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!诞生了无限膨胀的 BANG! Giving birth to an endless expanding existence
时间、空间和物质。 of time, space and matter.
现在所见超乎我们的想象，超越了客观认知极限， Now, see further than we've ever imagined beyond the limits of our existence,
那地方我们称之为“宇宙”。 in a place we call... THE UNIVERSE.
夜空中一闪一闪的恒星， Each star you see twinkling in the night sky,
是超热气体形成的发光球体， is luminous sphere of superheated gas,
远远大于任何一个行星。 much larger than any planet.
每一颗都有一个故事， And each has a story to tell.
生命戏剧性地 A dramatic birth,
诞生在宇宙的边缘。 a life on the edge.
引力使小质量块集中集中成恒星， Gravity collects the star in the first place,
然后使之坍缩， and then gravity wants to crush it.
最后在引力的作用下消亡。 And a death that rattles the heavens.
整个过程就这样瞬间完成了 The whole thing goes off in a blinding flash,
宇宙中巨大的爆炸。 the biggest explosion in the Universe.
宇宙暴力动荡动感十足... The Universe at its most volatile and action-packed...
恒星的诞生与毁灭。 Life and Death of a Star.
宇宙第一季第十集
恒星的诞生与毁灭 Life & Death of A Star
就像是沙漠中金光闪闪的城市里一样， Like glittering cities in the desert,
星系在宇宙中最黑暗的角落诞生。 galaxies arise out of the great darkness of the Universe.
星系是由数十亿计、闪耀的宇宙灰尘所组成的，它们被叫做恒星。 Galaxies made of billions of blazing lights called stars.
宇宙里有数以百亿计的恒星， There are billions and billions of stars.
实际上银河系里就有四千亿颗恒星。 In fact, in our galaxy there are 400 billion stars,
还只算银河系， just in our galaxy.
但是这些恒星是如何诞生的? But how were these stars born?
它们会如何消亡? How will they die?
为什么地球上所有的人类， And how can it be that all human beings on Earth
多亏恒星的消亡才得以生存? owe their lives to the deaths of stars?
问题的答案从这里开始， The quest for answers begins here,
气体和尘埃组成的云。 in a cloud of dust and gas
盘旋在无尽的星际沙漠， hovering in the interstellar desert.
你所看到的是创造之柱， You are looking at the Pillars of Creation.
创造之柱其实是恒星托儿所， The Pillars of Creation are a stellar nursery.
新的恒星在中心区域孕育诞生， New stars are in the process of being born in the central regions.
离地球7000光年之遥。 Located 7,000 light years from Earth,
这些柱子是鹰状星云的一部分， the pillars are part of the Eagle Nebula,
宇宙中这样的恒星孕育不计其数。 which is just one of billions of star forming regions in the Universe.
这些柱子是尘埃和氢气形成的塔状星云。 The pillars are towering clouds of dust and hydrogen gas.
如果你还记得化学课上的元素周期表， If you remember the Periodic Table of elements from chemistry class,
那你应该知道周期表顶部的轻元素， you have the light elements up at the top,
氢、氦，锂等等。 hydrogen, helium, lithium, this sort of thing.
周期表越往下元素的原子质量越大， And then the really heavy ones as you get lower down.
氢元素宇宙中最轻而且最充足的元素之一。 It's hydrogen, the lightest, simplest most abundant element in the Universe,
它是恒星构成中的关键元素。 that is the key component of stars.
在星云中成团的灰尘还有气体， Within a nebula, clumps of this gas and dust
慢慢的经过数百万年时间聚合成小云团。 slowly coalesce into smaller clouds over millions of years,
而这种作用力大家很熟悉， pulled together by a very familiar force.
也就是， The same force that
我们和地球之间形成纽带的同一种力。 connects us here to the Earth, that keeps us on the Earth,
引力同样使物体互相吸引， gravity, is the same force that pulls things together
这样才逐渐形成了... in a way that gives us...
宇宙中的行星恒星星系。 planets and stars and galaxies in the Universe.
引力从某种程度上说是天文学里最重要的力。 Gravity, in many senses, is the most important force in astronomy.
当引力作用于宇宙万物， And when gravity acts in the Universe
最基本的产物就是恒星。 one of the basic things that it produces is stars.
恒星是引力作用下质量集中在一起， Stars are sort of the most basic unit of mass
所形成的最基本单元。 that is produced when gravity pulls mass together.
每朵承包商星云， Each contracting cloud
能够形成少到几十颗， can produce anywhere from a few dozen
多到上千颗恒星。 to thousands of stars.
想要形成太阳那样的恒星， To form a star like our Sun,
直径一百万英里。 which is a million miles across,
那就需要比我们整个太阳系， it takes a clump of gas and dust
总体积大100倍的气体和尘埃团。 100 times the size of our Solar System.
这些星云诞生初期温度极低， These clouds start off their lives bitterly cold,
低到华氏零下几百度。 with temperatures hundreds of degrees below zero Fahrenheit.
但由于引力摩擦和挤压他们， But as gravity fragments and compresses them,
温度开始显著上升。 the heat begins to soar.
再过个几十万年， Within a few hundred thousand years,
这些星云自旋成扁碟， the cloud spins into a flattened disc.
引力使得扁碟的中心凝聚成球体。 Gravity coalesces the centre of the disc into a sphere,
那里的温度炙热到200万度， where the heat rises to a scorching 2 million degrees.
这个发光系统被称之为“原恒星”。 This glowing system is now known as a "protostar".
再过个一千万年， Ten million years later,
羽翼未丰恒星灼热的氢核心， the searing hydrogen core of the fledgling star
温度突破1千800万度。 soars past 18 million degrees,
不可思议的事发生了， and something incredible happens.
核心的温度如此之高以至于能持续核聚变， The core becomes so hot, it can sustain thermonuclear fusion.
核聚变... Thermonuclear fusion...
这么一长串字就表示高温超高， is a lot of syllables but it just means it's hot there
小原子变大原子， and small atoms become big atoms.
氢原子剧烈运动， Hydrogen atoms are moving fast enough
以至于互相聚变， that they actually will fuse together
形成氦原子。 and will form a helium atom.
这种核反应产生巨大的能量， It's this nuclear reaction that produces the energy
使得恒星维持生命。 to power the star throughout its life,
保持着持久的光源和热源， giving it a constant source of light and heat.
恒星自己燃烧自己给自己产生热量， It's self-luminous, it generates its own heat.
这就是恒星之所以称之为恒星的本质。 And that's the essence of what makes a star a star.
有了核聚变就有了恒星， If you've got fusion, you've got a star.
恒星一旦诞生它的生命就是一场持久战， Once born, a star's life will be a constant battle,
对抗引力的全面战争。 an all-out war against gravity.
引力凝聚了恒星然后使之坍缩， Gravity collects the star in the first place, and then it wants to crush it.
引力从不怠慢想把所有的东西都拉到一起。 Gravity never gives up, gravity wants to pull everything together.
如果恒星想要寿命长足够的长， So if the star is going to have a life, and a long life,
那么就必须找到抗衡引力的方法。 it has to find a way to fight against gravity.
引力总是常伴你左右，当你想要跳跃时、 You feel gravity all the time. When you try to jump
当你想要攀岩时， or you try to climb a rock,
引力总是把你往下拉。 there's always gravity pulling you back down.
想要抗衡引力，你必须想方设法 And in order to fight against gravity, you have to have some way
另找外力， of applying a force
其作用方向正好和引力相反。 which works in the opposite direction than gravity.
比如有根绳子的话你用力拉绳子， So, if there's a rope, you can use your muscles to pull on the rope,
就有了一股力能抗衡甚至超越引力。 and therefore resist, and even overcome, gravity.
但这并不意味着引力就认输了， But that doesn't mean gravity gives up.
引力总是作用着， Gravity is always working.
所以你用来抗衡的力必须维持作用才不会使得你落地。 So you have to keep applying this force in order to not fall off.
如果你松手或者绳子断了的话， And if you give up or let go or the rope breaks,
引力马上就获胜你落地。 gravity immediately wins and you fall.
恒星的状况亦是如此。 The same kind of thing happens with stars.
恒星也尽力维持自身抗衡引力的坍缩作用。 Stars are also trying to hold themselves up against gravitational collapse.
引力想要恒星坍缩到最中心， Gravity wants to crush the star down to the middle.
对恒星而言核聚变就提供了绳子， For stars, nuclear fusion provides the rope,
以压力的形式， in the form of pressure.
热能使得恒星内的粒子超高速运动， The heat gets all the particles in the star moving around quickly,
伴随着向外的爆炸力， and they bang outwards,
这就提供了压力。 and that produces a pressure
维持了恒星自身对抗了引力， which can actually hold the star up against gravity.
把恒星往外推的压力正好等于 The amount of pressure pushing out on the star just matches
把恒星往里拉的引力。 the amount of gravity pulling in on the star.
只要有燃烧恒星就能稳坐泰山直到出现了意外， And it can sit there and burn happily until something changes.
恒星大部分时间都处于平衡状态。 A star will spend most of its life in this state of equilibrium.
科学术语是“主序”。 It's a phase scientists call the "main sequence".
所以说太阳处于”主序”状态，我们很高兴沐浴阳光。 So, our Sun is in the main sequence, we're very happy it's there,
太阳每天提供给我们相同的能量， it provides us the same amount of energy almost every day,
从而创造了生命。 and that's what makes life possible.
处于”主序”的恒星各不相同， All stars in the main sequence aren't alike.
有的远比太阳更小更冷， Some are much smaller and cooler than the Sun.
而有的更大更热。 Others, much larger and hotter.
有证据显示物体的热量， So, it turns out that how hot something is
和其发出的光色有着紧密联系。 is related to the colour of the light that it emits.
那么太阳那样的恒星， So, a star like the Sun,
发出的光亮大多属于黄色光。 most of the light that comes out from it is sort of a yellow-type colour.
要是太阳更热， If the Sun were much hotter,
那么其主要光的波长就处于蓝光波段， the predominant wavelength of light would come out into the blue.
甚至处于紫外线波段。 Or even into the ultra-violet.
热量低的恒星发出更多的红色光， And cooler stars emit more red light.
小冷红的恒星比如比邻星， Small, cool, red stars, like Proxima Centauri,
离太阳最近的恒星也叫”红矮星”， the nearest star to the Sun, are known as "Red Dwarfs".
可能只有太阳质量的十分之一， They can be as little as 1/10 the mass of the Sun.
表面温度比太阳低数千度。 With surface temperatures thousands of degrees cooler.
红矮星是宇宙中最普遍的恒星模式， Red dwarfs are the most common type of stars in the Universe.
成千上万这种昏暗的红矮星， There are many, many more of these sort of very dim, red dwarfs
漂浮在宇宙数量远超像太阳的那种恒星。 floating out in space than there are stars like the Sun.
当然仰望星空时， Of course, when you look in the night sky,
你不会见到这种最常见的恒星， you don't see the most common kinds of stars,
你看不到红矮星因为它们太暗了， you don't see these red dwarfs 'cause they're so faint.
你仅仅见到非常稀有非常明亮的恒星， You merely see the very rare, very bright stars
正好离我们非常遥远。 that turn out to be very, very far away.
波长段处于最短处， On the opposite end of the spectrum,
正是巨大的蓝色主序恒星， are the large blue, main sequence stars.
平均表面温度达到4万5千华氏度， Averaging a surface temperature of 45,000
质量可能是太阳的20倍， They can be 20 times the mass of the Sun.
比太阳亮一万倍。 And 10,000 times more luminous.
对于恒星的生老病死质量当然是关键。 In the life and death of a star, size definitely matters.
质量是最基本的属性， Mass is the fundamental thing
决定着一颗恒星的发展历程。 which drives the life history of a star.
质量越大的恒星， The more massive stars
比起质量较小的恒星寿命更短。 live much shorter lives than the less massive stars.
这听上去很奇怪， And that's perhaps a little bit strange sounding,
因为质量越大燃料也就越多， because the massive stars have more fuel to burn
所以你误认为它们寿命更长。 you'd think they'd live longer.
直觉总是认为大质量恒星， So, it's counterintuitive that more massive stars
比起小质量恒星， will burn through their fuel
消耗燃料的速度快得多。 more quickly than the lower mass stars.
试想两个赌徒对峙同一个21点赌桌， Imagine two gamblers sitting down at a blackjack table.
你会认为带钱最多的那个赌徒带着“更多的燃料”， You would expect the one with the most money, the most "fuel to burn",
能坚持更长时间， would last the longest.
但如果那个钱多的赌徒每局下注很大会如何? But what if the big-time gambler is making huge bets on every hand?
钱多的赌徒下注也就更大， A gambler that is gambling with a lot more money
每局下注1万美元， and putting down $10,000 at a time
这样他的钱很快就花光了。 is gonna burn through that money much more quickly.
所以质量越大温度越高压力越强， So the more mass you have, the higher temperature, the higher pressure,
核聚变速度也就越快。 the higher the fusion rate.
而且消耗速率--质量曲线是非线性的， It goes much more quickly with the more mass you have.
不是简单的算术题:你有多少燃料， And it's always just simply the calculation: how much fuel do you have,
燃料转换速率是多少。 and at what rate are you converting it.
大质量恒星寿命更短， The high-mass stars live their lives faster.
好比蜡烛两头烧它的人生处于短跑线。 They burn the candle at both ends, it's life in the fast lane.
大质量恒星寿命通常短于100万年， A high-mass star could die within a million years.
一颗质量是太阳十倍的恒星， A star 10 times as massive as our Sun,
寿命可能就短了1000倍。 might live for only 1/1000 as long.
假如我们的太阳寿命是100亿年， So our Sun will live for about 10 billion years in total.
一颗质量是太阳10倍的恒星， A star 10 times as massive as our Sun,
可能寿命只有1000万年。 might live only 10 million years in total.
大质量恒星的寿命数量级是百万年， While massive stars have lifespans measured in millions of years,
最小质量的恒星寿命的数量级， the lowest mass stars measure their lives
是百亿年甚至万亿年。 in tens of billions, if not trillions, of years.
小质量恒星不断诞生于宇宙， Every low mass star that has ever been born in the Universe,
宇宙不断制造恒星已经有100亿年了。 and the Universe has been making stars for more than 10 billion years,
小质量恒星还都处于婴儿期， all of those stars are still in their infancy.
还没有哪个小质量恒星濒临灭绝。 No such star that's ever been born has ever come close to dying.
但对所有恒星而言包括太阳， But for all stars, including our own Sun,
主序状态不可能永远维持下去， life on the main sequence can't go on forever.
只能维持到燃料烧光那天， It can only last as long as the star has fuel to burn.
燃料烧光了核聚变停止了引力也就...获胜了。 If it runs out of fuel, fusion stops and gravity... wins.
引力从不认输， Gravity never gives up,
要是有燃料当然也就能坚持一段时间。 whereas fuel, of course, can run out after a while.
恒星和登山者面临着同样的问题， And so the star and the climber both have this terrible problem,
要是他们不能和引力打持久战就难逃一死， that if they don't maintain their fight against gravity, they will end in death.
永世不得超生。 A cataclysmic death.
恒星的大小不仅决定着寿命长短， Not only does the size of a star influence how long it will live,
也决定着恒星如何消亡。 it also determines how it will die.
大质量恒星会在剧烈核聚变爆炸中消亡， Massive stars explode from the scene in violent fury,
小质量的则慢慢变暗直到油尽灯枯。 while smaller ones are doomed to slowly fade away.
50亿年来， For 5 billion years,
太阳低质量的中龄恒星， our Sun, a lower mass, middle-aged star,
养尊处优地消耗着氢燃料， has been happily burning through its supply of hydrogen fuel.
就好比赌徒下注慢条斯理， Like a gambler slowly plowing through a pile of chips.
这赌徒可能要赌很长一段时间了， The gambler may sit there for a long period of time,
就好比恒星燃烧氢燃料换得长寿命， just like a star burns its hydrogen for a really long period of time.
然而最终你还是难逃输得精光。 However, at some point, you're gonna run out of money.
科学家预言再过50亿年， Scientists predict that 5 billion years in the future,
太阳就要面临生死存亡: our Sun will reach this critical crossroads:
它的氢燃料将会被消耗殆尽， Its supply of hydrogen fuel will have been completely exhausted,
核聚变将停止， nuclear fusion will cease,
引力使得恒星坍缩， and gravity will begin to crush the star.
那时一切陷入绝望。 At that point the situation is desperate.
想要活命太阳那样的恒星就必须找新的燃料源， In order to survive, a sun-like star must find a new source of fuel.
它手头有氦... It has helium on hand...
但想要燃烧氦它的核心， but in order to start burning helium, the core has to be
就必须比燃烧氢时温度高上10倍。 10 times hotter than it was during its lifetime burning hydrogen.
它不会使得氦聚变成更重的元素， It won't be able to fuse that helium into heavier elements,
比如碳和氧， like carbon and oxygen,
除非核心足够热。 until the core gets sufficiently hot.
由于把氦核聚在一起 And that's because it's harder to get the helium nuclei close enough together
再把接力棒交给强粒子作用力， for the strong nuclear force to take over,
抓住对方引起核聚变不是件容易事。 grab them, and cause them to fuse together.
随着合同到期， As it continues to contract inward,
自然给了恒星寿命上限。 nature throws the star a lifeline.
核心会变成超高温， The core actually becomes superheated
这是由于引力坍缩造成的挤压力。 by the very gravitational pressure that's trying to crush it.
当温度达到华氏18亿度时氦原子聚变成碳原子， When it reaches 180 million degrees, it can start fusing helium into carbon,
存活几率渺茫。 in a desperate gamble to survive.
所以绝望的恒星变卖家产贷款， So the desperate gambler might go take out a loan on the house
换得更多的钱。 and get more money.
虽然借了更多的钱花， But in getting more money to burn through,
只不过是苟延残喘终究会破产。 it's really just delaying the inevitable, which is to go bust.
对恒星而言就是难逃一死， And for a star, the inevitable is to die.
恒星花了100亿年烧光了氢。 The star which took 10 billion years to burn through its hydrogen,
现在烧氦换得了仅仅100万年寿命， now powers through its supply of helium in a mere 100 million years.
戏就是这样上演的。 And then the action begins.
氢燃料用完了...开始氦聚变， It runs out of hydrogen... starts fusing helium.
氦用完了...企图碳聚变但无济于事。 Runs out of helium... attempts to fuse carbon and will fail.
但是整出戏， But all the action,
所有的高潮部分就发生在恒星最好10%的寿命里。 all the "what's going on now", happens in the last 10% of the star's life.
氦燃烧的超高温， The searing heat of the helium burning
将会使得恒星的外层膨胀。 actually causes the outer layers of the star to swell.
到那时太阳最外面的大气层， At that point, the outer atmosphere of our star
受到的引力作用就相当小， will be held in by gravity so weakly
就会有蒸发掉的趋势。 that it'll start sort of just evaporating away.
经历一连串我称之为“宇宙打嗝”的过程， Through a series of what I call "cosmic burps", it will actually eject
就会把受引力作用小的外层气体抛射出去。 the outer envelope of gases, which are only weakly held by gravity.
炙热核心就会把气体层往外推， That'll send some shells of gas outward
并照亮气体。 illuminated by the hot central star.
这会产生所谓的”行星状星云”现象， And that will cause what's called the "planetary nebula" phenomenon.
凄美的光亮气体层围绕着濒死的太阳核心。 Beautiful shells of glowing gas surrounding the dying core of our sun.
当核心再也不能产生任何核聚变时， With the core unable to muster any more nuclear fusion,
有没有可能逃脱引力坍缩的厄运? can it possibly survive gravity's crushing grip?
一颗太阳大小的恒星死亡时抛射其外层， As a star the size of our Sun dies, it ejects its outer layers.
没有核反应产生向外的压力， With no nuclear reactions to generate outward pressure,
引力占了上风， gravity gains the upper hand.
恒星向自己的中心坍缩。 The star begins to fall in on itself,
就好比攀岩者抓绳子太累了而松手， like a climber too tired to hold on to his rope.
攀岩者还剩下最后一根救命稻草， There's one possibility that the rock climber might be able to use
当他累到再也抓不紧任何绳子时， if he gets too tired to hold on to the rope any more,
就是在他攀登的岩石上找个立足之处， and that is if he can find a ledge on the rock that he's climbing.
引力的确不放过他， Gravity can pull on him only once
但立足之处能使他远离引力的烦恼。 but the ledge itself will support him against gravity.
他不必自己花力气赢得这场战斗， And he doesn't have to provide any more energy to win his fight.
有一种恒星如我们的太阳，事实上就是个例子。 There's a certain kind of star, and our Sun is actually an example of this,
恒星能够找到一条“出路”来对抗引力， where the star finds that it has an "out" in this fight against gravity.
合同到期的恒星不可思议的找到了立足之处:电子。 The contracting star finds its ledge in a surprising place: electrons,
小小的带负电的微粒， tiny, negatively charged atomic particles.
电子群不喜欢被压缩所以互相靠的很近， Electrons don't like being compressed so they're very close to one another,
由于电子的互斥力极强， because electrons effectively don't like each other.
要是你把他们使劲往里压所产生的电子斥力， If you compact the electrons hard enough, the pressure of the electrons themselves
能挽救恒星对抗引力。 is able to hold up the star against gravity.
当太阳那样濒死恒星的核心， When the core of our dying Sun-like star
坍缩到地球那样大小时， is crushed to about the size of the Earth,
所谓的”电子兼并压力”大显身手。 this so-called "electron degeneracy pressure" takes over.
引力无法使得恒星进一步坍塌 Gravity can collapse the star no further.
最后会慢慢冷却成奇怪的恒星残余，成为“白矮星”。 It's left to slowly cool into a bizarre stellar remnant known as a "White Dwarf".
比如说这颗天狼星B， Like this one, Sirius B,
只能在其同伴天空最亮恒星天狼星的光辉下， which can be seen only faintly aside its companion Sirius,
隐约被观察到。 the brighter star in our sky.
白矮星是一种非常奇怪的恒星， Now, a white dwarf is a very strange type of star.
密度极高， It's very, very dense.
那颗白矮星的质量有地球的3万倍。 The white dwarf has about 300,000 times the mass of the Earth,
如果把它压缩成地球那样的体积， compressed into a volume the size of the Earth.
那里一调羹物质的质量就有好几吨重， If you had just a teaspoon full of material, it would weigh several tons.
真是神奇的物质。 So, it's really amazing stuff.
白矮星是太阳那样恒星生命的最后舞台， A white dwarf is the final stage in the life of a Sun-like star.
但还没有入土为安， But it's not quite dead yet.
它还会继续发光几十亿年， It will continue to shine for billions of years
直到把其一生的能量通通辐射殆尽。 as it gradually radiates away a lifetime of energy.
我喜欢称白矮星为“退休的恒星”， I like to call white dwarfs "retired stars",
意思是它们现在发出的所有光线， in the sense that all of the light that they are shining,
是它们正值恒星壮年时积累下来的。 is energy that they accumulated during their normal lives as stars,
他们过去把轻元素聚变成重元素， while they were fusing light elements into heavy elements,
就像太阳现在正在干的事。 as our Sun is doing right now.
它在花费着一生的积蓄这就是退休的恒星， So, it's spending its life savings, it's a retired star.
这也将是太阳的命运。 That will be the fate of our Sun.
但某些白矮星最后还能潇洒走一回， But some white dwarfs can have one last hurrah,
多亏了某位朋友拔刀相助。 thanks to a friend who lends a helping hand.
因为尽管我们的太阳是宇宙浪人， Because, although our Sun is a cosmic loner,
但是宇宙中超过半数的恒星至少有一名伴侣。 more than half of all stars travel through life with at least one companion.
多数恒星处于双星系统甚至多星系统。 Most stars are members of binaries, or possibly even multiple star systems.
靠的很近的双星， Close binary stars
比起普通的单星命运截然不同。 can have very different fates from the ordinary single stars.
要是一颗白矮星和另一颗恒星互相吸引， If a white dwarf is gravitationally bound to another star
作为双星系统， as part of a binary system,
它就能把对方毕生的血汗钱偷过来。 it can essentially steal the lifeblood from its companion.
体积小但密度高的白矮星引力如此之强， The small but dense white dwarf exerts such a strong gravitational pull
以至于能虹吸氢气。 that it will start siphoning off a stream of hydrogen gas.
要是它能从对方星体那里获取物质， If it gathers material from a companion star,
就能增加自己的质量。 and is able to grow in mass,
最终白矮星的质量到达无法稳定的极限， then eventually, the mass of the white dwarf can reach an unstable limit,
大约太阳质量的40%， roughly 40% more than the mass of our Sun.
到那时白矮星将会发生灾难性的大爆炸。 At that point, the white dwarf undergoes a catastrophic explosion,
一切在转眼间灰飞烟灭， where the whole thing goes off in a blinding flash.
我们称之为整颗恒星的“热失控”， What's called the "thermonuclear runaway" of the entire star.
这种顶级爆炸称为Ia型超新星。 This mammoth explosion is known as a Type Ia Supernova.
要是我们的太阳这样虽然不会这样， So, if our Sun were to do this, and it won't,
太阳会相对安静的死去... it'll die in a relatively quiet way...
但如果真的这样大爆炸，你要准备好 But if it were to do this, you'd need
几十亿瓶防晒霜或者防超新星霜， sunblock or supernova-block of a few billion
保护你自己免受灰飞烟灭。 in order to protect yourself from the blinding flash.
加州大学伯克利实验室的天文学家亚历克·菲利潘科 University of California Berkeley astronomer, Alex Filippenko,
是全世界最成功的超新星猎手， is one of the world's most successful supernova hunters.
他的队伍在过去10年间发现了超过600颗超新星。 His team has found over 600 of them in the past decade.
真是难以置信的壮举， An incredible feat
因为一个星系平均100年只会发生2次超新星爆炸。 considering they occur perhaps twice per century in each galaxy.
搜寻超新星， Searching for supernovas
就好比在人山人海的足球场用肉眼扫描足球， is akin to scanning a crowded football stadium with binoculars,
希望捕捉到某个在比赛中某一瞬间， in hopes of catching the one person who might be taking a flash photograph
突然进球的射手。 at a given point in time.
要是你面面俱到谁都观察， If you were to look at each person individually, one by one,
那你将会很难做到。 you would have a hard time
捕捉射手电光火石的一瞬间， finding the person who happens to be taking a flash photo.
菲利潘科增加了他的发现几率。 Filippenko increases his odds
他的观测目标不是单颗恒星， by expanding his search beyond single stars,
甚至不是单个星系。 or even single galaxies.
想要成功他必须依赖一名高科技助手， To do this he enlists the help of a very high-tech assistant.
这是一台机器搜索引擎， So this is a robotic search engine
探寻爆炸的恒星超新星， for exploding stars, supernovae.
它被编程为每个夜晚机械性地， It has been programmed to robotically take photographs
拍下超过1000个星系的照片。 of over a thousand galaxies a night,
那么一星期就能拍下7000到8000个星系的照片， and over the course of a week it does 7 or 8,000 galaxies,
然后重演过程， and then it repeats the process
通过把星系的新照片对比老照片。 comparing the new pictures of each galaxy with old pictures.
通常两张照片前后没啥变化，但偶然地 Usually there's nothing new in the new picture, but occasionally,
一颗恒星爆炸了超新星诞生了。 a star blows up, a supernova goes off.
然后你在新照片那里就会发现一个亮点， And then you can see in the new picture a bright point of light
老照片就没亮点， that wasn't there in any the old pictures.
尽管超新星非常非常之亮。 Though a supernova is visually very, very bright,
但可见光只占其总能量的百分之一的百分之一， the visible light is only one percent of one percent of the total energy.
也就是巨大的爆炸发射的总能量的万分之一。 1/10,000 of the entire energy emitted by this colossal explosion.
尽管IA超新星是由白矮星演变而来， Although type IA supernovas come from exploding white dwarfs,
还有其他许多被称为第二类超新星， many others, known as Type II supernovas,
标志着更大质量恒星的戏剧性死亡。 signal the dramatic deaths of much more massive stars,
也许质量比我们的太阳大8倍到10倍， perhaps 8 or 10 times more massive than the Sun.
不像他们的小辈们。 Unlike their smaller cousins,
大质量恒星耗尽氢燃料时， when massive stars exhaust their hydrogen fuel,
他们有原始动力聚变其他元素。 they have the raw power to start fusing other elements.
每次核反应留下的灰烬成为下次反应的燃料， The ashes of each set of nuclear reactions become fuel for the next,
所以在生命尽头时大质量恒星好比洋葱， so that near the end of its life, a massive star resembles an onion
一环包着一环最外层是原始燃料氢， in cross-section, with an outer layer of the original fuel, hydrogen,
包围着里面一层更比一层重的元素。 surrounding layer after layer of heavier and heavier elements.
它的生命历程先是氢聚变成氦， It goes through its normal life fusing hydrogen into helium,
然后氦聚变成碳和氧， then helium into carbon and oxygen,
氧再聚变成氖和镁， then oxygen into neon and magnesium,
再聚变成硅和硫... and then silicon and sulfur...
再聚变成铁。大质量恒星制造了一个铁核心。 And then, iron. The massive star builds up a core of iron.
铁聚变成更重元素的过程， The fusion of iron into heavier elements
对恒星没有任何好处，不能保持恒星内部炙热。 doesn't do the star any good, it doesn't keep the star hot inside,
因为把铁聚变成更重的元素， because fusion of iron into heavier elements
需要吸收能量而非释放能量。 requires energy and absorbs energy, it doesn't liberate energy.
所以铁核的形成没有聚变参与其中， So the iron core builds up without fusing,
最终会变得不稳定。 and eventually becomes unstable,
一旦铁核达到太阳1.5倍质量时就会崩溃， one it reaches something like 1.5 times the mass of our Sun, it collapses.
这种崩溃能量肆虐， And the collapse is violent.
半秒内地球大小的铁核， Within half a second a core the size of the Earth
就坍缩成直径只有大约10英里。 is crushed into an object roughly 10 miles across.
崩溃的铁核还会再度反弹， For a moment the collapsing core rebounds,
撞击恒星的外层， smashing into the outer layers of the star,
足以和宇宙最大的爆炸媲美。 and kicking off one of the most massive explosions in our Universe
自大爆炸以来， since the Big Bang.
铁核的坍缩， The collapse of the iron core
在毁灭性的爆炸中使得恒星其他部分灰飞烟灭， blows apart the rest of the star in a colossal explosion.
真是难以置信的奇观。 It's truly an amazing, incredible event.
科学家深信超新星的爆炸对宇宙而言， Scientists are convinced that supernovas mean much more to the Universe
不仅仅是几道闪光， than spectacular light shows.
这就是我们身边组成万物的重元素 They are in fact the source of the heavy elements
的来源。 that make up everything around us.
这个铸造厂生产的所有铁， All of the iron in this foundry
都来源于恒星爆炸剧烈的大爆炸。 came from exploding stars, from gigantic explosions.
所有一切你现在看到的所有铁都来源于恒星爆炸。 All of it. All the iron you see everywhere came from exploding stars.
事实上所有比铁更重的元素， And, in fact, all the elements heavier than iron
都直接或间接地来源于恒星爆炸。 directly or indirectly were made by exploding stars.
这些元素被庞大的爆炸吹散到宇宙的四面八方。 And those elements were ejected into the cosmos by these gargantuan explosions.
随着这些爆炸的产物， As material from these explosions
散播到整个宇宙，它又组成了 spread out through the Universe, it became the stuff of
行星、卫星、新恒星甚至更奇特的东西... planets, moons, new stars and something even more extraordinary...
要是你能把你的族谱追溯到最早， If you could trace your ancestry back to its earliest reaches,
你会发现你的祖宗就是爆炸的恒星。 you would find an exploding star in your family tree.
我们的身体就是由恒星物质或星尘组成。 We are essentially made of star stuff, or stardust,
正如卡尔萨根常说的那样， as Carl Sagan used to say.
你身体内的元素并不平凡而是特殊， The elements in your body, not just generically, but specifically,
你身体内比氢和氦重的元素， the elements in your body heavier than hydrogen and helium,
来自很久以前死亡的恒星。 came from long-dead stars.
你骨头里的钙呼吸的氧气， The calcium in your bones, the oxygen that you breathe,
红细胞里的铁大多数细胞里的碳... the iron in your red bloodcells, the carbon in most of your cells...
所有这些元素都来源于恒星内部的核反应， all those things were created in stars through nuclear reactions,
然后再被超新星发射出去。 and then ejected by supernovae.
最重的元素铁以及排在其后的元素， And the heaviest elements, iron and above,
都是由他们自己的爆炸超新星产生的。 were produced by the explosions themselves, by the supernovae.
当第二类超新星爆炸， While the explosion of a Type II supernova
给全宇宙沐浴着重元素时， showers the Universe with heavy elements,
爆炸恒星的核心还完好无损。 the core of the exploding star is left intact.
引力的使命就是摧毁它， Destroying that is gravity's job.
但想要使得比白矮星还小的核心坍缩， But to crush the core any smaller than the size of a white dwarf,
就必须征服那股神奇的力电子简并压力。 it will have to overcome that strange force, electron degeneracy pressure.
引力其实有办法征服 Gravity actually finds a way of defeating
电子间互相排斥的趋势。 that tendency the electrons have to push each other apart,
通过把电子和质子融合形成中子， by combining the electrons with the protons and turning them into neutrons.
现在整个物体基本全是由中子组成的。 You now have an object which is made almost entirely out of neutrons,
引力获胜了整个系统能够进一步坍缩， and gravity wins, it now allows the system to collapse further,
没有电子阻挡， there're no longer electrons stopping that,
引力似乎稳操胜券。 and gravity seems to win.
除了...中子他们好像同样不喜欢对方， Except... neutrons, it turns out, also don't like each other,
结果演变成一个不能再小的稳定物体， and you end up with a new stable object even smaller,
密度更大称为”中子星”。 even more dense called a "Neutron Star".
比起普通的恒星中子星就是宇宙中的石子 Compared to normal stars, neutron stars are cosmic pebbles.
小到直径只有10英里 They can be as small as 10 miles across.
想象一下一颗比我们太阳大1.5倍的恒星， So imagine that you take a star about 1.5 times the size of our Sun
把里面所有的物质压缩到一个极小的空间， and then you compress all that material down into a very small space,
大约曼哈顿的大小， about the size of Manhattan.
中子星就这样诞生了。 You just made yourself a neutron star.
把如此巨量的物质压缩到小小的空间， Squeezing that amount of mass into such a small space
创造了一个密度超高的物体， makes for an extremely dense object.
一调羹中子星的物质重达十亿吨。 One teaspoon full of neutron star material would weigh a billion tons.
中子星是天文学家在宇宙中 Neutron stars are some of the most exciting
研究的最激动人心，最怪异迷幻的天体。 and weird objects in the Universe that astronomers study.
要是一个人站立在中子星上， If a human being were to stand on a neutron star,
那他的感觉会极为不适， it would be a somewhat uncomfortable experience.
在地球上如果他们重150磅那么在中子星上， On Earth, if they weighed about 150 lbs. on a neutron star they would weigh
他们将会重达100亿吨。 something like 10 billion tons.
我们的生物体承受不住这等压力， Our biology can't stand that amount of pressure
那么人体一定会被压成馅饼。 and so, a human being would essentially be squashed flat
在中子星的表面上， against the surface of the star.
此外中子星的自转速度难以置信的快， In addition to that, neutron stars are spinning at an incredibly high rate.
有些甚至能达到每秒几百圈。 Hundreds of times per second in some cases.
正是这种高速自转， It's this rapid spin
使得天文学家能够初步判断中子星。 that enabled astronomers to first identify neutron stars.
有些中子星真的自转很快， Some neutron stars are spinning really rapidly,
它们的磁场能量难以置信的高。 and they have a really amazingly high magnetic field.
磁场连同自转， That magnetic field, together with the spin,
迫使一束带电粒子电子 forces a bunch of charged particles, electrons,
沿着其磁场感应线运动， to go along the axis of the magnetic field.
加速着电子放电的过程 And those accelerated electrons give off light,
形成一道极为致密的光亮。 they produce a very focussed beam of light.
这就好比一座昼夜不息的灯塔， Now, this is like a lighthouse whose beam is always on,
但是你只能 but you only see it
在灯塔光线进入你视野时看见它， when the lighthouse beam intersects your line of sight.
也就是是你能够看见中子星， In a similar way, we might see the shining neutron star
只有当它把光线照向你时。 only when the beam points at us.
这种天体称之为“脉冲星”。 That object is called a "Pulsar".
有些恒星质量之高大约是太阳质量的25倍或40倍。 Some stars are so massive, perhaps 25 or 40 times the mass of the Sun,
就算是中子星也不能承受它们崩溃时自己的重量。 that not even a neutron star can hold up under the weight of their collapse,
引力使之进一步坍缩， and gravity will crash them even further,
变得密度出奇的大， into an object of infinite density
甚至密度几乎是无限大: and almost equally limitless fascination:
黑洞。 a Black Hole.
可以说黑洞是恒星最顶级的死法。 In some sense, a black hole represents the ultimate death of a star.
黑洞就是引力彻底完胜质量， A black hole is basically gravity's victory over mass.
是恒星大质量恒星的完全坍缩。 It is complete collapse of a star, a very massive star.
这种崩溃创造了一隅之地， This collapse creates a region of space
那里物质被压缩到如此大的密度， where matter is compressed into such a high density
它的引力场无法被挣脱。 that its gravitational field is inescapable.
黑洞真是奇异没有任何物体能逃脱那里， Black holes are remarkable and nothing can escape from them,
甚至连我们已知的最高速物体光都无法逃脱。 not even the fastest moving thing we know of, which is light.
你向那里打个手电筒， You shine a flashlight beam up
连光线都无法反射回来。 and even it won't leave,
光线会被弯曲到黑洞里， the beam will curve back around.
所以你无法从外界观察黑洞。 So, you won't be able to see it from the outside.
因此得名“黑洞”。 Hence the name "black hole".
一个普遍的误解是， A common misperception
黑洞只是把宇宙万物使劲往里吸， is that black holes just go sucking up everything in the Universe.
就好像宇宙真空吸尘器， Like cosmic vacuum cleaners
把附近所有东西吸进去。 sucking up everything in their vicinity.
这其实不是真的， That's actually not true.
离黑洞很近的物体的确会被吸进去， Now, objects that are very close to black holes do get sucked in,
但假如你离黑洞足够远的话， but if you're comfortably far away,
运行轨迹合适的话就不会被吸进去。 with the proper trajectory you won't get sucked in.
科学家长期怀疑是否还有另一类超新星， Scientists have long suspected that there is yet another class of supernova
是更大质量恒星的更剧烈爆炸产生的。 involving even bigger stars and even more powerful explosions.
这种崩溃具有如此灾难性， Stars that collapse so catastrophically
以至于没有留下任何残留物甚至黑洞也没留下。 that they leave behind no remnant, not even a black hole.
但直到现在，还没有人 But no one had ever seen one
亲眼看见过。 until now.
已经诞生了几十亿年， Even after billions of years,
但宇宙的原始动力仍使我们叹为观止。 the Universe is still surprising us with its raw power.
在2006年秋天， In the fall of 2006,
天文学家观测到人类目睹的最大的 astronomers observed the largest stellar explosion
星体爆炸， ever witnessed by Man.
远离地球24亿光年， 240 million light years away from Earth,
一颗大质量恒星自爆了。 a massive star blew itself apart.
亚历克·菲利潘科和他加利福尼亚大学伯克利实验室的团队， Alex Filippenko and his team at the University of California, Berkeley,
被那次爆炸的威力征服了， were amazed at the power of the explosion.
发射的总能量有普通恒星爆炸 And the total energy emitted was 100 times as much
产生的能量100倍之多。 as the energy of a normal massive explosion.
那真是神奇威力无穷的大爆炸。 It's an amazing, really powerful explosion.
这里说的”普通”恒星爆炸其留下的超新星， A normal supernova comes from the explosion of a star
有我们太阳的10倍物质。 10 times more massive than our Sun.
难以置信的是超新星2006GY，天文学家推测 Incredibly, supernova 2006GY, as astronomers have dubbed it,
似乎是一颗比太阳大150倍甚至200倍的 seems to have signalled the death of a star
恒星死亡而来。 150, or even 200 times more massive.
最大的恒星莫过于此， That's about as massive as a star can get.
科学家仍在研究这次爆炸的后果， Scientists are still studying the aftermath of the explosion,
但他们认为超新星2006GY but they think supernova 2006GY
给我们留下许多参考。 has a lot to teach us
关于我们宇宙诞生的首批恒星， about the first stars that populated our Universe.
我们普遍认为第一代的恒星， We actually think that the first generation of stars
都是超大质量的。 tended to be really massive.
他们的爆炸可能就是这种机理， And they probably exploded by this mechanism.
正是这种超级爆炸， It's these mega-explosions
给早期的宇宙播种了重元素。 that likely seeded the early Universe with heavy elements.
这些超大质量恒星， These extremely massive stars
就是宇宙最大的炼钢厂。 are the largest iron factories in the Universe.
仅仅一颗150倍太阳质量的恒星， A single star, 150 times the mass of the Sun,
就能制造20-25倍太阳质量的铁， can produce 20 or 25 solar masses of iron.
真是不可思议。 It's incredible.
生命的周而复始不仅发生在地球也发生在宇宙。 In the cycle of life, not only here on Earth but in the Cosmos,
当恒星死亡时，尤其是那些死得惊天动地的 as stars die, particularly those that die spectacular deaths,
大质量恒星， the high mass stars that manufactured
在核心制造重元素， heavy elements in their cores,
这就为新一代恒星的诞生播种然后... those give the seeds of the next generations of stars that then...
增加了 increased the likelihood
下一代恒星可能拥有行星的可能性。 that that next generation will have planets,
这些行星能够自给自足。 and planets that contain ingredients of life itself.
超新星不仅是恒星诞生消亡的能量运动， Supernovas aren't the only energetic events in the life and death of a star.
现在整个宇宙有千余对恒星， Right now, across the Universe, there're a thousand pairs of stars
在火焰的舞蹈中订婚， engaged in brilliant dances of fire.
某些舞蹈可能会以灾难告终。 For some this dance will end in catastrophe.
天体物理学家约书亚·巴恩斯来自夏威夷大学， Astrophysicist Joshua Barnes of the University of Hawaii,
专门研究恒星相撞的后果。 studies what happens when stars collide.
我们没有荣幸能一睹恒星相撞， We don't have the luxury of watching stars collide.
一对靠得足够近的恒星相撞时， A pair of stars as they draw close enough to collide
即使用我们最大的望远镜观察， would just be a single dot of light,
也就是一个亮点而已。 even in the largest telescopes that we have.
所以我们必须用计算机探索这些目标， So, we need to investigate these things with a computer.
利用电脑模型， Using computer models,
天体物理学家就能设定任意两种恒星， astrophysicists can take any two types of stars
看看他们的星际撞击会造成什么后果。 and find out what happens if they become involved in a stellar smash-up.
这些模型假设了状况，然后我们就观察结果。 The models pose hypothetical situations and then see what happens.
你可以把这想象成研究汽车相撞， And you can sort of imagine this is like studying collisions of cars,
你把车面对面放在停车场互相撞击， and you were taking them out and smashing them together in the parking lot,
二虎相争看看结果如何？ one after the other to see what came out of that.
天体物理学家建立的模型中，最具破坏力的相撞 Among the most explosive collisions modelled by astrophysicists
就是两颗共同转动的中子星的相撞。 is the clash of two orbiting neutron stars.
通常他们的关系就是互相绕着对方转动， Typically, they're bound together as a pair orbiting one another
当他们转动时打乱了周围的时空， and as they orbit they disturb the space-time* around them
创造了能量波， and create waves of energy.
这种能量波使得中子星减速， And the energy to do that slows the stars down,
这样他们离对方就越来越近， so they get closer and closer together.
当他们靠近到一定程度时他们的转速， As they get really close together, they're orbiting around
达到每秒上百转甚至上千转。 hundreds or even thousands times per second.
最后的结果非常戏剧性， The final event is very dramatic.
当两颗中子星相撞时他们的速度接近光速， When two neutron stars collide, they're moving at nearly the speed of light.
虽然最后的撞击过程只有0点几秒， Although the final collision takes only a fraction of a second,
其释放的能量比太阳一辈子创造的能量还多得多。 it unleashes more energy than the Sun will generate in its entire lifetime.
多亏了电脑模型，我们能预测出 Thanks to computer modelling we can also predict what would happen
如果一颗高密度白矮星和太阳相撞时会发生什么？ if a highly dense white dwarf collided with our Sun.
那将是惊天动地的撞击。 It would be a frightening collision.
靠近到一定程度时，白矮星的引力场 When it got close enough, the gravitational field of the white dwarf
就会扭曲太阳太阳不再是球体了， would start to distort the Sun, so it would no longer remain a sphere,
靠近时太阳的形状变得像个鸡蛋， it would turn into an egg-shape as this thing came close.
随着白矮星以超音速撞击太阳， As the white dwarf ploughs into the Sun at supersonic speed,
它的引力就会在整颗星球产生一道巨大的冲击波， its gravity would send an enormous shockwave throughout the star.
释放出如此巨大的热核能， And that would produce so much thermonuclear energy
最终引爆太阳。 to, essentially, explode the Sun.
令人惊奇的是只需仅仅1个小时， Amazingly, it would take only about an hour
白矮星就能撞击并歼灭太阳。 for the white dwarf to plough through the Sun and annihilate it.
要是殃及池鱼，地球就会生灵涂炭。 If this scenario came to pass, life on Earth would be doomed.
所幸的是这种可能性微乎其微， Fortunately, the chances of this happening are slim,
因为太阳居住在银河系的穷乡僻壤， because the Sun is in a very uncrowded part of the Milky Way.
单颗恒星可谓孤家寡人。 Individual stars are kind of jostling and weaving
当他们绕着银河系中心转一个大圈， as they make their great circuit around the galactic centre.
交通状况虽然复杂， So, it's a complicated traffic situation,
但由于恒星间的距离足够的大， but because the space between the stars is so great
撞击可能性就很小。 there's not much chance of a collision.
你要是想躺在沙滩上，静候着太阳和另一颗恒星 If you were to wait out here on this beach until you saw the collision
互相撞击那可真是守株待兔。 between the Sun and another Star, you would wait a long time.
终其一生，太阳大约 Even over its entire life, the Sun has probably
只有10亿分之一的几率和另一颗恒星相撞。 a billion in one chance of colliding with another star.
但星系里某些地方， But there are places within galaxies
恒星撞击的可能性就相当大。 where the odds of a collision are much greater.
那里成百上千甚至几百万恒星， Regions where hundreds of thousands or even millions of stars
被引力聚到一块形成球状星团， are crowded together by gravity into a globular cluster.
与银河系的螺旋臂相比， Compared to the spiral arms of the Milky Way,
球状星团就好比碰碰车场。 a globular cluster is like a demolition derby.
银河系螺旋臂处2颗恒星的撞击几率， The odds of two stars colliding in the spiral arms of our galaxy
只有10亿分之一。 are only about one in a billion.
但在球状星团里恒星， But within a globular cluster, stars are packed
比银河系其他地方密集100万倍。 a million times more densely than elsewhere in the Milky way.
在银河系大家都朝一个方向运动， In the Milky Way everybody is pretty much going in the same direction,
但球状星团里全是无规则运动， but in a globular cluster there's no organized motion.
他们都围绕着一个中心转， They're basically all orbiting around the centre
他们的轨道方向各不相同， on orbits that are aligned in all sorts of different directions,
有些朝一个方向运动另一些正好反方向... so some are going one way, some are going the opposite way...
在这种无序混沌的情况下恒星撞击几率， In these crowded, chaotic conditions stars collide on average
平均1万年发生一次。 once every 10,000 years.
星团内部的恒星大概是在相同时间段诞生的， Every star in a cluster was born at roughly the same time,
所以当天文学家观察一个老龄星团时， so when astronomers look at an old cluster
别指望能发现任何年轻的恒星。 they don't expect to see any young stars,
但奇怪的是球状星团通常掩盖着一些神秘的陌生人， but strangely a globular cluster usually conceals some mysterious strangers.
巨大的蓝色恒星远远比周围那些小小的昏暗恒星年轻， Large blue stars, far younger than the small dim stars surrounding them.
这些不可思议的恒星， These seemingly impossible stars
被称为“蓝掉队星”。 are known as "Blue Stragglers".
蓝掉队星的神秘之处是， The mystery of blue stragglers is that they're,
比他们本该有的年龄小， in some sense, younger than they have any right to be.
拥有如此质量和光亮的恒星， All of the stars of that mass and that luminosity
在这些星团里本该几十亿前就消亡了。 would have died off billions of years ago in these clusters,
谜团是它们从何而来， so the puzzle is, where do these things come from,
当初如何进入球状星团， how did they get into the star clusters.
天体物理学家约书亚·巴恩斯认为自己知道答案。 Astrophysicist Joshua Barnes thinks he knows the answer.
他认为蓝掉队星是二颗年老 He believes blue stragglers are the result of collisions
昏暗主序恒星相撞后的产物。 between older and dimmer main sequence stars.
2颗主序恒星的相撞， A collision of two main sequence stars,
比如两颗太阳那样的恒星撞击其实相对轻微， two Sun-like stars, is actually relatively gentle.
恒星互相间的引力把自己锁在自螺旋内， The mutual gravity of the stars locks them in a spiral.
它们会失去动能，最终会回归 They've lost energy of motion and they will come back
然后多次相遇， and have multiple subsequent passages.
温度上升变得红肿有点互相绕着对方旋转， They heat up and swell up and kind of spiral around each other,
相遇几次， making several passes,
每次相遇距离被拉近， each closer than the last one,
直到最后融合成一颗恒星， until they finally come together and the stars merge.
最后并非引爆一场大灾难。 In the end, rather than triggering a catastrophe,
两颗恒星互相融合形成一个更大质量的恒星， the two stars merge to form one more massive star.
你要做的就是把两颗小体积老年恒星， What you're basically doing is taking two small old stars,
把他们捆在一起并成为一颗2倍质量的恒星。 piling* them together to make one star now which is twice as massive,
因此质量更大亮度越高更蓝， and therefore being more massive it's brighter and bluer
比起星团内其他恒星而言， than the rest of the stars in the cluster.
所以它似乎没跟上其他恒星的脚步， So it seems to be straggling behind the rest of the stars.
蓝掉队星之谜似乎被解开了。 While the mystery of the blue stragglers seems to have been solved,
天空中还有很多不同寻常的天体， the heavens are bursting with unusual objects
大胆的科学推测也难以解释。 that dare science to explain them.
黑洞中子星白矮星， Black holes, neutron stars and white dwarfs,
都代表着风光一时的恒星消亡。 all represent the end of remarkable stellar lives.
但有些天体一辈子也没机会发出光亮， But there are other strange celestial objects that never got a chance to shine.
不是行星也不是恒星，这些是灰矮星。 Not quite planets, not quite stars, these are the brown dwarfs.
灰矮星是一颗报废的恒星。 A brown dwarf is basically a failed star.
夏威夷大学的天文学家刘·迈克尔搜寻着这些难以捉摸的物体。 University of Hawaii astronomer Michael Liu, searches for these elusive objects.
只要恒星能放出大量光线，它们就内在很远处被观测到。 Stars produce a lot of light, they're very easy to see a long way away.
灰矮星的温度非常低， The brown dwarfs are very low temperature
所以只发出一点点光线。 so they emit very, very little light.
正因为它们如此暗淡，也就是说 Because they're so dim, it means
我们只有在近距离才能看到它们。 we can only see them if they're very close to us.
灰矮星的物质成分和恒星一样， A brown dwarf has the same ingredients as a star,
只不过它没有足够的物质维持核聚变。 but it simply doesn't have enough mass to sustain nuclear fusion.
它诞生之初质量就不到太阳的百分之一， It's something that's borne with less than 1% the mass of the Sun,
所以不能给自己创造足够的能量， so it can't produce its own energy,
本质上就是报废的恒星。 it's essentially a failed star.
没有核聚变，这些报废的恒星更像是行星。 Without fusion, these failed stars start to act more like planets.
假如你乘坐太空飞船飞过灰矮星表面， If you were flying in a spaceship across the surface of the star,
你不会看到任何像是 you wouldn't really see anything that looked like
云、山之类的景物。 clouds or mountains or anything like that.
当你进入灰矮星一切就变了， When you go to a brown dwarf things begin to change.
我们认为灰矮星的大气层 We think their atmospheres in some ways might be similar
类似于大质量行星，比如木星的大气层。 to things like very massive versions of the planet Jupiter.
要是你熟悉木星的照片， If you're familiar with pictures of Jupiter
你就会看见木星带状结构及其表面的云层。 you see Jupiter has also a banding structure and clouds on its surface.
虽然我们从未拍摄到灰矮星表面的照片， Although we've never taken a picture of the surface of a brown dwarf,
我们认为灰矮星有着类似的云层结构。 we think brown dwarfs may also have a similar cloud structure.
这些不是我们地球上那种通常的云层， These aren't normal kinds of clouds like we know about on the Earth,
铁蒸汽组成了这些云层， you have iron vapour making these clouds,
然后云层的厚度到达一定程度， and then the clouds may get thick enough
这些云竟然会下起铁雨。 that you get iron droplets raining out of the clouds.
显然没人愿意住在那里，因为那可是融化的铁。 Obviously a person wouldn't want to be there 'cause these are molten iron.
至今为止科学家们仅仅发现了200多颗灰矮星， To date astronomers have located only a couple hundred brown dwarfs,
这些难以捉摸的星体仍有许多未解之谜， and they still have many questions about these elusive objects.
问题是科学家知道有些灰矮星 For one, they know some brown dwarfs
周围环绕着碟状的尘埃和气体， have discs of dust and gas around them.
这些碟状物是否会演化成行星? Might those discs form into planets?
这还只是众多未解之谜的冰山一角。 That's just one of many mysteries yet to be solved
随着我们继续探究恒星， as we continue to probe the stars.
现在科学家们已经揭示了宇宙是一个魔幻领域， But already, science has revealed the Universe to be a magical realm
里面有着矮星、巨星、掉队星和超新星 of dwarfs and giants, stragglers and supernovas,
隐藏在恒星爆炸的历史中。 and hidden within the explosive life story of stars
他们已经发现了宇宙历史许多篇章， they have found the very history of the Cosmos,
谢谢观赏 Thanks For Viewing
以及探寻我们起源的钥匙。 and a key to understanding our own origins.