I'm really glad to be here. I'm glad you're here, because that would be a little weird. I'm glad we're all here. And by "here," I don't mean here. Or here. But here. I mean Earth. And by "we," I don't mean those of us in this auditorium, but life, all life on Earth --
我好高興可以喺度 我都好高興你哋可以喺度 因爲冇你哋嘅話,會些少奇怪 我好高興我哋都喺度 我講嘅「呢度」 唔係指 TED 呢度 或者呢度 係呢度 我指嘅係地球 而我所講嘅「我哋」唔係指 呢度演講廳嘅咁多位 而係生命 地球上所有嘅生命
(Laughter)
(笑聲)
from complex to single-celled, from mold to mushrooms to flying bears.
由複雜細胞到單細胞 由黴菌到蘑菇 到飛天熊都係
(Laughter)
(笑聲)
The interesting thing is, Earth is the only place we know of that has life -- 8.7 million species. We've looked other places, maybe not as hard as we should or we could, but we've looked and haven't found any; Earth is the only place we know of with life. Is Earth special? This is a question I've wanted to know the answer to since I was a small child, and I suspect 80 percent of this auditorium has thought the same thing and also wanted to know the answer. To understand whether there are any planets -- out there in our solar system or beyond -- that can support life, the first step is to understand what life here requires.
有趣嘅係 地球係我哋知道唯一有生命嘅地方 八百七十萬種生物 我哋人類其實有睇過其他地方 不過可能冇畀心機搵喇 但係我哋搵咗之後都冇發現有生物 地球係我哋知道唯一有生命嘅地方 地球特殊嗎? 呢個問題由我細時就已經想知 而我估呢座禮堂八成嘅人 都諗過同樣嘅事 亦都想知道答案 要知道有冇其他行星 喺我哋太陽系或者其他地方 能夠支持生命 第一步需要了解地球嘅生命需要啲乜
It turns out, of all of those 8.7 million species, life only needs three things. On one side, all life on Earth needs energy. Complex life like us derives our energy from the sun, but life deep underground can get its energy from things like chemical reactions. There are a number of different energy sources available on all planets. On the other side, all life needs food or nourishment. And this seems like a tall order, especially if you want a succulent tomato.
事實證明,喺呢八百七十萬個物種之中 生命只需要三件事 三張相嘅一邊 地球上所有生命都需要能量 好似我哋咁嘅複合生物體 需要從太陽取得能量 但係地下深處嘅生物 可以由化學反應取得能量 能量嘅來源喺每個星球都有好多種 相片另一邊 所有生命都需要食物或者營養 咁聽起嚟係過分要求
(Laughter)
尤其當你想要一隻多汁嘅番茄時
(笑聲)
However, all life on Earth derives its nourishment from only six chemical elements, and these elements can be found on any planetary body in our solar system. So that leaves the thing in the middle as the tall pole, the thing that's hardest to achieve. Not moose, but water.
但係地球上所有嘅生命 只需由六種化學元素取得營養 呢啲元素都可以喺我哋嘅太陽系 任何一個行星上面發現 所以剩低中間嘅嘢最難達到 唔係麋鹿,係水
(Laughter)
(笑聲)
Although moose would be pretty cool.
雖然如果係麋鹿都幾型
(Laughter)
(笑聲)
And not frozen water, and not water in a gaseous state, but liquid water. This is what life needs to survive, all life. And many solar system bodies don't have liquid water, and so we don't look there. Other solar system bodies might have abundant liquid water, even more than Earth, but it's trapped beneath an icy shell, and so it's hard to access, it's hard to get to, it's hard to even find out if there's any life there.
唔係冰結嘅水,亦唔係氣態嘅水 而係液態水 水係所有生命生存都需要嘅嘢 太陽系好多星球都冇液態水 所以我哋唔去呢啲星球度搵 但有啲太陽系嘅星球可能有大量液態水 甚至多過地球 但啲水都係困喺冰層底下 所以好難接近,好難用到 亦都令到我哋好難探測 冰層下面有冇生命
So that leaves a few bodies that we should think about. So let's make the problem simpler for ourselves. Let's think only about liquid water on the surface of a planet. There are only three bodies to think about in our solar system, with regard to liquid water on the surface of a planet, and in order of distance from the sun, it's: Venus, Earth and Mars. You want to have an atmosphere for water to be liquid. You have to be very careful with that atmosphere. You can't have too much atmosphere, too thick or too warm an atmosphere, because then you end up too hot like Venus, and you can't have liquid water. But if you have too little atmosphere and it's too thin and too cold, you end up like Mars, too cold. So Venus is too hot, Mars is too cold, and Earth is just right. You can look at these images behind me and you can see automatically where life can survive in our solar system. It's a Goldilocks-type problem, and it's so simple that a child could understand it.
咁只剩低幾個星球值得考慮 所以等我哋簡化一下問題 我哋只要諗喺星球表面搵到液態水就好 咁我哋嘅太陽系裡邊 只有三個星球可以諗 按太陽嘅距離依次序為: 金星、地球、火星 因為你想大氣層畀到水係液體狀態 所以要對大氣層非常講究 大氣層唔可以太厚或者太暖 因為咁樣嘅話會好似金星一樣咁熱 而且冇可能有液態水 但係如果你嘅大氣層太薄太凍 結果就會好似火星一樣咁凍 所以金星太熱,火星太凍 地球就啱啱好 睇下我後邊嘅相,你自然會睇到 我哋嘅太陽系邊度可以有生命 呢個係「金髮女孩 與三隻熊故事」嘅問題 簡單到兒童都可以理解
However, I'd like to remind you of two things from the Goldilocks story that we may not think about so often but that I think are really relevant here. Number one: if Mama Bear's bowl is too cold when Goldilocks walks into the room, does that mean it's always been too cold? Or could it have been just right at some other time? When Goldilocks walks into the room determines the answer that we get in the story. And the same is true with planets. They're not static things. They change. They vary. They evolve. And atmospheres do the same. So let me give you an example.
不過,我想提醒各位兩件事 喺金髮女孩與三隻熊個故事裡面 我哋經常忽略、但我認為非常切題嘅事 第一 當金髮女孩行入屋時 如果熊媽媽碗粥太凍 咁碗粥係咪一路都係凍嘅呢? 定係喺之前係暖嘅呢? 金髮女孩行入屋時就一口咬定咗個答案 行星都一樣 行星唔係靜態嘅嘢,佢哋一直改變緊 佢哋會變化、會演化 大氣層都一樣 我舉一個例子
Here's one of my favorite pictures of Mars. It's not the highest resolution image, it's not the sexiest image, it's not the most recent image, but it's an image that shows riverbeds cut into the surface of the planet; riverbeds carved by flowing, liquid water; riverbeds that take hundreds or thousands or tens of thousands of years to form. This can't happen on Mars today. The atmosphere of Mars today is too thin and too cold for water to be stable as a liquid. This one image tells you that the atmosphere of Mars changed, and it changed in big ways. And it changed from a state that we would define as habitable, because the three requirements for life were present long ago. Where did that atmosphere go that allowed water to be liquid at the surface?
呢個係我最鍾意嘅火星圖片 佢唔係最高解析度,亦唔係最靚 都唔係最新嘅相 但係佢顯示行星表面嘅河床 液態水流動而形成嘅河床 河床要上百上千甚至上萬年先能形成 依家嘅火星冇可能發生呢件事 依家嘅火星大氣層太薄太冷 導致水唔可以維持液態 呢張相話我哋知火星嘅大氣層改變咗 而且改變好大 佢由可居住嘅狀態變成依家咁 以前之所以可居住係因為 生命三大要素曾經喺嗰度出現過 以前大氣層可以令地表維持液態水 但依家火星嘅大氣層去咗邊度?
Well, one idea is it escaped away to space. Atmospheric particles got enough energy to break free from the gravity of the planet, escaping away to space, never to return. And this happens with all bodies with atmospheres. Comets have tails that are incredibly visible reminders of atmospheric escape. But Venus also has an atmosphere that escapes with time, and Mars and Earth as well. It's just a matter of degree and a matter of scale. So we'd like to figure out how much escaped over time so we can explain this transition.
一種理論係佢逃逸去到太空 話大氣粒子有足夠嘅能量 走出行星嘅引力 散逸到太空,一去不返 呢種現象喺有大氣層嘅星球上面 都會發生 彗星嘅尾就係大氣逃逸嘅最佳例子 但係金星嘅大氣都會隨著時間逃逸 火星與地球都會 只不過係程度同規模嘅問題 所以我哋要搵出逃逸嘅速率 先能夠解釋大氣層消失嘅現象
How do atmospheres get their energy for escape? How do particles get enough energy to escape? There are two ways, if we're going to reduce things a little bit. Number one, sunlight. Light emitted from the sun can be absorbed by atmospheric particles and warm the particles. Yes, I'm dancing, but they --
大氣點得到逃逸所需嘅能量? 粒子點得到足以逃逸嘅能量? 如果我哋簡單嚟睇,有兩種方法 第一,陽光 大氣粒子吸收太陽發出嘅光 令到粒子增溫 係,我跳緊舞,不過粒子佢哋…
(Laughter)
(笑聲)
Oh my God, not even at my wedding.
該煨,我喺自己嘅婚禮都冇跳過…
(Laughter)
(笑聲)
They get enough energy to escape and break free from the gravity of the planet just by warming. A second way they can get energy is from the solar wind. These are particles, mass, material, spit out from the surface of the sun, and they go screaming through the solar system at 400 kilometers per second, sometimes faster during solar storms, and they go hurtling through interplanetary space towards planets and their atmospheres, and they may provide energy for atmospheric particles to escape as well.
佢哋增溫就已經得到足夠嘅能量 去逃離引力 第二種方法係靠太陽風 由太陽表面噴出嘅粒子、物質 會喺太陽系裡邊 以每秒 400 公里嘅速度呼嘯而過 太陽風暴嚟嗰陣有時仲會快啲添 佢哋穿梭行星之間 向著行星同行星嘅大氣飛去 佢哋可能畀到大氣粒子能量去逃逸
This is something that I'm interested in, because it relates to habitability. I mentioned that there were two things about the Goldilocks story that I wanted to bring to your attention and remind you about, and the second one is a little bit more subtle. If Papa Bear's bowl is too hot, and Mama Bear's bowl is too cold, shouldn't Baby Bear's bowl be even colder if we're following the trend? This thing that you've accepted your entire life, when you think about it a little bit more, may not be so simple. And of course, distance of a planet from the sun determines its temperature. This has to play into habitability. But maybe there are other things we should be thinking about. Maybe it's the bowls themselves that are also helping to determine the outcome in the story, what is just right.
呢個就係我覺得有興趣嘅嘢 因為呢個同適居性有關 我講過金髮女孩嘅故事 有兩樣嘢你哋要留意一下 而第二件事更加微妙︰ 如果熊爸爸碗粥太熱 而熊媽媽碗粥太凍 咁熊寶寶碗粥咪應該更加凍? 如果我哋跟著個趨勢諗 呢件你成世人都以為嘅事 如果仔細諗下,可能冇咁簡單 當然,行星溫度取決於佢同太陽嘅距離 就同適居性有關 但係我哋可能需要考慮其他事情 可能碗本身都會決定個故事嘅結局︰ 亦即係乜為之啱啱好
I could talk to you about a lot of different characteristics of these three planets that may influence habitability, but for selfish reasons related to my own research and the fact that I'm standing up here holding the clicker and you're not --
我可以同大家講好多 關於呢三個行星唔同嘅特性 點樣影響適居性 但係因為我研究嘅關係 同埋因為我係講者 (笑聲)
(Laughter)
I would like to talk for just a minute or two about magnetic fields. Earth has one; Venus and Mars do not. Magnetic fields are generated in the deep interior of a planet by electrically conducting churning fluid material that creates this big old magnetic field that surrounds Earth. If you have a compass, you know which way north is. Venus and Mars don't have that. If you have a compass on Venus and Mars, congratulations, you're lost.
所以我想花一兩分鐘同你哋講下磁場 地球有磁場;金星同火星就冇 地球內部深處有一啲電導液體物質 呢啲電導液體物質流動嗰陣 會形成地球嘅磁場 如果你有指南針,你就會知道邊邊係北 但金星同火星都冇磁場 如果你喺金星同火星上面用指南針 恭喜!你盪失路
(Laughter)
(笑聲)
Does this influence habitability? Well, how might it? Many scientists think that a magnetic field of a planet serves as a shield for the atmosphere, deflecting solar wind particles around the planet in a bit of a force field-type effect having to do with electric charge of those particles. I like to think of it instead as a salad bar sneeze guard for planets.
磁場會影響適居性嗎? 會點影響? 好多科學家認為行星嘅磁場 就好似大氣層嘅防護罩 令行星四周嘅太陽粒子改變方向 屬於力場效應嘅一種 亦都同粒子嘅電荷有關 我鐘意將佢比喻為 麫包鋪廚窗揭得開嘅玻璃蓋
(Laughter)
(笑聲)
And yes, my colleagues who watch this later will realize this is the first time in the history of our community that the solar wind has been equated with mucus.
係嘅,之後睇呢段片嘅同事會發覺 呢個係我哋第一次 將太陽風等同為口水唾沫
(Laughter)
(笑聲)
OK, so the effect, then, is that Earth may have been protected for billions of years, because we've had a magnetic field. Atmosphere hasn't been able to escape. Mars, on the other hand, has been unprotected because of its lack of magnetic field, and over billions of years, maybe enough atmosphere has been stripped away to account for a transition from a habitable planet to the planet that we see today.
好,所以地球之所以 幾十億年嚟都受到保護 全因我哋有磁場 以至大氣冇辦法逃脫 另一方面因為火星冇磁場 火星嘅大氣冇保護 以致可能幾十億年嚟火星失去嘅大氣 足以令到呢個原本可以居住嘅行星 變成今日我哋睇到嘅樣
Other scientists think that magnetic fields may act more like the sails on a ship, enabling the planet to interact with more energy from the solar wind than the planet would have been able to interact with by itself. The sails may gather energy from the solar wind. The magnetic field may gather energy from the solar wind that allows even more atmospheric escape to happen. It's an idea that has to be tested, but the effect and how it works seems apparent. That's because we know energy from the solar wind is being deposited into our atmosphere here on Earth. That energy is conducted along magnetic field lines down into the polar regions, resulting in incredibly beautiful aurora. If you've ever experienced them, it's magnificent. We know the energy is getting in. We're trying to measure how many particles are getting out and if the magnetic field is influencing this in any way.
其他科學家認為磁場可能更似船嘅帆 令行星可以同太陽風交換更多嘅能量 磁場可以收集太陽風嘅能量 畀更加多嘅大氣脫逃到 呢個理論仲需要去證實 但係佢嘅效應同運作方式睇起來好明顯 咁係因為我哋知道 太陽風嘅能量已經注入緊 我哋地球嘅大氣層度 嗰股能量順著磁力線傳導 向下導入兩極 化成無比璀璨嘅極光 如果你有睇過極光,你就知佢有幾壯麗 我哋知道能量入緊嚟 我哋想計下有幾多粒子逃逸 同埋睇下磁場係咪真係有影響
So I've posed a problem for you here, but I don't have a solution yet. We don't have a solution. But we're working on it. How are we working on it? Well, we've sent spacecraft to all three planets. Some of them are orbiting now, including the MAVEN spacecraft which is currently orbiting Mars, which I'm involved with and which is led here, out of the University of Colorado. It's designed to measure atmospheric escape. We have similar measurements from Venus and Earth. Once we have all our measurements, we can combine all these together, and we can understand how all three planets interact with their space environment, with the surroundings. And we can decide whether magnetic fields are important for habitability or not.
我有一個問題畀大家 但係我未有答案,我們冇答案 但係我哋努力緊。我哋係點努力呢? 我哋送咗太空船去呢三個行星度 有啲圍繞緊行星 包括 MAVEN 太空船 目前喺火星嘅軌道上面 呢項計劃我都有參與 而且係由呢度嘅科羅拉多大學帶領 個計劃為咗測量大氣逃脫 我哋喺金星同地球都有類似嘅量度 當我哋集齊所有嘅量度數據 我哋就可以將佢哋併埋一齊 就可以了解呢三個行星 點樣同周圍嘅太空環境互動 我哋就可以決定磁場係咪對適居性重要 就算我哋有咗答案 但係點解你哋要咁在乎?
Once we have that answer, why should you care? I mean, I care deeply ... And financially as well, but deeply.
我意思係,我好在乎 我亦都在乎研究經費
(Laughter)
(笑聲)
First of all, an answer to this question will teach us more about these three planets, Venus, Earth and Mars, not only about how they interact with their environment today, but how they were billions of years ago, whether they were habitable long ago or not. It will teach us about atmospheres that surround us and that are close. But moreover, what we learn from these planets can be applied to atmospheres everywhere, including planets that we're now observing around other stars. For example, the Kepler spacecraft, which is built and controlled here in Boulder, has been observing a postage stamp-sized region of the sky for a couple years now, and it's found thousands of planets -- in one postage stamp-sized region of the sky that we don't think is any different from any other part of the sky.
首先,呢個問題嘅答案 會教我哋更多關於 金星、地球以及火星嘅事 唔單止包括佢哋點樣同現今嘅環境互動 仲包括佢哋幾十億以前嘅狀態 同埋佢哋好耐以前係咪適合居住 答案會揭示大氣層嘅嘢 另外,我哋從呢幾個行星嘅 大氣層學到嘅知識 可以應用喺其他星球嘅大氣層度 包括我哋觀察緊嘅 幾個環繞著其他恆星嘅行星 舉個例子,喺波德呢度 建造同埋控制嘅哈勃太空望遠鏡 已經好幾年觀察緊 一塊郵票咁大嘅天空範圍 佢目前已經喺郵票咁大嘅天空裏面 發現咗幾千個行星 而我哋唔覺呢塊天空 同其他天空有咩唔同
We've gone, in 20 years, from knowing of zero planets outside of our solar system, to now having so many, that we don't know which ones to investigate first. Any lever will help. In fact, based on observations that Kepler's taken and other similar observations, we now believe that, of the 200 billion stars in the Milky Way galaxy alone, on average, every star has at least one planet. In addition to that, estimates suggest there are somewhere between 40 billion and 100 billion of those planets that we would define as habitable in just our galaxy.
廿年裏邊 我哋由一個太陽系以外嘅 行星都唔認識 到依家知道有咁多行星 我哋都唔知應該由邊度開始探索 任何幫手都歡迎 其實,跟據哈勃太空望遠鏡得到嘅觀察 加上其他類似嘅觀測,我哋宜家相信 剩係我哋銀河系二千億個星裡邊 平均每個恆星至少有一個行星 除此之外,單單喺我哋嘅銀河 我哋估計有大概四百億 到一千億個行星係適居嘅
We have the observations of those planets, but we just don't know which ones are habitable yet. It's a little bit like being trapped on a red spot --
我哋得到呢啲行星嘅觀測資料 但係我哋仲未知邊一個係適合居住嘅 有點似被困喺台上嘅呢塊紅地氈一樣
(Laughter)
(笑聲)
on a stage and knowing that there are other worlds out there and desperately wanting to know more about them, wanting to interrogate them and find out if maybe just one or two of them are a little bit like you. You can't do that. You can't go there, not yet. And so you have to use the tools that you've developed around you for Venus, Earth and Mars, and you have to apply them to these other situations, and hope that you're making reasonable inferences from the data, and that you're going to be able to determine the best candidates for habitable planets, and those that are not.
但係你又知道仲有其他世界存在 你又極想了解佢哋 你又想調查睇下有冇一兩個星球 好似自己嘅星球 但係你就係做唔到,你去唔到 所以你要用上 為到金星、地球同火星開發嘅工具 你要將工具用喺其他情況度 並確保能夠從數據裏面作出合理嘅推斷 從而揀出最有可能適居嘅行星 同埋搵出最冇可能適居嘅行星
In the end, and for now, at least, this is our red spot, right here. This is the only planet that we know of that's habitable, although very soon we may come to know of more. But for now, this is the only habitable planet, and this is our red spot. I'm really glad we're here.
最終,同埋至少目前 呢個就係我哋嘅紅地氈,就喺呢度 呢個係目前我哋所知唯一適居嘅行星 雖然好快我哋可能會發現仲有其他嘅 但係目前,呢個係唯一適居嘅行星 呢個就係我哋嘅紅地氈 我真係好高興我哋都喺度
Thanks.
多謝
(Applause)
(掌聲)