Hubble telescope.
our next-generation Hubble telescope.
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事實上，
我們期待下一代哈伯望遠鏡。
我們期待下一代哈伯望遠鏡。
15:10
And this is called the James Webb
Space Telescope,
Space Telescope,
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我們稱它為詹姆斯偉伯太空望遠鏡，
15:12
and that will launch in 2018,
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將在 2018 年送上太空，
15:14
and that's what we're going to do,
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這是我們計劃要做的事，
15:16
we're going to look
at a special kind of planet
at a special kind of planet
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我們將觀察一種特殊的行星
15:18
called transient exoplanets,
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稱為凌日外行星，
15:20
and that will be our first shot
at studying small planets
at studying small planets
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那是我們第一次嘗試研究小行星
15:23
for gases that might indicate
the planet is habitable.
the planet is habitable.
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以找尋該行星上
存在適合人類居住的氣體。
存在適合人類居住的氣體。
15:27
JC: I'm going to ask you
one follow-up question, too, Sara,
one follow-up question, too, Sara,
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吉恩：莎拉，
接著我也要問你一個問題，
接著我也要問你一個問題，
15:30
as the generalist.
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一個普通的問題。
15:31
So I am really struck
by the notion in your career
by the notion in your career
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在你的職業生涯中
15:34
of the opposition you faced,
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我對你所面臨的問題感到震驚，
15:36
that when you began thinking
about exoplanets,
about exoplanets,
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當你開始思考外行星時，
15:38
there was extreme skepticism
in the scientific community
in the scientific community
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科學家對於它們是否存在
15:40
that they existed,
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抱著極端懷疑的態度，
15:42
and you proved them wrong.
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你證明他們的想法是錯誤的。
15:43
What did it take to take that on?
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你是如何做到？
15:45
SS: Well, the thing is that as scientists,
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莎拉：身為科學家，
15:47
we're supposed to be skeptical,
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我們理應對事情持有懷疑的態度，
15:49
because our job to make sure
that what the other person is saying
that what the other person is saying
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因為我們的工作是
確認他人的觀點
確認他人的觀點
15:52
actually makes sense or not.
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其說法是否合理。
15:53
But being a scientist,
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但是身為科學家，
15:56
I think you've seen it from this session,
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我想你們已從這段演講中看到，
15:58
it's like being an explorer.
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科學家像一個探索者。
16:00
You have this immense curiosity,
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有強烈的好奇心，
16:02
this stubbornness,
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堅決的心，
16:03
this sort of resolute will
that you will go forward
that you will go forward
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堅定不移的意志
勇往直前
勇往直前
16:06
no matter what other people say.
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無論其他人說了什麼。
16:08
JC: I love that. Thank you, Sara.
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吉恩：說的太好了，謝謝你，莎拉。
16:09
(Applause)
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（掌聲）
ABOUT THE SPEAKER
Sara Seager - Exoplanet expertSara Seager’s research led to the first discovery of an atmosphere on a planet outside our solar system. Now she’s on the hunt for a twin Earth.
Why you should listen
Having helped pave the way for the current torrent of discoveries of planets outside of our solar system (or exoplanets), 2013 MacArthur Fellow Sara Seager is now preparing to fulfill her life dream of discovering a planet with nearly identical conditions to our own.
Seager’s present research and discovery mission projects include Earth-orbiting nanosatellite telescopes as well as the Starshade, a sunflower-shaped giant screen to block intrusive starlight, allowing a space telescope to zoom in on the small exoplanets that have thus far eluded our sight.
More profile about the speakerSeager’s present research and discovery mission projects include Earth-orbiting nanosatellite telescopes as well as the Starshade, a sunflower-shaped giant screen to block intrusive starlight, allowing a space telescope to zoom in on the small exoplanets that have thus far eluded our sight.
Sara Seager | Speaker | TED.com