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Lucianne Walkowicz 談尋找繞著其他恆星運轉的行星

Lucianne Walkowicz: Finding planets around other stars

 

Photo of three lions hunting on the Serengeti.

講者:Lucianne Walkowicz

2011年7月演講,2011年8月在TEDGlobal 2011上線

 

翻譯:洪曉慧

編輯:朱學恆

簡繁轉換:洪曉慧

後製:洪曉慧

字幕影片後制:謝旻均

 

影片請按此下載

MAC及手持裝置版本請按此下載

閱讀中文字幕純文字版本

 

關於這場演講

我們如何尋找繞著其他恆星運轉(甚至適合居住)的行星?藉著觀察行星經過其母星前方時,導致母星亮度稍稍變暗的現象,TED會員Lucianne Walkowicz和克卜勒任務已發現大約1200個潛在的新行星系統。隨著新技術的發展,人們甚至可能發現擁有適合生命發展條件的行星。

 

關於Lucianne Walkowicz

Lucianne Walkowicz在美國航空暨太空總署(NASA)進行克卜勒任務,研究黑子及「如暴風雨般劇烈噴發的恆星耀斑」。

 

為什麼要聽她演講

Lucianne Walkowicz研究恆星各種高深莫測的面貌,尋找與其核心內部運作情形有關的線索。她於約翰霍普金斯大學就讀時,發現自己對天文學的興趣,並為哈伯太空望遠鏡新相機(於2002年裝設)的探測器進行測試。她相當喜愛銀河系中的黯淡恆星-紅矮星,並將其當作她在華盛頓大學的博士論文題目。她目前在美國航空暨太空總署(NASA)進行克卜勒任務,研究黑子及如暴風雨般劇烈噴發的恆星耀斑,以瞭解恆星的磁場。她特別感興趣的是,來自恆星的高能輻射,對環繞在其四周的行星是否適合居住來說,會造成什麼影響。Lucianne也是大型綜合巡天望遠鏡這個新計畫的領導者;在為期10年的時間裡,大型綜合巡天望遠鏡每晚都會掃描天空,製作出以我們宇宙為主角的大規模宇宙電影。

 

「Walkowicz的計畫也致力於瞭解暗能量的性質(「我們將著手尋找我們並不瞭解的東西」)... ...」

-David Rowan,《連線》雜誌英國版

 

Lucianne Walkowicz的英語網上資料

Home: astro.berkeley.edu/~lucianne/

TED Profile: Lucianne Walkowicz

Twitter: @shaka_lulu

 

[TED科技‧娛樂‧設計]

已有中譯字幕的TED影片目錄(繁體)(簡體)。請注意繁簡目錄是不一樣的。

 

Lucianne Walkowicz 談尋找繞著其他恆星運轉的行星

在我們太陽系之外的其它行星系統就像一座遙遠的城市,我們可以看見其中閃爍的光,但無法在它的街道上行走。但藉著研究這些閃爍的光,我們可以瞭解恆星和行星如何相互作用,形成它們自己的生態系統,並創造出適合生命生存的環境。

 

在這張東京天際線的照片中,隱藏著一些來自最新型搜尋行星太空望遠鏡觀察到的資料,即所謂的克卜勒任務。你們看得出來嗎?我們來看一下。這只是克卜勒太空望遠鏡所觀察的天空範圍中很小的一部分,它藉著每半個小時,非常精確地同時測量超過15萬顆恆星發出的光來搜尋行星。

 

我們尋找的是,當行星經過其中一顆恆星前方,擋住了一些我們所能接收到的星光,而導致恆星亮度稍稍變暗的情形。在短短兩年多的運作期間裡,我們發現1200多顆繞著其他恆星運轉的潛在新行星系統。給你們一些更清楚的概念吧!在之前未使用克卜勒太空望遠鏡進行探索的二十年期間,我們只發現了大約400顆像這樣的行星。

 

當我們觀察到這些微的亮度變暗情形時,可以判斷出幾件事:一方面我們可以判斷出那裡存在著一顆行星,但也可以判斷出這顆行星的大小,以及它與其母星相距多遠。這個距離相當重要,因為我們能藉此得知這顆行星整體上接收到的光有多少。知道這個距離及其接收的光量相當重要,因為這有點像圍坐在營火旁的情形;你希望在離營火夠近的地方,以便取暖,但不希望距離近到讓你感覺溫度太高,彷彿要燒起來的程度。

 

然而,除了瞭解行星整體上接收到的光量之外,我們還必須對其母星進行更多的瞭解,我會告訴你們其中原因。這是我們的恆星,這是我們的太陽,圖中顯現出的是可見光部份,就是以人類肉眼能看見的光。你會發現它看起來相當像我們小時候所畫的、典型的黃色圓球圖像,但你還會發現別的東西,即太陽表面上的一些斑點。這些斑點就是所謂的太陽黑子,是太陽磁場的顯現方式之一,它們也會使恆星的光度產生變化,我們可用克卜勒太空望遠鏡對此進行非常精確的測量,並追蹤它們造成的影響。

 

然而,這些只是冰山一角。如果我們眼睛能看見紫外光或X射線,就能真正看到太陽磁場活動的動態情形及其所產生的巨大影響,這種情形也會發生在其他恆星上。思考一下,即使現在外面是陰天,這種情況時時刻刻都在你頭頂上的天空中上演著。因此,當我們想瞭解一個行星是否適合居住,是否有適合生命生存的可能性時,我們想知道的不僅是它接受到的光照總量及其溫度,我們還想知道它周遭的太空天氣,即恆星所產生的高能輻射、紫外線和X射線對於身處在這些高能輻射中的行星有何影響。

 

因此,我們無法像觀察我們太陽系中的行星那樣,鉅細靡遺地觀察環繞在其他恆星周圍的行星。圖上顯示的是金星、地球和火星,三個位於我們太陽系中的行星,其大小大致相同,但其中只有一個是真正適合生存的地方。但同時,我們能做的是,測量由我們恆星所發出的光,並瞭解行星與其母星之間的關係,找出線索,看看宇宙中哪些行星可能是探索生命存在與否的好地方。

 

克卜勒太空望遠鏡無法鉅細靡遺地探索每一顆圍繞著恆星的行星,但不可否認的,它做的每一次測量都相當珍貴,因為它能讓我們瞭解恆星與行星之間的關係,以及恆星發出的光如何為宇宙中生命的形成打下基礎。雖然觀察太空是克卜勒望遠鏡的任務,但搜尋宇宙中的生命是我們的任務。

 

謝謝。

 

(掌聲)

 

以下為系統擷取之英文原文

About this Talk

How do we find planets -- even habitable planets -- around other stars? By looking for tiny dimming as a planet passes in front of its sun, TED Fellow Lucianne Walkowicz and the Kepler mission have found some 1,200 potential new planetary systems. With new techniques, they may even find ones with the right conditions for life.

About the Speaker

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

Transcript

Planetary systems outside our own are like distant cities whose lights we can see twinkling, but whose streets we can't walk. By studying those twinkling lights though, we can learn about how stars and planets interact to form their own ecosystem and make habitats that are amenable to life.

In this image of the Tokyo skyline, I've hidden data from the newest planet-hunting space telescope on the block, the Kepler Mission. Can you see it? There we go. This is just a tiny part of the sky the Kepler stares at, where it searches for planets by measuring the light of over 150,000 stars, all at once, every half hour, and very precisely.

And what we're looking for is the tiny dimming of light that is caused by a planet passing in front of one of these stars and blocking some of that starlight from getting to us. In just over two years of operations, we've found over 1,200 potential new planetary systems around other stars. To give you some perspective, in the previous two decades of searching, we had only known about 400 prior to Kepler.

When we see these little dips in the light, we can determine a number of things. For one thing we can determine that there's a planet there, but also how big that planet is and how far it is away from its parent star. That distance is really important because it tells us how much light the planet receives overall. And that distance and knowing that amount of light is important, because it's a little like you or I sitting around a campfire. You want to be close enough to the campfire so that you're warm, but not so close that you're too toasty and you get burned.

However, there's more to know about your parent star than just how much light you receive overall. And I'll tell you why. This is our star. This is our Sun. It's shown here in visible light. That's the light that you can see with your own human eyes. You'll notice that it looks pretty much like the iconic yellow ball -- that Sun that we all draw when we're children. But you'll notice something else, and that's that the face of the Sun has freckles. These freckles are called sunspots, and they are just one of the manifestations of the Sun's magnetic field. They also cause the light from the star to vary. And we can measure this very, very precisely with Kepler and trace their effects.

However, these are just the tip of the iceberg. If we had UV eyes or X-ray eyes, we would really see the dynamic and dramatic effects of our Sun's magnetic activity -- the kind of thing that happens on other stars as well. Just think, even when it's cloudy outside, these kind of events are happening in the sky above you all the time. So when we want to learn whether a planet is habitable, whether it might be amenable to life, we want to know not only how much total light it receives and how warm it is, but we want to know about its space weather -- this high-energy radiation, the UV and the X-rays that are created by its star and that bathe it in this bath of high-energy radiation.

And so, we can't really look at planets around other stars in the same kind of detail that we can look at planets in our own solar system. I'm showing here Venus, Earth and Mars -- three planets in our own solar system that are roughly the same size, but only one of which is really a good place to live. But what we can do in the meantime is measure the light from our stars and learn about this relationship between the planets and their parent stars to suss out clues about which planets might be good places to look for life in the universe.

Kepler won't find a planet around every single star it looks at. But really, every measurement it makes is precious, because it's teaching us about the relationship between stars and planets, and how it's really the starlight that sets the stage for the formation of life in the universe. While it's Kepler the telescope, the instrument that stares, it's we, life, who are searching.

Thank you.

(Applause)

 


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