I am in search of another planet in the universe where life exists. I can't see this planet with my naked eyes or even with the most powerful telescopes we currently possess. But I know that it's there. And understanding contradictions that occur in nature will help us find it.
我一直在尋找宇宙中 另一顆存在生命的行星。 我無法通過肉眼, 甚至也無法借助我們現有的 最先進的望遠鏡觀測到這顆行星。 但我知道這顆行星是存在的。 而理解自然界中發生的一些矛盾或衝突, 則將會幫助我們尋找到這顆行星。
On our planet, where there's water, there's life. So we look for planets that orbit at just the right distance from their stars. At this distance, shown in blue on this diagram for stars of different temperatures, planets could be warm enough for water to flow on their surfaces as lakes and oceans where life might reside. Some astronomers focus their time and energy on finding planets at these distances from their stars. What I do picks up where their job ends. I model the possible climates of exoplanets. And here's why that's important: there are many factors besides distance from its star that control whether a planet can support life.
在我們地球上, 但凡有水的地方,就會存在生命。 因此,我們所要尋找的就是 按照某個適當的距離, 圍繞著恆星旋轉的那種行星。 這適當的距離,就是圖上藍色區域部分, 標示了行星與不同溫度恆星 之間的適當距離, 行星的溫度就足夠溫暖, 從而能使水源在它們的表面流動起來 就像湖泊和海洋, 生命就可能存活於這些水中。 一些天文學家 便把他們的目光及精力集中在 尋找這種與恆星有 維持適當距離的行星研究上。 而我的工作則是基於 這些天文學家們的研究結果而展開的。 我通過構建模型來模擬 太陽系以外的行星上可能出現的氣候。 我這項工作之所以重要, 是因為,除了距離, 還有其他很多因素會決定 一個行星是否能夠維繫生命的存在。
Take the planet Venus. It's named after the Roman goddess of love and beauty, because of its benign, ethereal appearance in the sky. But spacecraft measurements revealed a different story. The surface temperature is close to 900 degrees Fahrenheit, 500 Celsius. That's hot enough to melt lead. Its thick atmosphere, not its distance from the sun, is the reason. It causes a greenhouse effect on steroids, trapping heat from the sun and scorching the planet's surface. The reality totally contradicted initial perceptions of this planet. From these lessons from our own solar system, we've learned that a planet's atmosphere is crucial to its climate and potential to host life.
拿金星舉例來說。 金星這個名字來源於古羅馬 的愛神、美神維納斯, 因為它在天空中看上去輕盈且柔美。 但宇宙飛船的數據卻揭示了 金星另一個不同的故事。 金星地表溫度接近900華氏度, 也就是500攝氏度。 那樣的高溫足以熔化金屬鉛。 造成高溫的原因不是 金星與太陽之間的距離近, 而是金星自身厚重的大氣層。 它造成了類似施打了 類固醇的溫室效應, 這大氣層困住了來自太陽的熱量 並烘烤著行星表面, 這一事實完全違背了 (人們對於金星)最初的認識。 這些來自我們太陽系的教訓告訴我們, 行星的大氣層對它的氣候 以及它是否可能維繫生命 有著決定性的作用。
We don't know what the atmospheres of these planets are like because the planets are so small and dim compared to their stars and so far away from us. For example, one of the closest planets that could support surface water -- it's called Gliese 667 Cc -- such a glamorous name, right, nice phone number for a name -- it's 23 light years away. So that's more than 100 trillion miles. Trying to measure the atmospheric composition of an exoplanet passing in front of its host star is hard. It's like trying to see a fruit fly passing in front of a car's headlight. OK, now imagine that car is 100 trillion miles away, and you want to know the precise color of that fly.
我們無從知道這些行星 究竟有什麼樣的大氣層。 因為,相對於恆星而言, 這些行星不僅太小還昏暗不清, 而且這些行星距離我們非常遙遠。 比如,距離我們最近的一顆 可能存在地表水的行星, 它叫“格利澤667 CC”。 多棒的一個名字, 對,跟電話號碼一樣的有趣的名字。 這顆行星距離我們23光年, 那也就是100萬億英里 (約161萬億千米)以外。 對這樣一顆繞行與某顆恆星的 系外行星而言, 測量它的大氣層成分非常困難。 這就像是試圖去看清楚 一隻飛過車燈果蠅一樣。 那麼,現在試想一下, 當那輛車離你有100萬億英里那麼遠, 而妳還想知道那隻飛過(車燈前)的果蠅 是什麼精確的顏色。
So I use computer models to calculate the kind of atmosphere a planet would need to have a suitable climate for water and life.
因此,我採用電腦模型 去計算哪樣的行星大氣層 可能產生出一種適宜的氣候。 這種適宜的氣候 可以保證水源和生命的存在。
Here's an artist's concept of the planet Kepler-62f, with the Earth for reference. It's 1,200 light years away, and just 40 percent larger than Earth. Our NSF-funded work found that it could be warm enough for open water from many types of atmospheres and orientations of its orbit. So I'd like future telescopes to follow up on this planet to look for signs of life.
這是來自於一位藝術家的關於(行星) “卡普勒62F”的一個概念(作品), 用地球作為參照。 這顆行星距離地球有1200光年, 並且只有比地球大40%。 我們這項得到美國國家科學基金會資助 的研究發現這顆行星可能足夠溫暖 從而存在水源, 在很多種類型的大氣層和很多 不同方向的運行軌道的情形下都是這樣。 因此,我希望未來的望遠鏡 可以跟蹤這顆行星, 看看能不能發現生命的跡象。
Ice on a planet's surface is also important for climate. Ice absorbs longer, redder wavelengths of light, and reflects shorter, bluer light. That's why the iceberg in this photo looks so blue. The redder light from the sun is absorbed on its way through the ice. Only the blue light makes it all the way to the bottom. Then it gets reflected back to up to our eyes and we see blue ice. My models show that planets orbiting cooler stars could actually be warmer than planets orbiting hotter stars. There's another contradiction -- that ice absorbs the longer wavelength light from cooler stars, and that light, that energy, heats the ice.
行星表面上存在的冰 對於氣候也有重要的影響。 冰會吸收光譜中波長 更長、更紅的那些光, 而反射回去波長相對較短、更藍的光。 照片上的冰山之所以會顯得那麼藍 正是因為這個原因。 太陽光中更紅的光 會在穿透冰塊的過程中被(冰塊)吸收, 只有藍光才能真正穿透到達冰塊底部。 這樣一來,它(藍光)就會反射出來, 反射到我們的眼睛裡, 我們便因此看到了藍色的冰。 我的模型顯示, 圍繞溫度較冷的恆星旋轉的行星 會實際上比那些圍繞 溫度較高的恆星旋轉的行星溫度更高。 另外還有一個矛盾。 那就是,冰會吸收從溫度較低的恆星上 發射出來的波長較長光; 而這些(被吸收的)光,這些能量, 會使冰本身的溫度升高。
Using climate models to explore how these contradictions can affect planetary climate is vital to the search for life elsewhere.
借助氣象模型去探索 這些矛盾如何影響行星上的氣候 對於尋找(地球以外的)生命 有至關重要的意義。
And it's no surprise that this is my specialty. I'm an African-American female astronomer and a classically trained actor who loves to wear makeup and read fashion magazines, so I am uniquely positioned to appreciate contradictions in nature --
這也解釋了為什麼這 (借助模型尋找生命的研究方法) 成為了我的研究專長。 我是一名非裔美國女性天文學工作者, 同時還是一名接受過正統訓練的演員, 我愛化妝, 愛讀時尚雜誌。 所以,我特別適合去欣賞 和領悟自然中的矛盾。
(Laughter)
(笑聲)
(Applause)
(鼓掌)
... and how they can inform our search for the next planet where life exists.
而且認識到這些矛盾 可以引領我們尋找 存在於另一顆行星的生命。
My organization, Rising Stargirls, teaches astronomy to middle-school girls of color, using theater, writing and visual art. That's another contradiction -- science and art don't often go together, but interweaving them can help these girls bring their whole selves to what they learn, and maybe one day join the ranks of astronomers who are full of contradictions, and use their backgrounds to discover, once and for all, that we are truly not alone in the universe.
我的一個組織名為Rising Stargirls。 它利用劇院、文字著作和視覺藝術去教 那些有色種族的中學女生天文學知識。 這裡還有另一個矛盾—— 科學和藝術並不是經常同時出現的。 但是,將這兩者結合起來是可以幫助 這些女孩們全身心地投入到 她們的所學中去的。 也許某一天,她們會(如我這般)自身充滿矛盾,而躋身到天文學者的隊伍中去。 而憑藉她們自己的背景 去發現原來我們真的 不是浩瀚宇宙中唯一的生命。
Thank you.
謝謝。
(Applause)
(鼓掌)