一一一笨鸟字幕一一一 因为爱好而翻译此字幕
外星人 narrator: Aliens...
小绿人 Little green men.
一千只眼睛或一只眼睛 A thousand eyes or one-eyed.
……科幻电影中的怪物 Narrator: ...Sci-fi movie monsters.
自由浮动的触角 Free-floating with tentacles.
某种未知的超先进文明 Some unknown hyper-advanced civilization.
科幻小说能成为现实吗？ Narrator: Could science fiction ever become fact?
我认为好莱坞对第一次 I think it's really simple why hollywood
与外星人接触的概念着迷的原因很简单 is fascinated with the concept of first contact with aliens,
因为那可能是人类历史上 because that would be probably the greatest
最伟大的科学发现 scientific discovery in all of human history.
问题是，我们的宇宙创造了巨大的障碍 Narrator: Problem is, our universe creates massive barriers
来阻挡我们遇见外星人 to meeting extraterrestrials.
这就好像是宇宙故意阻止我们 It's almost as if the universe is deliberately
进行第一次接触 stopping us from making first contact.
我们在探索宇宙 Narrator: We're searching the cosmos.
我们会找到有智慧的外星生命吗？ Will we ever find intelligent alien life?
还是只有我们？ Or are we alone?
宇宙是如何运行的 本字幕翻译自Discovery官方指定字幕
第八季第2集 寻找外星人证据 本字幕翻译自Discovery官方指定字幕
[爆炸] [ explosion ]
♪
波多黎各的阿雷西博天文台 <波多黎各——西印度群岛中的大安的列斯群岛东端岛屿> arecibo observatory, puerto rico.
45年前，它向太空深处发送了一个强大的 45 years ago, it sent a powerful radio message
无线电信息 deep into space,
开始了我们第一次联系的努力 kickstarting our efforts to make first contact.
帕西尼:阿雷西博的信息是第一次 Pacini: The arecibo message was the first communication
与银河系或银河系外 or attempt to communicate with a possible civilization
可能存在的文明进行交流的尝试 out there in the galaxy or outside of our galaxy.
今天，这条信息 Narrator: Today, that message is speeding towards
正在向2.5万光年外的 the m13 galaxy cluster
m13 星系团加速 25,000 light-years away.
它包含关于我们世界的信息—— It contains information about our world --
我们在哪里 where we are,
甚至我们 dna 的组成 even the makeup of our dna.
帕西尼:这条信息的目的，当然 Pacini: The purpose of this message was, of course,
就像，试着打个招呼 like, trying to say hi,
也像是提出这个问题： and also, like, to light up this question about,
我们是宇宙中唯一的吗？ are we alone in the universe?
但是一个智慧的外星种族 Narrator: But what chances are there
在那里等待接收我们的信息的机会 that an intelligent alien race is out there
有多大呢？ waiting to receive our message?
宇宙中还有 Do I think there's other intelligent life
其他智慧生命吗？ out there in the universe?
答案是肯定的 是的,我肯定 The answer is a resounding yes. Yes, I do.
我们知道，地球上的生命 We know that life began on earth
几乎是在地球固化后开始的 pretty much as soon as our planet solidified.
那为什么在其他地方不会发生这种事呢？ So why wouldn't that have happened somewhere else?
如果生命在其他星球上进化 Narrator: If life has evolved on other worlds,
那么我们可能接触到的 just how many alien civilizations
外星文明到底有多少呢？ are out there that we could potentially contact?
天文学家弗兰克·德雷克提出了一个方程 Astronomer frank drake developed an equation
来帮助回答这个关键问题 to help answer this crucial question.
德雷克方程是一个非常令人钦佩的尝试 The drake equation is a really admirable attempt
它将定量推理应用到 to apply some quantitative reasoning
地球之外存在生命的 to the probability, or the possibility,
可能性上 that there is life beyond the earth.
弗里兹:用我们星系中 Freese: You multiply the star formation rate
恒星的形成概率 for stars in our galaxy
乘以每颗恒星的 times the number of planets that each star has
行星数量 times the probability
乘以在这颗行星上有生命形成的概率 that you would have life forming on that planet
再乘以生命形式变得有智慧的概率 times the probability that that life form becomes intelligent.
他们估计在我们的星系中 And they estimated that there were about
大约有10000个智慧文明 10,000 intelligent civilizations within our galaxy.
♪
自从德雷克方程第一次被提出以来 narrator: Since the drake equation was first proposed,
我们对星系的理解已经发生了根本的转变 our understanding of the galaxy has radically transformed.
我们现在已经发现了太阳系外的世界—— We have now discovered worlds outside our solar system --
系外行星 exoplanets.
菲利平科:太阳系外行星到处都在被发现 Filippenko: Exoplanets are being discovered all over the place.
现在已知的大约有4000种 There are about 4,000 of them now known,
而且现在的技术每天都在发现更多 and techniques are finding more every day.
科学家们相信我们的发现 Narrator: Scientists believe what we've found
只是冰山一角 is the tip of the iceberg.
所以，如果宇宙如此善于制造行星 So if the cosmos is so good at making planets,
也许它可以创造出 perhaps it can produce the conditions
在宇宙中制造生命的条件 to make life throughout the universe.
当德雷克方程在几十年前被提出来的时候 When the drake equation was devised all those decades ago,
我们还不知道系外行星的存在 we didn't know that exoplanets existed.
现在我们认为行星的数量 And now we think that there are quite literally more planets
比宇宙中恒星的数量还多 than there are stars in the universe.
所以，即使生命非常罕见 So even if life is really rare,
它也有大量的机会 there are an enormous number of chances
在宇宙中扎根 for it to take hold in the universe.
由于这个原因，宇宙中很可能 And for this reason, it is very likely that
存在相对丰富的生命 there is life relatively abundant in the universe,
包括数不清的先进的外星文明 including an uncountable number of advanced alien civilizations.
这不是科幻小说 This isn't science fiction.
这是基本概率 It's just basic probability.
可能性表明 Narrator: Probability suggests
有很多外星文明的存在 a multitude of alien civilizations are out there.
所以我们还没有进行第一次联系是不是有点奇怪？ So isn't it a little strange we haven't made first contact?
塞勒:我认为有充分的理由相信 Thaller: I think there's every reason to believe
那里有文明存在 that there are civilizations out there,
但我们还没有证据 but we have no evidence of them yet.
为什么我们还没有在那里发现其他文明？ Why haven't we found other civilizations out there?
一个答案可能是 Narrator: One answer could be
宇宙的巨大 the sheer vastness of the cosmos.
布洛克:看看窗外的 Bullock: Look at all these lights out here
这些灯光 over the cityscape.
你可以把这些光想象成，银河系中的星星 You could think of these lights as, like, stars in the galaxy.
现在，如果银河系中有10000个 Now, if there's 10,000 communicating civilizations
可以交流的文明，你可能会想，“哦，天哪，看” out there in the galaxy, you might think, "oh, man, look.
“街那头就有一家” There's one right there right down the street."
问题是 the problem is
银河系中有数千亿颗恒星 there are hundreds of billions of stars in the galaxy,
这意味着我们可以与之交流的最近的邻居 which means that maybe our nearest neighbor
可能并不在那里 that we can communicate with is not right there
而是在城市的另一边 but way across the city.
我们住在银河系的郊区 Narrator: We live in the suburbs of the milky way
离最远的边缘有七万五千光年远 75,000 light-years from the furthest edge.
无线电信号以光速传播 Radio signals travel at the speed of light.
这一速度限制意味着 This speed limit means that any signal sent
任何发送到星系另一边的信号 to the opposite side of the galaxy
都需要75000年才能到达目的地 would take 75,000 years to reach its destination.
布洛克:你要记住的是 Bullock: The thing you have to remember
银河系是巨大的 is the galaxy is gigantic.
即使银河系中有10000个文明 Even if there are 10,000 civilizations in the galaxy,
也有可能恒星之间的距离太过遥远 it's possible that the distances between stars are just so huge
以至于我们永远无法相互交流 that we're never gonna be able communicate with each other.
所以45年的阿雷西博无线电信息 Narrator: So the 45-year-old arecibo radio message
可能还需要数万年的时间才能到达 could still be tens of thousands of years away
任何潜在的外星文明 from any potential alien civilization.
目标距离这里25000光年 The target was 25,000 light-years from here.
信息现在距离这里45光年 The message is now 45 light-years from here
因为它以光速传播 'cause it's traveling the speed of light,
所以它离目标还很远 so it's really far from the target.
浩瀚的宇宙是第一次接触的 Narrator: The vast size of the universe is a huge roadblock
巨大障碍，物理学定律 to making first contact, and the laws of physics
阻止了无线电信号克服它 prevent radio signals from overcoming it.
你的速度不能超过光速 You just cannot go faster than the speed of light.
所以我们的星系也许充满了生命，充满了文明 So our galaxy may be filled with life, filled with civilizations,
但它们太遥远了 but they're so far away.
特朗布莱:我不想告诉你坏消息 Tremblay: I don't want to be the bearer of bad news.
但宇宙实在是太大了 But the universe is just really, really far too large.
宇宙也许很大 Narrator: The universe may be large,
但是我们正在使用地球上 but we're putting the most advanced technology on earth
最先进的技术来加速搜索 into action to try and speed up the search.
确实有一个严肃的、科学的 There really is a serious, scientifically valid way
有效的方法去寻找其他文明 to go looking for other civilizations.
这个突破性的倾听项目 And the breakthrough listen project is really
是我们目前最好的项目 the best thing we have right now.
世界上最先进的设备—— State-of-the-art facilities around the world --
射电望远镜，光学望远镜—— radio telescopes, optical telescopes, as well --
都在一起仰望天空 are all looking up to the sky together.
“突破倾听”的目标是100万颗恒星 Narrator: Breakthrough listen is targeting the 1 million stars
和100个离地球最近的星系 and 100 galaxies closest to earth.
这是迄今为止对外星通讯 It is the most comprehensive search
进行的最全面的搜寻 for alien communications ever undertaken.
如果有一架飞机发出雷达信号 If there was an aircraft giving off a radar signal,
而这架飞机在离我们最近的1000颗恒星中的任何一颗恒星附近 and that aircraft was around any of the 1,000 nearest stars,
突破性的侦听项目就可以听到这些信号 the breakthrough listen project could hear that.
所以，如果有什么东西 So if there's something out there
真的在发出信号 that's actually giving off a signal,
突破性的倾听就有机会找到它 breakthrough listen has a chance to find it.
突破性的倾听从收听离地球最近的 Narrator: Breakthrough has started by listening in
1700颗恒星开始 on the nearest 1,700 stars to earth.
有进展了吗？ So far?
一片寂静 Silence.
泰勒:这就是我们发现 Thaller: This is the wonderfully,
自己所处的奇妙而又令人沮丧的境地 beautifully frustrating position that we find ourselves in.
我们还没有听到任何消息 We haven't heard anything yet.
所以我们现在的处境是 So we're in this position where a negative result
否定的结果并不意味着没有文明存在 doesn't mean there aren't civilizations,
但我们没有证据证明有其他文明的存在 but we have no proof that there are.
“突破倾听”才刚刚开始寻找 Narrator: Breakthrough listen is just beginning its hunt.
宇宙中有更多的空间 There's much more real estate in the cosmos
供它探索 for it to search.
这是一项艰巨的工作，需要大量的耐心 It's a big job, demanding a lot of patience.
普莱特:如果你通过 Plait: If you go through drake's equation
德雷克方程 and find this number
找到10000个智能文明 of 10,000 intelligent civilizations out there,
银河系中大约有2500亿颗恒星 there are something like 250 billion stars in the galaxy,
所以每2500万颗恒星中只有1个文明 so that's only 1 civilization per 25 million stars.
这是是有多“冷”的电话 That's a lot of cold calling.
我们宇宙的大小意味着 Narrator: The size of our universe
我们可能要等很长一段时间 means we could be waiting a very long time
才能接收到任何外星人的信息 to pick up any alien communication.
但即使我们接收到信号 But even if we pick up a signal,
它也可能来得太晚了 it may have arrived too late.
奥卢西:如果我们真的收到信息 Oluseyi: If we do receive a message,
考虑到它可能花了很多年才到达这里 given that it probably took years to get here,
那个文明说不定早就消失了 that civilization could be long gone.
那么我们是不是太迟了？ Narrator: So are we simply too late?
是否有可能外星人已经灭绝了？ Have any aliens out there already died out?
[爆炸] [ explosion ]
地球已经绕太阳运行了 narrator: Earth has orbited the sun
45亿年 for over 4.5 billion years,
这段时间足以让人类进化成 time enough for humankind to evolve into an intelligent
一个智慧的、技术先进的物种 and technologically advanced species.
但与宇宙的年龄相比 But compared to the age of the universe,
地球还只是个孩子 planet earth is just a kid.
普莱特:地球已经有45亿年的历史了 Plait: The earth is over 4 1/2 billion years old,
我们认为它花了这么长时间 and we think it's taken this long
才创造出第一个科技文明—— to create the first technological civilization --
我们人类 us.
有一些恒星系统比我们的年龄大得多 There are star systems out there much older than we are.
宇宙有138亿年的历史 The universe is 13.8 billion years old.
卡罗尔:我们总觉得自己很了不起，对吧？ Carroll: We tend to think we're hot stuff, right?
我们有技术能力，我们可以建造火箭 We're technologically capable, we can build rockets,
我们可以收听无线电波 and we can listen to radio waves.
但一个典型的其他智慧先进文明 But a typical other intelligent advanced civilization
在技术上确实比我们领先 would be literally millions of years ahead of us
数百万年 in technology.
如果一个外星社会比我们存在的时间更长 Narrator: So if an alien society has been around longer than us,
那么他们的技术会先进多少？ how much more technologically advanced could they be?
卡尔达肖夫指数 One method of measuring just how much
提供了一种测量的方法 is provided by the kardashev scale.
特朗布莱:卡尔达肖夫指数 Tremblay: The kardashev scale classifies
将潜在的外星文明分为三种类型 potential alien civilizations into three types
就是基于他们能够从当地环境中 based on the amount of energy that they're able to harness
利用的能量 from their local environment.
第一类文明只能利用 A type-one civilization can harness the energy
其母星的能量 of only its home planet.
第二类假设可以利用 Type-two could hypothetically harness the energy
母恒星的能量 of its own solar system.
第三类可以利用整个星系的 And a type-three could harness the energy
潜在能量 potentially of an entire galaxy.
如果你想知道我们在这个范围内处于什么位置 Narrator: If you're wondering where we fit on that scale,
请准备好听到一些坏消息 prepare for some bad news.
我们在0和1之间 We are somewhere between zero and a one.
我们不能利用地球上所有的资源 We can't use all of earth's resources.
大概是0.7 So we're at about a 0.7.
一个先进的物种达到卡尔达谢夫2级 Narrator: An advanced species reaching kardashev level two
甚至3级 or even three
就可以创造出高度先进的结构 could create highly advanced structures
来利用恒星的能量 that can harness the power of a star.
普莱特:如果你成为一个足够先进的文明 Plait: If you get to be an advanced enough civilization,
而你的能源需求又非常巨大 eventually if your energy demands are so huge,
最终你可能会建造太阳能电池板 you might build solar panels
把你的恒星包裹起来 that you have enveloped your star.
这是由弗里曼·戴森首先想到的 This was first thought of by freeman dyson,
所以我们称这之为戴森球 and so we call these dyson spheres.
如果这种史诗般的工程 Narrator: If such epic engineering occurs
发生在其他恒星系统甚至其他星系 in other star systems or even other galaxies,
我们能否找到一些证据 could we pick up some evidence
然后进行第一次接触？ and then make first contact?
普莱特:戴森球的特点是 Plait: The thing about a dyson sphere is that
你已经完全阻挡了 you've completely blocked
恒星发出的所有光线 all the light coming out from a star,
除了红外线 except for the infrared
因为这些面板吸收了阳光 because these panels are absorbing that sunlight
并且正在升温 and warming up.
当你加热一个物体时 When you warm up an object,
它会发出所谓的热红外光 it gives off what's called thermal infrared light.
你可以扫描天空寻找这个信号 You can scan the skies looking for that signature
看看那里是否有任何的戴森球 to see if there are any dyson spheres out there.
2015年—— Narrator: 2015 --
美国航空航天局的广域红外探测探测器 nasa's wide field infrared survey explorer
扫描了10万个附近的星系 scanned 100,000 nearby galaxies
通过观察从戴森球泄漏出来的红外光线 to locate advanced kardashev civilizations
来定位先进的卡尔达肖夫文明 by observing infrared light leaking away from dyson spheres.
他们的搜寻结果…… They detected...
什么都没有 Nothing.
菲利平科:没有发现这样的星系 Filippenko: No such galaxy was found,
所以他们没有找到任何红外线确凿证据 so they didn't find any infrared smoking gun.
考虑到我们的宇宙如此古老 Narrator: Given our universe is so old,
其他文明当然应该有时间进化 surely other civilizations should have had time to evolve.
如果是这样，也许我们只是错过了它们 If so, maybe we've simply missed them.
普莱特:完全有可能出现了文明 Plait: It's entirely possible that civilizations arose,
试图与他们周围的星系交流 tried to communicate with the galaxy around them,
问题是他们对我们的请求太早了 and the problem was they were asking too early for us.
他们想敲我们的门 They're trying to knock on our door,
但我们的房子还没建好 but our house wasn't built yet.
地球已经存在了宇宙138亿年寿命的 Narrator: Earth has been around for under one-third
三分之一不到的时间 of the universe's 13.8-billion-year lifespan,
人类只有30万年 the human race just 300,000 years,
对于第一次接触而言这是一个 a relatively tiny window of opportunity
相对较小的机会窗口 to make first contact.
我们观测天空已经有几十年了 We've been looking at the sky for tens of years,
大概是这样 something like that.
在这些时间内 What is the likelihood that at that exact moment
有人向我们发出信号的可能性有多大？ someone is gonna be beaming a signal toward us?
也许宇宙 Narrator: Perhaps the universe prevents
阻止了智慧文明存活太久的时间 intelligent civilizations from surviving for very long,
使得我们第一次接触的机会 making our chances for first contact
更加渺小 even more unlikely.
普莱特:也许外面有什么东西 Plait: Maybe there is something out there
在过滤我们，让我们看不到它们 that is filtering us from seeing them.
我们把它叫做伟大的过滤器 We actually call this the great filter.
也许有一些东西在说 Maybe there is something that says,
“是的，你不能通过这里” "yeah, you're not getting past here."
像我们这样的岩石行星是孕育生命的理想场所 narrator: Rocky planets like ours are ideal for hosting life,
但它们很脆弱 but they're fragile.
这种脆弱意味着 And this fragility means the universe
宇宙可以迅速过滤掉智慧生命 could filter out intelligent life quickly.
♪
我们发现了非常剧烈的恒星爆炸 we've discovered very violent star explosions
比如伽马射线爆发 like gamma-ray bursts.
这些能量足够强大它们甚至可以 These are powerful enough, they may sterilize planets
毁灭整个星系的行星 even across an entire galaxy.
即使聪明的物种在自然现象中幸存下来 Narrator: And even if intelligent species
他们仍然可能被过滤掉 survive natural phenomenon,
因为他们有可能 they may still be filtered out
按下了自毁的按钮 by hitting the self-destruct button.
勒布:根据我们自己的经验 Loeb: As we can tell from our own experience,
从我们开始开发技术的那一刻起 the moment that we started developing technology,
我们也开发了自我毁灭的技术手段 we also developed the means for our own destruction
通过改变地球的气候 by changing the climate on our planet,
以及通过开发大规模杀伤性武器 by developing weapons of mass destruction.
所以很有可能 And so it's quite possible that civilizations
足够先进的文明是短暂 that are advanced enough are short-lived.
如果它们是短命的 And if they're short-lived,
那就能解释为什么在这个时间点上 that would explain why, at this point in time,
很少有机会 there are very few of them that might be around
与我们交流了 to communicate with us.
找到一个灭绝的外星文明的遗迹 Narrator: Finding the relics of an extinct alien civilization
可能是对人类的终极宇宙警告 could be the ultimate cosmic warning for the human race.
斯特里克:如果我们在那里发现一个 Stricker: If we were to find a civilization out there
可能因污染或冲突而 that may have destroyed themselves by pollution
毁灭自己的文明 or conflict,
那几乎就像盯着一面镜子一样 it would be almost like staring into a mirror,
这将是一个非常可怕的预兆 and it would be a very grim foreshadowing
也许这是对我们地球上的人类来说是一个教训 and maybe a lessons-learned for us humans here on earth.
我们只能希望一些先进的外来物种 Narrator: We can only hope that some advanced alien species
能逃脱宇宙的致命过滤器 escaped the universe's deadly filter.
但即使外星人仍然存在 But even if e.T.S still exist out there,
第一次接触的可能性仍然很大 the odds are still stacked against first contact.
♪
关于我们与外星人接触的故事 one other way that we've got this alien-contact story
另一个有点错误的方式是物理学定律 a bit wrong is just down to the laws of physics.
每一天，宇宙的物理现象 Narrator: Every day, the physics of the cosmos
都让我们联系的机会越来越少 makes our chances of contact worse
因为我们的宇宙在膨胀 because our universe is expanding,
而且膨胀得很快 and it's expanding fast.
[爆炸] [ explosion ]
♪
2018年2月—— narrator: February 2018 --
俄克拉何马大学的天体物理学家 astrophysicists at the university of oklahoma
发现了一系列38亿光年以外的 find a potential series of rogue planets
流浪行星 3.8 billion light-years away.
大小介于月球和木星之间 Ranging between the size of our moon and jupiter,
这将是我们在银河系外发现的 these would be the first alien worlds
第一个外星世界…… ever discovered outside our galaxy...
……也许是许多中的第一个 ...And maybe the first of many.
仅我们的星系就有数万亿颗行星 Our galaxy alone has trillions of planets.
可观测的宇宙有数万亿个星系—— The observable universe has trillions of galaxies --
据估计大约有2万亿 it's estimated about 2 trillion.
所以有数万亿？ So trillions of trillions?
拜托 Come on.
但是发现系外行星并不能保证 Narrator: But finding exoplanets is no guarantee
找到外星生命 of finding alien life.
当涉及到与外星人接触时 And when it comes to contacting extraterrestrials,
我们的努力却遭遇了沉默 our efforts have met with silence.
奥卢西伊:我们对生命的探索已经失败 Oluseyi: Our search for life has come up empty.
我们需要改变策略吗？ Do we need to change our tactics?
我们做错什么了吗？ Are we doing something wrong?
卡罗尔:我认为要找到 Carroll: I think it's gonna be very, very hard
我们正在寻找的外星智慧生物 to find extraterrestrial intelligence
是非常非常困难的 the way that we're looking for it.
我们必须非常非常幸运 We would have to get really, really lucky.
但我不认为我们会有好运 But I don't think we're gonna get lucky.
我认为，如果我们想知道 I think that if we want to know
宇宙中是否存在生命 whether there's life out there in the cosmos,
我们必须去访问它 we have to go visit it.
我们已经把新的地平线探测器 Narrator: We've sent the new horizons probe
发射到太阳系数十亿英里（约16亿公里）外的冥王星 billions of miles across the solar system to pluto.
也许有一天，我们能够发射宇宙飞船 Perhaps one day we'll be able to send spacecraft
穿越宇宙 across the universe
在遥远的流浪行星上寻找外星生命 to search for alien life on distant rogue planets.
♪
但是，如果一艘宇宙飞船离开我们的星系去访问这些新的世界 but if a craft left our galaxy to visit these new worlds,
它的任务将是艰难的 its mission would be tough
这要感谢宇宙物理学 thanks to the physics of the cosmos.
从我们在银河系的角度来看 From our perspective here in the milky way,
平均而言，每个星系都在远离我们 every galaxy is, on average, receding away from us.
看起来好像没人喜欢我们 It looks like nobody likes us
想要离我们越远越好 and is trying to get as far away from us as possible.
这是因为我们巨大的宇宙在膨胀 Narrator: This is because our giant universe is expanding.
弗里斯:当我们谈论膨胀的宇宙时 Freese: When we talk about the expanding universe,
我们并不是指星系在做一些积极的事情 we don't mean that galaxies are doing something active
来逃离彼此 to run away from one another.
实际上，是潜在的空间在膨胀 Actually, it's the underlying space that's expanding,
星系被嵌在其中 and the galaxies are embedded in that,
这就是导致万物 and that's what causes everything to move apart
远离万物的原因 from everything else.
距离我们300万光年 Narrator: The regions of the universe
以内的宇宙区域 within 3 million light-years of us
正在以每秒45英里（约72.4公里）的速度扩张 are expanding at around 45 miles a second.
也就是每小时超过16万英里（约26万公里） That's over 160,000 miles an hour.
泰勒:那么，以我们目前的技术 Thaller: So with our current technology,
我们有机会真正看到 do we have any chance of actually seeing
其他行星的样子吗？ what these other planets are like?
那么，想想我们目前拥有的 Well, think about the fastest and farthest things
最快和最远的东西，比如旅行者号宇宙飞船 we have right now, like the voyager spacecraft.
它们已经在太空中旅行了30多年 They've been in space for more than 30 years
以惊人的速度飞行——每小时38000英里（约61200公里） going incredibly fast -- 38,000 miles an hour.
3万8千英里（约61200公里）的时速是很快的 Narrator: 38,000 miles an hour is fast.
但离我们最近的星系 But the closest galaxies to us
正在以四倍于这个速度向外移动 are moving away at over four times that speed.
探测器被送到的地方越远 And the further away a probe is sent to travel,
任务就越艰巨 the tougher its task.
关于宇宙膨胀的一个问题是 The thing about the expansion of the universe
物体离你越远 is that the farther away something is,
它离开你的速度也越快 the faster it's moving away from you.
两个物体距离越远，它们之间的空间就越大 The more distant two objects are away from each other,
它们之间的空间越大 the more space there is between them,
就有越多的空间 and the more space there is between them,
可以扩展 the more space there is to expand.
奥卢西伊:它们移动的速度 Oluseyi: The rate at which they're moving away
与它们的距离成正比 is proportional to their distance.
如果距离是两倍，它就以两倍的速度移动 If it's twice as far away, it moves away twice as fast.
距离地球三倍远 It is three times farther away,
移动的速度也是三倍快 and moves away three times as fast.
把它放大到我们在38亿光年之外 Narrator: Scale it up to the planets we've discovered
发现的行星 3.8 billion light-years away,
“感谢”宇宙的膨胀 and thanks to the expansion of the universe,
那些星系外的世界也正在以 those extra-galactic worlds are moving away from us
每秒49000英里（约78900公里）的速度远离我们 at over 49,000 miles per second.
想像一下，你是一名跑步者，你看到了终点线 Imagine that you're a runner, and you see the finish line.
你离它越来越近了 You're getting a bit closer to it,
但是现在，实际上，赛道本身在扩张 but now, actually, the track itself is expanding.
随着赛道扩张的速度越来越快 And as the track expands faster and faster,
它的扩张速度超过了你的极限 it's expanding faster than you can possibly run.
突然之间，终点线开始后退 All of a sudden, that finish line starts receding,
而你永远都无法到达终点 and you're never, ever gonna reach it.
假设有一天我们能够建造一个探测器 Narrator: Say one day we're able to build probes
以物理学所允许的最快速度飞行 that travel at the fastest speed physics allows --
也就是光速 the speed of light.
即使这样也可能不够 Even that might not be enough
因为有时候宇宙本身 because sometimes the universe itself
并不遵守规则 doesn't play by the rules.
物体在太空中以超光速进行传播 It's not possible for things to travel through space
是不可能的，但是空间 faster than the speed of light, but it is possible for space
以超光速进行扩张却是可能的 to expand faster than the speed of light.
特朗布莱:我们看的每一个地方 Tremblay: Everywhere we look, we see very distant galaxies
我们都能看到非常遥远的星系它们明显在以 that are apparently receding, or moving away from earth,
大于光速的速度远离地球 at greater than the speed of light.
布洛克:我们可以在天空中看到遥远的星系 Bullock: There are distant galaxies we can see in the sky that,
即使我们建造最先进的宇宙飞船 even if we were to build the most advanced spaceship possible
甚至能以光速飞行 that could even move at the speed of light,
我们也永远无法到达那里 we could never get there.
我们在遥远的天空中看到的星系中 97% of the galaxies that we can see in the distant sky
有97%是我们无法到达的 are actually unreachable to us.
所以对于所有的星系 Narrator: So for all the galaxies out there
和所有可以孕育生命的行星来说 and all the planets that could harbor life,
大多数都是我们无法触及的 most of them are out of our reach.
宇宙物理学对第一次接触 The physics of the universe has dealt an immense blow
造成了巨大的打击 to first contact.
宇宙的真相将永远对我们隐藏 The true reality of the universe will always be hidden from us
因为这个，因为这个膨胀 because of this, because of this expansion.
我们越是看宇宙的外面 Narrator: The further we look out into the universe,
第一次接触就越不可能 the more unlikely first contact becomes.
我们可能需要一个先进的 We might need an advanced alien race
外星种族来拜访我们 to come and visit us instead.
假设我们很幸运 Suppose we get that lucky.
即便如此，第一次接触真的可行吗？ Even then, would first contact actually be feasible?
奥卢西:我们认为外星人和我们一样 Oluseyi: We think aliens are like us.
他们也不行 They're not.
我们假设生命和我们一样 We're assuming that the life is like us
他们的行星环境也和我们一样 and that their planetary environment is like ours.
我不认为宇宙中的大多数生命 I don't think that's gonna be the case
都是这样的 for most of the life in the universe.
那么，外星人能够在与我们 Narrator: So, could extraterrestrials
和我们的星球的第一次接触中存活下来吗？ even survive first contact with us and our planet?
[爆炸] [ explosion ]
2019年7月—— narrator: July 2019 --
测试卫星发现了一个距离我们 the test satellite discovered a new alien world
31光年的新的外星世界 31 light-years from us
名为 gj 357 d named gj 357 d.
它的质量是地球的六倍多 At over six times the mass of our home planet,
被认为是一个超级地球 it's thought to be a super earth.
根据我们的观察 And from our observations,
超级地球似乎是最好的生命家园 super earths appear to be prime real estate.
我们所看到的是最常见的 What we see is that the most common type
类地行星类型是我们所说的超级地球 of terrestrial planet is what we call a super earth.
所以这意味着它是一颗类地行星 So that means it's a terrestrial planet,
但质量要大得多 but much more massive.
更大的质量意味着更大的重力 Narrator: More massive can mean more gravity,
创造了一个完全不同于我们的行星环境 creating a planetary environment completely unlike our own
和完全不同于我们的生命 and life completely unlike ours.
奥卢西:如果他们在一个超级地球的表面 Oluseyi: If they're on the surface of a super earth,
那么重力可能会更 强 it could be that gravity is gonna be way stronger.
所以这些外星人不会很高 So these aliens aren't gonna be very tall,
但他们会非常强壮 but they are gonna be very strong.
超级地球只是宇宙创造的 Narrator: Super earths are just one of the many avenues
众多途径之一 the universe creates.
还有其他的系外行星围绕着 There are other exoplanets orbiting red stars
比我们的太阳小10倍的 10 times smaller than our sun
红色恒星运行，还有其他的 and others making binary systems
由两颗而不是一颗恒星组成的双星系统 comprising two stars instead of one.
我们看到各种形状和大小的行星 We see planets of all shapes and sizes around stars
围绕着各种形状和大小，以及各种形态的恒星 of all shapes and sizes, of all sorts of configurations.
生命的潜力远比我们 The potential for life is much more rich and varied
以前想象的丰富多样 than we ever thought before.
五号和六号火箭发射 Retro rockets five and six fired.
科幻小说中的画面激发了 Narrator: Images of science fiction
无数关于第一次接触的幻想 have fueled numerous fantasies of first contact,
但我们对宇宙的了解表明 but our knowledge of the universe suggests
现实可能还很遥远 reality could be far, far stranger.
不管怎样，好莱坞在展示 If anything, hollywood has kind of
那么多外星人方面 constrained our imagination
限制了我们的想象力 in terms of presenting so many aliens
这些外星人基本上看起来像，你懂的 that basically look like, you know,
穿着橡胶套装的人类或其他什么 humans wearing a rubber suit or something.
降下起落架 Lower landing legs.
我们必须 放下这种执念 We have to, have to, let go of this obsession
认为他们会和我们一样 that they're gonna be anything like us.
所以如果我们要找两条腿的人，算了吧 So if we're looking for two-legged dudes, forget it.
♪
假设有一个聪明的外星物种 narrator: Say an intelligent alien species lives
生活在我们的恒星附近 in our stellar neighborhood
想要和我们进行第一次接触 and wants to make first contact with us.
如果那个外星人是在一个超级地球上进化的 If that alien evolved on a super earth
或者是围绕一颗红色恒星而不是黄色恒星运行的 or orbited a red star instead of a yellow one,
那么它的生物学特性 it's wildly different biology
就会大不相同，可能会让它永远无法 may prevent it from ever setting foot,
踏上地球的土地或者触碰地球 or tentacle, on planet earth.
斯特里克:当你观察地球上的生命时 Stricker: When you look at life here on earth,
它就好像是为这种温度 it's almost as if it was custom-made
这些元素、这种环境 for this temperature, for these elements,
量身定做的 for this environment.
一颗具备支持生命条件的系外行星 An exoplanet with conditions to support life
可能与地球上的生命 could still be completely different
完全不同 than life here on earth.
普莱特:如果一个外星世界它的钾含量比地球高一些 Plait: What are things gonna be like on an alien world
或者平均温度比地球的高一些 which has a little bit more potassium
或者大气层更厚一些 or is warmer than average on earth
那么这个世界会是什么样子呢？ or has a thicker atmosphere?
每一个微小的变化 Each one of these small variations
都可能意味着一个完全不同的生态系统 can mean a completely different ecosystem.
那么当一个外星生物 Narrator: So could an alien organism
降落在地球上时，它真的能适应我们的生态系统吗？ really adapt to our ecosystem when it lands on earth?
也许我们还没有第一次联系 Maybe we haven't made first contact
是因为他们不能来看我们 because they can't actually visit us.
达特奈尔:他们可能会穿过宇宙飞船的气闸 Dartnell: They could step through the airlock
来到地球上然后发现一些 of their spaceship and onto the earth
我们的环境中有毒的一些东西 and just find something toxic with our environment,
或一些、一些其他原因 some some reason they're not compatible
它们与地球表面不兼容 with the surface of the earth.
就好像宇宙在那里故意阻止 It's almost as if the universe is out there
我们与任何外星人见面一样 deliberately trying to stop us meeting any aliens.
生物学为第一次接触 Narrator: Biology creates another obstacle
创造了另一个障碍 for making first contact,
但行星科学家贾尼·拉德堡发现 but as planetary scientist jani radebough finds,
即使是地球上的生命也会变得非常奇怪 even life on earth can get pretty weird,
会采取极端措施 taking extreme measures to adapt
来适应潜在的敌对环境 to a potentially hostile environment.
拉德堡:这是大盐湖 Radebough: This is the great salt lake.
这是过去一个大得多的 It is the remains of what used to be
湖泊的遗迹 a much larger lake in the past.
当它蒸发的时候，留下了所有的盐 And when it evaporated away, it left behind all of the salt.
这个巨大的盐湖几乎比地球上的海洋 Narrator: The great salt lake is nearly 10 times saltier
咸十倍 than earth's oceans.
极端的含盐量 The extreme salt content
使它不适合生命生存 should make it an inhospitable place for life.
尽管如此，水中还是有很多生物在茁壮成长 Despite this, there are organisms thriving in the water.
拉德堡:当我们观察这个巨大湖泊中的生命时 Radebough: As we look at life in this vast lake
我们发现有数十亿的微生物 and find that there are billions of microbes living here
生活在这个意想不到的环境中 in this unexpected environment, then we start to realize,
然后我们开始意识到生命以我们意想不到的方式存在 well, life forms in ways that we just don't expect,
在我们意想不到的地方生存 in places we don't expect.
被称为极端微生物的微生物 Narrator: Microbial life known as extremophiles
进化出了一种巧妙的方式在湖里生存 have developed an ingenious way to survive in the lake.
实际上，他们是用这些“太阳能泵” Well, they actually use these solar-powered pumps
把盐从细胞中抽出来 to pull the salt out of their cells
这样细胞就能正常工作了 so that they can operate more normally.
但为了做到这一点，它们必须生活在 But in order to do that, they have to live
离地表非常近的地方 very close to the surface,
这意味着它们会受到大量的紫外线辐射 which means they get a huge amount of u.V. Radiation.
所以你们看到我身后的这些粉红色 So all this pink color that you see behind me
实际上是生物体的粉红色 is actually the pink of the organisms,
它有点像内置的防晒霜 and it's sort of like a built-in sunscreen
帮助它们抵御紫外线辐射 that helps protect them against the u.V. Radiation.
极端微生物正在改写我们对地球上生命 Narrator: Extremophiles are rewriting our expectations
可以在哪里生存的期望 of where life can survive on earth.
外星生物是否比我们想象的更有弹性？ Could alien biology be much more resilient than we think?
这些极端微生物应该提醒我们 These extremophiles should be a little reminder
我们考虑的还不够多 that we haven't been thinking big enough.
也许外星人可以很容易地适应我们的环境 Narrator: Maybe e.T. Could readily adapt to our environment,
或者他们有其他的想法 or perhaps they've got other ideas,
利用技术来克服任何生物障碍 using technology to overcome any biological barriers.
也许我们遇到的第一个外星人会是机器人 Maybe the first aliens we meet will be robots.
如果他们不把自己限制在肉袋里 They can build much more powerful life
他们可以建立更强大的生命 if they don't limit themselves to meat bags.
先进的外星人可能已经离开了 Narrator: Advanced aliens could have left
他们的生物大脑和身体 their biological brains and bodies behind,
而是以移动人工智能的方式旅行 traveling instead as mobile artificial intelligence.
泰格马克:我们倾向于认为智力和意识 Tegmark: We tend to think of intelligence and consciousness
是一种神秘的东西 as something mysterious that can only exist
它们只能存在于像我们这样的生物体内 inside of biological organisms like us
因此无法被复制 and somehow therefore can't be copied.
但是，是什么给了我们整个人工智能革命，对吧—— But what's given us the whole a.I. Revolution, right --
智能，不 the idea that, no,
可能还有意识 intelligence and probably consciousness, too,
都只是信息处理 is just information processing,
而信息处理才是真正重要的 and it's just the information processing that really matters.
也许外星人可以将自己的意识 Perhaps an alien would be able to download
下载到某种电脑中 its consciousness into some sort of computer
然后以一种脱离身体的意识进行旅行 and travel as a disembodied consciousness.
在这种状态下，你基本上是永生的 In this state, you'd be essentially immortal.
所以一个先进的物种可能会找到方法 Narrator: So it's possible an advanced species could find ways
来面对第一次接触的挑战 to face the challenges of first contact.
但是如果有一个外星文明存在 But if an alien civilization is out there
并且比我们更先进 and more advanced than us,
会不会有更大的问题在起作用吗？ could there be an even bigger issue at play?
也许聪明的外星人 Maybe the reason that intelligent aliens
从未来地球拜访我们的原因 haven't ever come to the earth to visit us
可能是我们没有那么有趣 is maybe we're just not that interesting.
也许第一次接触的最大障碍是 Narrator: So maybe the biggest barrier for first contact
外星人并不想见我们 is the fact that aliens don't actually want to meet us.
[爆炸] [ explosion ]
♪
在电影中，第一次接触通常会导致 narrator: In the movies, first contact usually leads
外星人的入侵 to an alien invasion.
城市被击溃 Cities get zapped.
[爆炸] [ explosion ]
人类面临毁灭 humanity faces annihilation.
[尖叫的人们] [ people screaming ]
也许是外星人的来访 maybe a visit from e.T.
根本就不是一件好事 Isn't such a good thing, after all.
想象一下如果我们，如果我们收到一封星际电子邮件 Imagine if we if we got an intergalactic e-mail,
你懂的，来自“外星文明.Org” so from, you know, superioraliencivilization.Org,
说“嘿，30年后我们会出现” saying, "hey, we're gonna show up in 30 years."
我们会不会只是想，“哦，好吧” would we just be like, "oh, all right,
“我们继续看我们的真人秀节目” let's get back to watching our reality tv shows
“等他们来了再担心这个问题”？ and worry about that when they get here"?
不，我们会被吓坏的 No, we would seriously freak out.
人们可能会被吓到，但事实是 Narrator: People might freak out,
几十年来，我们一直在宇宙中 but the truth is we've been sign-posting our location
标明我们的位置 into the cosmos for decades.
达特奈尔:100年以来，地球一直是一个 Dartnell: The earth has been a detectably technological world
技术上可探测的世界 for about 100 years.
我们一直在广播信号 We've been broadcasting signals,
但是，这显然没有引起任何人的注意 and yet, that apparently hasn't attracted anyone's attention.
值得注意的是 It's pretty noteworthy
他们中没有一个人表现出任何兴趣 that none of them has shown any interest,
如果他们愿意，他们可以把地球 when they could have turned earth into a parking lot
变成停车场，对吗？ if they wanted, right?
也许没有外星人要重新开发地球 Narrator: Perhaps no one has redeveloped planet earth
因为一个先进的文明 because an advanced civilization
根本不想进行第一次接触 simply doesn't want to make first contact.
坦白说，如果他们那么聪明 Frankly, if they're that intelligent,
他们就不会对我们感兴趣 they're not gonna be very interested in us.
也许这就是为什么他们懒得联系我们 So maybe that's why they haven't bothered to make contact.
菲利平科:如果外星人很先进 Filippenko: And if the alien is that advanced,
我们可能对它不太感兴趣 we're probably not very interesting to it.
这有点像，你懂的 It's a little bit like, you know,
在外面闲逛，看到人行道上的蚂蚁 wandering around outside and seeing ants on the sidewalk.
外星人的入侵造就了伟大的科幻小说 Narrator: Alien invasion makes for great science fiction,
但我们在地球上到底有什么 but what do we actually have on earth
值得外星人付出这么多努力的呢？ that's worth all that alien effort?
达特奈尔:好莱坞的这些描述 Dartnell: How realistic really are
有多少是真实的？ these depictions from hollywood?
一个常见的比喻是外星人来吞噬人类 One common trope is the aliens coming to devour the human race.
但科学并不支持这种可能性 But the science doesn't really support this being possible.
外星人能消化人体吗？ Would an alien even be able to digest the human body?
吃东西的时候，我们消化系统中的酶 Narrator: When eating, enzymes in our digestive system
会分解食物中的分子 break down molecules in our food.
我们可以吃的食物，对它们进行 The food we can eat, and these enzymes are very specific
攻击和分解分子的这些酶非常特殊 to the molecules they can attack and break down.
同样的规则也适用于饥饿的外星人 The same rules would apply to a hungry alien.
达奈尔:为了能够消化我们 Dartnell: To be able to digest us
让我们对它们来说有营养 and for us to be nutritious for them,
我们必须有一种非常非常相似的生物化学物质 we'd have to have a very, very similar biochemistry
就像外星人的家园一样 to what exists on the alien's home world,
它们的身体已经适应了这种生物 what their bodies have adapted to.
所以外星人来这里 Narrator: So it seems highly unlikely
寻找食物的可能性很小 that aliens would come looking for food.
那喝一杯怎么样？ But how about a drink?
我们所知道的生命的存在 In order for life as we know it to exist,
都需要液态水 one needs liquid water.
如果外星人生活在一个贫瘠的沙漠星球上 Narrator: If aliens live on a barren desert planet,
像我们这样的水世界可能非常有吸引力 a water world like ours could be highly attractive.
虽然我们称自己为蓝色星球 While we call ourselves the blue planet,
但我们的海洋并非独一无二 our oceans are not unique.
宇宙提供了更多的水资源 The universe offers far greater water resources.
萨特:在我们的太阳系中，我们发现 Sutter: In our solar system, we're finding that
大部分液态水存在于气体巨星周围的卫星中 most of the liquid water exists in moons around the gas giants.
我们相信木星的卫星木卫二 Narrator: We believe jupiter's moon europa
有一层大约15英里（约24公里）厚的水冰 has a layer of water ice around 15 miles thick
漂浮在100英里（约161公里）深的海洋上 floating on an ocean up to 100 miles deep.
这颗卫星所含的水可能是地球上 This single moon may have twice as much water
所有海洋总和的两倍 as all earth's oceans combined.
木卫二是我们太阳系的水世界 Europa is the water world of our solar system
而不是地球 and not the earth.
所以，如果你是一个寻找水的外星人 So if you were an alien looking for water,
你不会费事去找像地球这样的大行星 you wouldn't bother going to a big planet like the earth
然后通过某种巨大的吸管把水吸进走 to suck it up through some kind of giant straw.
你会去外太阳系 You'd go to the outer solar system.
你可能会收获冰冷的卫星 You might harvest icy moons.
与其对抗 Narrator: Instead of working against
地球强大的引力 the powerful gravitational pull of earth,
外星种族可以从木卫二取水 an alien race could draw water from europa,
那里的引力比地球弱十倍 where gravity is almost 10 times weaker.
那么我们还能提供什么资源呢？ So what other resources have we got to offer?
也许外星人是来开采地壳上的 Maybe aliens come to strip mine the earth's crust
金属——比如铁、钛或铂 for metals -- iron or titanium or platinum.
外星人可能会用这些金属 Aliens might use these metals
做和我们完全一样的事情—— for exactly the same things that we do --
建造宇宙飞船，建造他们的技术 for building spaceships, for building their technology.
这些材料对于任何 Narrator: Such materials could be useful
缺乏矿产资源的外星文明来说都是有用的 for any alien civilization short on mineral resources.
问题是，我们星球上的很多金属 Problem is, a lot of our planet's metals
都深埋在地球内部 are buried deep in the earth's interior.
地球形成时，大量的铁 When the earth formed, the great deal of its iron
沉入地球的核心 sunk down into the core of our planet
并带走了大量的金属 and took a lot of metals with it.
所以它们在地球上很难开采 So they're actually quite hard to mine on the earth.
一个外星种族在小行星带寻找 Narrator: An alien race would be better off prospecting
会更容易获得的矿物资源 for more accessible minerals situated in the asteroid belt.
在小行星带中，有一颗叫做普赛克的小行星 In the asteroid belt, there's an asteroid called psyche,
它由纯铁镍组成 which is made up of pure iron nickel,
就像地心一样 just like the core of the earth.
普赛克提供了一个近150英里（约242公里）长的 Narrator: Psyche provides a near-150-mile
裸露的铁镍带 exposed strip of iron nickel,
这是另一个外量人不需要麻烦我们的原因 yet another reason e.T. Wouldn't need to bother with us.
在我看来，这些原因 For my money, none of those reasons
都不会吸引外星人来地球 would draw aliens to earth.
所有这些东西在其他地方都很容易找到 All these things can be found far more easily elsewhere.
第一次接触的可能性 Narrator: The possibility of first contact
听起来越来越遥远 is beginning to sound increasingly remote.
宇宙设置了巨大的障碍 The universe throws up massive barriers
阻止我们与有智慧的外星种族交流 stopping us from communicating with an intelligent alien race,
而这个种族很可能完全没有兴趣 a race that might very well have absolutely no interest
与我们联系 in contacting us,
除非，当然，他们已经有兴趣了 unless, of course, they already have.
有没有可能我们已经探测到外星人的信号 Is it possible that there have been alien signals
但我们没有意识到它们是什么？ that we've already detected but we didn't realize what they are?
科学家们发现了一个 Narrator: Scientists have discovered
他们无法解释的强大的宇宙信号 a powerful cosmic signal that they cannot explain.
这最终会成为第一次接触吗？ Could this finally be first contact?
[爆炸] [ explosion ]
2018年7月—— narrator: July 2018 --
不列颠哥伦比亚省的齐姆望远镜 the chime telescope in british columbia
探测到一股比眨眼还要快的 detected a short flash of radio energy
射电短闪 quicker than a blinking eye.
它被称为快速无线电暴 It's called a fast radio burst.
这些都是非常强大的，非常非常短 These are intensely powerful, very, very short
的无线电脉冲，在射电波长上 lived radio bursts that can be 1,000 times brighter
比太阳亮1000倍 than the sun at radio wavelengths,
瞬间到达并消失 that arrive and disappear in an instant.
大多数快速无线电脉冲都是一次性的 Narrator: Most fast radio bursts are one-offs,
一闪而过，然后就永远消失了 blinking into existence, then disappearing forever.
但这个不是 But not this one.
几天后，科学家们再次捕捉到了闪光 A few days later, scientists caught the flash again.
产生这样的爆发所需要的能量 The amount of energy that it takes to produce
对于我们在地球上 a burst like this,
从数十亿光年外 for us to detect it here on earth
探测到它，是极其巨大的 from billions of light-years, is immense.
我们以前也遇到过类似的事情—— And we've run across things like this before --
爆炸的恒星，伽马射线爆发 exploding stars, gamma-ray bursts.
这些都是非常奇怪的物体 These are all very strange objects,
但这无法解释这个现象 but that does not explain these
因为一些快速的无线电脉冲会重复 because some of these fast radio bursts repeat.
所以不管是什么能产生这种能量 So whatever it is that can generate this kind of energy,
它都能产生不止一次 it can do it more than once.
光有很多不同的波长 Narrator: Light comes in many different wavelengths.
无线电波是最长的，因此很适合 Radio waves are the longest, making them good
远距离通信 for long-distance communication.
我们使用无线电波已有100多年的历史 We've used radio waves for over 100 years,
从无线收音机到电视 from wireless radio to tv,
从手机通话到用太空探测器 from cellphone calls to communications
进行通信 with space probes.
外星文明是否可以使用更大的规模的 Could alien civilizations be using radio waves,
无线电波进行通信？ but on a much larger scale?
如果我们已经截获了外星人的通讯 What if we already intercepted alien communications,
只是我们不知道呢？ but we just don't know it?
我们的无线电和电视信号 Narrator: Our radio and television signals
只使用无线电频谱的一个很窄的波段 only use a very narrow band of the radio spectrum.
快速无线电爆发则不同 Fast radio bursts are different,
这是也个问题 and that's a problem.
关于快速射电暴的问题是—— Here's the thing about fast radio bursts --
它们发射的波长范围很广 they are emitting a broad range of wavelengths,
所以它不是最好的通信方式 so it's not the best way to communicate.
如果是外星人，那么他们可能不是很聪明的外星人 If these are aliens, they're not very smart aliens.
事实证明，宽波长 Narrator: It turns out that broad-range wavelengths
很容易扭曲 are easy to distort.
恒星之间有一种非常稀薄的气体 There is a very thin gas out there between the stars,
当你发射无线电波时 and when you emit radio waves,
无线电波会与这种气体相互作用 the radio waves interact with this gas.
它们相互作用的方式 And the way they interact
取决于你所说的波长 depends on the wavelength you're talking about.
如果你使用广范围的波长 If you use a broad range of wavelengths
在星际空间发送信号 to send a signal across interstellar space,
当有人接收到它的时候 by the time somebody receives it,
它可能会有点扭曲和奇怪 it can be a little distorted and weird.
如果外星人发出无线电脉冲 Narrator: If aliens are sending out radio bursts,
信号到达我们这里的时候会退化 the signal would get so degraded that by the time it reaches us,
我们再无法破译它 we wouldn't be able to decipher it.
作为“名片”，并不是很有用 As a calling card, not incredibly useful.
不管这些神秘的爆发 Narrator: Whether these mysterious bursts really are
真的是外星人试图打招呼还是只是一个自然现象 aliens trying to say hello or just a natural phenomenon,
这不是第一次接触 this is not first contact,
至少现在还不是 at least not yet.
我必需要谨慎，对吧？ I want to be careful here, right?
我不是一个反对者 我也不会对外星人嗤之以鼻 I'm not a naysayer. I'm not gonna pooh-pooh aliens.
但是，你要知道，让我们先看看其他的东西 But, you know, let's go through the other things first
因为宇宙中充满了奇怪的东西 because the universe is filled with weird stuff,
让我们看看那是什么 and let's see what that is.
如果我们把这些都排除了，剩下的就只有外星人这种可能 And if we eliminate all those, and all that's left is aliens,
好的，我们就来谈一谈 yeah, let's talk.
如果外星生物存在 Narrator: If extraterrestrial species are out there,
我们的宇宙让我们很难 our universe makes it extremely difficult
联系到他们 to contact them.
但尽管困难重重 But in spite of all the obstacles,
也许还是有希望的 maybe there's still hope.
我们曾经认为，仅在银河系 We once thought that there could be 10,000
就可能有1万个智慧文明 intelligent civilizations in the milky way alone.
现在我们知道宇宙中充满了 Now we know that our cosmos is filled with planets
有待发现的行星 just waiting to be found.
我们的技术正在发展 Our technology is evolving.
搜索正在扩大 Searches are expanding.
事实上，我们第一次接触的任务是这样的—— The truth about our mission to make first contact is this --
我们才刚刚开始 we are only just getting started.
我希望明天早上能有一些 I'd love for tomorrow morning some sort of interstellar tweet
星际微博对着地球 to be beamed at the earth,
后我们就会意识到 and we would then realize
我们在宇宙中并不孤单 that we are not alone in this cosmos.
帕西尼:我已经准备好庆祝了 Pacini: I'm all ready to celebrate.
在这里，我们已经有了一瓶加冰的香槟 Here we have already a champagne on ice
[笑] 等他们找到的时候就可以打开了 [laughs] to pop when they find it.
塞勒:科学家们真的希望有一天 Thaller: Scientists really do hope we find evidence
我们能找到外星生命的证据 of extraterrestrial life someday.
我们有观测天空的天文台和卫星 We have observatories and satellites that look at the sky.
整天、整夜、每一天 All day, all night, every day.
在某种程度上，外星生命的发现 The discovery of alien life would simultaneously be,
并不令人惊讶 in a way, unsurprising
但同时也是人类历史上最伟大的发现 and yet the greatest discovery in all of human history.
即使生命非常非常罕见 Even if life is really, really rare,
宇宙也非常非常大 the universe is really, really big,
所以可能有无数的外星文明存在 and so there could be countless alien civilizations out there.
但当真正地发现或被证实—— But the actual discovery or confirmation of that --
我想不出比这更伟大的科学发现了 I can think of no greater scientific discovery.
它将彻底改变我们的整个文明 It would quite literally change our entire civilization.
♪