04:25
TEDGlobal 2011

Lucianne Walkowicz: Finding planets around other stars

ルシアン・ウォーコウィッチ:太陽系の外にある惑星を探す

Filmed:

他の恒星の周りにある惑星、しかも居住可能な惑星をどうやって見つけるのか?惑星が恒星の前を通過するとき恒星の光がわずかに弱まる現象を探すことによって、TEDフェローのルシアン・ウォーコウィッチが携わるケプラー計画では1,200あまりの新たな惑星系の候補が見つけられています。今までになかった手法で、生命が存在し得る環境を持つ惑星さえ見つけることができるかもしれません。

- Stellar astronomer
Lucianne Walkowicz works on NASA's Kepler mission, studying starspots and "the tempestuous tantrums of stellar flares." Full bio

Planetary systems outside our own
太陽系外にある他の惑星系は
00:15
are like distant cities whose lights we can see twinkling,
灯りは見えても そこまで行くことはできない
00:17
but whose streets we can't walk.
遠くの街のようなものです
00:20
By studying those twinkling lights though,
でも灯りの瞬きを調査すれば
00:23
we can learn about how stars and planets interact
恒星と惑星がどう関係し合い 独自の環境を形成し
00:25
to form their own ecosystem
生命が存在できる場を
00:28
and make habitats that are amenable to life.
作るのか知ることができます
00:30
In this image of the Tokyo skyline,
この東京の夜景写真には
00:33
I've hidden data
最新の宇宙望遠鏡で惑星探査を行う
00:35
from the newest planet-hunting space telescope on the block,
ケプラー計画の
00:37
the Kepler Mission.
データが隠してあります
00:39
Can you see it?
どこか分かりますか?
00:41
There we go.
ここです
00:43
This is just a tiny part of the sky the Kepler stares at,
これはケプラーが観測している宇宙の片隅です
00:45
where it searches for planets
この領域で15万個以上の
00:48
by measuring the light from over 150,000 stars,
恒星の光を測定し 惑星を探しています
00:50
all at once, every half hour,
30分ごとに一斉に
00:53
and very precisely.
精密な測定を行います
00:55
And what we're looking for
探しているのは
00:57
is the tiny dimming of light
わずかな光の弱まりです
00:59
that is caused by a planet passing in front of one of these stars
惑星が前を通るときに恒星の光がわずかに遮られ
01:01
and blocking some of that starlight from getting to us.
私たちに届く光が弱くなるのです
01:04
In just over two years of operations,
稼働して2年あまりで
01:07
we've found over 1,200
他の恒星を中心とする
01:10
potential new planetary systems around other stars.
惑星系の候補が 新たに1,200以上見つかりました
01:12
To give you some perspective,
これに比べると
01:15
in the previous two decades of searching,
ケプラー以前の20年間の探査で
01:17
we had only known about 400
見つかったのは
01:20
prior to Kepler.
わずか400個たらずです
01:22
When we see these little dips in the light,
このかすかな光の弱まりの観察から
01:24
we can determine a number of things.
いくつものことが判断できます
01:26
For one thing, we can determine that there's a planet there,
例えば そこに惑星があること
01:28
but also how big that planet is
また その惑星がどのくらい大きいか
01:30
and how far it is away from its parent star.
恒星からどのくらい離れているかも分かります
01:33
That distance is really important
この距離は非常に重要です
01:36
because it tells us
その惑星が全体的にどの程度の光を
01:38
how much light the planet receives overall.
浴びているか分かるからです
01:40
And that distance and knowing that amount of light is important
距離と光の量を知るのが重要な理由は
01:42
because it's a little like you or I sitting around a campfire:
例えばキャンプで焚き火を囲んでいるとき
01:45
You want to be close enough to the campfire so that you're warm,
暖まるために火に近づきたい一方
01:48
but not so close
近づきすぎて熱くなったり
01:50
that you're too toasty and you get burned.
火傷したくはないのと同じです
01:52
However, there's more to know about your parent star
でも恒星については 全体的に受ける光の量以外にも
01:54
than just how much light you receive overall.
知るべきことがあります
01:57
And I'll tell you why.
理由をお見せしましょう
01:59
This is our star. This is our Sun.
これは私たちの恒星である太陽です
02:01
It's shown here in visible light.
可視光線で見た様子です
02:04
That's the light that you can see with your own human eyes.
人間の目で見える光です
02:06
You'll notice that it looks pretty much
図像として描かれる黄色い球体と
02:08
like the iconic yellow ball --
ほぼ同じに見えます
02:10
that Sun that we all draw when we're children.
子供の頃に描いた太陽です
02:12
But you'll notice something else,
でも もう1つ気づくのは
02:14
and that's that the face of the Sun
太陽の表面に
02:16
has freckles.
斑点があることです
02:18
These freckles are called sunspots,
この斑点は太陽黒点と呼ばれ
02:20
and they are just one of the manifestations
太陽の磁場活動の
02:22
of the Sun's magnetic field.
現れの1つです
02:24
They also cause the light from the star to vary.
これによっても恒星からの光は変わります
02:26
And we can measure this
ケプラーはこの観測を
02:29
very, very precisely with Kepler and trace their effects.
非常に精密に行って その影響を追跡できます
02:31
However, these are just the tip of the iceberg.
しかしこれも氷山の一角に過ぎません
02:34
If we had UV eyes or X-ray eyes,
人間が紫外線やX線で見ることができたら
02:37
we would really see
私たちは太陽磁場活動の
02:40
the dynamic and dramatic effects
ダイナミックで劇的な様子を
02:42
of our Sun's magnetic activity --
目の当たりにしているはずです
02:44
the kind of thing that happens on other stars as well.
これは他の恒星でも起きていることです
02:46
Just think, even when it's cloudy outside,
たとえ外が曇っていても
02:49
these kind of events are happening
このような事象は空の上で
02:51
in the sky above you all the time.
常に起こっているのです
02:53
So when we want to learn whether a planet is habitable,
ですから惑星が居住可能か 生命が存在しうるか
02:57
whether it might be amenable to life,
調べたいときには
03:00
we want to know not only how much total light it receives
その惑星が総合的に受ける光の量や
03:02
and how warm it is,
暖かさだけでなく
03:04
but we want to know about its space weather --
その宇宙の「天気」についても知りたいのです
03:06
this high-energy radiation,
高エネルギー放射線や
03:09
the UV and the X-rays
紫外線やX線が
03:11
that are created by its star
恒星から発せられて
03:13
and that bathe it in this bath of high-energy radiation.
惑星に降り注ぎます
03:15
And so, we can't really look
他の恒星の
03:18
at planets around other stars
周りにある惑星を
03:20
in the same kind of detail
太陽系にある惑星と
03:22
that we can look at planets in our own solar system.
同じように詳細に見ることはできません
03:24
I'm showing here Venus, Earth and Mars --
こちらは金星 地球 火星
03:27
three planets in our own solar system that are roughly the same size,
太陽系にある大きさの似た3つの惑星です
03:29
but only one of which
でもこの中で生命の営みに
03:32
is really a good place to live.
適しているのは1つだけです
03:34
But what we can do in the meantime
とりあえず私たちにできるのは
03:36
is measure the light from our stars
恒星の光を測定し
03:38
and learn about this relationship
恒星と惑星の
03:41
between the planets and their parent stars
関係について学ぶことです
03:43
to suss out clues
そして宇宙にあるどの惑星が
03:45
about which planets might be good places
生命を探すのに適した場所か
03:47
to look for life in the universe.
手がかりを検討することです
03:49
Kepler won't find a planet
ケプラーは観測する全ての恒星の周りで
03:51
around every single star it looks at.
惑星を見つけるわけではありません
03:53
But really, every measurement it makes
でも1つひとつの観測結果は
03:55
is precious,
本当に貴重なのです
03:57
because it's teaching us about the relationship
恒星と惑星の関係や
03:59
between stars and planets,
宇宙で生命が形成される
04:01
and how it's really the starlight
状態を作るのは
04:03
that sets the stage
恒星の光であることを
04:05
for the formation of life in the universe.
教えてくれるからです
04:07
While it's Kepler the telescope, the instrument that stares,
観測しているのはケプラー望遠鏡という機械ですが
04:09
it's we, life, who are searching.
探索をするのは私たち命あるものなのです
04:12
Thank you.
ありがとうございました
04:15
(Applause)
(拍手)
04:17
Translated by Sawa Horibe
Reviewed by Yasushi Aoki

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About the Speaker:

Lucianne Walkowicz - Stellar astronomer
Lucianne Walkowicz works on NASA's Kepler mission, studying starspots and "the tempestuous tantrums of stellar flares."

Why you should listen

Lucianne Walkowicz is an Astronomer at the Adler Planetarium in Chicago. She studies stellar magnetic activity and how stars influence a planet's suitability as a host for alien life. She is also an artist and works in a variety of media, from oil paint to sound. She got her taste for astronomy as an undergrad at Johns Hopkins, testing detectors for the Hubble Space Telescope’s new camera (installed in 2002). She also learned to love the dark stellar denizens of our galaxy, the red dwarfs, which became the topic of her PhD dissertation at University of Washington. Nowadays, she works on NASA’s Kepler mission, studying starspots and the tempestuous tantrums of stellar flares to understand stellar magnetic fields. She is particularly interested in how the high energy radiation from stars influences the habitability of planets around alien suns. Lucianne is also a leader in the Large Synoptic Survey Telescope, a new project that will scan the sky every night for 10 years to create a huge cosmic movie of our Universe.

More profile about the speaker
Lucianne Walkowicz | Speaker | TED.com