TED@NAS
Mike Brown: The search for our solar system's ninth planet
麥可 · 布朗: 在我們的太陽系中尋找第九個行星
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有沒有可能，我們太陽系中有個遙遠的小型天體，能帶領我們找到驚人的大發現？天文學家麥可 · 布朗認為，在我們的太陽系遠方有一個新的巨大行星存在，而這個行星存在的痕跡可能已在我們眼前。
Mike Brown - Planetary astronomer
Mike Brown scans the skies searching for and intensely studying distant bodies in our solar system in the hope of gaining insight into how our planet and the planets around it came to be. Full bio
Mike Brown scans the skies searching for and intensely studying distant bodies in our solar system in the hope of gaining insight into how our planet and the planets around it came to be. Full bio
Double-click the English transcript below to play the video.
00:13
I'm going to tell you a story
from 200 years ago.
from 200 years ago.
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讓我跟各位說一個
兩百年前的故事。
兩百年前的故事。
00:16
In 1820, French astronomer Alexis Bouvard
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1820 年，法國天文學家
阿列西布瓦爾
阿列西布瓦爾
00:20
almost became the second person
in human history to discover a planet.
in human history to discover a planet.
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幾乎成為人類史上
第二個發現某個行星的人。
第二個發現某個行星的人。
00:25
He'd been tracking the position
of Uranus across the night sky
of Uranus across the night sky
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他一直在用古老的星表
來追蹤天王星在夜空中的位置，
來追蹤天王星在夜空中的位置，
00:28
using old star catalogs,
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00:30
and it didn't quite go around the Sun
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天王星並沒有完全依照
他預測的方式繞著太陽轉。
他預測的方式繞著太陽轉。
00:32
the way that his predictions
said it should.
said it should.
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00:35
Sometimes it was a little too fast,
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有時它會移動太快，
00:37
sometimes a little too slow.
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有時則是有點太慢。
00:39
Bouvard knew that
his predictions were perfect.
his predictions were perfect.
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布瓦爾知道他的預測是完美的。
00:42
So it had to be that those
old star catalogs were bad.
old star catalogs were bad.
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所以問題一定是出在
那些古老的星表。
那些古老的星表。
00:46
He told astronomers of the day,
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他告訴那時的天文學家：
00:48
"Do better measurements."
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「把測量做更好一點。」
00:50
So they did.
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他們真的做了。
00:51
Astronomers spent the next two decades
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接下來的二十年，天文學家
00:54
meticulously tracking the position
of Uranus across the sky,
of Uranus across the sky,
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非常仔細地追蹤天王星
在天空中的位置，
在天空中的位置，
00:58
but it still didn't fit
Bouvard's predictions.
Bouvard's predictions.
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但仍然不符合布瓦爾的預測。
01:01
By 1840, it had become obvious.
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到了 1840 年，事實變得很明顯。
01:04
The problem was not
with those old star catalogs,
with those old star catalogs,
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那些古老的星表並沒有問題，
01:07
the problem was with the predictions.
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有問題的是預測。
且天文學家知道原因。
01:10
And astronomers knew why.
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01:11
They realized that there must be
a distant, giant planet
a distant, giant planet
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他們明白一定有個遙遠、巨大的行星
01:15
just beyond the orbit of Uranus
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在天王星的軌道外面，
在那軌道上造成牽引力，
在那軌道上造成牽引力，
01:17
that was tugging along at that orbit,
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01:19
sometimes pulling it along a bit too fast,
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造成天王星有時會移動太快，
01:21
sometimes holding it back.
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有時則會讓它減速。
在 1840 年，感覺一定很挫折，
01:24
Must have been frustrating back in 1840
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01:26
to see these gravitational effects
of this distant, giant planet
of this distant, giant planet
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看得到這個遙遠、巨大的行星
所產生的引力效應，
所產生的引力效應，
01:30
but not yet know how to actually find it.
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卻不知道要怎麼找到它。
相信我，那真的很讓人挫折。
01:34
Trust me, it's really frustrating.
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01:36
(Laughter)
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（笑聲）
01:37
But in 1846, another French astronomer,
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但在 1846 年，另一位
法國天文學家奧本 · 勒維耶，
法國天文學家奧本 · 勒維耶，
01:39
Urbain Le Verrier,
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01:41
worked through the math
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運用數學計算找出方法
來預測該行星的位置。
來預測該行星的位置。
01:42
and figured out how to predict
the location of the planet.
the location of the planet.
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01:45
He sent his prediction
to the Berlin observatory,
to the Berlin observatory,
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他把他的預測交給柏林天文台，
01:48
they opened up their telescope
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他們打開了望遠鏡，就在第一晚，
01:49
and in the very first night
they found this faint point of light
they found this faint point of light
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他們發現了一個極微弱的光點，
緩慢地在天空中移動，
緩慢地在天空中移動，
01:52
slowly moving across the sky
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他們發現了海王星。它和勒維耶
預測的位置只差這麼一點點。
預測的位置只差這麼一點點。
01:54
and discovered Neptune.
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01:56
It was this close on the sky
to Le Verrier's predicted location.
to Le Verrier's predicted location.
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02:01
The story of prediction
and discrepancy and new theory
and discrepancy and new theory
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這個做出預測、
發現不一致、提出新理論、
發現不一致、提出新理論、
成功發現的故事，實在非常經典，
02:06
and triumphant discoveries is so classic
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02:09
and Le Verrier became so famous from it,
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勒維耶也因此成名，
02:12
that people tried to get in
on the act right away.
on the act right away.
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讓大家都馬上想要如法炮製。
02:15
In the last 163 years,
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在過去一百六十三年間，
02:17
dozens of astronomers have used
some sort of alleged orbital discrepancy
some sort of alleged orbital discrepancy
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有數十位天文學家用了
某種他們宣稱的不一致，
02:23
to predict the existence
of some new planet in the solar system.
of some new planet in the solar system.
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來預測有某個新的行星
存在於太陽系中。
存在於太陽系中。
02:28
They have always been wrong.
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他們全錯了。
02:32
The most famous
of these erroneous predictions
of these erroneous predictions
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這些錯誤預測中最有名的
是帕西瓦爾 · 羅威爾的預測，
是帕西瓦爾 · 羅威爾的預測，
02:34
came from Percival Lowell,
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02:35
who was convinced that there must be
a planet just beyond Uranus and Neptune,
a planet just beyond Uranus and Neptune,
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他深信在天王星和海王星之外
一定還有一個行星
一定還有一個行星
02:40
messing with those orbits.
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影響那些軌道。
02:42
And so when Pluto was discovered in 1930
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所以，1930 年羅威爾
天文台發現冥王星時，
天文台發現冥王星時，
02:45
at the Lowell Observatory,
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02:46
everybody assumed that it must be
the planet that Lowell had predicted.
the planet that Lowell had predicted.
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大家都假設它一定是
羅威爾預測的那個行星。
羅威爾預測的那個行星。
02:51
They were wrong.
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他們錯了。
02:53
It turns out, Uranus and Neptune
are exactly where they're supposed to be.
are exactly where they're supposed to be.
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結果發現，天王星和海王星的位置
就是它們應該在的位置。
就是它們應該在的位置。
02:57
It took 100 years,
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花了一百年的時間，
02:59
but Bouvard was eventually right.
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才證明布瓦爾是對的。
03:01
Astronomers needed to do
better measurements.
better measurements.
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天文學家的確需要
把測量做得更好。
把測量做得更好。
03:04
And when they did,
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當他們真的做到時，
03:06
those better measurements
had turned out that
had turned out that
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那些更好的測量證明了
03:09
there is no planet just beyond
the orbit of Uranus and Neptune
the orbit of Uranus and Neptune
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並沒有其他行星在天王星
和海王星的軌道之外，
和海王星的軌道之外，
03:14
and Pluto is thousands of times too small
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冥王星至少還要再大數千倍
03:17
to have any effect on those orbits at all.
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才有可能影響到那些軌道。
03:20
So even though Pluto
turned out not to be the planet
turned out not to be the planet
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所以，雖然後來發現冥王星
並不是原來所想的那個行星，
03:23
it was originally thought to be,
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但這是第一次發現
我們現在所知的現象：
我們現在所知的現象：
03:25
it was the first discovery
of what is now known to be
of what is now known to be
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03:28
thousands of tiny, icy objects
in orbit beyond the planets.
in orbit beyond the planets.
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在行星之外的軌道上
有數以千計的小型、結冰天體。
有數以千計的小型、結冰天體。
03:33
Here you can see the orbits of Jupiter,
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各位在這裡所看到的是木星、
土星、天王星，和海王星的軌道，
03:36
Saturn, Uranus and Neptune,
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03:39
and in that little circle
in the very center is the Earth
in the very center is the Earth
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地球則是在中間的小圓圈裡，
03:42
and the Sun and almost everything
that you know and love.
that you know and love.
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那圓圈裡還有太陽
及你所知和所愛的一切。
及你所知和所愛的一切。
03:45
And those yellow circles at the edge
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邊緣上的黃色圓圈
03:47
are these icy bodies
out beyond the planets.
out beyond the planets.
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就是在行星之外的結冰體。
03:49
These icy bodies are pushed and pulled
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這些結冰體會被行星的
重力場給推開或拉近，
重力場給推開或拉近，
03:52
by the gravitational fields of the planets
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03:54
in entirely predictable ways.
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這些移動是完全可以預測的。
03:56
Everything goes around the Sun
exactly the way it is supposed to.
exactly the way it is supposed to.
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繞行太陽的所有東西都完全
依照它們應該的方式在繞行。
依照它們應該的方式在繞行。
幾乎是所有東西。
04:02
Almost.
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04:04
So in 2003,
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2003 年，
04:06
I discovered what was at the time
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我發現了當時
04:08
the most distant known object
in the entire solar system.
in the entire solar system.
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在太陽系中最遙遠的已知天體。
很難不看著遠方那孤獨的
天體，然後說，當然，
天體，然後說，當然，
04:11
It's hard not to look
at that lonely body out there
at that lonely body out there
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04:14
and say, oh yeah, sure,
so Lowell was wrong,
so Lowell was wrong,
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羅威爾錯了，海王星
之外沒有其他行星，
之外沒有其他行星，
04:16
there was no planet just beyond Neptune,
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但這個，這可能是一個新的行星。
04:18
but this, this could be a new planet.
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04:21
The real question we had was,
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我們真正要問的是，它繞行
太陽時走的是什麼軌道？
太陽時走的是什麼軌道？
04:22
what kind of orbit
does it have around the Sun?
does it have around the Sun?
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它是否像行星一樣走圓形的軌道？
04:24
Does it go in a circle around the Sun
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04:26
like a planet should?
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04:28
Or is it just a typical member
of this icy belt of bodies
of this icy belt of bodies
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或者它只是這結冰體
所形成的冰帶中的一員，
所形成的冰帶中的一員，
04:32
that got a little bit tossed outward
and it's now on its way back in?
and it's now on its way back in?
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先前被稍微向外拋出來，
現在它只是在回家的路上？
現在它只是在回家的路上？
04:36
This is precisely the question
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兩百年前在研究天王星時，
04:39
the astronomers were trying
to answer about Uranus 200 years ago.
to answer about Uranus 200 years ago.
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天文學家努力想要解答的
也正是這個問題。
也正是這個問題。
04:43
They did it by using
overlooked observations of Uranus
overlooked observations of Uranus
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在發現它的九十一年前，
有許多被忽略的觀察資料，
有許多被忽略的觀察資料，
04:47
from 91 years before its discovery
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他們的做法就是使用這些資料
04:49
to figure out its entire orbit.
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來推測出它的整個軌道。
04:51
We couldn't go quite that far back,
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我們沒有用到那麼早的資料，
04:53
but we did find observations
of our object from 13 years earlier
of our object from 13 years earlier
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但我們確實發現，十三年前
就有這個天體的觀察資料，
就有這個天體的觀察資料，
04:58
that allowed us to figure out
how it went around the Sun.
how it went around the Sun.
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讓我們能想出它如何繞行太陽。
所以，問題是：
05:00
So the question is,
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它和行星一樣
沿著圓形的軌道繞行太陽？
沿著圓形的軌道繞行太陽？
05:02
is it in a circular orbit
around the Sun, like a planet,
around the Sun, like a planet,
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05:04
or is it on its way back in,
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或者它和那些結冰體
一樣是在回程途中？
一樣是在回程途中？
05:06
like one of these typical icy bodies?
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05:08
And the answer is
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答案是，
05:10
no.
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皆非。
05:11
It has a massively elongated orbit
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它有個非常巨大的細長軌道，
05:14
that takes 10,000 years
to go around the Sun.
to go around the Sun.
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繞行太陽一圓要花一萬年。
我們將這個天體命名為賽德娜，
伊努伊特海洋女神的名字，
伊努伊特海洋女神的名字，
05:18
We named this object Sedna
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05:20
after the Inuit goddess of the sea,
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05:21
in honor of the cold, icy places
where it spends all of its time.
where it spends all of its time.
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它一生都在冰凍的環境中，
這個名字也是在對這項特點致敬。
這個名字也是在對這項特點致敬。
05:26
We now know that Sedna,
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現在，我們知道賽德娜的體積
約是冥王星的三分之一，
約是冥王星的三分之一，
05:27
it's about a third the size of Pluto
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05:29
and it's a relatively typical member
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它是海王星之外的那些結冰體中，
相對比較典型的一個。
相對比較典型的一個。
05:31
of those icy bodies out beyond Neptune.
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05:34
Relatively typical,
except for this bizarre orbit.
except for this bizarre orbit.
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相對比較典型，
但不包括它的怪異軌道。
但不包括它的怪異軌道。
05:38
You might look at this orbit and say,
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你可能會看著這個軌道，說：
「繞行太陽要一萬年是很怪異。」
「繞行太陽要一萬年是很怪異。」
05:40
"Yeah, that's bizarre,
10,000 years to go around the Sun,"
10,000 years to go around the Sun,"
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但那還不是怪異的部分。
05:42
but that's not really the bizarre part.
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怪異的是，在那一萬年中，
05:44
The bizarre part is
that in those 10,000 years,
that in those 10,000 years,
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賽德娜完全不會接近
太陽系中的任何其他東西。
太陽系中的任何其他東西。
05:46
Sedna never comes close
to anything else in the solar system.
to anything else in the solar system.
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05:50
Even at its closest approach to the Sun,
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即使在它離太陽最近的點，
05:53
Sedna is further from Neptune
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賽德娜和海王星的距離
也比海王星和地球的距離更遠。
也比海王星和地球的距離更遠。
05:55
than Neptune is from the Earth.
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05:59
If Sedna had had an orbit like this,
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如果賽德娜有這樣的軌道，
06:01
that kisses the orbit of Neptune
once around the Sun,
once around the Sun,
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繞行太陽一圈就會
和海王星的軌道接觸一次，
和海王星的軌道接觸一次，
06:03
that would have actually been
really easy to explain.
really easy to explain.
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那就會很容易解釋了。
06:06
That would have just been an object
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那就只是在結冰體的區域中
06:08
that had been in
a circular orbit around the Sun
a circular orbit around the Sun
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以圓形軌道繞行太陽的天體，
06:10
in that region of icy bodies,
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有一次太靠近海王星，
06:12
had gotten a little bit
too close to Neptune one time,
too close to Neptune one time,
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因此被彈出去，
現在正在返回的途中。
現在正在返回的途中。
06:14
and then got slingshot out
and is now on its way back in.
and is now on its way back in.
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06:19
But Sedna never comes close
to anything known in the solar system
to anything known in the solar system
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但賽德娜從未接近過
太陽系中的任何已知的東西，
太陽系中的任何已知的東西，
06:24
that could have given it that slingshot.
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不可能造成那樣的彈射。
06:26
Neptune can't be responsible,
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不會是海王星造成的，
06:28
but something had to be responsible.
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但總是有成因。
06:31
This was the first time since 1845
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那是 1845 年之後第一次
06:34
that we saw the gravitational effects
of something in the outer solar system
of something in the outer solar system
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我們看到了在外太陽系的
某樣東西產生引力效應，
某樣東西產生引力效應，
06:39
and didn't know what it was.
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卻不知道它是什麼。
06:42
I actually thought I knew
what the answer was.
what the answer was.
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我曾經以為我知道答案。
的確，
06:45
Sure, it could have been
some distant, giant planet
some distant, giant planet
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它有可能是外太陽系
一個很遙遠、巨大的行星，
一個很遙遠、巨大的行星，
06:49
in the outer solar system,
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但，在這個情況中，
這個想法很荒謬，
這個想法很荒謬，
06:50
but by this time,
that idea was so ridiculous
that idea was so ridiculous
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06:52
and had been so thoroughly discredited
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且完全不足採信，
所以我並沒有認真看待它。
所以我並沒有認真看待它。
06:54
that I didn't take it very seriously.
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但，四十五億年前，
06:56
But 4.5 billion years ago,
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06:57
when the Sun formed in a cocoon
of hundreds of other stars,
of hundreds of other stars,
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當太陽在數百個其他
天體的包裹之中形成時，
天體的包裹之中形成時，
07:02
any one of those stars
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那些天體中的任何一個
都有可能太靠近賽德娜，
都有可能太靠近賽德娜，
07:04
could have gotten
just a little bit too close to Sedna
just a little bit too close to Sedna
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07:06
and perturbed it onto the orbit
that it has today.
that it has today.
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影響它，讓它進入
現今的這個軌道中。
現今的這個軌道中。
07:10
When that cluster of stars
dissipated into the galaxy,
dissipated into the galaxy,
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當那群天體消散在銀河中，
07:14
the orbit of Sedna would have been
left as a fossil record
left as a fossil record
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賽德娜的軌道應該會變成
太陽最早歷史中的化石記錄。
07:18
of this earliest history of the Sun.
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07:20
I was so excited by this idea,
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這個想法讓我好興奮，
07:22
by the idea that we could look
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這表示我們可以去研究
太陽誕生的化石歷史，
太陽誕生的化石歷史，
07:24
at the fossil history
of the birth of the Sun,
of the birth of the Sun,
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因此我用接下來十年的時間，
去尋找更多軌道像賽德娜的天體。
去尋找更多軌道像賽德娜的天體。
07:26
that I spent the next decade
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07:28
looking for more objects
with orbits like Sedna.
with orbits like Sedna.
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07:30
In that ten-year period, I found zero.
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在那十年間，我一個也沒找到。
07:34
(Laughter)
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（笑聲）
07:35
But my colleagues, Chad Trujillo
and Scott Sheppard, did a better job,
and Scott Sheppard, did a better job,
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但我的同事，查德 · 楚基羅
及史考特 · 雪柏都做得比我好，
及史考特 · 雪柏都做得比我好，
07:38
and they have now found several objects
with orbits like Sedna,
with orbits like Sedna,
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他們現在已經找到了好幾個
軌道類似賽德娜的天體，
軌道類似賽德娜的天體，
07:41
which is super exciting.
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超級讓人興奮。
07:43
But what's even more interesting
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但，更有趣的是，
07:45
is that they found that all these objects
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他們發現，所有這些天體
07:48
are not only on these distant,
elongated orbits,
elongated orbits,
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不僅是在遙遠、細長的軌道上運行，
07:51
they also share a common value
of this obscure orbital parameter
of this obscure orbital parameter
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它們複雜的軌道參數都有相同的值，
07:57
that in celestial mechanics we call
argument of perihelion.
argument of perihelion.
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在天體力學中，我們把這個
參數稱為「近日點輻角」。
參數稱為「近日點輻角」。
當他們發現這些近日點輻角
都差不多時，馬上手舞足蹈，
都差不多時，馬上手舞足蹈，
08:02
When they realized it was clustered
in argument of perihelion,
in argument of perihelion,
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08:05
they immediately jumped up and down,
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認為一定有個遙遠、
巨大的行星存在，
巨大的行星存在，
08:07
saying it must be caused
by a distant, giant planet out there,
by a distant, giant planet out there,
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這真的很讓人興奮，
只是，完全不合理。
只是，完全不合理。
08:10
which is really exciting,
except it makes no sense at all.
except it makes no sense at all.
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08:13
Let me try to explain it
to you why with an analogy.
to you why with an analogy.
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讓我試著用比喻來解釋為什麼。
08:15
Imagine a person walking down a plaza
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想像一個人走在一個廣場上，
08:18
and looking 45 degrees to his right side.
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看向他的右邊四十五度方向。
08:23
There's a lot of reasons
that might happen,
that might happen,
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可能有很多理由，
超容易解釋，沒什麼。
超容易解釋，沒什麼。
08:25
it's super easy to explain, no big deal.
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現在，想像很多不同的人，
08:27
Imagine now many different people,
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08:29
all walking in different
directions across the plaza,
directions across the plaza,
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都在廣場上朝不同的方向行走，
08:32
but all looking 45 degrees
to the direction that they're moving.
to the direction that they're moving.
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但都看向他們行進
方向的四十五度。
方向的四十五度。
08:36
Everybody's moving
in different directions,
in different directions,
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2018
大家行進的方向不同，
08:38
everybody's looking
in different directions,
in different directions,
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大家都看向不同的方向，
但他們看的都是
行進方向的四十五度。
行進方向的四十五度。
08:40
but they're all looking 45 degrees
to the direction of motion.
to the direction of motion.
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08:43
What could cause something like that?
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這種現象背後的成因會是什麼？
08:46
I have no idea.
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我不知道。
08:48
It's very difficult to think of any reason
that that would happen.
that that would happen.
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很難想出任何理由
會造成這種現象。
會造成這種現象。
08:51
(Laughter)
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（笑聲）
08:53
And this is essentially
what that clustering
what that clustering
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基本上，這就是一堆
相近的近日點輻角
相近的近日點輻角
08:56
in argument of perihelion was telling us.
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告訴我們的事。
08:59
Scientists were generally baffled
and they assumed it must just be a fluke
and they assumed it must just be a fluke
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科學家很受挫，
他們認為一定是僥倖
及不佳的觀察值造成。
及不佳的觀察值造成。
09:03
and some bad observations.
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09:04
They told the astronomers,
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他們告訴天文學家：
09:06
"Do better measurements."
194
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「把測量做更好一點。」
09:08
I actually took a very careful look
at those measurements, though,
at those measurements, though,
195
536792
3101
不過，我非常仔細地研究過
這些測量值，它們是對的。
這些測量值，它們是對的。
09:11
and they were right.
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這些天體真的都有同樣的
09:13
These objects really did all share
197
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09:15
a common value of argument of perihelion,
198
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近日點輻角值，
09:17
and they shouldn't.
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但不應該如此。
09:19
Something had to be causing that.
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547042
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背後一定有原因。
09:23
The final piece of the puzzle
came into place in 2016,
came into place in 2016,
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拼圖的最後一片在 2016 年出現，
09:27
when my colleague, Konstantin Batygin,
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康斯坦丁 · 巴蒂金是我的同事，
09:30
who works three doors down from me, and I
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他的辦公室就在附近，
我明白，大家都受挫的原因
09:32
realized that the reason
that everybody was baffled
that everybody was baffled
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09:35
was because argument of perihelion
was only part of the story.
was only part of the story.
205
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4726
是因為近日點輻角
只是故事的一部分。
只是故事的一部分。
09:40
If you look at these
objects the right way,
objects the right way,
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如果用對的方式來看這些天體，
它們在太空中排成一排，
朝向同樣的方向，
朝向同樣的方向，
09:42
they are all actually lined up
in space in the same direction,
in space in the same direction,
207
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09:46
and they're all tilted in space
in the same direction.
in the same direction.
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它們在太空中，
都朝同樣的方向傾斜。
都朝同樣的方向傾斜。
09:49
It's as if all those people on the plaza
are all walking in the same direction
are all walking in the same direction
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那就好像在廣場上的那些人
都朝同樣的方向行進，
都朝同樣的方向行進，
09:54
and they're all looking
45 degrees to the right side.
45 degrees to the right side.
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且都看向右邊四十五度。
09:57
That's easy to explain.
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那就很容易解釋。
他們都在看某樣東西。
他們都在看某樣東西。
09:59
They're all looking at something.
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10:01
These objects in the outer solar system
are all reacting to something.
are all reacting to something.
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在外太陽系的這些天體
都受到某樣東西影響。
都受到某樣東西影響。
10:07
But what?
214
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但，那東西是什麼？
10:08
Konstantin and I spent a year
215
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康斯坦丁和我花了一年時間，
10:11
trying to come up with any explanation
other than a distant, giant planet
other than a distant, giant planet
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599750
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想要找出一個不同的解釋，
不是在外太陽系中有個
遙遠、巨大的行星。
遙遠、巨大的行星。
10:16
in the outer solar system.
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10:17
We did not want to be the 33rd and 34th
people in history to propose this planet
people in history to propose this planet
218
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我們並不想要成為
第三十四及三十五位
第三十四及三十五位
提出這個行星存在
又被告知弄錯了的人。
又被告知弄錯了的人。
10:23
to yet again be told we were wrong.
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10:26
But after a year,
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但，一年後，
10:28
there was really no choice.
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真的沒別的選擇。
我們想不出其他解釋，
我們想不出其他解釋，
10:29
We could come up with no other explanation
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10:32
other than that there is a distant,
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唯一的可能就是有個
遙遠、巨大的行星，
遙遠、巨大的行星，
10:34
massive planet on an elongated orbit,
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沿著細長的軌道運行，
傾斜向這個太陽系的其他部分，
10:37
inclined to the rest of the solar system,
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10:40
that is forcing these patterns
for these objects
for these objects
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迫使形成這些外太陽系天體的模式。
10:42
in the outer solar system.
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10:44
Guess what else a planet like this does.
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猜猜這樣的行星還會做什麼？
10:46
Remember that strange orbit of Sedna,
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記得賽德娜的奇特軌道嗎？
10:48
how it was kind of pulled away
from the Sun in one direction?
from the Sun in one direction?
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它好像是被拉離太陽
朝向一個方向行進。
朝向一個方向行進。
這樣的行星會一直產生那樣的軌道。
10:51
A planet like this would make
orbits like that all day long.
orbits like that all day long.
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10:55
We knew we were onto something.
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我們知道我們有些眉目了。
10:57
So this brings us to today.
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這就把我們帶到現今。
11:00
We are basically 1845, Paris.
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基本上，我們是 1845 年的巴黎。
11:05
(Laughter)
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（笑聲）
11:06
We see the gravitational effects
of a distant, giant planet,
of a distant, giant planet,
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我們看到遙遠、巨大的行星
造成的引力效應，
造成的引力效應，
11:11
and we are trying to work out
the calculations
the calculations
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於是我們試著計算出往哪裡尋找，
11:13
to tell us where to look,
to point our telescopes,
to point our telescopes,
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把望遠鏡轉向哪個方向，
才能找到這個行星。
才能找到這個行星。
11:16
to find this planet.
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11:18
We've done massive suites
of computer simulations,
of computer simulations,
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我們做過大量的電腦模擬，
11:21
massive months of analytic calculations
241
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投入無數個月做分析計算，
11:23
and here's what I can tell you so far.
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目前，我能告訴各位的是：
11:25
First, this planet,
which we call Planet Nine,
which we call Planet Nine,
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3185
第一，我們把這個行星
稱為第九行星，
稱為第九行星，
11:29
because that's what it is,
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2583
因為它就是第九個，
11:32
Planet Nine is six times
the mass of the Earth.
the mass of the Earth.
245
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第九行星的質量是地球的六倍。
11:36
This is no slightly-smaller-than-Pluto,
246
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2226
這並非「它比冥王星小一點，
還要爭論它是不是行星」的情形。
還要爭論它是不是行星」的情形。
11:38
let's-all-argue-about-
whether-it's-a-planet-or-not thing.
whether-it's-a-planet-or-not thing.
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這是我們整個太陽系中
第五大的行星。
第五大的行星。
11:41
This is the fifth largest planet
in our entire solar system.
in our entire solar system.
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11:44
For context, let me show you
the sizes of the planets.
the sizes of the planets.
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為了說明起見，先讓各位
看一下這些行星的大小。
看一下這些行星的大小。
11:48
In the back there,
you can the massive Jupiter and Saturn.
you can the massive Jupiter and Saturn.
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4142
在後面，可以看到
巨大的木星和土星。
巨大的木星和土星。
11:52
Next to them, a little bit smaller,
Uranus and Neptune.
Uranus and Neptune.
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在它們旁邊的是天王星
和海王星，比較小一點。
和海王星，比較小一點。
11:54
Up in the corner, the terrestrial planets,
Mercury, Venus, Earth and Mars.
Mercury, Venus, Earth and Mars.
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在上面角落的是類地行星，
水星、金星、地球、火星。
水星、金星、地球、火星。
11:58
You can even see that belt
253
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甚至可以看到海王星外面的
結冰體帶，冥王星也是其中一員，
結冰體帶，冥王星也是其中一員，
11:59
of icy bodies beyond Neptune,
of which Pluto is a member,
of which Pluto is a member,
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12:02
good luck figuring out which one it is.
255
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猜猜是哪一個，祝好運。
12:04
And here is Planet Nine.
256
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2416
這是第九行星。
12:08
Planet Nine is big.
257
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第九行星很大。
12:11
Planet Nine is so big,
258
719042
1267
第九行星大到你應該要納悶
我們為什麼還沒找到它。
我們為什麼還沒找到它。
12:12
you should probably wonder
why haven't we found it yet.
why haven't we found it yet.
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12:14
Well, Planet Nine is big,
260
722958
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嗯，第九行星很大，
但它也非常非常遠。
但它也非常非常遠。
12:16
but it's also really, really far away.
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2101
12:18
It's something like
15 times further away than Neptune.
15 times further away than Neptune.
262
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4684
它的所在可能比海王星
還要遠十五倍。
還要遠十五倍。
12:23
And that makes it about 50,000 times
fainter than Neptune.
fainter than Neptune.
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那就表示它比海王星
還要微弱五萬倍。
還要微弱五萬倍。
12:26
And also, the sky is a really big place.
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此外，天空真的很大。
12:29
We've narrowed down where we think it is
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我們已經把它可能的所在範圍縮小
成天空中相對很小的一塊區域，
成天空中相對很小的一塊區域，
12:31
to a relatively small area of the sky,
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12:34
but it would still take us years
267
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但我們仍然要花數年的時間
12:35
to systematically cover
the area of the sky
the area of the sky
268
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才能系統性地找完
天空中的那個區域，
天空中的那個區域，
12:38
with the large telescopes that we need
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還得使用很大的望遠鏡
才能夠看到那麼遙遠、
那麼微弱的行星。
那麼微弱的行星。
12:40
to see something that's
this far away and this faint.
this far away and this faint.
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幸運的是，我們可能不用這麼做。
12:43
Luckily, we might not have to.
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就像布瓦爾使用
12:46
Just like Bouvard used
unrecognized observations of Uranus
unrecognized observations of Uranus
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當時仍未被發現的天王星
12:51
from 91 years before its discovery,
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之前 91 年的資料，
12:54
I bet that there are unrecognized images
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我敢說一定有些未被承認的影像
12:58
that show the location of Planet Nine.
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可以顯示出第九行星的位置。
13:02
It's going to be a massive
computational undertaking
computational undertaking
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這勢必要用到非常大量的計算，
13:05
to go through all of the old data
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才能分析完所有的舊資料，
13:07
and pick out that one faint moving planet.
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並挑出那一個微弱的移動行星。
13:11
But we're underway.
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但我們在進行了。
我認為我們快成功了。
13:12
And I think we're getting close.
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13:15
So I would say, get ready.
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所以，我要說的是，準備好。
13:17
We are not going to match Le Verrier's
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我們比不上勒維耶的
「做一個預測，
13:21
"make a prediction,
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13:22
have the planet found in a single night
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一個晚上就在離預測位置
不遠處找到行星」的記錄。
不遠處找到行星」的記錄。
13:24
that close to where
you predicted it" record.
you predicted it" record.
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13:26
But I do bet that within
the next couple of years
the next couple of years
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但我敢說，在接下來幾年內，
13:30
some astronomer somewhere
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某地的某個天文學家
13:33
will find a faint point of light,
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會發現有一個微弱的光點
13:35
slowly moving across the sky
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緩慢地在天空中移動，
13:37
and triumphantly announce
the discovery of a new,
the discovery of a new,
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並洋洋得意地宣佈
他真的在我們的太陽系中
他真的在我們的太陽系中
13:41
and quite possibly not the last,
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發現了一個新的行星，
且很可能還有其他的行星存在。
且很可能還有其他的行星存在。
13:43
real planet of our solar system.
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13:46
Thank you.
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謝謝。
13:47
(Applause)
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（掌聲）
ABOUT THE SPEAKER
Mike Brown - Planetary astronomerMike Brown scans the skies searching for and intensely studying distant bodies in our solar system in the hope of gaining insight into how our planet and the planets around it came to be.
Why you should listen
Mike Brown has discovered dozens of dwarf planets (and demoted one object from planet to dwarf planet) and is currently hot on the trail of Planet Nine -- a hypothesized body that is possibly the fifth largest planet of our solar system.
Brown is the Richard and Barbara Rosenberg Professor of Planetary Astronomy at the California Institute of Technology and has been on the faculty there since 1996. He has won many awards and honors for his scholarship, including the Urey Prize for best young planetary scientist from the American Astronomical Society's Division of Planetary Sciences; a Presidential Early Career Award; a Sloan Fellowship; the 2012 Kavli Prize in Astrophysics; and, of course, the one that started his career, an honorable mention in his fifth-grade science fair. He was inducted into the National Academy of Science in 2014. He was also named one of Wired Online's Top Ten Sexiest Geeks in 2006, the mention of which never ceases to make his wife laugh.
Brown received his AB from Princeton in 1987 and his MA and PhD from University of California, Berkeley, in 1990 and 1994, respectively. He is the author of How I Killed Pluto and Why It Had It Coming, a memoir of the discoveries leading to the demotion of Pluto.
Mike Brown | Speaker | TED.com