宇宙时空之旅

有朝菌，朝生而夕死，乃不知日夜 有蟪蛄，春生而夏死，乃不知四季 《逍遥游》里写过一个大致如此的故事 故事里还有一只灵龟 对该灵龟来说 五百年一季候 两千年一春秋 小时候看的蔡志忠 这个故事至今未被磨灭 人站在菌蛄和灵龟之间 前者渺若尘埃 弹指一挥 后者睥睨光阴 几至永恒 以人观之 朝菌和蟪蛄哪里配谈人生 灵龟则是人神话般的梦想 而在空间尺度上 囿于千百年来的技术桎梏 万物都被拉平在同一块天地之间 纵然是飞行 在人之眼中也不过是一种更便捷的移动方式 在地面奔驰 一样可以追云逐月 时空于我们的先祖来说 是诗情画意 是艺术命题 仅当我们谈及朝菌和蟪蛄时 它们因短暂而可悲的一生不禁令人俯身喟叹 当时我觉得 这种喟叹不过一厢情愿 朝菌不知日夜 蟪蛄不知四季 很可能这才使它们的一生得以坦然和丰满 无知无欲求 无觉无烦恼 哪里像人类 文化和科技把上下五千年都连接进了自己短暂的一生 即便是古人 也认得灵龟这种造物 与之相较 人之一生也不过须臾 加上求长生之术而不得的失落 很难讲人与菌蛄谁更快活 Cosmos 值得一看 还有类似的 Travel to the edge of the universe 我知道一些对这类电影 甚至是这类论题毫无热情甚至有些排斥的朋友 在宇宙之下 对人之生命和处所的知觉令他们感到深深的挫败和虚无 我理解这种心态 得知自己奋斗一生 在稍稍高远一些的视角下 可能不过是将一粒尘埃推动了一毫米 任谁都会难以振奋 智慧令我们成为万灵之长 令我们发问和探索 可探索到的事实不过是一再刷新和巩固人类之于宇宙的偶然和渺小 在我看来 对现状心有不甘是作为智慧的理所当然 对我们一直以来独特、唯一、无上的自觉的否定令我们难以承受 有限的世界更有助于我们成长快乐 但遗憾的是技术却一直在带着我们背离期待的方向 人生识字忧患始 苦苦求索并不能有助于解决智慧的诅咒 求索本身 更是诅咒的一部分 Cosmos 里有两个地方令我印象深刻 一个是宇宙年历和地球年历 将无论138亿还是45亿年压缩到一年365天之内 人类文明都是出现在跨年夜的最后几秒 这样的直观令人难以平静 从钻木取火到探路火星 令我们自己叹为观止的文明可能只不过是宇宙的一次心跳 一次呼吸 一次眨眼 甚至更细微 另一个 是 Neil 娓娓讲述中的阿波罗计划 在冷战时期的美苏军备竞赛中 我们有两个超级大国都掌握了足以毁灭文明的武器 并且这两个大国互相敌对 那可能是一场我们不敢想象、无可挽回的灾难 所幸最终它并未发生 将目光转向了高级火箭推进（说是航天，实际上还是为了运载弹头）并率先成功的美国人 史诗性地将人类的足迹踏在了月球表面 在这场技术的耀武扬威中 一张照片却意外并永远地开启了人类对于整个文明的思考 那是漂浮在黑暗的宇宙帷幕之下 孤零零的、蓝色的、我们的地球

第一次 我们开始意识到在这个渺小的星球上 我们是一个共同体 它的命运即是全人类共同的命运 我愿意相信当时的元首们在看到这张照片时会心有触动 遗憾的是 在其后关于碳排放、温室效应、全球变暖的章节中 很明显这触动并没能很持久和深入 一张从月球上得到的自拍照 或许在某种程度上让地球得以从核武器互射这种急性末日中暂时脱身 现有的研究认为 碳在大气中的含量在超过了一定程度之后 给气候带来的影响将是不可逆的 很遗憾 以部分科学家之外的人类的目光来看 我们并不觉得这是个问题 低碳成了各种广告的噱头 但却没有一个是出于对我们家园真正的关怀 地球很可能在温室效应这种慢性末日中奄奄一息 不过没关系 反正我们早就做好了掏空然后弃掉地球 飞向新家园的准备 在人类对自己未来的规划里（如果短视如人类也有过任何规划的话） 拯救地球的代价并不比弃掉它更划算 同所有科普类纪录片一样 Cosmos 一样落脚于对人类命运的关怀 科学在某种程度上就像技术纪元的新宗教 但又与宗教完全不同 它用真理和事实来引导我们探索并敬畏 并最终做正确的事情 Cosmos 的文案品质不够稳定 想象之舟的设定在前段看起来略显浮夸 不看到后面便不太能领会它的妙处

我们成功地（从外太空）拍到这张照片，细心再看，你会看见一个小点。就是这里，就是我们的家，就是我们。在这点上每个你爱的人、每个你认识的人、每个你曾经听过的人，以及每个曾经存在的人，都在那里过完一生。 这里集合了一切的欢喜与苦难，数千个自信的宗教、意识形态以及经济学说，每个猎人和搜寻者、每个英雄和懦夫、每个文明的创造者与毁灭者、每个国王与农夫、每对相恋中的年轻爱侣、每个充满希望的孩子、每对父母、发明家和探险家，每个教授道德的老师、每个贪污政客、每个超级巨星、每个至高无上的领袖、每个人类历史上的圣人与罪人，都住在这里，一粒悬浮在阳光下的微尘。 在浩瀚的宇宙中，地球不过是一个很小的舞台，想想过去的血流成河，那些芸芸众生为帝王将相而流的血，只为让他们在光荣和胜利中成为瞬间的伟人，去占有那一个小点中的一小部分。想想那无尽的残酷，图像里那一个小点的某个角落的民众，每天把残酷施加到与他们没有区别的另一个角落的同胞身上，他们之间的误解如此频繁，他们多么渴望杀死对方，他们之间的憎恨又如此狂热。 我们在装模做样，我们自以为很重要，妄想着我们人类地位特殊，在宇宙中与众不同，这一切，都因这泛着苍白蓝光的小点而动摇。我们的星球，不过是一粒孤独的微尘，笼罩在伟大的宇宙黑暗之中。我们默默无闻，沉浸在无尽的浩瀚里，没有一丝线索显示，除了我们自己，没人能拯救我们。 地球是目前唯一有生命的星球，再无其他去处，至少在不久的将来亦是如此，没有外星球，供人类迁移，只可参观，不能定居。不管你喜欢与否，现在，只有地球供我们立足。 一直有人说天文学是令人谦卑，同时也是一种塑造性格的学问。对我来说，希望没有比这张从远处拍摄我们微小世界的照片更好的示范，去展示人类自负和愚蠢。对我来说，这强调了我们应该更加亲切和富同情心地去对待身边的每一个人，同时更加保护和珍惜这暗淡蓝点，这个我们目前所知唯一的家。

——奈尔·德葛拉司·泰森

01 Standing Up in the Milky Way

To make this journey, we'll need imagination. But imagination alone is not enough, because the reality of nature is far more wondrous than anything we can imagine. This adventure is made possible by generations of searchers strictly adhering to a simple set of rules, test ideas by experiment and observation, build on those ideas that pass the test, reject the ones that fail, follow the evidence wherever it leads and question everything. Accept these terms, and the cosmos is yours.

You, me, everyone... we are made of star stuff.

All of recorded history occupies only the last 14 seconds, and every person you've ever heard of lived somewhere in there. All those kings and battles, migrations and inventions, wars and loves, everything in the history books happened here, in the last seconds of the Cosmic Calendar.

Who was I back then? I was just a 17-year-old kid from the Bronx with dreams of becoming a scientist, and somehow the world's most famous astronomer found time to invite me to Ithaca, in upstate New York, and spend a Saturday with him. I remember that snowy day like it was yesterday. He met me at the bus stop and showed me his laboratory at Cornell University. Carl reached behind his desk and inscribed this book for me. "For Neil, a future astronomer. Carl." At the end of the day, he drove me back to the bus station. The snow was falling harder. He wrote his phone number on a scrap of paper and he said, "If the bus can't get through, call me and spend the night at my home with my family." I already knew I wanted to become a scientist, but that afternoon, I learned from Carl the kind of person I wanted to become. He reached out to me and to countless others, inspiring so many of us to study, teach and do science.

02 Some of the Things That Molecules Do

The awesome power of evolution transformed the ravenous wolf into the faithful shepherd, who protects the herd and drives the wolf away.

Science works on the frontier between knowledge and ignorance. We're not afraid to admit what we don't know. There's no shame in that. The only shame is to pretend that we have all the answers.

03 When Knowledge Conquered Fear

Using nothing more than Newton's laws of gravitation, we astronomers can confidently predict that several billion years from now, our home galaxy, the Milky Way, will merge with our neighboring galaxy Andromeda. Because the distances between the stars are so great compared to their sizes, few if any stars in either galaxy will actually collide. Any life on the worlds of that far-off future should be safe, but they would be treated to an amazing, billion-year-long light show… a dance of a half a trillion stars… to music first heard on one little world by a man who had but one true friend.

04 A Sky Full of Ghosts

-Father... do you believe in ghosts? -Why, yes, my son! -You, you do? I would not have thought so. -Oh, no, not in the human kind of ghost. No... not at all. But look up, my boy, and see a sky full of them. -The stars, father? I do not follow. -Every star is a sun as big, as bright as our own. Just imagine how far away from us you'd have to move the sun to make it appear as small and faint as a star. The light from the stars travels very fast, faster than anything, but not infinitely fast. It takes time for their light to reach us. For the nearest ones, it takes years. For others, centuries. Some stars are so far away, it takes eons for their light to get to Earth. By the time the light from some stars gets here, they are already dead. For those stars, we see only their ghosts. We see their light, but their bodies perished long, long ago. John, I have seen further back in time than any man before me -- millions of years into the past.

If you somehow survived the perilous journey across the event horizon, you'd be able to look back out and see the entire future history of the universe unfold before your eyes.

He broke through the walls of heaven.

The ones that still shine their light upon us long after they're gone.

05 Hiding in The Light

His spectral lines revealed that the visible cosmos is all made of the same elements. The planets... The stars... The galaxies... We, ourselves, and all of life... The same star stuff.

06 Deeper, Deeper, Deeper Still

Every one of them a unique phrase of life's poetry, written in the atoms by eons of evolution.

07 The Clean Room

Today, scientists sound the alarm on other environmental dangers. Vested interests still hire their own scientists to confuse the issue. But in the end, nature will not be fooled.

08 Sisters of The Sun

I was to blame for not having pressed my point. I had given in to authority when I believed I was right. If you are sure of your facts, you should defend your position.

The words of the powerful may prevail in other spheres of human experience, but in science, the only thing that counts is the evidence and the logic of the argument itself.

Will the beings of a distant future, sailing past this wreck of a star, have any idea of the life and worlds that it once warmed?

When a massive star dies, it blows itself to smithereens. Its substance is propelled across the vastness to be stirred by starlight and gathered up by gravity. Stars to dust and dust to stars. In the cosmos, nothing is wasted.

09 The Lost Worlds of Planet Earth

Our sense of the stability of the Earth is an illusion due to the shortness of our lives.

The dinosaurs never saw that asteroid coming. What's our excuse?

All this beauty will have vanished and the Earth of our moment in time will take its place among the lost worlds. The great internal engine of plate tectonics is indifferent to life, as are the small changes in the Earth's orbit and tilt and the occasional collisions with little worlds on rogue orbits. These processes have no notion of what has been going on over billions of years on our planet's surface. They do not care.

10 The Electric Boy

Science is a harsh mistress.

Nothing is too wonderful to be true, if it be consistent with the laws of nature.

11 The Immortals

Every living thing is a masterpiece, written by nature and edited by evolution.

Space is so vast that it would take billions of years for a rock ejected from the Earth to collide with a planet circling another star.

They will gaze up and strain to find the blue dot in their skies. They will marvel at how vulnerable the repository of all our potential once was, how perilous our infancy, how humble our beginnings, how many rivers we had to cross... before we found our way.

12 The World Set Free

There are no scientific or technological obstacles to protecting our world and the precious life that it supports. It all depends on what we truly value and if we can summon the will to act.

We choose to go to the Moon in this decade and do the other things, not because they are easy, but because they are hard.

13 Unafraid of the Dark

It was as if we had been standing on the seashore at night, mistakenly believing that the froth on the waves was all there was to the ocean.

We call it "dark energy," but that name, like "dark matter," is merely a code word for our ignorance. It's okay not to know all the answers. It's better to admit our ignorance than to believe answers that might be wrong. Pretending to know everything closes the door to finding out what's really there.

That's here. That's home. That's us. On it, everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every superstar, every supreme leader, every saint and sinner in the history of our species, lived there... on a mote of dust suspended... in a sunbeam. The Earth is a very small stage in a vast, cosmic arena. Think of the rivers of blood spilled by all those generals and emperors so that in glory and triumph they could become the momentary masters of a fraction... of a dot. Think of the endless cruelties visited by the inhabitants of one corner of this pixel on the scarcely distinguishable inhabitants of some other corner. How frequent their misunderstandings, how eager they are to kill one another, how fervent their hatreds. Our posturings, our imagined self-importance, the delusion that we have some privileged position in the universe, are challenged by this point of pale light. Our planet... is a lonely speck in the great, enveloping cosmic dark. In our obscurity, in all this vastness, there is no hint that help will come from elsewhere to save us from ourselves. The Earth is the only world known so far to harbor life. There is nowhere else, at least in the near future, to which our species could migrate. Visit, yes. Settle, not yet. Like it or not, for the moment, the Earth is where we make our stand. It has been said that astronomy is a humbling and character-building experience. There is perhaps no better demonstration of the folly of human conceits than this distant image. To me, it underscores our responsibility to deal more kindly with one another and to preserve and cherish the Pale Blue Dot, the only home we've ever known.

Learning the age of the Earth or the distance to the stars or how life evolves-- what difference does that make? Well, part of it depends on how big a universe you're willing to live in. Some of us like it small. That's fine. Understandable. But I like it big. And when I take all of this into my heart and my mind, I'm uplifted by it. And when I have that feeling, I want to know that it's real, that it's not just something happening inside my own head, because it matters what's true, and our imagination is nothing compared with Nature's awesome reality. I want to know what's in those dark places, and what happened before the Big Bang. I want to know what lies beyond the Cosmic Horizon, and how life began. Are there other places in the cosmos where matter and energy have become alive... and aware? I want to know my ancestors-- all of them. I want to be a good, strong link in the chain of generations. I want to protect my children and the children of ages to come. We, who embody the local eyes and ears and thoughts and feelings of the cosmos, we've begun to learn the story of our origins-- star stuff contemplating the evolution of matter, tracing that long path by which it arrived at consciousness. We and the other living things on this planet carry a legacy of cosmic evolution spanning billions of years. If we take that knowledge to heart, if we come to know and love Nature as it really is, then we will surely be remembered by our descendants as good, strong links in the chain of life. And our children will continue this sacred searching, seeing for us as we have seen for those who came before, discovering wonders yet undreamt of... in the cosmos.