美国国家航空航天局“信使”号水星探测器发射升空 Lift off of Messenger on Nasa's mission to Mercury.
水 星
金 星
火 星
木 星
土 星
天 王 星
海 王 星
行星 第5集
在十分遥远的地方 Far, far away...
越过火星 ..beyond Mars...
穿过木星的风暴和土星环 ..past the storms of Jupiter, and the rings of Saturn...
太空中的环境变得截然不同 ..conditions become very different.
这里的温度骤降 不同行星之间的距离 Temperatures plummet, and distances between worlds
不再是数千万公里 而是以数十亿公里来计算 are measured not in millions, but in billions of kilometres.
太阳系所有行星中最神秘的一颗就在这里 Here lie the most mysterious planets of them all.
天王星 Uranus.
一颗有着大理石纹理的淡蓝色星球 A pale blue marble hanging in the dark,
悬在黑暗冰冷的太空深处 frozen depths of space.
在更加遥远的地方 And, further out...
则是太阳系最后一颗真正的行星 ..the solar system's final true planet...
海王星 ..Neptune.
再往远处去 人们一度以为 那里只有体积很小 死气沉沉 Beyond, we thought we'd only ever find tiny, lifeless worlds...
内核完全冰冻的天体 ..frozen to the core.
但我们完全错了 How wrong we were.
黑暗之地 太阳系外缘
在我们生活的这个时代 人类文明触及到了前所未有的空间范围 We live at a time when our civilisation has unprecedented
我们对火星保持了几乎长久性的探测 reach, and we have a near-permanent presence at Mars,
包括火星轨道和火星表面 我们发射的探测器 both in orbit and on the surface, and we've had spacecraft orbiting
已能环绕水星 金星 木星和土星完成长时间运行 Mercury, Venus, Jupiter and Saturn for extended periods.
但若要超出土星的距离 空间探测就变得困难许多 But, once we get beyond Saturn, things become much more difficult.
到达那里的距离极其遥远 The distances are vast.
飞行时间不是几个月 Travel times are measured not in one months,
而是几年甚至几十年 我们一次只能探访 but in years, decades, even. And that means that we've only
一颗太阳系外层的行星 visited the outer planets once.
每一次造访都是进入未知世界的远行 Each visit is a voyage into the unknown, as we strive
因为我们要前往人类所探索的最遥远的行星 to reach the most distant planetary systems ever visited.
当我们到达那里时 探测器的速度太快了 And, when we do get there, our spacecraft are travelling so fast
以至于它们只能径直飞过 that they fly straight through,
仅在行星范围内停留数小时 only spending a few hours in the system.
不过这几个小时里收集的数据 But those few hours of precious data have allowed us to begin
让我们得以开始了解那些隐藏在太阳系 to understand the mysteries that lie there on the outer edges
边缘空间的秘密 of the solar system.
“旅行者”2号探测器 1977年
点火完毕 发射完毕 We have ignition and we have liftoff.
用以探测太阳系外层空间
返回的报告表明两台固体发动机 Reports coming back indicate those twin, large, solid motors
运转完全正常 are functioning perfectly.
人类第一次飞向黑暗之地的任务能够完成 全都要归功于 Our first mission into the dark was only possible thanks to some
这些行星自身提供的帮助 help from the planets themselves.
每个行星的公转速度都是不同的 Each planet orbits at a different speed.
大部分时间里它们会分散在太阳的周围 And, for most of the time, they're scattered around the Sun.
但每隔175年 But once every 175 years...
就会出现一个相当奇妙的现象 ..something rather wonderful happens.
太阳系外层的这几颗行星会排成一条线 The outer planets align...
这就打开了一条 ..creating a path...
从地球出发 途经木星和土星的通道 ..that leads from Earth past Jupiter and Saturn...
并且能一直通向天王星和海王星 ..all the way to Uranus and Neptune.
“旅行者”2号正好赶在这个恰当的时机发射 Voyager 2 had been launched at precisely the right moment
以利用这一罕见的行星连珠现象 to take advantage of this rare planetary alignment.
它用了不到两年的时间到达木星 It arrived at Jupiter in a little under two years.
木星的质量是其它七大行星 Two and a half times more massive
质量总和的2.5倍还多 than all the other planets combined...
“旅行者”2号利用木星的引力把自己弹了出去 ..Jupiter gave Voyager a gravitational kick.
又过了两年 “旅行者”2号见证了 Another two years on, and Voyager witnessed
太阳系中最美丽的景象之一 one of the most beautiful sights in the solar system.
另一个气态巨行星的冰环 The icy rings of another gas giant...
这就是土星 ..Saturn.
然后探测器继续前进 And, then, on and on...
深入黑暗世界 ..further into the darkness.
在离开地球将近9年后 “旅行者”2号逐渐靠近了 Almost nine years after leaving Earth, Voyager approached
一个全新类型的行星 an entirely new class of planet.
天王星 距离太阳29亿公里
与木星和土星一样 天王星表面主要是 Just like Jupiter and Saturn, the planet's upper atmosphere
氢气和氦气形成的旋涡流 is composed mostly of swirling hydrogen and helium gas.
在表面之下隐藏的是罕见的冰状混合物 含有甲烷 And hidden beneath lies an exotic, icy mix of methane,
氨和水 ammonia and water.
但与气态巨行星不同的是 天王星几乎没什么明显的动态特征 But, unlike the other gas giants, Uranus is almost featureless.
“旅行者”2号在整个观测过程中 For all the time that Voyager stared at the planet,
只看到了10个云层 it saw just ten cloud formations.
人们很快发现了其中的原因 And we soon discovered why.
天王星只有零下224摄氏度 Uranus, at -224 degrees Celsius,
是太阳系最冷的行星 is the coldest planet in the solar system.
也是第一颗被发现的冰巨星 The first of the ice giants,
它处于永久性深度冻结状态 in a permanent state of deep freeze.
“旅行者”2号在天王星附近只逗留了6个小时 Voyager spent just six hours with Uranus...
随着视野扩大 它看清了整个天王星系统 ..and, as its gaze widened, it took in the entire system.
和土星一样 Just like Saturn...
天王星也有行星环 ..Uranus has rings.
它的行星环十分微弱 暗淡 很难从地球上 The rings are so dark, so faint, that they're very difficult
观察到 to see from Earth.
事实上 人们直到1977年才发现它们 In fact, we didn't discover them until 1977.
这些行星环一定是由某种不易反射太阳光的物质组成的 They must be made of some kind of material that doesn't reflect
但人们不知道那是什么 a lot of sunlight back, and we don't know what that is.
一定不是像土星环那样的水冰 It can't be water ice like the rings of Saturn,
不然它们的亮度会更亮 because they would be much brighter.
这些光环极脆 极薄 They're also extremely delicate and thin,
而且十分令人不解的是 我们本以为环内的微粒 and, again, that's a great mystery, cos you'd expect the particles
会发生碰撞 行星环会随着时间推移而延展 to collide and the rings to spread out over time.
但这种情况并未发生 That doesn't happen.
所以这些光环一定是被什么东西固定住了 So, something must be holding those rings in place,
“旅行者”2号拍到的这张照片 and the answer can be seen in this photograph
可以给出答案 taken by Voyager 2.
可以看到一个很细的光环 它叫ε环 You can see a bright, thin ring, which is known as the epsilon ring,
在它上面和下面可以看到两颗卫星 and, above it and below it, you can see two moons.
里面那颗是天卫六 外面那颗是天卫七 The inner one is called Cordelia, and the outer one is called Ophelia.
现在我们需要了解一下运行的轨道 Now, the thing you need to know about orbits, a moon or a ring
运行轨道离行星近的卫星或行星环粒子 particle that's orbiting closer to a planet is moving more slowly
要比轨道远离行星的卫星或行星环粒子移动速度慢 than a moon or ring particle that's orbiting further away.
所以如果ε环内的粒子 And, so, if there's a particle in the epsilon ring that maybe
发生碰撞损失能量后 开始往下落 has a collision, loses a bit of energy and starts to drop down,
天卫六就会帮助粒子加速 重新回到环内 then Cordelia tends to accelerate that particle back up into the ring
在引力作用下 使它加速 again to speed it up by its gravitational influence.
反过来如果ε环外部边缘的粒子 Whereas, if it's a particle on the outer edge of the epsilon ring,
获得了更多能量 并开始上升 it gets a bit more energy and raises up in altitude,
那么天卫七就会让它减速 then Ophelia tends to slow it down,
并重新回到光环里 and, so, it falls back into the ring again.
通过这种机制 这些卫星保证了行星环 And, by that mechanism, these moons keep the ring nice
完整有序地环绕在天王星周围 也正是这个原因 and neat around Uranus, and, for that reason,
它们又被称为牧羊卫星 these moons have become known as shepherd moons.
目前我们还未发现更多的牧羊卫星 Now, we haven't discovered any more shepherd moons.
要知道“旅行者”2号只在天王星系统待了几个小时 Voyager was only in the system for a few hours.
不过我们认为还存在更多 它们环绕天王星运转 But we assume that they're there, orbiting around Uranus,
确保其它的行星环各归其位 keeping the other rings precisely in place.
消失的卫星并非天王星唯一让人疑惑不解的谜团 The missing moons are not the only mysterious thing about the planet.
这颗行星以独一无二的方式环绕太阳运转 Uranus orbits the Sun in a unique way,
这是很久以前发生的一系列事件导致的结果 a consequence of events that happened long ago.
46亿年前
天王星诞生于年轻太阳周围 Uranus was born from the vast cloud of material
巨大的团状物质之中 that surrounded the young Sun.
久而久之 这团物质 Over time, this material grew together
在引力作用下聚集到一起 under the influence of gravity...
每颗行星都是这样形成的 ..forming each of the planets...
所有这些原始的气体尘埃云 ..all orbiting in the same anticlockwise direction
都以逆时针方向旋转 as the primordial cloud of gas and dust.
这样的自转一直持续至今 This rotation remains to this day.
几乎所有的行星都是沿自转轴 Almost all the planets spin on their axis in the same
以逆时针方向旋转 anticlockwise direction.
但出于一些我们尚未完全理解的原因 But, for reasons we don't yet fully understand,
金星和天王星都是以反方自转的 Venus and Uranus spin on their axes in the opposite direction.
天王星更是让人感到好奇 And Uranus is even more curious.
整颗星球都倒向一侧 The entire planet is on its side.
我们尚不确切了解为什么天王星以这种方式自转 It's not known for certain why Uranus spins in this way.
不过有可能是在 But it seems likely that, at some point,
遥远过去的某个时刻 它被另一个地球大小 probably in the distant past, it was hit by another planet,
甚至更大的行星撞了一下 possibly the size of Earth or even larger,
把它给撞倒了 而现代计算机 which knocked the planet over, and, indeed, modern computer
模拟结果也显示 如果行星本身发生这种情况 simulations suggest that when you do that to a planet,
它所有的卫星也会随之变化 最终这个行星 all the moons follow, and you end up with the planet
和它的卫星系统 甚至包括它的行星环 and its system of moons, and now its rings,
都是横躺着沿螺旋线环绕太阳运转的 sort of corkscrewing around the Sun on its side.
“旅行者”2号到达了人类探访过的距离最遥远的行星 Voyager had taken us to the most distant planets we had ever visited.
而现在 这台空间探测器和它将邂逅的下一个天体之间 And, now, an almost unthinkable distance of 1.6 billion kilometres
相隔着几乎难以想象的 距离达16亿公里的 of icy cold space lay between the spacecraft
冰冷宇宙空间 and its next encounter.
太阳系的规模之大是无法想象的 The size and scale of the solar system is impossible to imagine.
但如果把所有东西按比例缩小 就变得比较形象了 But, when we scale everything down, then it becomes easier to visualise.
太阳直径140万公里 The Sun is 1.4 million kilometres in diameter.
但如果用它的直径除以6亿 But scale that down by a factor of around 600 million,
它大概就是那盏灯那么大了 and it becomes the size of that light.
那么地球 火星和其它岩质行星 And the Earth, Mars and the rocky planets
按比例来说大约只有这么大 are about that big on this scale.
它们之间的距离则更加令人惊叹 And the distances are, I think, even more remarkable.
离太阳最近的水星 So, Mercury, the closest planet to the Sun,
就要一直往那边去 直到海边 would be all the way over there by the sea.
水星
这里就是水星的轨道 So, this would be where Mercury orbits.
相当于水星距离太阳96米 And Mercury is 96 metres away.
它的直径还不到一厘米 It's about just under a centimetre in diameter.
下一个行星金星就在那边 And the next planet, Venus, is somewhere over there.
水星 金星
从太阳出发飞行大约180米会经过金星 We'd fly past Venus about 180 metres away from the Sun.
然后继续向远处的地球进发 And then head onwards and outwards towards the Earth.
在地球的轨道这里 我们可以切身体会到 Here, at the Earth's orbit, the true scale of our fragility
地球
人类是多么脆弱 多么孤独 and isolation becomes apparent.
太阳在那里 有250米远 后面是遥远银河系 The Sun there, 250 metres away with the twinkling stars
闪烁的星星 地球的直径 of the galaxy beyond, and here's the Earth.
是两厘米 Two centimetres across.
人类的全部历史就在这卵石大小的地方上演 On that pebble, all of human history play out.
在大约380米处我们经过了火星 At around 380 metres, we pass by Mars,
这是最后一个岩质行星 然后继续深入黑暗空间 the last of the rocky planets, and then onwards into the darkness.
水星 金星 地球 火星
渡过海湾 我们将到达 Crossing the harbour takes us to the fringes
外太阳系的边缘地带 of the outer solar system.
行星之间的距离和行星的体积 And, now, the distances and the sizes
水星 金星 地球 火星
变得越来越大 are beginning to get really big.
木星是太阳系最大的行星 Jupiter, the largest planet in the solar system,
直径是地球的10倍还多 太阳在那里 is over ten times the diameter of our Earth, and there's the Sun,
木星
横跨海湾1.3公里 1.3km across the harbour.
走过几乎两倍于太阳到木星的距离之后 At almost twice the distance from the Sun to Jupiter,
我们到达了土星 we reach Saturn.
土星 木星
在这个比例下是2.4公里 2.4km on our scale.
接下来我们要真正进入太阳系的昏暗地带了 And we really are now entering the twilight of the solar system.
这里的亮度和地球的清晨或傍晚时分差不多 Light levels are like early morning or late evening here on Earth,
不过我们还是能够看到夜空中的土星 but we can still see Saturn in the night sky,
因为这颗行星和它的行星环高度反光 because the planet and its rings are highly reflective.
经过了所有岩质行星 经过了木星和土星 As far again as all the rocky planets, and Jupiter and Saturn,
我们到达了天王星 we reach Uranus.
天王星
要远离太阳30亿公里 我们开始充分体会到 3 billion kilometres from the Sun, and we begin to fully appreciate
“旅行者”2号究竟走了多么远 the distances Voyager had travelled...
这是一趟到达太阳系最远端的旅程 ..on its journey to the farthest reaches of the solar system.
旅程的终点是海王星 一个直径大约 Journey's end, Neptune, a ball of gas about
7.5厘米的气态星球 7.5 centimetres across.
在我们这个比例下它距离太阳7.4公里 7.4km away from the Sun on this scale.
海王星
我们依然还在这个岛上 在雷克雅未克的海湾 And we are still down there on the island in Reykjavik harbour.
小到肉眼看不见的蚂蚁在这颗卵石表面上爬来爬去 Little, microscopic ants crawling around on the surface of a pebble.
尽管用了12年之久 “旅行者”2号最终还是 It had taken 12 years, but Voyager had finally crossed
还是成功跨越了从地球到最遥远行星系统之间的 the great expanse of space between Earth and the most
广阔宇宙空间 distant planetary system.
海王星 距离太阳45亿公里
海王星 Neptune.
其质量是地球的17倍 甚至超过了天王星的质量 17 times the mass of the Earth, and even more massive than Uranus.
不过与它的姐妹行星形成对比的是 海王星的大气层 But, in contrast to its sister planet, Neptune's atmosphere
有着猛烈的气象活动 is bursting with activity.
我们发现这是一颗存在极端天气的行星 What we found was a planet of extreme weather,
高空的大风让白色的甲烷云团翻涌而起 风速超过了 where high altitude winds whip white methane clouds around at speeds
每小时2000公里 of over 2,000km/h.
这是整个太阳系风速最快的 Those are the highest wind speeds anywhere in the solar system.
南半球 大黑斑
“旅行者”2号看到了一个大黑斑 And Voyager saw a great, dark spot,
跟木星的大红斑有些相似 not unlike Jupiter's great, red spot.
这个风暴系统有地球大小 但当我们在四五年后 A storm system the size of Earth, that, when we looked only four
再观察时 发现它已经消失了 or five years later, we found had vanished.
多年以来 我们在海王星上观察到了 But, over the years, we've observed more storms raging
更多的风暴 over the planet.
这是行星探测领域的几大不解之谜之一 It's one of the great mysteries of planetary exploration,
为什么一个行星距离太阳如此遥远 why a planet so far from the Sun, with so little energy falling
大气层从太阳获得的能量如此之少 却会存在太阳系中 into its atmosphere from sunlight, can have the most extreme winds
最猛烈的强风 in the solar system.
“旅行者”2号还发现另一件令人困惑的事 And Voyager made yet another puzzling discovery.
平均气温 零下214摄氏度
尽管距离太阳更远 海王星却比天王星温度要高 Although further from the Sun, the planet is warmer than Uranus.
这些额外的能量来源至今仍是一个谜 The source of this extra heat remains a mystery.
出于某种原因 海王星散发的热量 But, for some reason, Neptune emits over two and a half times
是它从太阳接收热量的两倍半还多 the heat it receives from the Sun.
这种来自内部的热量或许解释了猛烈风暴的成因 And this internal heat helps to explain the ferocious storms.
在热量从行星核心一路向外散发到 As the heat makes its way from the core of the planet
宇宙空间的过程中 and out into space...
整个大气层被搅动 ..it churns up the entire atmosphere...
形成了不同于太阳系其它地方的大风 ..creating winds unlike anything seen elsewhere in the solar system.
风速如此之快 很可能是因为 The probable reason that wind speeds can be so high
像海王星这样的行星没有坚硬的表面 is because there's no solid surface on a planet like Neptune.
各种奇怪液体在下面流淌 各种气体在上面飘 It's exotic liquids further down, and gases further up.
但没有岩质的表面 But there's no rocky surface.
那里没有高山和大陆来阻断 There are no mountains and continents to break up the flow
大气中气体的流动 所以行星上的风暴 of atmospheric gases, and, so, the winds can just whip
达到了超音速的速度 around the planet at supersonic speeds.
“旅行者”2号在太阳系的这场宏大之旅就要结束了 Voyager 2 had almost completed its grand tour of the solar system.
不过它在进行孤独的 But before it began its lonely journey
星际旅行之前 out into interstellar space...
还有最后一个世界要探访 ..it had one, last world to visit.
海卫一 海王星14颗卫星中最大的一颗
海卫一 一颗巨大的卫星 表面覆盖着冻结的固态氮 Triton, a vast moon covered in a sheen of frozen nitrogen.
我们本以为这个世界寂静无声 We expected it to be a silent, still world,
但“旅行者”2号带来了最后一个惊喜 but Voyager was in for one, last surprise.
当“旅行者”2号到达时 But, when Voyager arrived,
我们发现这个冰冻世界上存在地质活动 we saw geological activity on that frozen world.
我们看到喷涌向太空的间歇泉 高度达8公里 We saw geysers erupting up into space 8km high,
裹挟着沿顺风方向 绵延100公里的深色物质 and then carrying dark material 100km downwind.
现在我们发现 理解喷发形成过程的关键在于 Now, the key to understanding what process caused those eruptions
喷发的间歇泉大都集中在海卫一表面 was that we noticed that the geysers tended to erupt on a place
一个有微弱阳光照射的地方 on Triton's surface below the faint Sun,
尽管太阳远在数十亿公里之外 even though it's so many billions of miles away.
这个过程中 阳光照射在一层薄薄的氮冰上 What's happening is the sunlight is falling on the thin layer
穿透冰层 然后使一层深色的 位于地表之下一米的 of nitrogen ice, going through, and heating up a layer of darker
物质温度变高 particles a metre below the surface.
仅仅4摄氏度的温度 A difference of just four degrees Celsius
就足以让热量向上升腾 is enough for the heat to radiate up
使冻结的氮蒸发形成气体 and vaporise the frozen nitrogen, creating gas.
气体在压力下最终冲破了氮冰 That gas is under pressure, and, ultimately,
裹挟着深色物质上升 it punches through the nitrogen ice
这也就形成了海卫一上面的间歇泉现象 carrying those dark particles up and making the geysers of Triton.
在太阳系这个最偏僻的角落 In the furthest reaches of the solar system,
阳光即便微弱 也足以产生力量 创造出这番 the faint light of the Sun is still enough to power the most
距离最遥远的地质奇观 distant of geological wonders.
不过这并不能完全解释海卫一的其它神秘特征 But this can't explain the rest of Triton's mysterious features.
表面覆盖数千个裂缝和凹坑
如此显著的地形特征 只可能是由 Terrain on this scale could only be created
一股更强大的力量创造的 by a much more powerful force.
线索似乎藏在海卫一奇特的运行轨道中 And a clue seems to be lurking in Triton's odd orbit.
不同于太阳系所有其它大个卫星 Unlike every other large moon in the solar system,
海卫一的公转方向与海王星的自转方向是相反的 Triton orbits in the opposite direction to the spin of the planet.
这说明海卫一和海王星 And that means it's highly unlikely
不太可能是同时形成的 that Triton and Neptune formed at the same time.
如果行星和它的卫星形成于同一片塌缩的气体尘埃云 If you formed a planet and a moon out of the same collapsing cloud
它们的自转和公转方向往住是一样的 of gas and dust, then they tend to spin and orbit in the same
与最初的尘埃云旋转方向相同 direction as the spin of the initial dust cloud,
所以最有可能的解释是 海卫一是海王星系统的 so, the most likely explanation for that is that Triton is a visitor
一个访客 不过没像“旅行者”2号一样再离开 to the Neptunian system, that, unlike Voyager, never left.
太阳系外围
一种理论认为 数十亿年前 One theory is that, billions of years ago,
海卫一并不是一颗卫星 Triton was not a moon at all.
它成长于海王星之外的一个区域 It grew up in a region of space way beyond Neptune...
这就是柯伊伯带 ..the Kuiper belt.
在这里 数万亿由水 氨和甲烷 Here, trillions of frozen lumps of water, ammonia
组成的冰体环绕着太阳 and methane circle the Sun.
它们是太阳系形成时的冰残留物 The frozen leftovers from the formation of the solar system.
或许海卫一后来来到了这个区域的内缘 Perhaps Triton ended up on the inner edge of this region...
然后由于足够靠近海王星 ..and ventured close enough
导致被引力捕获 to Neptune to be drawn in by its gravity...
直到它最终被拉出柯伊伯带 ..until, eventually, it was plucked from the Kuiper belt,
永远被困在了这个遥远蓝色行星的轨道里 and forever trapped in orbit around the distant, blue planet.
如今海卫一围绕海王星公转的轨道是一个十分规整的圆圈 Today, Triton orbits in a nice, regular circle around Neptune,
不过它的轨道最初并不是这样的 but it wouldn't have started out that way.
海卫一刚刚被捕获时 它应该是掠过了海王星 When it was first captured, it would have glanced
然后沿一个椭圆形轨道运行 past the planet and ended up in a wide, elliptical orbit,
有时候离海王星很远 有时候很近 sometimes being far away from the planet, and sometimes close.
这意味着在海卫一围绕海王星公转的过程中 That means that, as Triton orbited around Neptune,
万有引力是不断变化的 the gravitational pull was constantly changing,
它一直拉拽 碾压海卫一 并通过摩擦 and that stretches and squashes the moon, and heats up
使其内部温度上升 the interior by friction.
这个过程叫作潮汐加热 It's a process called tidal heating.
炽热的内部物质很可能通过海卫一外壳上的 The molten interior would have exploded up through cracks
裂缝和断层喷发出来 and faults in Triton's crust...
形成了我们今天看到的凹凸不平的表面 ..creating the ragged surface we see today.
现在剩下的就是一个冷却下来的卫星 And what you're left with is a cooling moon,
公转轨道为圆形 方向与行星自转方向相反 orbiting in a circle the wrong way around the planet,
它过去的动荡不得而见 the dramas of its past hidden from view.
保留下来的只有那些间歇泉 微弱的太阳光为它们提供能量 All that remains are the geysers, powered by the faint light
在如今沉寂的海王星表面留下了一道道深色纹路 of the Sun, painting dark streaks across the now-quiescent surface.
“旅行者”2号已经完成了它的使命 Voyager had fulfilled its mission,
现在它继续前进 准备飞出太阳系 and now headed onwards, out of the solar system...
它将不会再遇到另一颗行星了 ..where it would never encounter another planet.
不过在别处 另一个世界正等着我们到访 But, elsewhere, another world awaited our arrival...
一个更加深入黑暗的世界 ..far out in the darkness.
我们已经点火并发射了美国国家航空航天局的“新视野”号探测器 Mission... And lift off of Nasa's New Horizons spacecraft
它将在10年的漫长航行后 造访“行星”冥王星 然后继续前进 on a decade-long voyage to visit the planet Pluto and then beyond.
“新视野”号 2006年
迄今发射速度最快的探测器
“新视野”号 The New Horizons spacecraft,
踏上了前往太阳系最边缘的旅程 on its way to the very edge of our solar system.
前往冥王星飞行时间 9.5年
人类想要了解这个奇妙小世界的雄心能否实观 Our ambition to learn more about a small,
取决于“新视野”号能否成功完成航行 intriguing world depended on the success of New Horizons.
这个长度不到3米的小探测器 As the tiny probe, less than three metres in length,
被送进了宇宙深渊 was sent out into the abyss...
它的大部分电子器件和所有非必要系统 ..most of its electronics and all nonessential systems
都为了节约电力而关闭了 were shut down to save power.
它将在全长48亿公里的航程中 几乎一直处于休眠状态 It would hibernate for almost its entire 4.8 billion kilometre trek.
就在“新视野”号持续飞向冥王星的同时 Whilst New Horizons continued its voyage to Pluto,
地球上发生了一场关于冥王星定义 a controversy arose here on Earth about the definition
的争论 of Pluto itself.
我们过去一直都知道冥王星很小 See, we always knew that Pluto is small,
比海王星的卫星海卫一还要小 但直到哈勃空间望远镜 smaller than Neptune's moon Triton, but it was discoveries made
在冥王星附近有了新的发现之后 in the vicinity of Pluto by the Hubble Space Telescope
它的行星地位才真正受到了挑战 that really challenged its status as a planet.
从地球上看 远在柯伊伯带内缘的冥王星 From Earth, Pluto, far away on the inner edge of the Kuiper belt,
由于距离过于遥远 即使用哈勃望远镜 is so distant that, even with Hubble, it appears
也只能看到一个模糊的图像 as nothing more than a fuzzy image.
但冥王星并不孤单 But Pluto was not alone.
我们开始探测到其它遥远的天体 We began to detect other distant objects.
夸欧尔 发现于2002年
塞德娜 发现于2003年
妊神星 发现于2003年
鸟神星 发现于2005年
之后哈勃望远镜又发现了一个 Then, Hubble discovered that another world
几乎与冥王星同等大小的天体 is almost the same size as Pluto.
阋神星 直径2326公里
这些新发现的天体 让人们不得不重新思考 The discovery of these new worlds has forced us to reconsider
“行星”这个词的含义 what we mean by the word "planet".
国际天文学联合会对行星的定义包括三点 The International Astronomical Union has a three-part definition
第一 它必须围绕太阳公转 of a planet. Firstly, it has to orbit the Sun,
冥王星确实如此 and Pluto certainly does that.
它每248年公转一次 It goes round once every 248 years.
第二 它必须质量足够大 好让它在引力作用下 Secondly, it has to be massive enough for gravity to sculpt it
变成近似球形的形状 而冥王星基本也是一个球形 almost into a sphere, and Pluto indeed is almost spherical.
第二 它围绕太阳运行的轨道上不能有障碍物 But, thirdly, it has to clear its own orbit around the Sun,
这其实也是对质量的要求 and that's essentially a mass constraint as well.
它必须有足够大的引力来清除 It has to have enough gravity to throw things out
公转轨道上的天体 from its orbital path.
而冥王星并不符合这样的要求 And that's where Pluto falls down.
那么为什么要加上这一条呢 Now, why that extra idea?
说到底这是因为 如果冥王星大到足够成为一颗行星 Well, ultimately, it's because if Pluto is big enough
那么就体积而言阋神星也是行星 to be a planet, then Eris is big enough to be a planet,
鸟神星也是一样的情况 and Makemake is big enough to be a planet,
数十个 甚至数百个足够大的天体 and tens or even potentially hundreds of objects out there
都有可能成为行星 are big enough to be planets.
所以这个条件真的那么重要吗 Now, does it really matter?
我并不这么认为 Well, I don't think so.
冥王星终究还是一个天体 因此我们应该去探索它 Ultimately, Pluto is a world, and, therefore, we should explore it.
准备 1 2
这正是我们在2015年7月采取的行动 And, in July 2015, that's exactly what we did.
准备 中心平台
经过9年的飞行 “新视野”号被唤醒 After nine years of flight, New Horizons awoke.
收到 Copy that.
我们正与太空营进行遥感对接 We are locked by telemetry with the phase path.
冥王星 距离太阳59亿公里
我们第一次瞥见人类探测过的最遥远的星球 We had our first glimpse of the most distant world ever visited.
克苏鲁斑 3000公里宽的黑暗地带
超过5000个撞击坑
光晕状撞击坑 维加台地区域
（最大的撞击坑 50公里宽）
丹增山脉 最高峰高达6公里
冥王星十分美丽 Pluto is beautiful.
它完全不是一个冰冷的 毫无特色的星球 And, far from being a frigid, featureless world,
事实证明 一颗充满活力的行星 it turns out that it has all the characteristics
该有的特色它全部具备 of a dynamic, living planet.
没错 它的表面很冷 大约零下230摄氏度 And, yes, it is cold on the surface, about -230 degrees Celsius.
行走其上 脚下是坚硬的氮冰 I'd be walking over solid nitrogen.
而在哈勃空间望远镜 But the blotches that could be made out
模糊的图像上显示为黑斑的区域 in the grainy Hubble Space Telescope images turned out to be
其实是及其丰富多样的地质形态和结构 a tremendous variety of geological form and structure.
不过到目前为止辨识度最高的特征是一个叫作 But by far the most recognisable feature is the region known
汤博区的区域 as Tombaugh Regio,
它有一个更为人所熟悉的名字 冥王星之心 or to give it its more popular name, Pluto's Heart.
汤博区 冥王星之心
这个心形靠西的一瓣叫作斯普特尼克平原 The western lobe of the heart is called Sputnik Planitia.
这个广阔的平原由富含氮 甲烷和一氧化碳的冰体构成 A giant plain of frozen nitrogen, methane and carbon monoxide...
面积达100万平方公里 ..that stretches for a million square kilometres.
平原的边缘是绵延的山脉 And, at its edge, lies a range of mountains made of pure,
由纯净的水冰组成 frozen water ice...
高出平原6公里之多 ..that rise up to 6km above the plain.
不过这个区域有个不同寻常的特点 But there's something very strange about the region,
使它有别于这个矮行星其余所有地方 something that sets it apart from the rest of this dwarf planet.
冥王星表面遍布撞击坑 The surface of Pluto is covered in craters, the scars
是数十亿年前天体撞击留下的疤痕 of impacts that have taken place over many billions of years,
就像月球的表面一样 just like the surface of our moon.
但我们看到的斯普特尼克平原十分平坦 Except, if you look on Sputnik Planitia, it is absolutely smooth.
上面是完全没有撞击坑存在的 连一个也不存在 There are no craters there at all, not a single one.
在宇宙空间中 没有撞击坑是很不可思议的 From space, the lack of craters is striking.
我们观察的距离越近 它的秘密就越发让人不解 And, the closer you look, the stranger the mystery gets.
“新视野”号传回的精细图像显示 Detailed imagery beamed back by New Horizons revealed a network
一大片六边形和五边形的结构 of hexagon and pentagon shapes...
在氮冰表面纵横交错 ..that crisscross the frozen nitrogen surface.
找到成因的一个线索就在这些图像里 A clue to what might be happening can be seen in these images.
这类地表形态在宇宙的其它地方也能找到 Those kind of patterns are found elsewhere in nature.
比如这个是在太阳表面 Here, for example, on the surface of the Sun.
或者这个 从下方被加热的液体物质 Or here, in a liquid that's been heated from below.
这些图案是对流的典型特征 These patterns are characteristic of convection.
它要有一个热源让物质做上升运动 There's a heat source which is causing material to rise up,
物质冷却后又会下降回来 对流的液体 and then it cools and falls back again, and in those circulating
不断循环往复之后 就会出现这样的图案 convection currents, you tend to get patterns like this.
所以斯普特尼克平原下面可能是这种情况 So, what could be happening below the surface of Sputnik Planitia
地下深处有一个热源 它不断融化氮冰 is that there is a heat source deep down which is melting the nitrogen
导致它上升 冷却 然后下降 ice and causing it to rise, cool and then fall again,
那些对流的液体不断重塑着这一地区的面貌 and those convection currents are constantly resurfacing the area.
冥王星这样的小星球依然很活跃 这是个巨大的惊喜 That a small world like Pluto is still active was a huge surprise.
我们对此最合理的解释就是 Our best theory of how this could be
星球内部深处的某个地方 is that somewhere deep in its interior...
一些放射性物质在它们衰变的过程中不断产生热量 ..there are radioactive elements that generate heat as they decay.
这股热量不断温暖着一个没有光照 呈半冰冻状态的海洋 This heat warms a sunless, half-frozen ocean of water
它已在冥王星地表之下存在了数十亿年之久 that has existed for billions of years beneath the surface of Pluto.
来自斯普特尼克平原的证据表明 Now, the evidence from Sputnik Planitia that there is still
星球内部的热源依然存在 通过研究冥王星 an internal heat source, and studies of other geological features
其它的地质特征 一些科学家推测 on Pluto, have led some scientists to suggest that
那个海洋可能还在原地 that ocean of water might still be there.
一个相对较暖的海洋 And the relatively warm ocean
或许能解释为什么斯普特尼克平原没有撞击坑 could explain the lack of craters on Sputnik Planitia.
在氮冰表面缓慢上升的过程中 The entire area is constantly being repaved as the nitrogen
整个区域不断地被重塑 surface is slowly turned over.
但是为什么这种地质活动只会在这里出现呢 But why all this activity here and nowhere else?
也许冥王星之心所在的地方发生过猛烈撞击 Perhaps Pluto's heart is the site of a huge impact...
很久以前 它的表面被撞出了一个大洞 ..that, long ago, punched a large hole in the surface,
几乎深及那片广阔的地下海洋 almost down to the vast ocean beneath.
这个洞渐渐地被并不坚硬的氮冰所填满 A hole that's slowly filled with soft nitrogen ice...
这个温暖海洋促使其上的氮冰缓慢翻腾 ..that now gently churns just above a warmer ocean.
想象一下 Imagine that.
有一片海洋 距离太阳数十亿公里之遥 An ocean billions of miles away from the Sun,
位于太阳系寒冷的边缘地带 on the frozen frontier of the solar system.
在这个最令人惊讶的星球上 On this most surprising of worlds,
也许仍然存在着大量的水 there may still be an ocean of water.
“新视野”号与冥王星最亲密的邂逅只持续了数小时 New Horizons' closest encounter with Pluto lasted just hours...
这个过程中只有一个半球是可见的 ..during which only one hemisphere was visible...
它的另一面仍是一个谜 ..leaving the other side a mystery.
冥王星给了我们最后一个惊喜 Pluto held a final surprise.
就在“新视野”号调转镜头 准备再看最后一眼时 As New Horizons turned its camera back for one, last look...
它拍到了冥王星大气层 ..it captured an image of Pluto's atmosphere,
在黑暗中闪耀的图像 glowing in the dark.
个薄薄的蓝色大气层 下面隐藏着一片汪洋 A thin, blue sky over a hidden ocean of water...
这个地方与地球的距离是48亿公里 ..4.8 billion kilometres from Earth.
人类取得的成就是巨大的 We've come a long way.
通过仅仅半个世纪的空间探测 After just half a century of space exploration...
我们造访了太阳系的每一个行星 ..we've reached every one of the planets in the solar system...
并开始讲述关于它们的故事 ..and begun to tell their story.
我们所呈现的是永不停息的变化 What's emerging is a tale of never-ending change...
扣人心弦的起源 ..of dramatic origins...
充满希望的瞬间 ..moments of hope...
还有逝去 ..and loss.
8个岩质的 冰冻的以及气态的尘埃 Where just eight motes of rock, ice and gas...
以黑暗的宇宙空间为幕布 ..set against the dark backdrop of space...
它们齐心协力 至少在其中一个世界创造出了生命 ..have conspired together to produce life on at least one world.
有些人会问 我们为什么要探索宇宙 "Why do we explore?" some people ask.
难道我们不应该先处理好地球上的种种问题 然后再投入时间 Shouldn't we deal with the problems here on Earth before committing time
精力和资源 去探索那些星星吗 and energy and resources to exploring the stars?
我认为把注意力完全放在地球 这个宇宙尘埃上 Well, I think focusing entirely on our mote of dust
是莫大的错误 would be a profound mistake.
那将意味着我们人类决定蜷缩在 It would mean that we've taken the decision to sit huddled
太阳系的一个小角落里 in a tiny corner of the solar system,
对我们所做的事情迷惑不解 wondering what we're doing here.
那将意味着我们人类决定为了 It would mean that we've taken the decision to fight amongst
越来越珍贵的资源而相互斗争 ourselves for ever-more-precious resources,
把自己限制在一层薄薄的大气之下 一块渺小的岩石之上 confined below a thin shell of air on a small rock,
而不是去探索那条由夜晚星光 rather than following the three-dimensional path marked out
勾勒出的立体的路径 by the lights in the night.
我们住在一个充满奇迹的太阳系 We live in a solar system of wonders,
这里有风暴肆虐的行星 冰冻的卫星 还有各种地貌和景观 of planets of storms and moons of ice and landscapes and vistas
它们激发我们的想象力 丰富着我们的精神世界 that stir the imagination and enrich the soul,
太阳系有着无尽的资源 无与伦比的美丽 a system of limitless resources, limitless beauty
以及无限的潜力 and limitless potential.
我们对太阳系的探索才刚刚起步 A system that we've only just begun to explore...
而这趟旅程已经给了我们众多收获 ..in a journey that has already rewarded us with so much.
《行星》幕后故事
冥王星是美国国家航空航天局计划探测过的最遥远的星球 Pluto was the most distant world that Nasa had ever planned to visit.
10 9 8 7 Ten, nine, eight, seven...
“新视野”号的发射格外紧张刺激 The launch of New Horizons was incredibly dramatic.
点火 升空 Mission... And liftoff.
它升空的速度太快了 And it just shoots up so fast.
是地球上速度最快的一次发射 It's the fastest launch ever from Earth.
速度大约是每秒10英里 About ten miles per second.
为了确保探测器能在宇宙中持续飞行10年之后 In order to ensure that it was going to last for the decade across space
戴维-格林斯普恩博士 行星科学研究所
还能正常工作 他们做了很多备份工作 and actually work there, they built in a lot of redundancy.
基本上所有东西都有备份 包括计算机 There were sort of two of everything, computers
导航系统 and the guidance systems,
他们还想出了让它休眠的办法 and they figured out how to hibernate.
它是第一个休眠的探测器 The first spacecraft that hibernated.
我们让探测器大部分时间在睡觉 To put the spacecraft largely to sleep let the spacecraft
让它只是安静地漫游太空 just silently coast,
这样我们就能延长电子器件的寿命了 then we could extend the life of the electronics.
此前没有一架探测器 No spacecraft mission had ever really used hibernation
艾伦·斯特恩 “新视野”号首席研究员
以连续休眠的方式飞越太阳系 as a day-to-day way to cross the solar system.
这架探测器在睡梦中 As the spacecraft slept,
加速飞离地球 驶向了它的目的地 it sped away from Earth towards its destination...
那是几乎在整个人类历史长河中 ..to a world that had lain hidden
都淹没在群星中的一个星球 amongst the stars for almost all of human history.
冥王星发现于1930年 一个来自堪萨斯州的 The discovery of Pluto was in 1930, when Clyde Tombaugh,
哈尔·韦弗 “新视野”号项目科学家
农场小伙克莱德·汤博 a Kansas farm boy,
用亚利桑那州当地一座天文台的望远镜发现了它 was using the telescope at the Lowell Observatory in Arizona.
每个晴朗的夜晚 Every clear night,
克来德都会到外面 Clyde would go out and take images
凯西·奥尔金 “新视野”号副首席研究员
用带底片的相机拍摄夜空 然后在多云 of the sky on photographic plates, and when it was cloudy
或者白天的时候 比较这些底片 or during the day, he would compare those plates.
克莱德·汤博发现有个小光点 And Clyde Tombaugh noticed that there was this little speck
在群星中移动 moving across the stars.
后来在1930年 克莱德·汤博发现了冥王星 And, then, in 1930, Clyde Tombaugh discovered Pluto.
然而汤博没能亲眼近距离观察冥王星 But Tombaugh would never see Pluto up close.
他逝世于“新视野”号发射前9年 He died nine years before the launch of New Horizons,
享年90岁 at the age of 90.
他曾提出 如果有探测器能够发射 他的一部分骨灰 He had asked if a mission ever did get launched some of his ashes
可以一同踏上旅程 could be sent on the journey.
想想看 克莱德的骨灰飞过了冥王星 And to think that Clyde's ashes, you know, flew by Pluto,
他终于拜访了自己发现的 and, you know, he was finally visiting the place
那个星球 这真是太酷了 that he discovered, that was pretty cool.
我想说 冥王星在很多方面都令人震惊 让人大开眼界 Now, I mean, Pluto was a shock and a revelation in so many ways.
我们简直都惊呆了 Our jaws just dropped to the floor.
我们若没有发射前往那里的探测器 This amazing world that we would never have known about,
我们永远无法了解这个不可思议的世界 unless we sent a spacecraft out there.
赖特山 可能为冰火山 高4千米
刀状地貌 塔尔塔洛斯山脊地区
飞越冥王星后 “新视野”号并没有停下脚步 But New Horizons didn't stop after its flyby of Pluto.
它还要再飞三年 It continued on for three more years,
深入探索柯伊伯带 ever deeper into the Kuiper belt.
那里的温度几乎达到了绝对零度 The temperatures out there are almost absolute zero,
所以一切都保存完好 so everything is so well preserved.
柯伊伯带彻底改变了一切 The Kuiper belt completely changed everything.
可以说它就像一个考古发掘现场 让我们可以了解 It's an archaeological dig, if you will, into the early history
太阳系的早期历史 它就是科学世界里的一个仙境 of our solar system, so it's a scientific wonderland.
2019年新年这一天 On New Year's Day, 2019,
“新视野”号达到了柯伊伯带中心 New Horizons had reached the centre of the region...
它即将邂逅人类迄今探测过的最遥远的天体 ..and was about to encounter the most distant object ever visited.
小行星天涯海角
（长31公里）
这可能是人类探测器 This object may be the most primitive object
遇到过的最原始的天体 ever encountered by a spacecraft.
看着现在的天涯海角 我们相当于回到了 By looking at Ultima Thule today, we think we're looking back in time
太阳系起源的时期 to the origin of the solar system.
46亿年前
天涯海角也许就诞生于无数次天体撞击中的一次 Ultima Thule's formation was perhaps just one of the countless collisions
正是这些撞击形成了各个行星 that formed the planets themselves.
但它不知怎么逃脱出来 被扔进了 But, somehow, it escaped and was flung far out
遥远的柯伊伯带 into the Kuiper belt.
在距离太阳数十亿公里的地方 The worlds out there, which are billions of miles
那些天体隐藏了太多的谜团 from the Sun, there are so many mysteries kept in these objects,
诺亚·啥蒙德博士 行星科学家
我们能够真的走出去 去探索它们 and we can really go out and explore them, and start
去解开这些谜团 to understand these mysteries.
与在它之前的每一次探测任务一样 “新视野”号帮助我们 Like every mission before it, New Horizons has helped write
书写出关于这些行星的故事 the story of the planets.
而这个故事的讲述才刚刚开始 A story that we're only just beginning to tell.
利·弗莱彻博士 莱斯特大学
太阳系的那些行星就在我们的后院 The planets of our solar system, they're in our back yard.
我们拥有的技术使我们得以走出去 We have the technology to be able to go
并踏足行星表面 and stand on these surfaces.
我希望能够到太空去 能够继续这项 To be able to go out there and be able to continue doing
埃德加·里韦拉-瓦伦丁博士 月球与行星研究所
关于人类自然本质的事业 something that is very natural and intrinsic to all of us,
我想解答一些重大的问题 去探索未知世界 and that is answering the big questions and exploring the unknown.
我觉得我们对行星的探索绝对只是 I feel as though we're absolutely just at the beginning
刚开了一个头 of planetary exploration.
还有很多探索工作等着我们去完成 There's a lot of exploration left for us.
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