我们为什么存在？ 我们来自哪里？ Why are we here? Where do we come from?
这是人类一直在问的问题 These are the most enduring of questions.
追根问底 寻找答案 这是人类的本性 And it's an essential part of human nature to want to find the answers.
人类的起源可以追溯到千万年前 And we can trace that ancestry back hundreds of thousands of years to the dawn of humankind.
但事实上 我们的故事还要早得多 But in reality, our story extends far further back in time.
从宇宙诞生之日起 就已经揭开了序幕 Our story starts with the beginning of the universe.
一切开始于137亿年前 It began 13.7 billion years ago.
如今 宇宙中有数千亿个星系 And today it's filled with over 100 billion galaxies,
每个星系又包含数千亿颗恒星 each containing hundreds of billions of stars.
在这档节目中 我要向您讲述宇宙的故事 In the series, I want to tell that story
因为归根到底 我们都是宇宙的一部分 because ultimately we are part of the universe.
所以 宇宙的故事就是我们的故事 So its story is our story.
有一个东西非常重要 It's a story that you couldn't tell
没有它 宇宙的故事就无从讲起 without something so fundamental
没有它 就无法想像宇宙会变成什么样 that it's impossible to imagine the universe without it.
它存在于宇宙的每一个角落 那就是时间 It's woven into the very fabric of the cosmos. Time.
时间的流逝造就了宇宙的演变 The relentless flow of time has driven the evolution of the universe
也诞生了许多非凡的奇迹 and created many extraordinary wonders.
这些奇迹见证了宇宙的初生 These wonders take us from the very first moments
也将伴随它走向灭亡 in the life of the universe to its eventual end.
命运
这里是秘鲁西北海岸线上的Chankillo This is Chankillo on the north-western coast of Peru.
一个鲜为人知的南美洲考古遗址 And it's one of South America's lesser known archaeological sites.
我却觉得 这片地方无比引人入胜 But, for me, it is surely one of the most fascinating.
大约2500年前 存在着一个我们所知甚少的文明 Around 2,500 years ago, a civilisation we know almost nothing about
他们在沙漠中建造了这座坚固的庙宇 built this fortified temple in the desert.
庙宇的围墙曾经是亮白色的 上面画着人物 Its walls were once brilliant white and covered with painted figures.
如今 几乎所有的装饰 Today, all but the smallest fragments
都早已随风飘散 of the decorations are gone.
一切文化和语言的蛛丝马迹也已经遗失 The details of this culture and all traces of its language are lost.
然而 如果你站在正确的位置上 依然能体会到 And yet, if you stand in the right place, you can still experience
Chankillo的真正意义 the true purpose of Chankillo,
理解古人在修建它时 想要传达的讯息 in just the same way as you could the day that it was built.
不过要想揭开Chankillo的奥秘 But, to do that, you have to be here
你得在日出之前来到这里 before the sun rises.
这些古塔组成了一个太阳历 These towers form an ancient solar calendar.
随着一年里日期的改变 Now, at different times of year,
日出点在地平线上的位置也有所不同 the sunrise point is at a different place on the horizon.
12月21日 在南半球这里 21st December, which here in the southern hemisphere
是夏至 也就是一年中日照时间最长的一天 is the summer solstice, the longest day,
而太阳正好会移动到最右边的塔上 从那里升起 the sun rises just to the right of the right-most tower.
随着时间流逝 日出点会沿着这些塔移动 Then, as the year passes, the sun moves through the towers
直到6月21日 冬至 日照时间最短的一天 until on 21st June, the winter solstice, the shortest day,
太阳会移动到最左边的塔上 从那儿升起 it rises just to left of the left-most tower.
实际上就在远处的山和最左边那座塔之间 Actually just in between that mountain you can see in the distance and the left-most tower.
一年中的任何时间 只要你观察日出 So, at any time of year, if you watch the sun rise,
就可以根据日出点 得知大概的日期 you can measure its position and you can tell,
误差很小 只有两三天 within an accuracy of two or three days, the date.
今天是9月15日 Today's date is September the 15th.
也就是说 太阳会在第五和第六座塔之间升起 So that means the sun will rise between the fifth and the sixth towers.
Chankillo的日历依然准确 Chankillo still works as a calendar
因为从那时到现在 because the sun still rises in the same place today
太阳一直从相同的地方升起 as it did when these stones were first laid down.
红彤彤的太阳从塔上蓬勃而出 多么壮观啊 That's a magnificent sight, as the sun burns through the towers.
在这里 你能触摸到过去 想像一下它以前的样子 You can almost feel the presence of the past here. Imagine what it must have been like.
成千上万的居民站在这里迎接太阳 Thousands of citizens stood here to greet the sun,
太阳是神的存在 是他们的上帝 which was almost certainly a deity. Almost certainly their god.
这是多么伟大的成就 What a magnificent achievement.
它可能是人类对于星球运行规律 Probably one of our earliest attempts
最早的探索之一 to begin to measure the heavens.
历经千年之后 Over the millennia,
这种对茫茫宇宙的探索欲望 that desire to measure what's going on in the sky
启迪我们开创了现代天文学 has led to modern astronomy
为现代文明打下了基石 and the foundations of our modern civilisation.
我也要在花园里建一排这样的塔 I might build one in my garden.
多有趣啊！ I want one!
这十三座连成一排的塔 体现了人类 The 13 towers that line this ridge stand testament to our
对天体运行规律的持续不断的兴趣 enduring fascination with the clockwork of the heavens.
也印证了人类和宇宙的深邃联系 And to the direct connection between our lives and the cosmos.
日升 日落 犹如心跳一般 The rising and setting of the sun provides an epic heartbeat
告诉我们时间在流逝 that allows us to mark the passage of time.
一天有24小时 这是地球自转一周的时间 A day on Earth is the 24 hours it takes our planet to rotate once on its axis.
一个月有29.5天 Our months are based on the 29-and-a-half days
这是月亮在夜空中呈现出阴晴圆缺的周期 it takes the moon to wax and wane in the night sky.
一年有365.25天 And a year is the 365-and-a-quarter days
这是地球绕太阳一周的时间 it takes us to orbit once around the sun.
这些我们熟悉的时间尺度 标志了我们生命的节奏 These familiar timescales mark the passing of our lives.
相比较而言 宇宙的生命却长得多 But the life of the universe plays out on a much grander scale.
当我们仰望星空时 看到的不只是恒星 When you look up into the night sky, you don't just see stars.
所有的星星点点 就像无数个不同的时钟 Those tiny points of light are a million different clocks,
这些恒星见证了数十亿 甚至数万亿年的流逝 whose lifespans mark out the passage of time over billions, or even trillions, of years.
这部影片向您讲述时间的广度 This film is about the greatest expanses of time.
时间无处不在 它雕琢了我们的宇宙 The deep time that shapes the universe.
从欲火而生 到无数代的恒星 行星和星系 From its fiery beginnings, through countless generations of stars, planets and galaxies,
直到最终的消亡 to its eventual demise,
宇宙的命运 由时间之手全然掌控 the fate of the universe is determined by the passage of time.
宇宙里的时间尺度非常大 Timescales in the cosmos seem so unimaginably vast,
几乎没有任何东西能与之相提并论 it's almost impossible to relate to them.
然而 在地球上的某些地方 Yet there are places on Earth
能让我们对此有一些认识 where we can begin to encounter time on these universal scales.
这里是位于哥斯达黎加北部 This is Ostional
太平洋海岸上的Ostional on the northern Pacific coast of Costa Rica.
我来这里观察一个自然现象 And I've come here to witness a natural event that's been happening
这个现象在人类诞生之前就已存在了无数年 long before there were any humans here to see it.
我认为 这是一扇观察远古地球的窗口 And I suppose it really is a window into the distant past of life on our planet.
每当日落西山 月亮升起 海潮到来之时 Once the sun has dipped below the horizon and the moon conspired to make the tides just right,
就会有一些史前生物造访这个沙滩 this beach is visited by prehistoric creatures.
在夜幕的掩护下 它们从海水中涌上来 Under the cover of darkness, they emerge from the ocean.
Playa Ostional是世界上为数不多的 Playa Ostional is one of the few beaches in the world
海龟筑巢地之一 where large numbers of sea turtles make their nests.
最另人称道的是 这幅景像已经在这里 But what makes this truly remarkable is the sheer length of time
上演了亿万年的岁月 scenes like this have been playing out.
这是地球上最古老的生物之一 This is part of one of the oldest life-cycles on Earth.
在过去一亿年里 每到这样的夜晚 海龟们 On nights like these, for the last 100 million years, turtles like this
都会在这里上岸产蛋 have been hauling themselves out of the ocean to lay their eggs.
这么长的时间 太不可思议了 It's an almost incomprehensible timespan.
一亿年前 恐龙还在地球上四处游荡 100 million years ago, there were dinosaurs roaming the Earth,
不过那时的地球和现在有很大不同 but the Earth itself looked very different.
南美洲和北美洲并不相连 South America was not connected to North America.
北美洲在欧洲附近 North America was somewhere over close to Europe.
而澳洲和南极接壤 Australia was connected to Antarctica.
这真是... It really is quite...
能和这种远古生物近距离接触 真是太不可思议了 wonderful to be so close to such an ancient cycle of life.
我能听到他的呼吸声 I can hear breathing, actually.
这种经历太神奇了 So, a remarkable experience.
在这样一个平凡的夜晚 I mean, it really is beautiful to see that.
我们看到了数亿年前的生物 这种感觉实在太美妙了 On one night of many hundreds of millions of nights stretching back into the past.
她走了 And she's gone.
在这一刻 远古时代大门仿佛向我们洞开 To witness a moment like this is to open up a connection to the deep past.
让我们见识到人类诞生之前的远古时代 To experience timespans far longer than the history of our own species.
然而即使是这些海龟上亿年的故事 Yet even the 100-million-year story of the turtles
和宇宙近乎无限的时间跨度相比 只是短短一瞬 only begins to connect us with the vast sweep of cosmic time.
我们整个太阳系 Our entire solar system is travelling
正绕着银河系的中心 on an unimaginably vast orbit,
在一个极其广阔的轨道上旋转 spinning around the centre of our galaxy.
而围绕银河系转一圈 就要花上两亿五千万年 It takes 250 million years to make just one circuit of the Milky Way.
在整个人类史中 In the entire history of the human race,
太阳系走过的路程 还不到这轨道的1% we've travelled less than a tenth of 1% of that orbit.
这些周期看上去 是永恒不变的 These cycles seem eternal and unchanging,
但当时间的故事慢慢展开 一条真理也随之被揭示 but as the story of time unfolds, a fundamental truth is revealed.
万物都不能长久 Nothing lasts forever.
这是时间最深刻的特质 This is the most profound property of time.
在广袤的宇宙中是如此 And it plays out just as vividly here on Earth
而在地球上 我们也能找到同样鲜活的例证 as it does in the depths of space.
这是阿根廷南部巴塔哥尼亚地区的莫雷诺冰川 Well, this is the Perito Moreno Glacier in Patagonia in southern Argentina.
这是上百条从巴塔哥尼亚南部冰原地区 And it's one of the hundreds of glaciers
延伸下来的冰川之一 that sweep down the continent from the southern Patagonian ice fields.
如果你朝着这个方向再往南走一千公里 And, you know, if you carry on that way, south about 1,000 kilometres,
你就到达了南美洲的最南边 you get to the end of South America.
自此之后 一直到南极之间 只有茫茫大海 From then on, there's nothing to the Antarctic.
...这儿还真有南极的感觉 And it feels like that today.
这些延展如此宽广的冰川 第一眼看上去 The glacier is such a massive expanse of ice that, at first sight,
就像宇宙中的周期一样 是静止的 一成不变的 just like the cycles of the heavens, it appears fixed and unchanging.
但若细细观察 就会发现 冰川正在不停地移动着 Yet, seen close-up, it's continually on the move.
千万年来一直如此 As it has been for tens of thousands of years.
整个冰川的边缘向湖中 The whole face of the glacier is moving into the lake
每天移动大概这么长 something like that much every day.
这意味着每年有两亿五千万吨的冰 That means that well over a quarter of a billion tonnes of ice
从冰川上坠落到湖里 drop off the face of the glacier into the lake every year.
算下来大约是每天10万吨 That's about a million tonnes a day.
并且你可以通过声音感受到它的运动 And you can hear it happening.
时不时的 你就会听到那种巨大的破碎声 Just every now and again, you hear this tremendous cracking sound.
就好像这地方是活着的一样 It really is like the place is alive.
当这些庞大的冰块坠落到湖里时 You know, it's quite disturbing
让人感到有些害怕 when these enormous chunks of ice fall into the lake.
虽然冰川看上去平静 而且运动速度极度缓慢 Although this thing seems stable and the movement seems glacially slow,
也会有很猛烈的崩塌 actually there can be really violent collapses.
这是一个极度活跃的地方 It's an incredibly dynamic place to be.
冰川的运动从一个侧面让我们体察到时间的本质 The movements of the glacier provide an insight into the nature of time.
这就是事物发生的顺序性 It is simply the ordering of events into sequences.
一步接着一步 One step after another.
随着时间推移 雪花飘落 冰川形成 As time passes, snow falls, ice forms,
一寸寸地向山谷下前进 the glacier gradually inches down the valley
最后大片的冰块崩塌入湖 and huge chunks of ice fall into the lake below.
但这种简单的顺序包含着深厚的道理 But even this simple sequence contains a profound idea.
事物永远是以相同地顺序发展的 Events always happen in the same order.
他们不会跳跃 也不会回头 They're never jumbled up and they never go backwards.
你永远也不会看到它们反过来运行 Now that's something that you would never see in reverse.
但有趣的是 从来没有任何一条 But, interestingly, there's nothing in the laws of physics that describe how all those
描述水分子运动的物理定律规定 water molecules are moving around that prevent them
这些水分子不能从湖面上 from all getting together on the surface of the lake,
一跃而起 冻结在一起 变成一块冰 jumping out of the water, sticking together into a block of ice
然后粘回冰川的前沿 and then gluing themselves back on to the surface of the glacier again.
但有意思的是 But, interestingly,
我们能够理解为什么这一切不会倒转 we do understand why the world doesn't run in reverse.
这是有原因的 There is a reason.
我们有科学的解释 We have a scientific explanation.
叫做“时间箭头” And it's called the arrow of time.
我们绝不会看到浪花穿过湖面 We never see waves travelling across lakes,
聚合在一起 变回冰川上的一部分 coming together and bouncing chunks of ice back onto glaciers.
我们被迫走向未来 We are compelled to travel into the future.
这是因为 时间箭头决定了当时间流逝 And that's because the arrow of time dictates that as each moment passes,
一切都要改变 things change.
而一旦变化发生 就绝没有回头的可能 And once these changes have happened, they are never undone.
永恒的变化 对我们人类有着根本性的意义 Permanent change is a fundamental part of what it means to be human.
随着时间流逝 我们慢慢老去 We all age as the years pass by.
人们出生 成长 然后死亡 People are born, they live, they die.
我觉得 这就是生命中必须承受的悲喜的一部分 I suppose it's part of the joy and tragedy of our lives.
但在宇宙中 But out there in the universe,
似乎所有的史诗般的周期 看上去是那么永恒不朽 those grand and epic cycles appear eternal and unchanging.
但这只是错觉 But that's an illusion.
其实 宇宙的生命 就和我们的生命一样 You see, in the life of the universe, just as in our lives,
一切都在不可逆转地改变着 everything is irreversibly changing.
通过一次次的改变 By building change upon change,
时间箭头推动着整个宇宙的演变 the arrow of time drives the evolution of the entire Universe.
当我们细细观察宇宙深处的时候 And as we look out deep into the cosmos,
就能看出一些端倪 we can see that story unfold.
这是一张狮子座里很小一片夜空的图像 This is an image of a tiny piece of night sky in the constellation of Leo.
其实也就是在狮子嘴附近的一小块 It's actually where the mouth of the lion would be.
虽然看上去很稀松平常 And, despite appearances,
不过这在近年来的天文史里 算是重量级的图像了 it is one of the most interesting images taken in recent astronomical history.
有趣的东西就是这个小小的红点 The interesting thing is this little red blob here,
看上去很是平常 which looks very unremarkable.
但其实 这个红点 But what that red blob is is the afterglow
是一次巨大的天体爆炸的余辉 of an enormous cosmic explosion.
这显示的是一颗恒星的死亡 It's the death of a star.
这颗恒星 That was about...
大约是我们的太阳的40到50倍重 40 or even 50 times the mass of our sun.
它叫做GRB 090423 Poetically named GRB 090423,
曾经是一颗沃尔夫-拉叶型星 it was once a Wolf-Rayet star.
沃尔夫-拉叶型星：简称白巨星，白超巨星 是一种在正在演化的大质量恒星
虽然被快速旋转的气体星云遮蔽 Shrouded by rapidly swirling clouds of gas,
它依然我们的太阳还要亮一万倍 it burned 10,000 times more brightly than our sun.
但正是因为如此之亮 它的寿命极端的短 But because it burned so brightly, it was extremely short-lived.
当它死亡时 巨大的恒星向内心坍塌 As it died, the giant star collapsed in on itself.
这导致大量的光线与恒星物质 That caused massive jets of light and stellar material
从它的两级喷射而出 to be ejected from its poles,
这次爆炸闪烁的光芒 是太阳的一亿亿倍 in an explosion that shone with the light of 10 million billion suns.
这场浩劫的余辉 And it's the afterglow of this catastrophic explosion
在我们的星球上看来 只是一个淡淡的小红点 that is just visible from this planet as a faint red dot.
但这不是GRB 090423最有意思的地方 But that's not what's so interesting about GRB 090423.
当我们仰望星空 看那些遥远的星星与星系时 You see, when we look up into the sky, at distant stars and galaxies,
其实看到的是过去的景象 then we're looking back in time
因为光的运行也需要时间 because the light takes time to journey from them to us.
而这个红点的光线传到我们眼里所花费的时间 And the light from that red dot has been travelling to us
几乎是整个宇宙的历史那么长 for almost the entire history of the universe.
其实 我们看到的这个事件 You see, what we're looking at here is an event that happened
早在130亿年前就发生了 13 billion years ago.
那时 大爆炸刚刚发生了6千万年 That's only about 600 million years after the Big Bang.
也就是宇宙刚刚形成了6千万年 After the universe began.
所以 这算得上是宇宙最早期的历史了 So this is something incredibly early in the universe's history.
实际上 它是我们能够观测到最早的物体 In fact, this is the oldest single object that we've ever seen.
这个红点 是宇宙中第一批恒星的 What we're looking at here is the explosive death
爆炸和死亡历程 of one of the first stars in the universe.
随着宇宙的不断演化 会进入不同的时期 As it evolves, the universe passes through distinct eras.
这些宏大的纪元 它们的开始和结束 Vast ages, whose beginnings and endings
都有着独特的里程碑 are marked by unique milestones.
那就是一个个奇迹的诞生和消亡 The births and deaths of its wonders.
第一批恒星的诞生 The moment the first stars were born is one of the most important changes
是茫茫宇宙史上的浓重一笔 in the evolution of the cosmos.
它标志着宇宙原始期的结束 It signals the end of the Primordial Era
原始期：宇宙五纪元中的第一个
以及第二个宇宙纪元的开始 and marks the beginning of the second great age of the universe.
也就是我们生活的这个时代 The time in which we live.
它叫做“造星期” The Stelliferous Era -
是众星璀璨的纪元 the age of the stars.
恒星不光点缀了夜空 还带来了我们的白昼 Starlight illuminates the night sky and starlight illuminates our days.
太阳就是银河系中2000亿颗恒星之一 Our sun is just one of 200 billion stars in our galaxy.
而银河系 又是我们能观测到的1000亿个星系之一 Our galaxy is one of 100 billion in the observable Universe.
仿佛在浩瀚的海洋中 有无数星星的岛屿一样 And countless islands of countless stars.
尽管宇宙的寿命已经超过了130亿年 Although the universe is over 13 billion years old,
我们依然生活在造星期的众星之间 we still live close to the stars of the Stelliferous Era.
这个纪元的宇宙 美不胜收 多姿多彩 令人惊叹 It's an age of astonishing beauty and complexity in the universe.
宇宙中充满了恒星 The cosmos is absolutely awash with stars
还有伴随它们的无数星云和行星 surrounded by nebulae and systems of planets.
这些数不胜数的世界 我们永远也探索不完 Countless billions of worlds that we've yet to explore.
然而 宇宙并非一潭死水 毫无变化 But the cosmos isn't static and unchanging.
它不会永远是这个样子 It won't always be this way.
因为在时间的雕琢之下 Because, as the arrow of time plays out,
宇宙的美是动态的 变幻的 it produces a universe that is as dynamic as it's beautiful.
我们目睹了恒星的诞生 也目睹了它们的死亡 We've seen stars born and we've seen stars die.
我们知道 时间一去就不复返 And we know that tomorrow won't be the same as today
因为时间箭头告诉我们 because the arrow of time says
未来和过去是绝然不同的 the future will always be different from the past.
但这变化又因何而起？ But what drives this evolution?
过去和未来 它们为何会有不同？ Why is there a difference between the past and the future?
时间箭头的意义何在？ Why is there an arrow of time at all?
我们每个人都对时间有着清晰的感觉 We all have an intuitive understanding of the arrow of time.
对于我们来说 斗转星移 昨日不再 It seems obvious to us that things change
这些都再自然不过了 and the future will be different to the past.
这是因为年复一年 我们见证了时间的作用 We know that because we see the effects of the passing years all around us.
这里是卡曼斯科 一处废弃的钻石矿业城镇 This is Kolmanskop, an abandoned diamond mining town
它位于纳米比亚的南部 in southern Namibia.
这座小镇建立于1908年 This entire town was founded in 1908,
当时 一位工人正在修建从吕德里茨港 when a worker who was building the railway from the port of Luderitz
通向纳米比亚内地的铁路 他在这里的沙漠中 inland into the centre of Namibia found a single diamond
发现了一颗钻石 here in this desert.
在接下来的40年里 这里变成了一个 For 40 years, this was a
人丁兴旺的社区 有一千多居民 thriving community of up to 1,000 people.
人人都有机会一夜暴富 A place where you could become a millionaire,
只要你能在这沙漠里找到钻石 picking diamonds out of the sand.
财富滚滚而来 他们修建了豪华的住宅 While the money rolled in, they built grand houses
在这苍茫的沙漠之中 享受着上流生活 and lived a champagne lifestyle in the desert.
而当钻石被采掘一空 小镇随即被荒弃了 But when the diamonds dried up, the town was abandoned.
又经过了半个世纪 这里的一切 And for half a century it's fallen into disrepair
都已年久失修 正慢慢地回归沙漠 as it's slowly reclaimed by the sands.
Kolmanskop这里发生的一切 在宇宙里随处可见 The processes at play here at Kolmanskop are happening everywhere in the universe.
因为时间箭头理论的重点并不仅仅是“变化” Because it isn't simply permanent change that's central to the arrow of time.
而是“衰亡” It's decay.
然而 解释这一切的科学理论 But the scientific explanation for why that is...
并非来自人们对时间的探索 ..didn't come from attempting to understand the effects of time in the universe.
而是来自于建造更快火车的努力 It came from trying to build a faster train.
19世纪 工程师们想尽各种办法提高蒸汽机的效率 Back in the 19th century, engineers were concerned with the efficiency of steam engines.
火该烧多热？ How hot should the fire be?
要用哪种物质的蒸汽？ What substance should you boil in the steam engine?
是该用水 还是其他的什么？ Should it be water or something else?
这些都是至关重要的问题 These were profound questions.
而一个新的学科也应运而生 名叫热力学 And out of those questions arose the science of thermodynamics.
也就是从那时开始 像热量 温度 能量这些概念 It's when concepts like heat and temperature and energy
走进了科学的研究领域 entered the scientific vocabulary for the first time.
随之而来的 是一些更深层次的知识 Now, along with that deeper understanding
这也许是最关键的一条物理定律 emerged what is probably the most important law of physics
它能让我们理解时间的推移和宇宙的演化 for understanding the evolution of the universe and the passage of time.
它的名字是“热力学第二定律” It's called the Second Law of Thermodynamics.
这条定律意义非凡 The reason the Second Law of Thermodynamics was so profound
因为它的核心 是一个标新立异的概念 was because, at its heart, it contained a radically new concept.
也就是物理学家们常说的“熵” Something physicists call "entropy".
熵的概念能够解释 Entropy explains why,
为什么在没有外力干预的情况下 left to the mercy of the elements,
墙壁会断裂 玻璃会破碎 房屋会坍倒 mortar crumbles, glass shatters and buildings collapse.
要想理解熵的概念 我们不能把物体 And a good way to understand how is to think of objects
看作是一个单一的东西 not as single things,
而要认识到它由许多部分组成 but as being made up of many constituent parts.
就像组成这沙堆的沙粒 Like the individual grains that make up this pile of sand.
熵 就是沙堆在保持原样的同时 Now, entropy is a measure of how many ways I can rearrange those grains
能够被重新组织的可能性 and still keep the sand pile the same.
当然 对于这个沙堆来说 可能性是无穷无尽的 And there are trillions and trillions and trillions of ways of doing that.
无论我对这个沙堆做了什么 搅和它 移动它 I mean, pretty much anything I do to this sand pile, if I mess the sand around and move it around,
它依然保持着刚才的形状和结构 then it doesn't change the shape or the structure at all.
用熵来说 就是这个沙堆有很高的熵值 So, in the language of entropy, this sand pile has high entropy
因为我有很多方法重新组织它 because there are many, many ways
而它的结构保持不变 that I can rearrange its constituents and not change it.
那现在我来为宇宙造出点秩序 Now let me create some order in the universe.
在这座小沙堡里 沙粒的数目 Now, there are approximately as many sand grains in this sandcastle
和这个沙堆应该差不多 as there are in the sand pile.
但是现在 无论我对它做什么 But now, virtually anything I do to it will mess it up,
几乎都会破坏它的结构和秩序 will remove the beautiful order from this structure.
因此 这座沙堡熵值很低 And because of that, the sandcastle has a low entropy.
是一种有序得多的状态 It's a much more ordered state.
总的来说 如果有多种重组沙粒的方式 So many ways of rearranging the sand grains
又能保持结构 那么熵值就高 without changing the structure, high entropy.
如果重组这些沙粒 Very few ways of rearranging the sand grains
而不破坏结构的可能性小 那么熵值就低 without changing the structure, without disordering it, low entropy.
试想我把这沙堡扔在这一整天 Imagine I was to leave this castle in the desert all day.
接下来的事情可想而知 Then it's obvious what's going to happen.
沙漠中的风会把沙子吹走 The desert winds are going to blow the sand around
这座沙堡将会瓦解 and this castle is going to disintegrate.
它的有序度会降低 最后又变回沙土 Is going to become less ordered. Is going to fall to bits.
但从最根本的层面上思考一下 But think about what's happening on the fundamental level.
你看 风会带走沙堡的沙子 I mean, the wind is taking the sand off the castle
把它们吹走 变成沙堆 and blowing it over there somewhere and making a sand pile.
然而 没有一条物理定律规定 There's nothing fundamental in the laws of physics
风不能从这里卷起沙子 that says that the wind couldn't pick up some sand from over here,
吹到这儿 deposit it here
然后精确地堆积成沙堡的形状 and deposit it in precisely the shape of a sandcastle.
理论上 风完全能够自发地把沙丘吹成沙堡 In principle, the wind could spontaneously build a sandcastle out of a pile of sand.
这种事情并非绝无可能 There's no reason why that couldn't happen.
而只是可能性微乎其微 It's just extremely, extremely unlikely because there
因为把沙粒堆积成沙堡的方法少之又少 are very few ways of organising this sand so that it looks like a castle.
而最有可能发生的 It's overwhelmingly more likely
就是当风卷起沙粒时 that when the wind blows the sand around
会把低熵值的沙堡 it will take the low entropy structure of the castle
变成一个高熵值的沙堆 and turn it into a high entropy structure, the sand pile.
所以 熵值永远在增加 究其原因 So, entropy always increases. Why is that?
就是因为高熵值的状态拥有更高的概率 Because it's overwhelmingly more likely that it will.
不可思议的是 It seems incredible that
这条规定“风不会自动堆出沙堡”的定律 a law that says that sandcastles don't spontaneously form on the wind
解开了物理学最深的谜团 could solve one of the deepest mysteries in physics.
凭藉着“熵增法则” But by saying entropy always increases,
热力学第二定律解释了 the Second Law of Thermodynamics is able to explain
时间为何只有一个行进方向 why time only runs in one direction.
对我来说 热力学第二定律体现了物理学 The Second Law of Thermodynamics, for me, demonstrates everything
优雅而强大的一面 that's powerful and beautiful and profound about physics.
这条科学定律最开始是用来描述 You see, here's a law that entered science
热量的传导方式 as a way of talking about how heat moves around
以及蒸汽机效率的 and the efficiency of steam engines.
最终它却解释了物理史上最大的谜题之一 But it ended up being able to explain one of the great mysteries in the history of science.
为什么过去和未来存在区别？ Why is there a difference between the past and the future?
因为第二定律说 万事都从有序趋于无序 You see, the second law says that everything tends from order to disorder.
过去和未来的区别就在于此 That means that there is a difference between the past and future.
过去的宇宙是更有序的 In the past, the universe was more ordered.
而未来的宇宙 有序度只会越来越低 In the future, the universe will be less ordered.
也就意味着 时间的行进是有方向的 And that means there's a direction to the passage of time.
所以 热力学第二定律 So the Second Law of Thermodynamics has introduced the concept
引入了“时间箭头”的概念 of an arrow of time into science.
自从矿场1954年被废弃之后 The arrow of time has been playing out in Kolmanskop
一去不复返的时间箭头 消磨着Kolmanskop的一切 since the mining facility was abandoned in 1954.
而在宇宙中 这样的过程已经持续了140亿年 But in the universe, it's been playing out for almost 14 billion years.
也将为我们带来深远的影响 And it will have profound consequences.
因为它意味着恒星不能永远燃烧下去 Because it means stars cannot shine forever.
当然 我们太阳系中心的那颗恒星亦是如此 Including the star at the centre of our solar system.
在它的晚年 太阳不会简单地慢慢黯淡下去 At the end of its life, the sun won't simply fade away to nothing.
当太阳的燃料耗尽时 它的核心会坍缩 As it begins to run out of fuel, its core will collapse
而坍缩过程中产生的热量 and the extra heat this generates
又会导致它的外层膨胀 will cause its outer layers to expand.
这个持续十亿年的过程 In around a billion years' time,
将给我们脆弱的世界带来毁灭性的后果 this will have a catastrophic effect on our fragile world.
地球将会慢慢地变热 Gradually, the Earth will become hotter and hotter.
也就是说 地球的好日子终有到头的时候 So there will be one last perfect day on Earth.
最终 这个星球上所有的生命都将无法生存 But eventually the existence of all life on this planet will become impossible.
在生命绝迹之后很长时间 太阳会变得非常大 Long after a life has disappeared, the sun will have grown so much
它将充满整个地平线 it will fill the entire horizon.
它将会变成红巨星 It will become a red giant.
这是太阳生命的最后阶段 The last phase of its life.
我们的星球很难在这一时期幸存下来 Our planet might not survive to this point.
但即使幸存了 剩下的也不过是一块被烧焦的废石 But, if it does, little more than a scorched and barren rock will remain
见证着太阳的最后毁灭 to witness the final death throes of our star.
60亿年之后 我们的太阳将爆炸 In six billion years, our sun will explode.
将大量的气体与尘埃抛洒到太空中 Throwing vast amounts of gas and dust out into space,
形成一个巨大星云 to form a gigantic nebula.
而它的核心散发着微弱热量 And at its heart will beat
如一片记录过往的琥珀 a faintly glowing ember.
诉说着它辉煌夺目的过去 All that remains of our once magnificent sun.
那时 太阳的尺寸将会比地球还小 It will be smaller than the size of the Earth.
也就是不到现在太阳体积的百万分之一 Less than a millionth of its current volume
而亮度与现在相比更是微不足道 and a fraction of its brightness.
我们的太阳将变成一颗白矮星 Our sun will have become a white dwarf.
由于没有燃料可以燃烧 With no fuel left to burn,
白矮星微弱的亮光来自于它早年的余热 a white dwarf's faint glow comes from the last residual heat from its extinguished furnace.
太阳死了 The sun is now dead.
它在冰冷宇宙的深处 慢慢地散失掉最后一丝光热 Its remains slowly cooling in the freezing temperatures of deep space.
若从地球的位置望去 Looking at it from where the Earth is now,
这时太阳放出的光 只和晴朗夜空里的满月相当 it would only generate the same amount of light as the full moon on a clear night.
太阳的命运 和其他所有恒星是一样的 The fate of the sun IS the same as for all stars.
总有一天 所有的恒星都将死亡 One day, they must all eventually die
宇宙会陷入无休止的漫漫长夜 and the cosmos will be plunged into eternal night.
这就是时光不可倒流的结果 And this is the most profound consequence of the arrow of time.
因为我们居住的宇宙 Because this structured universe that we inhabit,
和其中的所有奇观 恒星 行星 以及星云 and all its wonders - the stars, the planets and the galaxies -
都无法永存 cannot last forever.
宇宙最终将会慢慢凋零 死亡 The cosmos will eventually fade and die.
首先到来的是造星期的终结 First will come the end of the Stelliferous Era.
万星增辉的纪元就此结束 The end of the age of starlight.
最大的恒星最先消失 The largest stars are the first to disappear,
猛烈地坍缩成为黑洞 violently collapsing into black holes.
它们的寿命通常只有几百万年 Just a few million years after their formation.
但在这些大型恒星消亡后很久 But long after they're gone,
只有一种恒星还留存着 just one type of star will remain.
这张照片显示的 就是离我们太阳系最近的恒星 This is a picture of the nearest star to our solar system,
比邻星 Proxima Centauri.
比邻星：半人马座α三合星的第三颗星
它离我们只不过4.2光年而已 而这颗恒星 It's only 4.2 lightyears away. But the reason it doesn't stand out
并不比远处的其他星星明亮多少 against the much more distant stars in this photograph
这是因为比邻星异常微小 is that Proxima Centauri is incredibly tiny.
这类恒星叫做红矮星 It's a kind of star known as a red dwarf star.
它的质量只有太阳的11%到12% It's only about 11-12% the mass of our sun.
在我们看来 它的亮度只是太阳的一万八千分之一 But to our eyes it would appear to shine 18,000 times less brightly.
但红矮星与那些比它大得多 But red dwarfs do have one advantage
亮得多的星星相比 有一个优势 over their much more luminous and magnificent stellar brethren.
因为它们很小 And that's because they're so small,
能以极慢的速度消耗核燃料 they burn their nuclear fuel incredibly slowly,
所以它们的寿命能达到万亿年之久 so they have lifespans of trillions of years.
这意味着 像比邻星这样的恒星 And that means that stars like Proxima Centauri
会在宇宙里坚持到最后 will be the last living stars in the universe.
如果我们能够存活到那么久的话 If we survive into the far future of the universe,
我们的后代很有可能会将他们的文明 then it's possible to imagine our distant descendants
建立在红矮星附近 building their civilisation around red dwarfs
以获取最后一丝仅存的光热 to capture the energy from those last fading embers of stars,
就像我们的祖先在寒冷的冬夜 just as our ancestors crowded around campfires
围绕在营火边取暖一样 for warmth on cold winter's nights.
比邻星燃烧得这么慢的原因 The reason why Proxima Centauri burns so slowly
是它的体积和引力都很小 is because its small size and low gravity
这意味着它内核的压力比那些更大的恒星要小很多 mean its core is under much lower pressure than larger stars.
也意味着它的内核会不停地流动 This also means that its interior is constantly churning,
并不断地从表面喷出来 whipping up the surface into a fiery turmoil.
虽然比邻星那么昏暗 它的表面 Explosive solar flares occur almost continually,
却在永无休止地发生着爆炸性的耀斑 even though it burns so dimly.
但最终 比邻星也会死亡 But Proxima Centauri will eventually die.
和我们的太阳相同 它也会变成一颗白矮星 And like our sun, it too will become a white dwarf.
当造星季临近结束 一切都将黯淡下去 As the age of starlight ends,
宇宙里只剩下最微弱的几丝亮光 all but the dimmest flicker of light in the universe will go out.
白矮星的幽光 将用它最后一抹亮色 The faint glow of white dwarfs will provide the only illumination
照耀着这个充斥着死亡恒星和黑洞的宇宙 in a dark and empty void, littered with dead stars and black holes.
到这时 宇宙已有一万亿年的历史了 By this point, the universe will be 100 trillion years old.
然而 在它宏大的生命中 And yet, even now, the vast majority of its lifespan
绝大部分的旅程还尚未开始 still lies ahead of it.
在地球上的某些地方 人们可以隐隐感知到 There are few places on Earth where you can get an inkling
遥远的未来会发生什么 of what the far future has in store.
这里是纳米比亚的骷髅海岸 This is Namibia's Skeleton Coast,
南大西洋的冰冷海水 where the cold water to the South Atlantic
和纳米布沙漠交汇于此 meet the Namib Desert.
这里是地球上环境最恶劣的地方之一 And it is one of the most inhospitable places on Earth.
早在17世纪 葡萄牙的水手 Back in the 17th century, Portuguese sailors
就把这里称为“地狱之门” used to call this place the gates to hell
因为 几乎每天早上这里都笼罩在这种浓雾之中 because this dense fog that you see pretty much every morning along this coast,
还有不断变换着形状的沙滩 coupled with the constantly shifting shape of the sandbanks,
年复一年 成千上万的船只 meant that over the years, literally thousands of ships
在这条海岸线附近失事沉没 were wrecked along this coastline.
就算你挣扎着登上沙滩 问题还是接踵而至 And even if you made it to shore, that wasn't the end of your problems
这里的海流很是强劲 because the currents are so strong here
一旦上岸 就再也没有可能回到海中 that there is no way of rowing back out to sea.
往那边看 会看见绵延数百公里的荒凉沙漠 If you look that way, there's just hundreds of miles of inhospitable desert.
这里确实是有去无回的地狱 So, it genuinely was a place of no return.
如果船只在此沉没 人们绝无生还的可能 If you were shipwrecked here, this WAS the end of your universe.
这是Edward Bohlen号 This is the Eduard Bohlen.
这条船曾经是条远洋轮船 She was once an ocean-going steamer,
在此地和欧洲之间航行 运送旅客和货物 ferrying passengers and cargo between here and Europe.
1909年9月5日 它在一场大雾中搁浅 On 5th September, 1909, she ran aground in thick fog.
跟所有在此沉没的船只一样 Yet, like all the vessels wrecked along this shoreline,
它在水中慢慢被腐蚀殆尽的时间 the time it takes her to decay to nothing
要比它航行时间的总和长得多 will be far longer than her time at sea.
在宇宙遥远的未来中 In the far future of the cosmos,
同样的命运也会落在剩下的白矮星身上 a similar destiny awaits the remaining white dwarfs.
黑矮星将是这些末日之星的最终形态 A black dwarf will be the final fate of those last stars.
异常冰冷的白矮星 White dwarfs that have become so cold
不会再散发出光和热 that they barely emit any more heat or light.
黑矮星是黑暗的荒凉星球 Black dwarfs are dark,
由高密度的简并态物质构成 dense decaying balls of degenerate matter.
简并态物质：一种密度极高的物质
大部分为恒星的遗骸 Little more than the ashes of stars.
构成它们的原子被高度压缩 Their constituent atoms are so severely crushed
因此 黑矮星的密度要比我们的太阳大一百万倍 that black dwarfs are a million times denser than our sun.
恒星要变成黑矮星需要相当长的时间 Stars take so long to reach this point,
在宇宙诞生140亿年后的今天 that after nearly 14 billion years
我们有理由相信 现在的宇宙中没有黑矮星存在 we believe there are currently no black dwarfs in the universe.
尽管还没有出现黑矮星 But despite never seeing one,
我们依然能预测出它们将如何消亡 we can still predict how they will end their days.
就好像船体的铁板会慢慢锈蚀 Just as the iron than makes up this ship
随着沙漠中的罡风灰飞烟灭一样 will eventually rust and be carried away by the desert winds,
黑矮星上那些宇宙中最后的物质 so we think that the matter inside black dwarfs, the last matter in the universe,
最终会挥发殆尽 在辐射中渐渐湮灭入无尽虚空 will eventually evaporate away and be carried off into the void as radiation,
一点儿痕迹都不会留下 leaving absolutely nothing behind.
黑矮星消逝之后 With the black dwarfs gone,
就再也没有一个物质的原子存在了 there won't be a single atom of matter left.
一度多姿多彩的宇宙 All that will remain of our once rich cosmos
只会剩下光子和黑洞 will be particles of light and black holes.
经过亿万年之后 After an unimaginable length of time,
就连黑洞也会湮灭 even the black holes will have evaporated
宇宙中空无一物 只剩一片光子的海洋 and the universe will be nothing but a sea of photons,
温度的差异也渐渐抹平 gradually tending towards the same temperature,
在宇宙膨胀的作用下 一切都会趋近于绝对零度 as the expansion of the universe cools them towards absolute zero.
绝对零度：即-273.15摄氏度
当我说到“亿万年”的时候 我真的指亿万年 And when I say "unimaginable period of time," I really mean it.
也就是10的100次方年 It's 10,000 trillion trillion trillion trillion trillion trillion trillion trillion years.
10的100次方有多大？ How big's that number?
如果一个原子代表一年 If I were to start counting with a single atom representing one year
把我们宇宙中的所有原子都用上 then there wouldn't be enough atoms in the entire universe
也远远不够10的100次方那么多 to get anywhere near that number.
当我们宇宙中最后物质的残余都消失不见 Once the very last remnants of the very last stars have finally decayed away to nothing,
当整个宇宙都达到了相同温度 and everything reaches the same temperature,
宇宙的故事就要划上句号了 the story of the universe finally comes to an end.
那时 将是宇宙第一次能够永恒不变 For the first time in its life, the universe will be permanent and unchanging.
熵值也终于停止增长 Entropy finally stops increasing
因为宇宙的无序度已经无法再增加 because the cosmos cannot get any more disordered.
没有什么发生 而且再也不会发生什么了 Nothing happens and it keeps not happening.
一直如此 Forever.
这就是所谓的“宇宙热寂说” It's what's known as the heat death of the universe.
到那时 宇宙会永远地保持 An era when the cosmos will remain
广阔 冰冷 荒凉沉寂的状态 vast and cold and desolate for the rest of time.
而到那时 过去 现在 和未来之间 But that's because there is no difference
完全不再有区别 between the past, the present and the future.
没有什么能够衡量时间的流逝 There's no way of measuring the passage of time
因为宇宙永远保持原样 不再变化 because nothing in the cosmos changes.
时间箭头被永远地凝固了 The arrow of time has simply ceased to exist.
这就是宇宙不可避免的宿命 It's an inescapable fact of the universe,
它早已写在了物理学的基本原理中 written into the fundamental laws of physics.
宇宙终将死亡 The entire cosmos will die.
在我们的银河系 Every single one of the 200 billion stars
2000亿颗恒星中的每一颗都难逃一死 in our galaxy will go out.
太阳的消亡 意味着地球上生命的终结 And just as the death of the sun means the end of life on our planet,
而每一颗恒星的消亡 so the death of every star
也都在抹煞着生命存在的可能性 will extinguish any possibility of life in the universe.
太阳最终会消亡 也会导致地球 The fact that the sun will die and it will incinerate the Earth
以及地球上一切生命的灭亡 and obliterate all life on our planet in the process,
这听上去也许会让人感到悲观 might sound a bit depressing to you.
你当然可以说 You might legitimately ask,
“那为什么不构建一个完全不同的宇宙呢？ "Well, surely you could build a universe in a different way?
在那个宇宙中 一切不会归于混沌 "Surely you could build it so it didn't have to descend
这样不是很好吗？” from order into chaos?"
答案是 不 我们做不到 只要还想让生命存在 Well, the answer is no, you couldn't, if you wanted life to exist in it.
时间箭头 以及那些会导致宇宙灭亡的微小改变 The arrow of time, the sequence of changes that slowly leads the universe to its death,
其实恰恰是最初的生命缔造者 is the very same thing that creates the conditions for life in the first place.
因为 物质的形成需要时间 Because it takes time for matter to form
在重力作用下 行星和恒星的形成也需要时间 and it takes time for gravity to pull it together into stars and planets.
正是时间的箭头 在宇宙的青春期 The arrow of time creates a bright window
打开了一扇明亮的窗户 in the universe's adolescence.
从而使生命成为可能 During which, life is possible.
但这扇窗户并不会开得太久 But it's a window that doesn't stay open for long.
同宇宙的生命 As a fraction of the lifespan of the universe,
也就是从宇宙形成之初到最后一个黑洞湮灭 相比 as measured from its beginning to the evaporation of the last black hole,
我们的生命只不过占了它的 life, as we know it, is only possible for one thousandth
10的86次方... of a billion billion billionth billion billion billionth
...分之一 billion billion billionth of a per cent.
这就是为什么对我来说 宇宙的奇迹不是某颗恒星 And that's why, for me, the most astonishing wonder of the universe isn't a star
某颗行星 或某个星系 or a planet or a galaxy.
我认为 宇宙的奇迹不是某个东西 It isn't a thing at all.
而是这时间长河里的须臾一瞬 It's an instant in time.
也就是现在 And that time is now.
在永恒的时间里 人类出现在地球上的这段时间 Humans have walked the Earth for just the smallest fraction
只是微不足道的一小部分 of that briefest of moments in deep time.
虽然我们在地球上只生存了20万年 But in our 200,000 years on this planet,
我们却已经取得了令人惊叹的进步 we've made remarkable progress.
仅仅在2500年前 我们还认为太阳是天神 It was only 2,500 years ago that we believed that the sun was a god
我们还在用建在山巅的石塔 and measured its orbit with stone towers,
来记录它的运行轨迹 built on the top of a hill.
现在 人们的好奇不再局限于太阳神 Today, the language of curiosity is not sun gods,
而是转向了科学 but science.
现代的天文台 与这13座塔相比 And we have observatories that are almost infinitely more sophisticated
简直要复杂无数倍 它们正在探索宇宙深处的奥秘 than the 13 towers, that can gaze out deep into the universe.
也许更令人赞叹的是 And, perhaps even more remarkably,
通过先进的理论物理和数学 through theoretical physics and mathematics,
我们可以计算出遥远的未来 宇宙将走向何方 we can calculate what the universe will look like in the distant future.
甚至能透过严密的推算 清晰地看到它的终结 And we can even make concrete predictions about its end.
我相信 只有通过对宇宙的不断探索 And I believe it's only by continuing our explanation of the cosmos
对自然规律的不断寻觅 and the laws of nature that govern it,
我们才能真正了解自己在宇宙奇迹中的具体位置 that we can truly understand ourselves and our place in this universe of wonders.
这也是我们这些地球居民短暂生命的意义所在 And that's what we've done in our brief moment on Planet Earth.
1977年 “旅行者1号”探测器 In 1977, a space probe called Voyager 1
开始了探索太阳系的征程 was launched on a grand tour of the solar system.
它先后抵达了气体巨行星木星 And it visited the great gas giant planets -
还有土星 在踏向茫茫宇宙之前 Jupiter and Saturn - and made some wonderful discoveries
做出了很多神奇的发现 before heading off towards interstellar space.
13年后 当它的任务基本完成 13 years later, after its mission was almost over,
它回头拍下了自己家园 太阳系的最后一张照片 it turned around and took one last picture of its home solar system.
就是这张照片 This is that picture.
这张照片的精彩之处就在于 And the beautiful thing about this picture
一抹微弱的亮光 is this single pixel of light
悬浮在宇宙黑色的背景之上 suspended against the blackness of space.
因为那抹亮光 那一个小点 就是我们地球 Because that pixel, that point, is Planet Earth.
这是一张我们星球最遥远的照片 The most distant picture of our planet ever taken.
拍摄点距地球60亿公里远 6 billion kilometres away.
虽然我觉得这张照片的科学价值有限 And whilst I suppose it has very limited scientific value,
但是 正是这一抹亮光 for me, this tiny point of light
才是人类特质最有力的证明 is the most powerful and profound demonstration of perhaps the most human of qualities.
我们拥有对宇宙 对家园 Our unique ability to reflect on the universe's existence
对世间万物的思考 and our place within it.
地球上的你我 都生存在这片小小的筏子上 Just as we, and all life on Earth, stand on this tiny speck
在无限宇宙中 一切生命 adrift in infinite space, so life in the universe will only exist
都只是转瞬即逝的 for a fleeting bright instance in time
因为生命 跟那些恒星 行星 星系一样 because life, just like the stars and the planets and the galaxies,
都不过是从有序到混沌的宇宙旅程中的匆匆过客 is just a temporary structure on the long road from order to disorder.
但是这并不意味着生命是无足轻重的 But that doesn't make us insignificant
因为我们的觉醒 才有了对宇宙的认识 because we are the cosmos made conscious.
从某种程度上讲 生命就是宇宙认知自我的过程 Life is the means by which the universe understands itself.
在我看来 我们存在的意义恰恰在于 And, for me, our true significance lies in our ability
我们对这个神奇宇宙的探索和认识的欲望 and our desire to understand and explore this beautiful universe.
# We have all the time in the world #
（片尾曲：Amalia Gre- We Have All Time In The World）
# Time enough for life to unfold #
# All the precious things love has in store... #
# Only now. #