遥远的拉帕努伊岛，曾经是一个家园 The remote island of Rapa Nui was once home
属于一个地球上最与世隔绝的文明 to Earth's most isolated civilisation.
他们以特有的石像闻名，他们曾经生活在这里 Famed for their stone effigies, they lived here
1,000年之久 for 1,000 years.
他们称这座岛屿‘陆地的尽头’ They called the island the End of the Land.
复活节岛是…，可以感受到，被与世隔绝的 Easter Island is, and feels, isolated.
到西边最近的太平洋小岛 It's at least 1,500 miles to the west,
就要1,500英里 to the nearest Pacific island -
需要5小时的飞行时间 five hours flying time
从这里到南美洲的智利首都，圣地牙哥 from the coast of South America and Santiago in Chile.
1722年，复活节那一天 But on Easter Day, 1722,
这个文明的寂静被打碎了 the civilisation's solitude was shattered.
荷兰舰队的到来 The arrival of a Dutch trading fleet
是他们和外来者面对面接触 was the moment they came face to face
的关键时刻 with aliens.
结果这只是一次短暂的邂逅 It turned out to be a solitary encounter.
当其他的船队50年后再次来到这里 When other ships returned 50 years later,
这个文明已经摇摇欲坠 the civilisation had fallen.
这个相遇只是纯綷的意外 It had been pure chance that they'd met at all,
这个孤独的岛屿 such was the island's isolation.
就像茫茫大海里的一根针 A pinprick in a vast ocean.
那在地球上的我们呢？ What then of us on Earth?
我们是不是孤独的生命之岛？ Are we a lone island of life
失落于无边无际的银河之中？ lost in a vast galaxy?
这样想一想 Think about this.
有着数十亿个类似地球一样可居住的世界 There are billions of habitable Earth-like worlds
散布在星系之中 out there in the galaxy,
但我们是孤独的 and yet we are alone.
这样想一想 Think about this.
有着数十亿个类似地球一样可居住的世界 There are billions of habitable Earth-like worlds
散布在星系之中 out there in the galaxy
我们并不孤独 and we are not alone.
还有其他人 There are others.
其中一个说法是对的 One of these statements is true.
至目前为止，我们知道 As far as we know,
我们人类在宇宙中是独一无二的 we humans are unique in the universe.
一个定居在太空中一颗极小星球上的物种 One species carried through space on one tiny planet...
身处于银河系2,000亿颗恒星之中 ..amongst the Milky Way's 200 billion stars.
问题是这样的，有人在看我们吗？ The question is, is anyone else staring back?
NATIVE AMERICAN CHANTING
在新墨西哥州，纳瓦伙族印第安人相信 ，In New Mexico, the Navajo tribe believe the stars
星星是其他灵魂意识的家园 are home to another consciousness.
一年一度他们聚在一起和灵体沟通 Once a year they come together to communicate with this entity,
透过这个净化仪式称作 "Yeibichai" in a healing ceremony called Yeibichai.
这是长达九天的歌颂和庆祝 t's a nine-day long festival of ritual and chanting.
最神圣的部份是 "夜咏唱" The most sacred of which is the night-chant
由巫医在私底下执行 performed by medicine men in private,
从没被拍摄过 never filmed,
只被录音过一次 and recorded just once.
HIGH-PITCHED VOCALISATION
这是由哥伦比亚大学的Willard Rhodes所录下的 This recording was made by Willard Rhodes of Colombia University
在1940年代初 in the early 1940s.
HIGH-PITCHED CHANT IN UNISON
而他绝对不可能想像到后来发生了什么事 And he could not have imagined what was going to happen to it.
1977年，这个录音被拷贝到四张黄金唱盘上 In 1977, the recording was transferred onto four golden records
然后雕刻出这个封面 and encased in these covers.
今天地球上只剩下两张 Today only two of them remain on Planet Earth.
另外两张镶嵌在两艘太空探测船上 The other two are bolted to the sides of two space probes -
航海家1号，和航海家2号 Voyager 1 and Voyager 2 -
现在正航行于太空深处 and are now travelling into deep space.
伴随着"夜咏唱"一起的是一套精选集 Accompanying the night-chant are an eclectic mix
包含了地球上各种图像和声音 of images and sounds from Earth.
莫扎特-魔笛，各国语言问候语 MOZART'S Magic Flute GREETINGS IN MANY LANGUAGES
我是联合国秘书长 'As The Secretary General of The United Nations,
'我代表地球上的人民向您问候' 'I send greetings on behalf of the people of our planet.'
航海家的主要任务 The Voyager's primary mission
是探索太阳系的外行星 was to explore the outer planets of the solar system.
但是这张唱片给予了探测船额外的任务 But adding the discs gave the spacecraft an extra purpose -
它们成为地球大使 they become Earth's emissaries,
带着明信片给我们的外星邻居 carrying postcards to our alien neighbours.
如果他们存在 If they exist.
但不只如此 But there's more than that -
我们把希望雕刻在这唱盘上 there's hope engraved into this cover, as well.
这是一个地图 Because here is a map,
这个标明了地球在宇宙中的位置 this identifies the position of the Earth in the cosmos.
这些线指向一种星体叫脉冲星 These lines point to stars called pulsars
它们以非常特殊的速率旋转 which rotate with a very specific rate.
所以任何外星文明看到这个的话 So any alien civilisation that captured this
就可以知道这些脉冲星的位置 would be able to find the positions of the pulsars
然后顺着这些线指向地球 and all of these lines point back to Earth.
然后这里有一个解码工具，这里 And there's also a means of decoding all that information...here.
这是一个氢原子的图片 This is a picture of a hydrogen atom -
这是宇宙中最常见的原素 the most common element in the universe.
氢原子会放射出电磁波 Now hydrogen atoms radiate radio waves
以一个特定的波长，21公分 with a very particular wavelength - 21 centimetres.
那给了你一把刻度尺，一只钥匙，可以解开密码 That gives you the distance scale - the key, if you like - to this code.
所以任何懂物理学的文明 So any civilisation that knows anything about physics,
任何有一点科技水平的文明 which is to say, any civilisation worth its salt,
就可以了解那个，然后就可以解码这个 would recognise that and be able to decode this.
他们就可以识别出地球的位置 They would be able to determine the location of Earth -
然后可以找到我们 they would be able to find us.
多美妙的点子 What a wonderful idea.
航海家2号已经航行了190亿公里 Voyager 2 is now 19 billion kilometres into its journey.
但是以星系旅行来说的话，它才刚刚踏出家门 But in galactic terms, it's only just left home...
因为横越银河系需要走上千亿再乘以千亿的公里数 ..because The Milky Way is a billion-billion kilometres across.
事实上，制作那唱片的科学家与工程师们 In truth, the scientists and engineers who made that record
知道唱片不会被找到，但这不是重点 knew that it wouldn't be found, but that's not the point.
重点是这个行为，把它发射到太空中 See the very act of launching it out into space
传达那心里最深处、最重要的 expresses something deep, something primal.
每个人都有这样的昐望，我真的这么觉得 It's a feeling we all share - I certainly feel it -
我们就和纳瓦伙族人一样，急迫的想要 and that's that the Navajo weren't alone in wanting
和那些住在星星里的人沟通 to talk to the people out there amongst the stars.
如果能和其他的文明接触，不是很美妙的事吗？ 'Wouldn't it be lovely to make contact with another civilisation
那些独自演化和发展的文明 'that has arisen and evolved independently?'
日复一日 Every hour of every day,
有些人在扫描天空 some among us scan the skies
聆听外星文明 listening for alien civilisations.
我们成功的机率 'The chance of success in,
在接收外星讯息上，很大一部份要看我们 'picking up messages directed our way depends in large part
有多努力的去 'on how serious we are
研究每一个可能的讯号 'at investigating such possible signals.'
他们叫自已 SETI They call themselves SETI -
"搜寻地外文明计划" the Search for Extra-Terrestrial Intelligence.
这里是北加州的"艾伦望远镜阵" This is the Allen Array in Northern California,
这是SETI最有抱负，最了不起的工具 and it is SETI's most ambitious instrument to date.
这里总共有42座电波望远镜 This collection of 42 radio telescopes
是用来探测外星文明的讯号 is optimised to detect signals from extra-terrestrial civilisations
它们非常的灵敏 and it's exquisitely sensitive.
如果一个讯号射向我们 If a signal were beamed to us
以目前现代科技 with the sort of power that we can generate
所带来的技术 using our current technology
讯号可能来自任何数百万颗中类似太阳一样的恒星 from any one of the million or so sun-like stars
距离地球1,000光年远，我们都可以听到 within 1,000 light years of Earth, then this would hear it.
这个尝试至今尚未接到ET打来的电话 This experiment has yet to detect a call from ET.
但我们还有希望 But they live in hope,
因为SETI曾经接收到一段令人惊讶的讯号 because SETI did once pick up a tantalising signal.
HIGH-PITCHED TONE
1977年，8月15号 On August the 15th, 1977,
一座电波望远镜叫"大耳朵"，侦测到了一个电波信号 a radio telescope called the Big Ear detected a radio signal
来自接近人马座的一个区域 from somewhere in the vicinity of the constellation Sagittarius,
这是那天晚上的列印资料 and this is the printout from that night.
你可以看到在接近东部标准时间 9:45pm的地方 You can see that somewhere around 9.45pm Eastern Standard Time
一个非常明显的电波信号在跳动 a very bright radio signal pulsed in.
它看起来像这样 It looks something like this -
你可以把它画出来 you can sketch it out.
它是一个波动 It was a pulse...
波宽大约是72秒 ..with a width of around 72 seconds,
波峰的数值很高 and a peak intensity -
波峰的数值 the peak brightness -
是30倍的强度 was over 30 times the brightness
于星系的无线电波背景 of the background radio emission from the galaxy.
真是让人着迷 So it's fascinating.
HIGH-PITCHED TONE
而且这个讯号的波长让SETI相信， And it came in on a wavelength that SETI believes
是一个智慧文明可能会选用的 an intelligent civilisation might choose -
这个波长和刻在航海家号黄金唱片上的，是一样的 the same wavelength etched into Voyager's golden disc.
波长为21公分 The wavelength was 21 centimetres.
那就是由氢原子 That's the wavelength of light,
所放射出的电波波长 of radio waves emitted from hydrogen atoms.
所以这个波长分布在整片天空 So the whole sky glows at that wavelength.
在1950年代，无线电天文学家推测 And, back in the 1950s, radio astronomers speculated
如果外星文明想要和我们沟通 that if an alien civilisation wanted to communicate with us,
那么他们应该会选择那特殊的、大自然中的波长 then they might well choose that very special, natural wavelength
来传达讯息 to send their message.
让人惊讶的是 So surprising was this,
在被发现的几天之后 that when it was spotted a few days later
一位叫Jerry Ehman的天文学家 by an astronomer called Jerry Ehman
他把这个波动圈了起来 he circled that pulse -
这个闪现72秒的电波讯号 the 72-second flash of radio waves -
然后在旁边写了一个字 "Wow！" and wrote "Wow!" next to it,
后来这就成为了今天我们熟知的”Ｗow！讯号" so this has become known as the Wow! signal.
今天，在"Wow讯号"被侦测到的35年之后 Today, over 35 years after the Wow! signal was detected,
依然没有一个让人满意的答案 there's still no satisfactory explanation.
它看起来不像是来自我们自已，军方或是卫星 It doesn't seem to have been local - a military signal or a satellite,
当然，应该没有人会去利用 and, indeed, nobody's supposed to transmit
氢原子频率的电波来沟通 at the hydrogen line frequency,
这被记录在无线电天文学里 it's reserved for radio astronomy.
但是科学结果需要能被重覆证明 But scientific results have to be repeatable,
可是在这之后，不管我们把望远镜， and even though we've turned our telescopes in the direction
对准人马座多少次 of Sagittarius many times since,
没有人能再听到任何东西 nobody has ever heard anything.
所以我想这可能只能归纳为有趣的天文事件 So I suppose it has to remain just an interesting anomaly.
目前，我们还维持着这美丽的孤立状态 For now, we remain in magnificent isolation...
银河系中宁静孤独的智慧文明 ..alone intelligence in a galaxy that remains quiet.
有一个人比起其他人 But one man more than any other
更坚定相信，这宁静 is convinced that the great silence
不会永远存在 will not last forever.
这不是不切实际的空想 This is not some fantastical idea,
而是认真的科学研究 but a serious scientific quest.
录音：这会是你能想像到 - RECORDING: - 'It would be the greatest bonanza in knowledge
最大的人类知识宝藏 'you could possibly imagine.
会震惊整个人类文明 'A surprise for the whole civilisation.'
Frank Drake博士是SETI的创立元老 Dr Frank Drake is SETI's founding father
他花了一生的时间在聆听 and has spent a lifetime listening.
如果我在1960年代的时候问你 So if I'd have asked you back in the 1960s -
到21世纪时，你预期会接收到讯号吗？ By the 21st century, do you expect to have seen a signal? -
你会怎么回答？ what would you have said?
我会回答: 会，我觉得我们会成功 I would have said, "Yes, I expect to succeed."
因为我们做了非常多的搜索 Because we were doing a lot of searching then.
这让你觉得失望吗？ Does that make you disappointed?
我是失望，但不惊讶 I'm disappointed, yes, but not surprised.
这些年我们学到的就是 What we've learned over the years
搜索必需要比我们50年前所了解的 is that the searching has to be much more comprehensive,
更广泛全面 - than we realised 50 years ago. - Mm.
但我们知道这还是可行的 But we know it's still doable,
只是要花的时间比我们想的更多 it just takes much more time than we imagined.
我给你看一样东西 Let me show you something.
这是兰花 This is an orchid.
一种非常少见的，美丽的兰花 A very peculiar and beautiful orchid,
非常香 very fragrant,
一年之中只会开花两天 which actually only blooms two days a year.
如果你是两天前来这里 If you would've been here two days ago,
你就不会看到这些兰花 you wouldn't have seen this orchid
你可能会觉得这盆植物从未开过花 and you might've thought that this plant never blooms.
SETI也是有这个问题 Well, so it is with SETI.
我们学到我们必须搜寻一次又一次又一次，年复一年 We've learned we must search over and over and over through the years,
直到我们找到正确的时间，正确的位置 till we are in the right place at the right time
才能有所发现 to make the discovery.
这花叫什么名字？这花叫"Stanhopea" - What are they called? - This is called a Stanhopea.
它的名字里面有"hope"这个字 It has "hope" in its name,
我们也希望有一天 and we have hope that some day
SETI能找到那个正确的时间、正确的位置 we'll be in the right place at the right time in SETI.
但Frank不是只一直抓着电话不话 But Frank wasn't content just to hang on the line
等ET打电话来 waiting for ET's call.
这个公式从恒星行成的速率开始 The equation starts out with the rate of star formation...
1961年，他设计建立了一个 In 1961, he devised what remains
实用的数学公式 a useful scientific framework
能够计算有多大的机率 for considering how likely it is,
我们和其他人共享这个星系 that we share the galaxy with others.
我了解到一共有七个因素 I realised that there were seven factors -
如果你知道这些数字，然后把它们算出来 if you knew these factors, and multiplied them together
它就可以给出一个预测 it would give you a prediction
我们银河系中可发现的文明数量 of the number of detectable civilisations in our galaxy.
要算出的就是N, 大Ｎ,我们这么叫它 The end result is N - Big N, as we call it -
代表了可发现的文明数量 which is the number of detectable civilisations,
它本身是一个让人感兴趣的数字 which in its own right is a very interesting number.
但它对我们计划搜寻方向上非常重要 But, also, it's very important in guiding us in planning our searches.
德雷克公式变的很有名 The Drake Equation has become famous
因为它给了我们一个工具继续搜寻 because it gives us a tool to continue the search.
它挑战我们去回答一些最有争论的科学问题 It dares us to answer a series of provocative scientific questions.
在左手边的数字是我们想要计算出来的 On the left-hand side is the number we want to measure -
星系中智慧文明的数量 the number of intelligent civilisations in the galaxy
我们可以和他们沟通的文明 that we can communicate with.
但这里有着许多条件 But then there's this group of terms
那真的要让我们问问自己 that really ask questions about ourselves -
生命在星球上产生的可能性有多大？ How likely is it for life to arise on a planet?
地球有多特别？ How special is the Earth?
太阳有多特别？ How special is the sun?
太阳系有多特别？ How special is the solar system?
高等智慧有多特别？ How special is intelligence?
然后这里是最后一个条件，"L" And then there's this last term, L,
这应该是最引人深思的一个条件 which perhaps speaks to us most profoundly of all -
智慧文明的生存期 the lifetime of intelligent civilisations.
文明存在的时间是长还是短？ Do civilisations live for a long or short time?
如果是短，是什么摧毁了他们？ And if it's short, what is it that destroys them?
会是自然灾害吗？ Is it a natural disaster?
我们毕竟是生活在一个暴力的宇宙环境之中 We do, after all, live in a violent universe.
又或者他们毁灭了自己呢？ Or are they condemned to destroy themselves?
我们得出有10,000个文明存在于银河系 We came up with the number 10,000 civilisations in the galaxy,
以今日来说，这是很很合理的数字 and that's sort of stood as a reasonable number to this day.
50年前，Frank的数字只是一个推测 50 years ago, Frank's number was really an educated guess.
但我们的世代用实据来取代了他的推测 But our generation is replacing his hunches with hard data,
所以我们可以用他的公式算出自已的解答 so we can arrive at our own solution to his equation.
然后我们可以开始，就像Frank一样 And we can begin, as Frank did,
去问: 我们的地球家园 by asking just how rare
到底有多稀有？ is our home planet?
而让我们了解的关键， And the key to understanding that can be found
可以在我们和最近的恒星关系之中找到 in the relationship we share with our nearest star.
秘鲁的安第斯山脉 The Peruvian high Andes,
印加帝国的家园 home to the mighty Incan Empire,
这个失落的文明称他们自己为"太阳的子民" a lost civilisation that called themselves the Children of the Sun
崇拜太阳为他们的神 and worshipped the star as their god.
直到今日，这个关系仍旧至为重要 Today, this connection remains just as vital.
小天使，该起床了
Carmen Pachako和她家人的生计 Carmen Pachako and her family's livelihood
完全依靠着太阳 depends entirely on the sun.
WOMAN SINGING
隐藏在圣谷深处的是古老盐矿 Tucked away deep in the Sacred Valley is an ancient salt mine.
直到今日，数百个梯田被当地居民细心照顾 To this day, hundreds of terraces are tended by the local community.
Carmen的工作是维持整个系统的运作 Carmen's job is to keep the whole system running.
她利用当地的泉水一一灌溉每个梯田 She floods each terrace in turn with saline water from the local spring.
然后把池塘交给太阳去蒸发 The ponds are then left to evaporate in the sun
留下来的是由盐晶形成的硬块 leaving behind a crust of salt crystals.
这个机制可以运转是因为，在地球上 This place works because, here on Earth,
条件刚好可以让水以三种形态存在 the conditions are just right for water to exist in three states -
有液态水，就是你在盐池你可看见的 there's liquid, that you can see in the salt pools,
有水蒸气，可以蒸发到天空上的云层 there's a vapour that can evaporate up into clouds in the sky,
还有固体像是冰晶或是雪花 and a solid as ice and snow,
你可以在那边的山顶上看到 that you can see over there on the tops of the mountains.
这种持续不断的水循环 This constant recycling of water
从一种型态到另一种 from one state to another
在地球上发生 happens here on Earth
因为我们从太阳获得恰到好处的能量 because we receive just the right amount of energy from the sun.
你可以想像把地球和太阳拉近一点吗？ Can you imagine dragging the Earth closer to the Sun,
加热一下 heating it up,
到一个程度上，温度会， then at some point the temperatures
上升到100度会更高 would rise to 100 degrees or greater,
所有的水都会蒸发或沸腾到大气层中 all the water would evaporate or boil away into the atmosphere,
而且，事实上，如果够热的话 and, in fact, if it got too hot,
水分子本身会离开大气层到太空中 then the water molecules themselves would escape off into space.
地球会成为干枯、荒芜的一颗石头 Earth would be a dry and barren rock.
接下来，想像如果我把地球拉离太阳 Then, if you imagine dragging the Earth further out,
一直拉到离开太阳系 further out into the solar system,
那么温度会下降 then temperatures would drop
最后，会非常寒冷 and, eventually, they'd be so cold
所有的水都会结冰 that all the water would freeze out.
地球表面不会有液态水存在 There would be no liquid on the surface
当然，也没有云在大气层 and, indeed, no clouds in the atmosphere.
所以，在我们的太阳系中有一个区域 So there's a region in our solar system,
让地球可以绕行 within which the Earth could orbit
它的环境条件可以让液态水， and the conditions would still be right for liquid water
存在于地球表面上 to exist on its surface.
这个地区我们称为 "适居带" That region is known as the habitable zone,
因为地球上所有的生命都需要液态水 because all life on Earth requires liquid water.
但是在安第斯山，水是相当稀有的 But in the high Andes, water is relatively scarce.
所以，对印加人来说，适居带也很重要 So, for the Incas, habitability was important too,
虽然是缩小到人类的角度 albeit on a more human scale.
这是自然形成的沉洞，由被水侵蚀的石灰岩形成 This is a natural sink hole cut out of the limestone of the high Andes.
在某个时刻，大约500到600年前 At some point, around 500 or 600 years ago,
印加人改良了它，造出这些圆型的台阶 the Inca modified it by cutting these circular steps
在沉洞的周围 into the side of the sink hole.
还没有一个共识，这些结构的用途是什么 There's no consensus as to what this structure was for,
但一个被广泛接受的理论是， but one of the more widely accepted theories is
这曾经是一个农业研究平台 that it was an agricultural research station.
印加人建造这个 So the Inca had built this
照顺序种植连续不同条件下的作物 in order to generate a series of different micro climates,
不同的温度 different temperatures,
不同的灌溉水量 different amounts of irrigation
看哪一种作物长的最好 to see which crops grew best
在各种不同的条件之下 in which different conditions.
同样的，在我们的太阳系 And so it is, in our own solar system.
一个极端的条件位于火星 On one extreme lies Mars...
距离太阳8,000万公里 ..80 million kilometres further out from the sun,
它的表面是绵延不断的干焦红色岩石 its surface is mile after mile of parched red rock...
但它的表面特征仍旧可以看得出来 ..but the surface features still recall a time
这里曾经有河流和平原 when they were rivers and flood plains -
在水离开这红色星球到太空之前， evidence of a long oceanic period before the Red Planet
这里曾经有一段漫长的海洋时期 lost most of its water to space.
靠近太阳一点，在适居带的极限区域 Closer to the sun, and on the inner limits of habitability,
位于金星 lies Venus.
和地球的大小差不多，它浓厚的大气层 About the same size as Earth, its dense atmosphere
让温度上升到超过摄氏400度 sees temperatures soar to over 400 degrees Celsius -
对水来说绝对太热了 far too hot for water.
但是在2008年，金星探测器发现了一个特征 But, in 2008, the Venus Express spacecraft detected a signature
强烈显示出，水也曾经在这里流动过 highly suggestive that water once flowed on the surface here, too.
在一个短暂的时刻，数百万年前，不只是一个，是三个世界 For a brief moment, billions of years ago, not one, but three worlds
拥有海洋和河流绕行着太阳 with oceans and rivers orbited the sun.
THUNDER AND HEAVY RAIN
假如外星生命曾经存在于火星和金星上 If alien life ever existed on Mars or Venus,
目前还没有任何遗迹被找到过 no trace of it has yet been found.
不过可以确定的是 What is certain, though,
那就是我们的太阳，是生命故事的主角 is that our star is central to the story of life
在我们的太阳系之中 in our solar system.
但是太阳只是银河系数千亿颗恒星中的一颗 But the sun is just one of billions of stars in the Milky Way...
所以在我们的搜寻外星生命之旅 ..so in our hunt for aliens,
我们必须要能知道，到底有多少颗这样的恒星 we must determine exactly how many of those stars
是有能力支持生命的 are capable of supporting life.
让我从这一颗开始，它叫做"红矮星" I'm going to start with that one - that's called a red dwarf.
过来这里 Come here.
这可以是太阳 This could be the sun.
你拿大的可以吗？ Are you OK for a big one?
这给你 There you go.
这是一颗小小的白矮星 This is a little tiny white dwarf.
这是娇小的白矮星，给你 There's a little white dwarf. There you go.
谢谢 Gracias. Thank you.
HE LAUGHS
你拿的动吗？给你 Can you hold that? There you go!
在我们的银河系有2,000亿颗恒星 So there are 200 billion stars in our galaxy
分成许多不同的种类 of many different types,
我们把整个家族全部呈现在这里 and we've got the whole menagerie represented here -
红巨星 enormous red stars,
蓝巨星 enormous blue stars,
红矮星 tiny red stars,
白矮星 tiny white stars.
科学家不是只观察这些星星 Now, science is not just about looking at the stars
然后说，这颗黄的不错，这颗蓝的不错 and saying, "There's a nice yellow one. There's a nice blue one."
事实上，非常知名的物理学家 Ernest Rutherford. In fact, the very famous physicist Ernest Rutherford
那位在曼彻斯特发现了原子核的人 who discovered the atomic nucleus in Manchester
曾经这样说，"除了物理之外的科学都不过是集邮" once said all science is either physics, or stamp collecting.
集邮只是看着那些恒星 Stamp collecting is just looking at the stars,
物理是把它们分门别类 physics is arranging them in a pattern
然后试着去了解它们，这就是我们在做的事 and trying to understand the pattern. That's what we'll do now.
我们要来做一个"赫罗图" We're going to make what's called the Hertzsprung-Russell diagram.
祝我好运 Wish me luck.
你们都过去那里 You guys go all the way over there.
你去那里，对 You go there. Yeah.
你过去那里 You go right over there.
你来这里 You come in here.
你来这里，你也是，来这里 You come here. You, as well, come here.
那是橘色的 There's an orange one.
你去那里 You go there.
那里 There.
就是那里 Exactly there.
赫罗图让我们能把恒星分类 The Hertzsprung-Russell diagram allows us to organise the stars
根据它们的颜色和亮度 according to their colour and brightness.
当把图表展开 When laid out on a graph,
几乎所有星系中不同的星星 nearly all the galaxies' different stars
都集中在一条线上 fall neatly onto a line.
这条线称作"主序带" This line is called the Main Sequence -
这里占了绝大部份星系中的恒星 these are most of the stars in the galaxy,
它们在核心里燃烧氢与氦 they're burning hydrogen into helium in their cores.
这是我们熟悉的太阳 So this is our familiar sun,
我们每天都在天空见到的太阳 the sun that we see in the sky every day,
它也坐落于主序带 and it sits on the Main Sequence.
你跟我来 If you come with me.
在这附近 Somewhere around here
一颗黄色的星，一般的星 a yellow star, an average star.
位于线另一边的恒星 The stars either side of the line
已经快走到生命的尽头 are reaching the end of their lives.
红巨星已经没有足够的氢可以燃烧 The red giant stars have run out of hydrogen to burn,
于是开始膨涨起来，吞噬掉任何靠近的行星 and are swelling in size, engulfing any nearby planets.
所以我们可以把红巨星排除掉 So we can discount the red giants.
那里，那里 Over there. Over there.
其他的，像蓝巨星 Others, like the blue giants,
太过巨大，以致于它们快速耗尽燃料 are so massive that they burn their fuel quickly...
坍塌并照亮整个星系，这是超新星爆炸 ..collapsing and illuminating the galaxy in a supernova explosion.
所以要找到有适居带行星的恒星 So the search for stars with habitable planets
必须要把注意力放在主序带 must focus on the Main Sequence.
复杂生命需要30亿年来进化 Complex life took three billion years to evolve -
在这些最亮的恒星附近不会有时间来进化 it wouldn't have time to evolve around these brightest of stars,
明亮，短命的恒星 the bright, short-lived stars.
所以白星也可以排除 So the white stars can go.
走吧 Go on.
如果你想找到可以支持生命的行星 If you want to look for planets that could support life
和文明，你要找类似太阳的恒星 and civilisations, you'd look at the sun-like stars -
G星和K星，也就是橘星和黄星 the G and K stars, the orange and yellow stars.
这些恒星占了银河系的五分之一 These make up one fifth of all the stars in our galaxy.
但现在研究显示，还有另一种恒星 But new research suggests that there's another type of star
也许可以扩大这个数字 that might significantly expand this number.
我们可以在红矮星附近 Could we find planets around red dwarfs
找到能支持复杂生命或文明的行星吗？ that can support complex life or civilisations?
这还有争论，有一个大问题 Well, the jury's still out - there are big problems.
红矮星，还在生命的初期，是非常活跃的恒星 Red dwarfs - certainly early on in their lives - are very active stars.
就算它们没有很亮 So even though they're dim,
它们射出巨量的辐射 they throw out vast amounts of radiation,
所以很多科学家觉得这会影响行星 which many scientists think would sterilise planets
妨碍生命出现在那些行星上 and prevent life from appearing on those planets.
但其他人觉得，如果有适当的大气层 But others think that with the right atmosphere,
行星就可以抵抗辐射的伤害 a planet could cope with the radiation.
如果他们是对的，那我们是孤单的机率就大辐降低了 If they're right, then our odds of being alone shorten immensely...
因为红矮星到目前为止 ..because red dwarfs are by far
是我们银河系中最多的恒星 the most numerous stars in our galaxy.
所以我们对生命的搜寻在理论上显示 So our theoretical search for life suggests
存在着数十亿个 that there are billions
有潜力的适居带恒星系统 of potentially habitable star systems...
如果是这样的话，那我们现在必须来看看 ..and it's to these, that we must now look.
尾随在地球后方，一座太空望远镜 , lies a space telescope
几乎已经完成它的任务 nearing the end of its mission
寻找新的世界 to seek out new worlds.
克卜勒太空望远镜，它目不转睛的注视着150,000个 Known as Kepler, it has stared unblinkingly at 150,000 sun-like
类似太阳的恒星和红矮星，超过四年的时间 and red dwarf stars for over four years.
克卜勒注视着天琴座的方向 Kepler looked in the direction of the constellation of Lyra.
它完成了一小部份 He studied a small patch -
大约是整片天空的0.3% about 0.3% of the entire sky -
大约3,000光年远 and about 3,000 light years deep.
它在寻找细微的线索 It was looking for a tell-tale,
遥远恒星的微小光线变化 minute dip in light from a distant star
这会揭露新的世界 that would reveal a new world.
从恒星前面通过的行星 A planet passing in front of its star.
它找到了603颗行星 It found 603 planets,
其中十颗是和地球相似的 of which ten were Earth-like
它们接收大约同等数量来自母星的能量 and received about the same amount of energy from their parent star,
就和地球一样，换句话说 as we do here on Earth - in other words -
十个在适居带的地球 ten Earths within the habitable zone.
克卜勒证明了我们孕育生命的星球并不孤单 Kepler has proved that our life-giving planet is not alone...
可能还有更多在那里等着被发现 ..and there may be far more out there waiting to be discovered.
克卜勒只能看到从恒星前面通过的行星 Kepler can only see planets that pass across the face of the star
从地球的视角 as seen from Earth,
而太阳系有许多不同的方位 and solar systems have many different orientations.
同时，因为它只观测了四年的时间 Also, because it only observed for around four years,
所以它不能看到轨道周期 it can't see planets that have orbital periods
超过四年以上的行星 that last longer than four years.
但是，我们可以修正这些事情 But, we can correct for all those things.
而当我们这样做了之后，我们发现那里有10,000个类地行星 And when we do that, we find that there are 10,000 Earth-size planets
环绕着克卜勒观测的恒星 in orbit around Kepler's stars.
而这只是在那一小块天空之中 But that's just in that tiny piece of sky -
10,000个地球，就在那里 10,000 Earths...just there...
在那一丁点大小的空间里 in a small volum\e of space.
要看到全貌 To get the full picture,
我们必须要扩展到整片天空 we have to extend that over the entire sky
而当我们这样做，我们发现 and when we do that, we find
外面有着100亿个适居的世界 that there are ten billion habitable worlds out there
在银河系围绕着类似太阳的恒星 in the Milky Way galaxy around sun-like stars.
而且可能还有更多 And there could be even more.
红矮星，又称M型主序星 The red dwarfs, the so-called M-class stars...
如果我们接受M型星 If we admit the possibility that M stars
也可能有适居带在它们周围 might also have habitable zones around them,
那么我们可以把数字放大3到4倍 and we can multiply that by three or four,
那代表了，可能有300亿个类地行星在那里 that means there might be 30 billion Earth-like worlds out there
在我们的星系 in our galaxy.
长久以来我们都猜想银河系中有这么多的恒星系统 We've long suspected that in a galaxy with so many star systems
地球不可能独一无二 Earth couldn't stand alone.
现在我们更深入的发现 But now we're on the verge of discovering
不只是有一把的地球 not just a handful of other Earths,
是数百亿个世界 but billions of worlds
那里有水在地表上流动 where water flows freely on the surface,
雨水从天空降下 and rain falls down from the skies -
数百亿个家园可供生命 billions of homes for life.
人类历史上的第一次 For the first time in human history,
我们有机会一见我们的孪生行星 we have the possibility of glimpsing our planet's twin.
第二个地球 A second Earth.
也许，只是也许，我们并不孤独 Perhaps, just perhaps, we have company.
这是一个可爱的想法，就是也许有一天 And it's a lovely thought that maybe one day
航海家，我们在银河里的瓶中信 Voyager, our galactic message in a bottle,
会漂流到某一个星球 might encounter such a planet.
MUSIC: Johnny B Goode by Chuck Berry
# Deep down in Louisiana, close to New Orleans... #
SONG FADES INTO DISTANCE
地球之音被冲上遥远的彼岸 The sounds of Earth may wash up on a distant shore.
问题是，那里会有人在聆听吗？ The question is, will there be anyone around to listen?
德雷克公式中一个决定性的条件， The final turns in the Drake equation shift the focus
把焦点从天文学转移到了生物学 from astronomy to biology...
这要从处理一个， ..and they begin by tackling
科学上长久以来最神秘难解的问题开始 one of the most enduring mysteries in science -
问题是这样的，生命有多常… ..the question of how often life
自发性的出现在星球上 spontaneously arises on a planet.
一个大问题是我们只有一种生命样本 The problem is that we only have one example of life
在整个宇宙之中 anywhere in the universe.
你可能会觉得我这么说很奇怪 Now you may think that's a strange thing to say -
这里有我，那里有鱼 there's me, there's fish,
有珊瑚，还有昆虫 there's coral, insects -
数以万千你可以举例的生物 all the living things you could imagine.
但了不起的地方就是，我们在化学组成上都是一样的 But the remarkable thing is we're all chemically the same,
以生物化学来说 in a biochemical sense.
我们的基本组成原素都是相同的 We all share the same basic building blocks.
而那是因为我们的祖先都是同样的 And that's because we're all descended
来自38亿年前的共同祖先 from the same common ancestor 3.8 billion years ago.
这里是极少数的地方你可以观察到活的建筑结构 This is one of the very few places where you can see living structures
使人想起了地球最早期的生命 reminiscent of early life on Earth.
像外星一样的景观你在这里所见的 Well, this alien-looking landscape that you see here
是一种叫叠层石的结构 is made of structures called stromatolites.
我现在要做的是，拨一小块下来 What I'm allowed to do is break a piece off...
它看起来像石头 It looks like rock.
但是你可以看到，它其实不是石头 But, you see... it's not really rock,
他被藻类包覆着，触感其实很软 it's covered in a bit of algae and it's quite soft to the touch.
他们是由细菌作用形成的 They're formed by the action of bacteria,
具体的说，在这个例子，是蓝菌 specifically, in this case, Cyanobacteria.
事实上在蓝菌里，现在我们知道 In fact inside Cyanobacteria, it's now known,
是光合作用第一次演化出来的地方 is the place where photosynthesis first evolved.
像这样的结构，曾经是 }Structures like these would have been the only visible signs
地球上唯一可见的生命 of life on Earth
大概20亿年 for perhaps two billion years.
这就是原始海洋看起来的样子 This is what the primordial ocean would have looked like.
虽然没有活生生的例子 Whilst there are no living examples
对于在叠层石之前出现的生命 of what came before the stromatolites,
我们发现的迹象显示，生命甚至在更早一些 we've found clues that life was around even earlier.
这是非常强大的证据 There's very strong evidence
显示生命是大约38亿年前开始出现在地球上 that life on Earth began around 3.8 billion years ago,
可以说是能多快就有多快的出现 which is pretty much as soon as it could have begun.
拼凑出这些证据，显示出生命， So that's taken as one piece of evidence to suggest that life,
只要给他适当的条件，是不可避免的 given the right conditions, is inevitable.
当然，有很多科学家 Indeed, there are many scientists
认为生命可能在不久的将来 who think that life may be created in a laboratory
可以在实验室创造出来 in the not-too-distant future.
所以这代表多数的科学家，我觉得 So that means that most scientists, I think,
猜想我们会在遥远的某处找到简单的生命 suspect that we will find simple life somewhere out there.
这是令人目眩的想法 It's a dizzying thought.
如果他们是对的，适居带的星球会导致生命 If they're right, and habitable planets do generate life,
那么数百亿个在银河中那样的星球 then with billions of such planets out there in the galaxy,
无疑的一定会有第二个创世纪 surely there must've been a second genesis
但是我们必须要小心，因为这个星球上的生命故事 But we must be careful, because the story of life on this planet
显示了从单细胞生物转变为复杂生物的过程 shows that the transition from single celled life to complex life,
也许不是不可避免的 may not have been inevitable.
生命必须战胜重重的演化瓶颈 Life had to overcome a significant bottleneck.
今天，所有我们称为复杂生物的 Everything we would call a complex living thing today,
共享着同样的基本结构 shares the same basic structure -
由真核细胞所建造 it's built out of cells called eukaryotic cells.
所以，简单的说，每一颗树 They're, roughly speaking, the same in every tree,
每一根草，每一条鱼，所有的昆虫 every blade of grass, every fish, every insect
甚至每一小片我膝盖上的皮肤 }and even in every piece of skin in my knee -
我身体内的每一个细胞 every cell in my body -
都是真核细胞 is a eukaryotic cell.
他们有非常大的不同和那些单细胞相比 And they're extremely different to the simple cells,
那些行光合作用的蓝菌 the bacteria that we've seen photosynthesising
我们在叠层石里面所看到的 in the stromatolites.
那这些细胞是怎么开始出现的？ So how did those cells come to exist?
一个被大家接受的理论是，是两个单细胞结合在一起 One popular theory is that it was two simple cells merging together
最后形成我们今日所见 that formed what we'd recognise today
这些你体内的复杂细胞 as the complex cells in your body.
不知怎么的，侵入者在宿主细胞的防卫中生存了下来 Somehow the invader managed to survive the host cell's defences.
而当细胞繁殖时，他们一起繁殖 And when the cells reproduced, they reproduced together.
我们仍然努力在了解这是如何发生的 We still struggle to understand how this happened,
因为这是让人难以置信的 because it's incredibly unusual.
这里是重点，因为地球上所有的复杂生命 Here's the point - because every complex animal and plant
都共享着同样的基本组成原素 shares that same basic building block
所以我们可以很肯定的说，这只发生了一次 we are very confident that it only happened once -
在原始地球海洋中的某处 somewhere in the oceans of the primordial Earth.
生物学家把这个结合称为 "命运的相遇"假说 Biologists call this merger the Fateful Encounter hypothesis,
一个很好的理由 for a good reason.
看起来这种两个简单生命形式的结合 It seems that that kind of merger between two simpler life forms
可说是极端罕见的 may be extremely rare.
一个有机生物进入另外一个 The idea that one organism can get inside another
但没有被杀死 and doesn't kill it -
他们一起生存下来，去做一些事 that they both survive to produce something
这让他们有了能力去做出那最壮丽的事 that's actually capable of doing magnificent things,
那些你能想像最复杂、最美妙的事 things that are far more complicated and wonderful
两个最简单的基本原素可以自已结合在一起 than the two simple building blocks can manage on their own
这似乎是，似乎是不可能的 seems to be... It seems to be unlikely,
"命运的相遇" a "fateful encounter".
如果是这样的话，那也许我们可以说 If that's the case, then that may suggest that complex life -
复杂的生命，有智慧的生命，在宇宙中是极端罕见的 that intelligent life - is extremely rare INDEED in the universe.
可能有一个巨大的瓶颈 Maybe there is a profound bottleneck
存在于银河系复杂生命演化过程 in the evolution of complex life in the Milky Way.
这也许就是为什么我们还持续沉浸在 And perhaps this is why we continue to bear
这无边的寂静之中 the great silence.
但是这里的生命，通过了瓶颈 But life here, did squeeze through.
而我们星球的例子显示，一但他通过 And the story of our planet suggests that after it did
所有的枷锁就松脱了 all hell broke loose.
只要给他适当的条件 So given the right conditions
于是5亿5千万年前 then 550 million years ago,
至少，在地球这里 at least, here on Earth,
"寒武纪大爆发"发生了 the Cambrian explosion happened
所有这些…，像达尔文说的 and all the...what Darwin called
"无尽的形式，无尽的美丽" endless forms most beautiful"
这些我们在地球上可看到的 that we see on this planet,
几乎是以一眨眼的速度出现 emerged almost in the blink of an eye
包含了一个文明 including one civilisation,
一个智慧的文明 an intelligent civilisation,
他们一路走来，最终 that's managed, ultimately,
有能力能发射太空船 to begin to launch spaceships
飞出我们的太阳系进入星空 beyond our solar system into the stars,
而且，看起来 and, it seems,
也产生了会泳游的猪 has also produced aquatic pigs!
这就是奇蹟 Such is the wonder
演化中的的自然选择 of evolution by natural selection
我要说 which I would argue
这就是大自然的规则 is a law of nature.
任何地方只要有适当的条件 Anywhere you get the right conditions
你就会得到 you will get...
得到这样的动物 You'll get animals like this.
就在寒武纪大爆发的1亿年之后 Just 100 million years after the start of the Cambrian explosion
我们的祖先从海里爬了出来 our ancestors crawled from the oceans...
对宇宙来说一眨眼的时间 And in the cosmic blink of an eye,
演化出了一个追根究底的物种 evolution threw up an inquisitive species
喜欢去问关于这个世界的各种问题 prone to asking questions about the world around it.
如果你对沟通有兴趣 If you're interested in communicating
和外星文明沟通 with an alien intelligence
那么一个问题很自然的浮现了 then I suppose a natural question arises, which is -
除了人类，地球上还有其他的生物 Are there animals on Earth other than ourselves,
有足够的智慧和他们沟通吗？ that are intelligent enough to communicate with?
在早期，SETI的历史中 Now, early on in the history of SETI
有一种动物得到了一致性的赞扬 there was one animal in particular that got an iconic reputation -
事实上，Frank Drake, Carl Sagan, John Lilly in fact, Frank Drake, Carl Sagan, John Lilly,
和其他SETI的开创者 and the other SETI pioneers
以这种动物的名字，把自已称为 called themselves, named themselves, after this animal -
他们称自己为"海豚的士兵" they called themselves The Order of The Dolphin.
在1960、70年代，John Lilly 个人 And, indeed, in the '60s and '70s, John Lilly, in particular,
进行了一系列先进的实验 carried out a series of increasingly eccentric experiments
想试着与海豚沟通 to try and communicate with dolphins.
海豚有着杰出的 Dolphins remain at the forefront
跨物种沟通能力 of inter-species communication efforts.
你的傻笑呢？ Where's your giggle?
VOCALISES A RAPID STUTTER
BLOWS WHISTLE
很好！ Good!
目前，并没有什么意义深长的对话 So far, there have been no meaningful conversations -
然而，有一只海豚 however there is a dolphin
在佛罗里达的Grassy Key研究中心 in the Grassy Key Research Centre in Florida
展现了他的高度智慧 that demonstrates a form of intelligence.
他是一只13岁的瓶鼻海豚男孩，叫Talon He's a 13-year-old bottlenose male called Talon.
好孩子 Good boy.
好的，Brian, OK, Brian.
我们要找出Talon是否能够了解 We're going to find out whether Talon can understand
关于多和少这样的抽象概念 the abstract concept of more or less.
好的，我们要做的就是把这些板子放上去 OK, so what we're going to do, Brian, is put these boards up
然后Talon要选出那块有较少圆点的板子 and Talon's going to choose the one that has the least amount of dots.
圆点的数量是由电脑随机生成的 The dots are randomised by the computer,
正确答案可能在任何一边 and the side of the correct answer.
先把这块放上来 So put this one up first.
好，所以永远先放左边的？ Oh, yeah. So always the left first?
先放左边的 Always the left first.
这样的话如果Talon从另外一边看到了 That way if Talon's watching from the other side -
就算我们已经有这个遮住了 even though we have these little blinders -
我们也不给他任何线索 we're not giving him any kind of cues,
来推测正确答案可能是在哪一边 on which side the correct answer might be on.
左边的先放 Left board up first...
TALON SPLASHES BRIAN CHUCKLES
嘿，小兄弟！ Yeah. Hi, buddy!
那是Talon,他在看 That is Talon. He is looking.
大多数的人类从很小开始， Most humans acquire the ability to distinguish between
就具备了能够分辨出数量大小的能力 numerical amounts fairly early in life -
差不多在6个月大的时候 at around the age of six months.
Talon!
这个实验要测试海豚是否有一样的感知能力 The experiment tests if dolphins share the same cognitive ability.
少 Less.
正确 Yes!
好，你可以把板子举上来…太棒了！ Yeah, you can move our hands back out... Excellent!
少 Less.
正确 Yes!
做的好，Talon！ Yeah, good job, Talon!
这是一个有趣的例子 This is quite an interesting example
因为这一个有5个圆点，另一个是6个 because this one's five and this one is six
但是因为分布的区域和方式不一样 but because of the difference in area, and placement,
我想就算是人类也要花一点时间看 I think it does take a while even for a human to look at it.
我们会做的大概就是去数它们 Probably, what we'd do, is count them.
少 Less!
正确 Yes.
毫不犹豫。你看到他有多快吗？ - Straightaway. - You see how quickly he chose that?
很让人佩服，真的 That was impressive, actually.
他甚至在指令下达之前就已经靠近板子了 He was actually going for that board before she even gave him the signal.
我们不了解Talon是如何处理这些资讯的 It's not known how Talon processes the information,
但他的成功率是令人关注的 but his success rate is interesting.
好的，非常棒！ All right. That was awesome!
做的好，Talon Good job, Talon.
这个实验结果显示了海豚具备着 What this experiment shows is that dolphins exhibit
我们所谓高级智慧的行为能力 a kind of behaviour that we associate with intelligence -
科学家称这个为"相对数量感" scientists call it relative numerosity -
这能力让你能说出哪一块板子有较多圆点 the ability to say which board has got more dots on it.
而这很有意思 And that's interesting,
因为如果你问 because if you ask the question -
我们和海豚的共同祖先在哪里？ Where is the common ancestor between me and a dolphin?
你必须要往回追朔到大约9,000万年前 - you've got to trace the timeline back about 90 million years.
那个时候恐龙还生活在地球上 That's when dinosaurs were on the Earth.
所以我们的共同祖先肯定没有辨法做到这样 So our common ancestor certainly wouldn't be able to do that,
没有辨法展现出这种智能 wouldn't exhibit that kind of intelligence.
所以事实上，不同种类的智慧在地球上形成很多次 So intelligence of a sort has arisen actually many times on Earth.
但从SETI的观点来看 But from the point of view of SETI -
搜寻地外文明计划 the Search for Extra-Terrestrial Intelligence -
这一点也不重要 that doesn't matter, at all.
我们需要一个文明可以懂得天文学 We need a civilisation that can do astronomy,
可以制造电波望远镜或太空船 that can build radio telescopes or spacecraft,
可以留下足迹 that can leave a signature
或传送信息能让我们识别 or send a message that we can recognise.
这可能是最难解的谜题 This is perhaps the greatest mystery.
我们根本无法知道复杂、有智慧的生命 }We simply don't know how often complex, intelligent life...
有多常可以发展成为高科技文明 ..develops into a technologically advanced civilisation.
我望着高挂天空的月亮 # I watch the moon hang in the sky
我感受到急促的行进 # I feel the traffic rushing by
黑夜中火车的引擎声 # Freight train engine in the night
我仍在这里 # I'm still here
等待着你 # Waiting for you
我望着高挂空中的月亮 # I watch the moon hang in the air
我感觉冷风吹过我的头发 # I feel the cool breeze through my hair
那眩目的光让我盲目 # My eyes' blind by her light's glare
我仍在这里 # I'm still here
等待着你 # Waiting for you... #
就在30年前 Just three decades ago,
我们不知道任何一颗太阳系外的行星 we knew of no planets beyond our solar system.
今天我们已经找到数千颗 Today we've found thousands of them
并推测还有数百亿颗在那里 and suspect that there are billions more.
我们对生命起源的知识也愈来愈深 Our knowledge of the origin of life has also deepened,
就和我们对人类自身的演化过程一样 as has our understanding of our own evolution.
我仍在这里 # I'm still here
等待着你 # Waiting for you... #
所有的一切都让我不禁去想 All this leads me to think that there must be
星系某处一定有 at least simple life
至少是简单生命的存在 elsewhere in the galaxy.
为了所有我们受过的苦 # For all the pain we saw... #
目前为止，沉默依旧 Yet the silence persists.
我们依然孤独 We remain alone.
我仍在这里 # And I'm still here
等待着你 # Waiting for you... #
这是一个难题 It's a puzzle,
但我觉得复活节岛 but I think Easter Island
也许可以给我们一个答案 may offer us an answer.
这个文明与世隔绝的生存了超过1,000年 The civilisation here survived in isolation for over 1,000 years...
直到300年前 ..until, 300 years ago,
它消失了 it vanished,
只留下了这些 leaving behind only a handful
孤独的石像 of stone statues.
看起来事情的经过是 What seems to have happened
他们耗尽了这个小岛的资源 is that they used the resources of this tiny island,
砍倒了所有的树 chopped all the trees down,
杀光了所有的动物，他们过度使用土地 they killed all the animals, they overused the land,
人口成长快速 the population grew too big,
导致了战争 they started warring,
他们推倒了自已的石像 it's thought that they toppled their own statues
不同部落间的战争不断 in battles between rival villages
最后，实质上来说，他们自已毁灭了自己 and so they essentially destroyed themselves.
这个文明瓦解很好的说明了 This collapse speaks powerfully
德雷克公式的最后一个要件 to the last factor in the Drake equation -
文明的存在时间 the length of time a civilisation lasts.
你可以想像 Imagine there are,
那里曾有着几千个，数百万个文明 and have been thousands or millions of civilisations
存在于银河系的历史之中 in the history of the Milky Way galaxy -
想像他们的生命是短暂的 and imagine their lifetimes are short.
不管他们是如何分布在时空之中 No matter how they're distributed in space and time...
他们从来没有重叠 ..they never overlap.
而我觉得这让人醒悟 And I think this is quite a sobering thought -
我们从来没有 the reason we have never
以后可能也不会听到 and WILL never hear
任何其他文明的原因 from any other civilisation,
是因为这些文明没有一个可以存在的够久 is because none of them ever last long enough
去和彼此沟通 to contact each other.
但我觉得这不是一个必要的答案 But I don't think that's necessarily the answer.
我觉得拉帕努伊人民的故事 I think the story of the Rapa Nui people
暗示了其他的事 hints at something else.
他们的岛曾经是最后目的地 Their island was the final destination
从人类殖民化地球开始 of the human colonisation of Earth.
这段旅程把我们带回自东非的起源开始 A journey that took us from our origins in East Africa
横跨了整个地球 to across the planet
在不到60,000年的时间 in less than 60,000 years.
而我觉得一个先进的外星文明 And I think a sufficiently advanced alien civilisation
会借镜这个殖民化过程 would mirror this process of colonisation.
在1940年代，数学家 John von Neumann In the 1940s, the mathematician John von Neumann
有了一个想法，就是建造一座 thought about the possibility that we could build
自我复制机 self-replicating machines -
他称作 "通用建造器" he called them Universal Constructors.
可以成为我们的太空探测器，飞出太阳系 So these would be space probes that could fly out to a solar system,
降落在小行星上，或是月球，或是其他星球 land on an asteroid, or a moon, or a planet,
然后它开采资源 and then mine the resources
然后它们进行自我复制 they needed to copy themselves.
这样的话自我复制机可以散布出去 In this way von Neumann's replicating machines could spread
到整个星系之中 across the entire galaxy...
就和人类散布到整个地球上一样 ..just as humans spread across the Earth.
想想玻里尼亚人殖民化太平洋岛屿 Think about how the Polynesians colonised the Pacific islands -
他们航行横跨大海 they sailed across the ocean,
他们停在无人居住的土地像是复活节岛 they landed on some uninhabited rock like Easter Island,
然后他们利用岛上的资源 and they used the resources they found there
进行自我复制 to make copies of themselves.
我们称作繁殖 We call it breeding.
今日，现代电脑模拟显示 Now, modern computer models suggest
像这样的策略可以让先进的外星文明 that such a strategy would allow an advanced alien civilisation
殖民整个银河系，只需要1,000万年的时间 to colonise the entire Milky Way galaxy in only ten million years -
对宇宙时间来说，只是一眨眼 the blink of an eye in cosmic time.
这些听起来像科幻小说 All this sounds like science fiction,
但如果这个理论是可行的 but if they're possible in principle
那么你也许会有这样的疑问 then you have to construct some kind of argument
为什么我们没有看到他们 as to why we don't see them,
而我没有辨法反驳你 and I can't construct one.
这也困扰着我 It bothers me.
这代表着如果某个高度先进的文明存在 It follows that if such an advanced civilisation had existed,
我们应该会知道 we'd know about it.
我们应该会看到一台自我复制机 We'd have encountered one of von Neumann's machines.
而我想这显示了只有一个 And I think that suggests that there is only one
先进科技文明在银河系中 technologically advanced civilisation in the Milky Way,
而且只曾经有过一次 - 那就是我们 and there only has ever been one - and that's us.
我们是独一无二的 We are unique.
有没有可能我们独自 Could it be that we alone
通过了重重关卡 have passed through the evolutionary bottlenecks
通过了那看来会阻碍文明 that seem to have prevented civilisations
出现的演化瓶颈 from arising elsewhere?
如果答案是YES, If the answer is yes,
我们是唯一的智慧文明 we are the only intelligent civilisation
在星系之中 in the galaxy,
那让我们成为了无比珍贵的瑰宝 and that makes us indescribably precious and valuable.
我们是唯一有意义的孤岛在无尽的宇宙银河之中 We are the only island of meaning in an infinite sea of lonely stars.
先让我不要在这里过度浪漫和感性 And without wishing to be overly romantic or sentimental about it,
在我看来这似乎授予了我们一个责任 that would seem to me to confer on us a responsibility -
必须要把这个文明维系下去的责任 the responsibility to act together as a civilisation to survive
然后，最终，去探索那些星系 and, ultimately, to explore those stars.
"我是联合国秘书长" "As The Secretary General of the United Nations
"我代表地球人民向您问候" "I send greetings on behalf of the people of our planet."
"你好，这是来自地球上的儿童" - SMALL CHILD: - 'Hello, from the children of Planet Earth...'