字幕菌：cnszw
校对菌：myname69
双语调整：那白岚
后期压制：那白岚
出品：纪录片之家
玄黄端现，太极混沌如鸡蛋，随着 In the beginning There was darkness, And then
轰的一声， BANG!
诞生了无尽膨胀的时间、空间和物质。 Giving birth to an endless Expanding existence Of time, space, and matter.
现在所见超乎我们的想象， Now, see further Than we've ever imagined
超越了客观认知极限， Beyond the limits of our existence
那地方我们称之为“宇宙”。 In a place we call “The Universe.”
在太阳系的偏远角落， In the distant corners Of our solar system
冰星体天王星和海王星都是动乱的世界， Ice giants, Uranus, and Neptune Are violent worlds.
烟雾缭绕的世界， Blanketed with smoky hazes
这些外行星非常混乱、动荡， These outer planets Are frenzied, turbulent
不可预知。 And unpredictable.
在太阳系中海王星拥有最快的风， Neptune claims the fastest winds In our solar system.
如同幻影。 Like an apparition
它的巨大黑斑来无影去无踪。 Its great dark spot Surfaces and vanishes Without warning.
天王星内部的卫星群， Uranus' inner swarm of moons
围绕天王星旋转时间不到一天。 Dash around the planet In less than a day
撞击不可避免。 And collisions are unavoidable.
这些远空行星最具争议的是 The most controversial Of the far off planets
它们不再属于行星。 Isn't even a planet anymore.
为何冥王星不再属于行星了呢? So why was Pluto demoted?
就是这个人在行星之列中抹去了冥王星。 The man who killed Pluto Makes his case
随我们一起来探索外行星。 As we explore the outer planets.
宇宙第一季EP11外行星
来会见这个抹杀冥王星的人。 Meet the man who killed Pluto.
很久以来冥王星就拥有行星称号。 Pluto had it coming For a long time.
加州理工学院天文学家麦克·布朗 Caltech astronomer, Mike Brown
通过调动一连串事件， Set in motion a chain of events That reduced
把我们太阳系中长久以来认可的行星数目 The long established number Of planets in our solar system,
从9颗减少到8颗， From nine to just eight.
但他对此并不感到后悔。 Yet, he feels no remorse.
九大行星中冥王星是唯一的一颗的冰球体， There was no way That Pluto could survive the its status
所以它身份与其他很不一样。 as the single Lonely ice ball
它会出列，一定会退出行星之列。 but it was--It was gonna fall, And it certainly fell.
在我们的行星之间 Among our planets,
冥王星一直都比较特别， Pluto was long considered To be a bit different,
比其他的行星小很多， Much smaller than the rest.
按自身大小比例算来，它却已有最大的卫星。 It has the largest moon In proportion to its own size.
它的公转轨道也是最倾斜和最椭圆， It also has the most inclined And eccentric orbit.
它的轨道形状有点像鸡蛋， Its orbit Is sort of shaped like an egg.
它的轨道有的地方靠太阳很近， Pluto's orbit causes it to get Significantly closer to the sun
有的地方离太阳又很远。 And then further away From the sun.
浩瀚宇宙中的这个小星球， This cosmic needle In a haystack
躲避天文学家的搜捕已有好几十年。 Eluded planet hunters For decades.
第八颗行星海王星发现于1846。 The eighth planet, Neptune, Had been discovered in 1846,
在19世纪末期，天文学家相信 And astronomers at the turn Of the century were convinced
还有第九颗行星 There was a ninth planet
在太阳系的远处。 In the far reaches Of our solar system.
帕西瓦尔·罗威尔启动了搜寻冥王星计划， The search for pluto Was started by Percival Lowell
在罗威尔天文台。 At Lowell Observatory.
他认为那里有个X行星， He thought there was A planet x there
因为X行星扰乱了天王星和海王星的轨道。 That was perturbing the orbits Of Uranus and Neptune.
在找到X行星之前， Before finding The elusive planet,
罗威尔就辞世了。 Lowell passed away.
但是天文台的研究助手克莱德·汤博 But the observatory's Research assistant, Clyde Tombaugh
继续了他的搜寻， Continued his quest.
在1930年他24岁那年， In 1930 at the age of 24,
汤博捕捉到一个星球的图像， Tombaugh captured an image Of an object
似乎验证了罗威尔的预言， That seemed to validate Lowell's predictions.
他向全世界宣布了这个发现， The discovery Was announced to the world
这个星球被正式取名为“冥王星”。 And the object Was given an official name-- “Pluto.”
但它是不是X行星呢? But was Pluto planet x?
一些科学家认为冥王星太小、 Some scientists argued That Pluto was far too small
质量不够大，不能明显地 And didn't have enough mass To significantly
扰乱它附近行星 Perturb the orbits Of its neighboring gas giants,
天王星和海王星的轨道。 Uranus and Neptune.
后来天文学家意识到 Astronomers have since realized
根本没有X行星存在， That there is no such planet x.
X行星的预测 It had been predicted
错误的估计了海王星的质量。 Using inaccurate estimates Of Neptune's mass.
即使冥王星不是X行星， Even though Pluto Wasn't planet x,
它是否有资格列为行星之列呢? Could it still be classified As a planet?
起初“行星”这个词只代表“天上运转的星体”， The first term for planet Just meant “wanderer In the sky.”
行星只是与恒星相对的运动的星体。 It was the things that moved Relative to the stars.
所以对古希腊人来说 So, to the ancient greeks,
月亮是行星、 The Moon was a planet,
太阳是行星， The Sun was a planet,
地球不是行星。 The Earth was not.
当然现在我们知道地球 Of course, When we realized that the Earth
实际是绕着太阳运动， Is actually going around the Sun
月亮绕着地球运动， And that the Moon Is going around the Earth,
行星的定义开始改变， The definition of planet Changed again.
地球成了行星， Earth became a planet.
而太阳和月亮就不算行星了。 The Sun and the Moon Were taken away
当时还有6颗行星， And there were Finally six.
后来发现了天王星、 And over time, Uranus was discovered.
发现了海王星， Neptune was discovered,
所以行星就有了7颗、8颗。 So there were--there were seven, There were eight.
尽管冥王星后来被证明比月球要小， Although it later proved To be smaller than our Moon,
但原以为冥王星与火星一般大小， Pluto was originally thought To be as large as Mars.
于是汤博发现的冥王星被认定为 So tombaugh's discovery Was anointed
第九颗行星。 As planet number nine.
当时没有人仔细想过冥王星， No one really thought Much else about it.
它是个陌生的物体， It was a strange object.
它有点古怪孤僻， It was sort Of this lonely oddball
位于太阳系的边缘地带， At the edge of the solar system,
没有其他的叫法，所以就把它叫做行星。 But nothing else to call it So it was called a planet.
由于它远离太阳， Because of its great distance From the Sun,
冥王星的名字来自于罗马的冥府之神。 Pluto takes its name From the roman god Of the underworld.
在最近处冥王星距离地球27亿英里， At its closest, Pluto is 2.7 billion miles From Earth.
它的直径是1485英里， Its diameter is 1,485 miles,
美国全宽的一半。 Half the width Of the United States.
冥王星绕太阳一周需用248个地球年， It takes 248 earth years For Pluto to orbit the Sun.
冥王星上一天约等于 And a day on the planet Is equivalent to about
6.5个地球日， 6 1/2 earth days.
地球上重150磅的物体 A 150 pound earthling
在冥王星上只重10磅。 Would weigh only 10 pounds On Pluto.
它是现代科技的象征， It's a testament To modern technology
靠它我们可以知道冥王星表层的一切。 That we know anything at all About the surface of Pluto.
我们几乎看不见冥王星， We can hardly see this thing.
就算用哈勃望远镜也难以看到。 Even with the Hubble Space Telescope,
我们也许能得到横向4像素， We get maybe Four pixels across,
总共也许才12像素， Maybe 12 pixels total.
即便是这样 But even with that,
我们也能看见冥王星的一部分，如煤一般黑。 We see that parts of pluto Are as dark as coal
而其他部分又如雪般明亮， And parts of pluto Are as bright as snow.
尽管来自远方。 Even from a far,
科学家们也能估量冥王星的组成， Scientists can measure The composition of the planet.
他们认为表面亮的区域 They believe That the bright areas Of the surface
由3种冰态物质组成， Are made up of three types Of ice.
一种是一氧化碳， One is carbon monoxide,
一种是甲烷，跟天然气一样， One is methane, Which is the same As natural gas.
然后还有一种是氮， And then, the third is nitrogen,
与我们大气中呼吸到的氮是一样。 The same stuff That we have breathing here In our atmosphere.
黑暗区域可能是固态岩石， The dark areas Are probably solid rock.
黑暗区域有很大可能是某种硅酸盐， The darker areas Are almost certainly silicates Of some sort.
硅酸盐不像我们这里看到的岩石一样， Silicates not unlike The rocks that we see here,
这意味着它们含有硅元素， That means There's silicon in them
还含有氧元素。 And there's oxygen in them.
我们这在落基山脉上， We're up here In Rocky Mountain
科罗拉多州的国家公园 National Park in Colorado.
附近有些雪， There's some snow around,
也有岩石， There's some rocks around.
这景观相似于 This is similar to what we see
冥王星上看到的景观。 What we're gonna see On the surface of Pluto.
去冥王星的旅行者会发现 A traveller to Pluto Would find
尽管表面冰雪覆盖， That despite the snowy surface,
但还是很暗淡。 It is a very dim place.
它和太阳的距离比地球和太阳的距离 It's about 30 or 40 times Further away from the Sun
要远30~40倍， Than the Earth is.
这意味着照耀冥王星表面的阳光 This means that the-- The sunlight Hitting the surface of Pluto
比地球上的阳光要微弱1000倍， Is about 1,000 times Fainter than it is on the Earth.
它的明亮度相当于 It's maybe About the same brightness
在深夜街上微弱的路灯下， As being outside Under a dim street light At night.
你也许还能 You could probably, you know,
拿本书， You could take a book.
光亮也许还足以阅读， You could probably Read it there.
但不过拿个照明灯或是手电筒 Take a headlamp though, Take a flashlight.
看书效果会更好。 It'd help out.
冥王星与太阳间的距离也使得它 Its distance from the Sun Also makes Pluto
成为太阳系中最寒冷的地方， One of the coldest places In the solar system
寒冷刺骨的平均温度达到 With a bone-chilling Average temperature
零下388华氏摄氏度。 Of minus 388 degrees fahrenheit.
由于它个头小密度小， And because of its small size And low density,
冥王星地表的重力比地球上要小很多。 Gravity on Pluto's surface Is far weaker than on Earth.
这样一来有的事在冥王星上做会更容易一些， Now, some things are gonna be A little easier to do on Pluto.
如果你要去攀岩， If you're really into Rock climbing
在这里垂直攀岩 we're doing Some vertical climbing here,
是项刺激的运动。 And while it's always exciting,
但克服重力往往是项难题， But gravity Is always the challenge.
冥王星的重力约是地球的15分之一， Pluto's gravity Is roughly 1/15th Of the Earth's.
这与站在地面不一样， It's not like if you're Standing on the surface,
你会飘开。 You would float away.
当你在冥王星上攀岩时，如果你脱离了岩壁， Now, if you fell off that face When you were climbing up Pluto
你仍然希望有绳索套着 You'd still want to have Your rope there.
你仍然会加速下落到地表， You'd still accelerate Down to the surface.
所以不要轻易放开绳索。 So don't leave the rope at home.
科学家希望能敲开冥王星表层， Scientists Would love to chip away At the surface of Pluto
因为藏在它的岩石里的是 Because hidden within its rocks
太阳系历史中不为人知的一章。 Is a whole missing chapter In the history Of our solar system.
冥王星是个伟大的星球， Pluto's-- Pluto is a great planet.
我是说我认为 I mean, it's--what i think
它的伟大在于 Is really great about it,
它就像是 It's sort of the--
我们太阳系的终极时间机器， The ultimate time machine In our solar system.
它向我们展示了 It really shows us what the--
45亿年前太阳系形成的时候 What the environment Of the solar system was like
太阳系的环境会是什么样子。 Four-and-a-half billion Years ago when it was formed.
它的地表层比 The--the surface there-- It's much more ancient
太阳系中别的大多数地方都要古老得多， Than you're gonna find Almost anywhere else In the solar system.
如果你寻找地球上 And if you're looking For rock on the Earth,
那个时期的岩石， The Earth has been around For that same time period,
约45亿年前的岩石， Four-and-a-half billion years Or so,
但你要在地球上寻找那么古老的岩石 But if you're looking for rock That's that old on Earth,
那你是找不到的， You're not gonna find it.
那是因为地球 That's because the Earth
会不停的回收更新它的物质。 Is sort of constantly Recycling its material.
随板块碰撞的进行， We have plate tectonics going on
会把所有物质吸回地幔之中， That sucks all this material Back into the mantle.
随火山作用的进行 We have volcanism going on
会喷放出新物质，改造地表。 That pumps out new material And processes the surface,
所以与冥王星上的古老地表层相比， So it's really A much younger surface On the Earth
地球的表层其实要年轻得多。 compared With the ancient surface That we're gonna see on Pluto.
我们正坐在这儿的岩石 The rocks that we're sitting on Here
曾经历过地球内部高压的塑造， have been processed By the high pressures In the Earth
在冥王星上会更加原始一些。 On Pluto, it's more primitive.
原始但并不质朴整洁。 Primitive, But far from pristine.
冥王星似乎到处都是撞击坑， Pluto is likely riddled With impact craters.
撞击坑是由小行星 Impact craters Are caused by asteroids
或是流星体撞击表面形成的。 Or meteoroids Impacting the surface.
这些基本上是太阳系的碎屑， These are essentially pieces Of the solar system
不够形成行星。 That were never made Into planet.
冥王星的外表层 Outer surface of Pluto,
没有大气、 You don't have an atmosphere,
没有冰川、 You don't have glaciers,
没有风、 You don't have wind,
没有雨、 You don't have rain,
没有腐蚀， You don't have erosion,
在表层你能看到的主要特征， the one dominant feature That you see on the surface
可能就是许多的撞击坑。 Is probably gonna be A lot of impact craters.
冥王星疮痍的表面。 Pluto's pockmarked surface
在它运转到近日点曾经历过变形。 Undergoes a transformation As it orbits near the Sun.
在异常的高温下 Under the additional heat,
一些凝固气体蒸发， Some of the frozen gases Evaporate
形成一个暂时的大气层。 to form A temporary atmosphere.
当冥王星远离太阳时 As Pluto recedes from the Sun,
气体再次冻结， The gases freeze again
落回冥王星地表。 And fall back down To the surface.
75多年来 For more than 75 years,
这个遥远的结冰体 This far out icy object
一直被认定为第九颗行星。 Staked its claim As our ninth planet.
那么为什么这个冰雪星球 So why is this little piece Of snowy rock
现在遭受到质疑了呢？ Now causing such controversy?
为何冥王星被踢出了太阳系中 Why was Pluto kicked Out of the solar system's
特有的行星之列呢? Most exclusive club?
这是加州理工学院的一间安静的办公室， It's a quiet office At the Caltech campus
在加州的帕萨迪纳，就是在这里 At Pasadena, California, And it was from here
冥王星被踢出行星之列。 That Pluto's demise As a planet began.
但天文学家麦克·布朗 But astronomer Mike Brown
本意不在剔除一颗行星。 Was never looking To destroy a planet.
配备有帕洛马天文台的48英寸望远镜， Equipped With Palomar Observatory's 48-inch telescope,
他在寻找太阳系的远端 He was seeking out Pluto-sized worlds
冥王星大小的星球。 At the far reaches Of our solar system.
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一个比冥王星还大并拥有自己卫星的星球， An object bigger than Pluto With its own moon,
都围绕太阳运转。 Both orbiting the sun.
当我第一次发现它时，它比冥王星还大。 When i first found this thing That's bigger than Pluto,
我仔细检查 I was looking through the images
望远镜事先拍下的照片， That the telescope had taken Just before
我在屏幕上发现了它， And i found it on the screen,
做了个粗略估计，意识到 And did a very quick Calculation, realized
它比冥王星还要大。 It was bigger than Pluto,
接下来做的第一件事就是拿起电话 And the very first thing i did Was picked up the phone
告诉我妻子我发现了一颗行星。 And called my wife and told her I just found a planet.
事实上冥王星曾当作行星 Indeed, Pluto was a planet,
已超过70年， And for more than 70 years, It had been.
那么为什么布朗新发现的星球 Then why wouldn't Brown's New world
也不属于行星? Be considered a planet too?
我认为它是第十颗行星。 I thought It was the 10th planet.
很长一段时间我都这么认为， I--for a long time, That's how i described it.
它是一颗行星， It was a planet,
所以我确定我找了 And so, i definitely felt Like i had found
第十颗行星。 The 10th planet.
它比冥王星大5%， It's five percent Bigger than Pluto.
它可能由同种物质构成， It's probably made Out of the same materials,
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里面是岩石， Rock on the inside,
外层是冰， Ice on the outside,
最外面是薄薄的一层霜， And a little thin layer of frost On the very outside
有时霜会喷发到大气层中 That sometimes puffs up Into an atmosphere
有时不会， And sometimes doesn't.
这与冥王星类似。 Very similar to Pluto In that way.
它有一颗卫星，绕行一圈16~17天。 It has a moon That goes around it Once every 16, 17 days.
冥王星也有一颗卫星， Pluto has a moon also,
所以它从很多方面看来， So it's--in many ways,
我认为它们几乎是双胞胎。 I like to think of it As almost as twins.
只是这个星球 This is just the twin
吃得多一点， That just ate a little bit more
在它婴儿时期长得大一点啊。 When it was a baby, Got a little bigger.
布朗考虑把它命名为“西娜” (女战神)， Brown considered Naming his object “Xena”
取名自电视中的战士公主。 After tv's warrior princess.
但最终名字定为“厄里斯”， But eventually, The name chosen was “Eris,”
取自希腊的不和女神， After the greek goddess Of discord.
结果证明这个名字很恰当。 As it turned out, this name Was entirely appropriate.
这一发现在天文学界引起轩然大波。 The discovery Kicked off a firestorm In the astronomical community.
现在行星的准确定义 Now, the very definition Of a planet
正处于激烈争论之中， Was being hotly debated.
厄里斯会正式成为我们的第十颗行星吗 Would Eris officially become Our 10th planet,
或者冥王星大小的星球会被重划分类？ Or would Pluto-sized objects Be reevaluated as a whole?
争论进入最后阶段， The argument Was brought to the table
2006年 In the 2006
布拉格的国际天文学联盟会议， meeting Of the international Astronomical union in Prague.
一票通过 A vote was taken
对“行星”这个词第一次作了科学的定义。 And the term “planet” Was defined scientifically For the first time.
那些支持决议6A的人 Those who are in favor Of resolution 6a,
引入一种新的分类... Which introduces This new category
海王星外天体以冥王星为原型， Of trans-neptunian objects With Pluto as a prototype.
好处是我们可以把冥王星 The recommendation Is that we consider Pluto
和其他类似的外海王星体归为特殊的一组， And other similar Trans-neptunian objects To be in a special class.
我们不再考虑冥王星的身份归属问题， We didn't reconsider Pluto's status
因为我们已听到太多相关的无聊讨论， Because we learned anything new About Pluto
这只会磨蚀掉你研究冥王星的兴趣。 That made it less interesting.
另一方面，科学家们说颁布这项决定 Instead, scientists say The issue was addressed
是因为他们了解到厄里斯 Because they learned about Eris
和其他库伯带的大星体。 And other large Kuiper belt objects.
库伯带有35亿英里宽， The kuiper belt Is a 3.5 billion mile wide
位于太阳系外围冥王星附近， Region in the outer solar system Near Pluto.
它容纳了成百上千的结冰体， It's home To hundreds of thousands Of icy objects,
第一个结冰体发现于1992年。 The first of which Was discovered in 1992.
历史上来说，我们认为太阳系外围 So historically, We thought Of the outer solar system
有天王星和海王星。 Where you've got Uranus and neptune out there.
他们是巨大的气态行星， They're these big Gaseous planets, giant planets.
在他们之外 And then just beyond that,
我们发现了小小的冥王星， You've got this little straggler Pluto
显得比较另类。 that doesn't really fit Into the picture.
现在当我们发现所有这些库伯带星体， Well, now when we've found All these other Kuiper belt objects,
如我们所见冥王星也许真是 What we're seeing Is that maybe Pluto Was really that,
库伯带众多星体中发现的第一颗， Just the first of these Many, many bodies Of the kuiper belt
这里有许多小个头的冰星体 that are--This wide diversity Of icy--small icy bodies
位于这个太阳系外围。 At the outer solar system.
国际天文学联合会投票结果定义了行星， The result of the iau vote Stipulated that a planet
是一个围绕太阳运转的球体， Is a spherical object That orbits the Sun
并在它的轨道上没有其它星体。 And clears out the neighborhood Around its orbital path.
自从发现冥王星附近充满了库伯带星体后， Since the area around Pluto Is full of other Kuiper belt objects,
新的行星定义使得克莱德·汤博 The new definition Would leave Clyde Tombaugh's
发现的冥王星不再属于行星。 Great icy discovery Out in the cold.
76年来，一直称作第九大行星的冥王星结束了行星的称号。 Pluto's 76-year reign As the ninth planet was over.
太阳系现在正式只由 Our solar system Would now officially consist
8颗行星组成， Of only eight planets.
像冥王星和厄里斯这样的星球赋予了新的类别， Objects like Pluto and Eris Were given The new classification,
“矮行星”。 “dwarf planets.”
矮行星与行星的特征相同， Dwarf planets Possess the same characteristics As planets,
但没有畅通的运转轨道。 But do not have A clear orbital path.
在新的定义下，谷神星 Under the new definition, Ceres,
这颗太阳系中最大的小行星也属于矮行星。 The largest asteroid In our solar system Is also a dwarf planet.
建立了新的术语 We have this new terminology
是因为太阳系外围的事物远超过了 Because there's more things In the outer solar system
我们已知的范围， Than we used to think.
就好像原先只看见一栋摩天大厦， It's like all you can see Is one skyscraper,
突然之间 And now all of a sudden,
在你面前涌现出整个城市的大厦。 You have a whole city In front of you.
同样，我们的太阳系外围城市 We have a whole city Full of objects
也充满了许多的星体。 In the outer solar system now.
国际天文学联合会投票 The iau vote
意在解决关于行星定义的争论， Was meant to settle the debate On what constitutes a planet,
但许多科学家拒绝接受投票结果。 But many scientists Refuse to accept the outcome.
他们仍然希望把它叫做行星， There are astronomers Who want it To be a planet still
他们一直努力想要恢复它行星的叫法， And they just keep On ripping those scabs Off whenever possible,
他们保持己见。 And they want to keep it fresh.
我相信冥王星是一颗行星， I believe Pluto is a planet.
我认为冥王星是不是一颗行星 And i don't think the question Of whether or not
这个问题实际并不重要， Pluto is a planet Is really that important Fundamentally.
这不是一个学术问题，是个名字问题。 It's not a scientific question, It's a question of names.
但从某种程度上来说， But in a way, in an odd way,
这问题成了行星科学上常见的话题， It's become one Of the highly visible subjects Of planetary science.
人们老是问冥王星是不是行星， People always ask Whether pluto Is a planet or not.
并没有明确的划分界限， There's not one Easy dividing line
没有界限划分在星球之间 it's not Where you move From being a planet over here
这里是行星， To being a planet over here,
而这里不是行星， To be not a planet over here.
就好像石头与卵石之间没有明确界限一样， Just like there's No dividing line Between a stone and a pebble.
更多的成了社会学问题， It's really more Of a sociological question.
成了单词定义的问题， It's a question Of definitions of words
而非学术问题。 Rather than a question Of science.
虽然它不再属于行星， Although no longer Officially a planet,
但科学家对冥王星的兴趣并未消退。 Scientific interest in Pluto Hasn't waned.
正在布拉格投票的当头， Even as the vote was being taken In Prague,
美国航天局一艘叫“新视野”的宇宙飞船 A nasa spacecraft Called “New Horizons”
准备起飞，前去探索这个遥远的世界。 Was already on its way To exploring To this far off world.
新视野号使者 The New Horizons mission
将是探索冥王星的第一艘飞船。 Will be the first spacecraft Ever to visit Pluto.
前往冥王星，研究它 By going to Pluto, Studying Pluto,
不再是单单针对它的任务， It's no longer a mission To a singular object,
实际上是一项研究这一类星球的 But it's actually a mission To one of a class of objects
其中一颗星球的任务。 That we'll get to learn about.
但新视野号需要达到星际速度， But New Horizons Needs to travel at warp speed
否则研究冥王星大气的宝贵机会 Or a valuable Research opportunity To study Pluto's atmosphere
就会至少推迟在200年之后。 Will be lost For at least the next 200 years.
新视野号飞船飞向冥王星上预设的地点， The New Horizons spacecraft Is headed For a rendezvous with Pluto.
航天器分离成功完成。 We have confirmation Of spacecraft separation.
但科学家们试图提前完成任务， But scientists Are trying to beat the clock
因为随着冥王星远离太阳， Because as Pluto Recedes from the Sun,
它62年长的冬季来临， Its 62-year-long winter Is coming.
冥王星的冬季 And when winter comes to Pluto,
会使矮行星的大气冻结 The dwarf planet's atmosphere Will freeze
而落回地表。 And fall to the ground.
若大气回落太多， If it collapses too much,
获得的信息就会受限， It might just be A lot less interesting,
结果也不会令人满意。 You might not have As interesting chemistry.
我们希望知道它的温度、组成 And we want to know What the temperature And the composition
结构和大气中的风。 And the structure and the winds On the atmosphere--
为及时赶到那里 To get there in time,
新视野号高速穿行在太阳系中， New Horizons is blazing Through the solar system
每小时飞行45千英里， At more than 45,000 miles An hour.
即是每秒12英里， That's 12 miles a second.
以那个速度 At that speed,
从洛杉矶飞行到纽约只用3.5秒。 A trip From Los Angeles to New York Would take about 3 1/2 minutes.
所以，它是地球上发射过的 So this is The fastest spacecraft
最快的宇宙飞船。 That was ever launched From the Earth.
实际上，它飞行了6小时 In fact, it took about six hours
就飞出了25万英里远 To get out To the quarter million miles
到达月球处。 To make it out to the moon.
你可以比较一下，同样一段距离 You can compare that To the couple of days
阿波罗号飞船则飞了几天才到月球， That it took The Apollo astronauts To get out that same distance.
新视野号13个月后会经过木星， New Horizons Will pass by Jupiter In just 13 months.
但太阳系外围太大 But the outer solar system Is so big
它将会再用8年时间才能到达冥王星， That it's gonna take us Another eight years To get to Pluto.
尽管以这个史无前例的速度飞行， Even with its Unprecedented speed,
新视野号也要到2015年7月才能到达冥王星。 New Horizons won't reach Pluto Until july of 2015.
冥王星是一个大谜团， Pluto is just a big mystery.
我很兴奋，因为这艘飞船已在去冥王星的路上。 It's exciting to me That there's a spacecraft On its way there
几年后，我们就会知道 And in few years we'll, You know,
这个我们所知几乎为零的世界， This sort of blank slate Of a world
将会获得详尽的图片和数据。 Will be richly filled in With pictures And detailed data.
离冥王星40亿英里远 About four billion miles From Pluto,
天王星就像一块迷人的蓝色大理石， Uranus is a mesmerizing Blue marble.
它真的很漂亮， And it's really Strikingly beautiful
与其它星球截然不同。 And different From the other planets.
它是一颗巨大的、蓝色的、灰蓝色的毛球， It's a giant, blue, Pale-blue, fuzzy ball
位于太空那里。 Sitting there in space Against the darkness of space.
它那显著的蓝色调 And it's just That striking blue color
{\c it seems unreal.
它看起来像是 It looks as though
做电影特效的人员做出来的一样， It was sort of created By some movie Special effects person
如何会有这么一颗行星，如此之大、 cause how could you have A planet that large
如此完美、如此均匀的纯蓝? And that perfect And just this giant, Featureless blue?
天王星离地球16亿英里远， Uranus is 1.6 billion miles From Earth.
直径将近32000英里， It has a diameter Of nearly 32,000 miles--
是地球直径的4倍。 Four times Earth's diameter.
天王星公转一周需用84个地球年， It takes 84 Earth years For Uranus to orbit the Sun.
天王星上的一天有17个多小时。 One day on Uranus Is a little over 17 hours.
如果你在地球上重150磅， If you weigh 150 pounds On Earth,
在天王星上就只重133磅了。 You would weigh 133 pounds On Uranus.
名字取自希腊的天神。 Named after the greek god Of the sky,
太阳系中天王星的自转轴线是最倾斜的， Uranus has the most Off-kilter axis of any planet In the solar system.
倾斜98度。 At an angle of 98 degrees,
天王星实际上是单边公转， The planet is actually spinning On its side.
也就是说每年一次交替地 What that means Is that at one time of the year,
{\c
另一面半球完全处于黑暗中。 And the other hemisphere Is complete darkness.
天王星公转时间是84年， The time for Uranus To orbit the Sun Is about 84 years,
意味着公转的一半时间，即40年。 Which means that For half of that time Of 40 years,
一个半球处于光照中， One hemisphere is in sunlight,
另一面半球处于黑暗中， And the other hemisphere Is in dark.
就像地球上的北极圈，不同的是天王星是整个星球都这样 It's like the arctic circle On Earth, except for It's the whole planet.
倾斜太大，某种意义上来说 That tilt is so extreme that, In a sense,
以至整个北半球都是北极区， The whole northern hemisphere Is the arctic
整个南半球都是南极区。 And the whole Southern hemisphere Is the antarctic.
天王星上的甲烷使它呈现蓝绿色， Uranus owes its cool Bluish-green color to methane.
甲烷吸收太阳光中红色和橙色的光波， The methane absorbs Red and orange wavelengths From sunlight
使它反射出蓝绿色。 But reflects blue and green.
柔软的外表是由于 And its soft appearance Is due to something
住在大城市的人们熟知的...烟雾。 That's familiar to anyone Who lives in a big city--smog.
加州南部烟雾已习以为常， In southern California, We're used to smog,
那是雾状物质产生的光化学反应， Which is Photochemically produced Haze material
使得大气中出现雾状外表， Which gives a hazy appearance In the atmosphere.
这与四大气态行星中的大气是相似的。 This is similar To the atmospheres Of the four gas giants.
在外围行星中 In the outer planets,
有甲烷，即天然气。 There's methane, Which is natural gas.
阳光把它转换成复杂的粒子， Sunlight converts it To complex particles as well,
粒子形成烟雾， Which forms a haze,
这也是为何这些行星看起来不那么轮廓尖锐， Which is the reason That planets don't have A very sharp
而是毛绒的轮廓。 But have a fuzzy look to them.
科学家推测天王星和它的邻居 Scientists speculate That Uranus And its celestial neighbor,
海王星，它们的形成是相同的。 Neptune, formed the same way.
当宇宙初期的气体和尘埃的原行星盘， As the early Proto-planetary disc of gas
在太阳系中安顿下来后， And dust In our solar system settled,
木星和土星收敛了最多的物质 Jupiter and Saturn gathered up The most material
变成了最大的气态星球。 And became the largest Of the gas giants.
随着木星和土星的轨道扩大， As Jupiter And Saturn's orbits grew,
它们扰乱了整个行星系统 They destabilized The planetary system as a whole.
动力相互作用使得天王星和海王星 Dynamic interactions Pushed Uranus and Neptune
被加速推挤到太阳系的边缘。 Outward to the edge Of the solar system At an accelerated rate
在边缘，它们吞食结冰体， Where they feasted On icy objects.
天王星和海王星还含有初期的气体， They have a lot Of that initial gas,
但它们也吸收许多冰态物质 But they also gathered A lot of icy material
和一些岩状物质以促进形成。 And some rocky material In their formation.
结果是 So consequently,
虽然它们拥有这些环绕的氢气 Although they have this Surrounding envelope of hydrogen
和氦气、甲烷、氮气、及其他物质。 And helium gas and some methane, Some nitrogen, some other stuff,
它们内部也有许多冰态物质， They also have A lot of icy material In the inside.
内部这些冰态物质使得 These icy interiors Have led some
它们被叫做冰雪巨人。 To call Uranus and Neptune The ice giants.
但它们并非固态冰的实心球体， But it's incorrect To imagine them As balls of solid ice
宇航员也并不能在上面行走， That an astronaut Could walk across.
如果我们将一个宇航员或探测器 Well, if we dropped An astronaut or a probe
放置在天王星或海王星的中心， Towards the center of Uranus Or Neptune,
首先 Well, first of all,
他们会陷入困难之中， They'd be in a lot of trouble.
这里没有可以立足的固体表面。 There's really no solid surface That they could stand on.
在这些星球核心也许会有一小块岩石核， There may be a small rocky core At the center of these planets,
但它们承受的压力 But the pressure That they would be experiencing
来自头顶大气的压力， From the atmosphere overhead
液态冰雪区的挤压力， And this liquidy icy region Would crush them,
这些压力是我们地球上大气压力的 Would be millions of times The pressure that we have
百万倍。 From our own atmosphere For example.
所以在他们抵达固体表面之前， So they would be flattened
他们就会被压扁。 Well before they ever reached The solid surface.
其他的气态星球气候恶劣， While the other gas giants Have wild weather patterns,
天王星似乎相对平静些。 Uranus seems to be Relatively calm,
科学家们知道这是为什么。 and scientists Think they know why.
天王星在气态行星中很特别， Uranus is unique Among the gas giant planets
唯有天王星没有 In that it is the only one That doesn't have
内部加热源， An internal heating source.
木星、土星和海王星都有加热源 Jupiter, Saturn, and Neptune All have heat coming
来自行星内部研究 From deep within the planet,
加热源可促进循环， And that helps Drive the circulation
这也解释了我们在其他三颗行星上发现的 And explains why we see A lot of the banded structure
许多带状结构。 That we do On those other three planets.
而天王星没有这样的内部加热源。 Uranus doesn't have This internal heating source.
天王星的出名还有另一个原因， Uranus has another claim To fame, The way in which
天王星被天文学家威廉·赫谢耳发现于1781年， It was discovered By astronomer William Herschel In 1781.
那时 At the time,
已知的行星 The only known planets
只有在地球上用肉眼可见的六颗。 Were the six visible To the naked eye from Earth,
但赫谢耳首次通过望远镜观察到天王星， But Herschel first laid eyes On Uranus through a telescope.
赫谢耳是一名业余天文学者 Herschel Was an amateur astronomer,
专业的音乐家和配镜师， Professional musician And an optician,
所以他有相关知识和能力造出 So he had the knowledge And ability to generate
那时世界上最好的望远镜。 The best telescopes in the world At that time.
天王星的发现在人类历史上 The discovery of Uranus Was incredibly significant
至关重要， In the history of humanity
因为它是第一颗由望远镜发现的行星， Because it was the first planet Discovered by telescope,
第一颗古人未曾发现的行星。 The first planet That the ancients Didn't know about.
1977年，美国航天局的库柏空中天文台 In 1977, Nasa's Kuiper Airborne observatory
有了另一震惊的发现， Made another exciting discovery
当天文学家将望远镜对准天王星时， When astronomers Aimed their telescope at Uranus.
他们本准备观察一件很平常的天文事件， They were planning to watch A fairly common Astronomical event,
天王星经过一颗恒星前面， The passage of the planet In front of a star.
但当天王星挡住恒星时候，恒星发出的光开始闪烁。 But as Uranus closed in, The star suddenly winked.
实际上，它靠近恒星时光忽明忽暗地闪烁了5次， In fact, it seem to flicker On and off five times As it neared the planet
接着，天王星移到另一边时光又闪烁了若干次， And then several more times As it emerged on the other side.
这个奇怪现象的原因是什么? What was the cause Of this strange phenomenon?
闪烁的恒星实际上是因为它位于行星的五道环后面， The flickering star Was actually passing Behind five planetary rings
这以前只在土星上见到过。 Features that had Only previously been seen On Saturn.
后来进行地面观察， Subsequent observations From the ground
然后派出航天器 And then the Voyager spacecraft,
确认行星环的存在。 Confirmed the rings' existence.
哈勃太空望远镜在2005年观察到 And observations made in 2005 From the Hubble Space Telescope
第二套行星环，距离行星几乎是 Found a second set of rings Orbiting almost twice
先前发现行星环的两倍。 As far away from the planet As the previously known rings.
不像土星厚而结冰的环， Unlike Saturn's Thick, icy rings,
天王星的环很暗淡很薄， Uranus' are dim and thin,
由暗黑的岩石尘埃构成。 Comprised of dark rocky dust.
部分天王星的行星环 可能形成于 Some of uranus' dusty rings Were likely formed by the impact
流星碰撞，或是它27颗卫星之间的碰撞。 Of a meteor or a comet With one of the planet's 27 moons.
它的内环可能就是 The inner rings Could be the result
由天王星的卫星碰撞产生的。 Of collisions Between the moons themselves,
尤其是卫星13 处在行星拥挤的内环， Especially the 13 that orbit In the planet's Kinetic inner swarm.
这儿有许多内环卫星， There are a lot Of inner moons around Uranus,
这些卫星非常小，非常靠近天王星， Moons that are very small And close to the planet.
它们都绕行速度都很快，绕行一圈大约一天， They tend to have Very fast orbits On the order of maybe a day.
其他卫星绕行一圈要12小时。 Other moons zip around uranus In just 12 hours.
相比之下， By comparison,
我们月亮围绕天王星1/4大小的地球一周 Our moon circles a planet Four times as small,
要花上28天。 And takes 28 days to do it.
天王星高速绕行的卫星就像赛车， With Uranus' moons Speeding around the planet Like race cars,
那么两颗卫星相撞 It's only a matter of time Before two of them end up
是迟早的事。 In another cosmic collision.
一群旋转的卫星围绕着天王星。 Circling the planet Uranus Is a swirling system of moons.
最近十年来 Even within the last decade,
发现它们无序的绕行，产生了实质变化。 Substantial changes Have been detected In their unruly orbits.
科学家相信 Scientists believe
两颗卫星轨迹相交是迟早的事。 It's only a matter of time Before two of them cross paths.
我们非常确定 You can be very certain
在一百万年或几百万年之间， That in the period of a million Or a few million years
它们中的一些就会互撞。 That some of them Will collide with each other.
我认为丘比特天(卫二十七)和贝琳达(天卫十四) I'm thinking particularly Of Cupid and Belinda,
这两颗小卫星， Which are two small moons
绕行轨道与对方靠得很近， That happen to be orbiting Very close to each other.
轨道相距只有几百英里。 Travelling at just A few hundred miles apart,
科学家期待有一天这些卫星 Scientists expect That at some point, these moons,
由于重力作用撞上对方， Due to gravitational forces That they impart Upon each other,
最终碰撞相互撕裂， Will eventually collide And rip each other apart.
这将是这些卫星的末日。 It will be a bad day For the moons,
但对天王星的行星环来说却是件好事， But a welcome event For the planet's ring system.
碰撞产生的碎片 The debris that's released From that
可能会在天王星周围形成一圈新的环。 Can potentially generate A new ring around uranus.
天王星与它的姐妹海王星，一同分享太阳系的外围世界。 Uranus shares The outer solar system With its sister planet Neptune
一颗发光的蓝宝石，离太阳30亿英里远。 A gleaming sapphire, Some three billion miles away From the Sun.
由于冥王星的降级， With the demotion of Pluto,
海王星现是我们靠最外的行星。 Neptune is now Our outermost planet.
海王星名字取自罗马的海神， Neptune takes its name From the Roman god of the seas.
海王星离地球26.8亿英里远， Neptune is 2.68 billion miles From Earth.
直径约30 000英里， Measuring roughly 30,000 miles,
海王星直径是地球直径的4倍。 Neptune's diameter is four times That of Earth's.
海王星上一年等于地球上的165年， A year on Neptune is equivalent To 165 Earth years,
一天有16.1小时。 And a day lasts 16.1 hours.
如果你在地球上重150磅， If you weigh 150 pounds On Earth,
你在海王星上将超过169磅。 You would tilt the scales At a 169 pounds on Neptune.
与所有外太行星一样 Like all the outer planets,
海王星自转比地球快得多， Neptune rotates Much faster than Earth,
这样的快速旋转产生了狂暴的风。 And this rapid spin Helps to create violent winds.
实际上 In fact,
在太阳系中，所有记载的行星上风速最快的 The highest winds Recorded on any planet In the solar system
要属海王星。 Are on Neptune.
海王星的风有时每小时1千多英里， We have winds of sometimes Over 1,000 miles per hour
上层大气的风一般有750英里每小时。 And commonly, 750 miles per hour Raging in that upper atmosphere.
我们不清楚为什么， And we're not quite sure why,
至今还是个秘。 So there's a little bit Of mystery.
让科学家困惑的就是为什么海王星上的风 What puzzles scientists Is why Neptune's winds
比其他外太行星要强劲， Blow even stronger than those On the other outer planets,
速度比木星的巨大红斑飓风 With speeds Two to three times faster
要快2~3倍。 Than in Jupiter's blustery Great red spot.
喷气推进实验研究人员麦克·密西拿 Jpl researcher, Michael Mishna,
研究其他行星上影响气候的驱动力， Studies what drives weather On other planets.
海王星上神秘的强风激起了他的兴趣。 He's intrigued by Neptune's Mysteriously strong winds.
如果我们把这些风车放到海王星上面去， If we were to put One of these windmills Up on Neptune
所放的高度决定了风车的转动状态， Depending on the altitude That we put it,
我们要么看见与现在所见的类似的风车转动， We would either see motion Similar to what we see now.
要么把风车放到高处， Or if we were to place it At the altitudes
那里的风速达到1000英里每小时， In which the winds Are going 1,000 miles an hour,
我们实际上看不到风车这样的转动。 We actually might not see Very much motion at all,
因为大气层太薄， And that's because The atmosphere is so thin
从风中得不到足够的动力 That there's just not enough force From that wind
来转动涡轮的螺旋桨， to actually turn The propellers of the turbine.
所以你可能一点也看不到风车转动。 So you might not actually see Any motion at all.
地球上，如果我们看一张气象图 On Earth we see high pressure And low pressure systems
可以看到高压区和低压区，这与外太行星上的气象图 If we look at weather maps And the same, to an extent,
在某种程度上是一样的， Can be seen On the outer planets.
我们无法准确地鉴定这里的特高压区， We can't exactly identify A big h in this location
或是这里的特低压区。 Or a big l in this location,
但我们可以鉴定 But there are generally regions
哪些区更暖，气压更高些； That are warmer And have higher pressure Than other areas,
哪些区更寒冷，气压更低些； Which are colder And may have lower pressure,
从高压区到低压区就会产生风， And that generates The winds that blow From high to low.
形成风的关键因素 A key factor In the creation of wind
是加热空气的热能源。 Is an energy source To heat the air.
地球上，太阳提供了这一热能源。 On Earth, The sun provides this energy.
但这颗刮风的海王星 But the windswept planet Neptune
与太阳的距离比地球要远30倍， Is 30 times farther from the sun Than Earth,
得到的太阳能也只有地球的1/900， And it gets only about 1/900th As much solar energy.
这点能量显然不足以产生海王星上的狂风。 It's simply not enough To power Neptune's Colossal winds.
科学家认为海王星 Scientists believe that neptune
从自己内部获得了另一部分能量， Gets its additional power From within.
航天器2号的数据测试显示，海王星 Measurements taken by Voyager II Showed that Neptune
从自己内部释放的能量是获得太阳能的两倍。 Radiates twice as much heat From its interior As it gets from the Sun
海王星的热能释放与热能吸收比例 The highest ratio Of heat outflow to inflow
是太阳系所有行星中最高的。 Of any planet In the solar system.
海王星的内热相对较多， Neptune has A relatively large amount Of internal heating
它的内热来自于内部物质的放射性衰变 Which is coming From radioactive decay Of materials inside
和发生的其他化学过程。 And other chemical processes That are occurring
这些衰变和化学过程就释放了许多热量。 And that releases a lot of heat From the inside.
只是为什么海王星内部 Just why The interior of Neptune
能产生如此多的能量这还是个秘。 Generates so much heat Remains a mystery.
有的人推测 It's lead some to speculate
海王星仍然还处于成长状态， That the planet Is still in the process Of forming,
内陷的气体被重力压缩时候 And the in-falling gases Are releasing heat
就会释放出热能。 As they are compacted By gravity.
内热源也能够解释 This internal heat source Could also explain
海王星大气中气体的对流， The convection of gases In Neptune's atmosphere
这些对流形成了迷人的云纹。 That leads To fascinating cloud patterns.
大气中有许多明亮白色的云层出现， There are many bright, White clouds that appear In the atmosphere.
明暗不同的区域镶嵌在海王星表层， There are different regions Of very bright and dark banding On the surface,
所以我们能够区分出不同的纬度。 So we'd be able to distinguish Different latitudes
依靠着云带的亮度， By the brightness of the bands.
科学家相信云带的样式 Scientists believe That the banding patterns
与海王星云的成分有关， Have something to do With Neptune's Cloud composition.
它们可能由甲烷组成。 These are probably Made of methane,
在行星表面行动得很快， And they move very fast Around the planet as well.
海王星上风的移动不同于我们所知的任何事物。 Neptune's wind movement Is unlike anything We are accustomed to.
海王星上巨大的风暴系统 These are Giant storm systems,
使得地球上的风暴相形见拙。 Storm systems That would dwarf anything That we see on Earth.
1989年 In 1989,
航天器2号拍下一张照片 Voyager ii snapped a photograph
震惊了业界的科学家， That shocked The mission's scientists.
海王星有一场巨大的风暴， Neptune had a huge storm,
在它南半球有一块巨大的黑斑， A great dark spot In its southern hemisphere.
延伸8000英里宽 Stretching 8,000 miles wide,
大到足够能把我们地球放进黑斑中心。 Large enough for our Earth To fit in the center,
这风暴类似与木星上声名狼藉的大红斑， The storm resembled Jupiter's infamous Great red spot.
大红斑是一块巨大的反气旋， The great red spot Is a huge anticyclone,
它由许多较小的风暴组成。 Which is fed By many smaller storms That keeps it alive, If you like.
否则它会驱散消失 Otherwise it would dissipate And disappear.
以大黑斑看来。 In the case Of the great dark spot,
我们相信大气中会是相当的动乱， We believe It's more of an instability In the atmosphere,
风暴涌入高速的大气层中，使得大气来回翻滚。 Which rocks back and forth Because of the flows In that very fast atmosphere.
恰在第一次发现大黑斑的5年后， Just five years After the spot Was first discovered,
科学家们再次大吃一惊， Scientist were in for another surprise
哈勃太空望远镜 The Hubble Space Telescope
对准海王星，发现 Turned its eye toward Neptune Only to see
海王星上最大的风暴消失了， That the largest storm On the planet was gone.
海王星的大黑斑发生什么事了? What happened To Neptune's great dark spot?
5年时间内 Within a span of five years,
该行星上最大的风暴 The largest storm on the planet
从南半球就这么轻易的消失了， Simply vanished From the southern hemisphere.
但这并不意味着海王星上所有风暴都停止了。 But that didn't mean the end Of mega storms on Neptune.
天文学家使用哈勃太空望远镜观测到 Astronomers using the Hubble Space Telescope observed
一块新的大黑斑出现了， That a new great dark spot Had appeared.
但这次黑斑出现在行星的北半球。 But this time, in the planet's Northern hemisphere.
似乎海王星上 It seems that on Neptune,
风暴系统出现在大斑迹之处， The storm systems that manifest As these big spots,
利用望远镜或飞行器你可以看得到。 You can see, With a spacecraft or telescope.
相比之下，它们有点来去匆忙。 They sort of come and go On shorter time scales Than,
比如说木星上的大红斑 say, The great red spot on Jupiter
已存在那里好几百年了。 Which has been there For hundreds of years.
这些风暴系统不仅短暂 Not only are these Storm systems transient,
而且古怪。 They are also eccentric.
科学家发现大黑斑的大小 Scientists observed That the size Of the great dark spot
振荡漂移了几千平方英里， Oscillated by several thousand Square miles
在仅仅8天之内 within a span Of just eight days.
消失、再现、完全奇异的移动， The disappearance And reappearance And overall erratic movement
使得海王星的暴风系统 Make Neptune's storm systems
成为太阳系中最难以预知的风暴之一。 Some of the most unpredictable In the solar system.
类似于其它外太行星邻居， Similar to its Outer planet neighbors,
海王星也有复杂的卫星体系。 Neptune has A complex system of moons.
目前已发现13颗卫星， Thirteen have been discovered So far.
海王星的一些卫星 Some of Neptune's moons
可能起源形成于太阳系的其他地方， May have originally formed Elsewhere in the solar system.
海王星捕获的这些卫星 Neptune is probably Capturing these moons
可能来自于太阳系中 From the vast amount of material That's actually
海王星和冥王星之外的大量物质， In our solar system Beyond the orbit Of Neptune and Pluto.
外太空有许多冰星体 There is a lot Of very icy bodies,
小行星体和其他岩类物质， Small bodies, planetesimals And other rocky things
穿行于太阳系碎片之间， That pass through Our solar system And other debris.
偶尔 Every so often,
一些碎片可能会互相撞击， Some of this debris Might collide with each other
这时碎片就可能被撞进太阳系， And then they get pushed in Towards the solar system.
有的冰冻碎片最后形成了彗星。 Some of these icy bodies End up as comets.
但如果碎片被撞向特定的方向， But if one is pushed In the right direction
被撞在特定的时刻， At the right time,
那么这一碎片就有可能被行星的引力吸住， It can be captured by a planet's Gravitational pull,
变成一颗卫星。 Becoming a moon.
海王星最大的卫星海卫一 Neptune's largest moon, Triton,
大小与月亮相当， Is roughly the size Of Earth's moon.
它是太阳系中现已知的最冷的星球， It is the coldest object In our solar system, Ever observed by astronomers
甚至比冥王星还要冷， Even more frigid than Pluto.
只有绝对零度以上40度， Only 40 degrees Above absolute zero,
大约-390华氏度。 About minus 390 degrees fahrenheit.
如此之冷以至于通常呈气态的氮气 So cold that the nitrogen Which would normally be In a gaseous form,
都成了冰态覆盖在极地区。 Forms an icy polar cap On this moon.
海卫一如此冷主要是因为它的表面反光性太好， Triton is so cold Primarily because the surface Is so reflective.
照在它表面光约有70% About 70 percent of the light That hits the surface of Triton
都反射了出去， Is reflected back.
所以海卫一吸收不到太多的太阳能， And with that much light Not being absorbed By the planet,
变得非常非常的冷。 It just gets very, very cold.
海卫一的组成成分与冥王星相似 Triton, it could well Be similar in composition To Pluto.
表面是冰雪覆盖， We see ices On the surface there.
在海卫一表面 One of the fascinating things
有一件奇妙的景观，羽毛状的烟云 That we see on the surface Of triton are actually plumes,
火山上空的烟云。 Essentially volcanoes.
我们来看看这些火山， And we see these plumes,
当航天器经过海王星和海卫一的时候， We've actually seen them Coming out in real time
我们可以看到火山的实时喷发， With the Voyager spacecraft When it went past Neptune and Triton.
不像地球上的火山， Unlike Earth's volcanoes,
海卫一喷泉似的火山爆发 Triton's geyser-like eruptions
喷出大量混合液，包含液氮、液态甲烷、氨水 Spew a mixture Of liquid nitrogen, methane, And ammonia.
并且喷出后的混合液 And an upsurge instantly freezes
飞上5英里高的大气中马上就结冰了。 As it rockets five miles high Into its thin atmosphere.
一旦到了空中 Once airborne,
在冰粒落下之前，冰粒将会被大气中的风带走 The ice can be carried Along for miles by winds In the atmosphere
带走好几英里。 before snowing Back down onto the surface.
海卫一上的这些地质活动引发了科学家的思考， Geological activity on triton Makes scientists wonder
在海卫一冰雪覆盖的地表之下，如果有水的存在呢? If there's water, Perhaps being heated Under Triton's Icy exterior
按照这一理论 And as the theory goes,
有水的地方就会有生命。 Where there's water, Life could be present.
如果有水的话 If that's the case,
海王星的最大的这颗卫星可能成为 Neptune's largest moon Could be home to
空前的最大发现之一。 one Of the biggest discoveries Of all time.
但由于计划和时间关系， But due to planning And transit times,
在飞行器抵达天王星和海王星之前 It will be at least two decades
至少还要等20年。 Before we approach Uranus or Neptune again.
我们有讨论，但目前还没有方案。 We've had discussions But there are no current plans.
利用飞行器我们可以 We could, with Voyager,
进行粗略的观察， Well, we just had a brief fly-by
获得许多的新发现。 And we managed to collect A lot of discovery.
但目前 But in fact,
我们仍需回来继续追捕新发现。 We need to get back To pursue those discoveries.
同时 In the meantime
科学家聚焦在新视野号的发射上， Scientists will be focused On New Horizons as it rockets
因为它会近距离接近冥王星。 Even closer to Pluto.
飞行板上除了一系列科学仪器 On board, In addition to a cluster Of scientific instruments
还有个小罐头装着冥王星发现者的骨灰， Is a small canister of ashes-- Those of Pluto's discoverer,
克莱德·汤博，死于1997年享年90岁。 Clyde Tombaugh, who died in 1997 At the age of 90.
我一点也没有参与新视野号任务， I'm not involved In the New Horizons mission At all.
但我可以告诉你我的想法， But i can tell you From my point of view,
对此任务我很兴奋， I'm very excited about it.
我们不用再去费心猜解 We really don't have Any good ideas
冥王星表面真正有些什么特征、会是什么样子， Of what the actual features On the surface of Pluto Are gonna be like.
这也是为什么这些小尺寸的 That's why These small scale pictures
实际的特写近照会有如此重要。 Getting actual close-ups Is gonna be so important.
当航天探测器和望远镜 As spacecraft probes And telescopes
被送往我们太阳系的边缘之处， Are sent to the far reaches Of our celestial neighborhood,
我们对浩瀚宇宙的认识又迈进了一步， We come one step closer To deciphering The expansive universe.
我们的科技和想象 Our technology And our imaginations
能够把这些遥远的外星世界拉近到我们的生活中。 Can help bring These far off alien worlds To life.
当我们敬畏而又好奇的观望， As we look at them with awe and wonder,
只能看到一个个深藏其中未解的谜团。 We can only fathom What unexplored mysteries Lie deep within.
谢谢观赏 Thanks For Viewing