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最终毁灭地球的会是什么? – 译学馆
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最终毁灭地球的会是什么?

What Will Destroy Planet Earth? | Space Time | PBS Digital Studios

有一大堆不愉快的事情包括核战争和小行星撞击
Lots of unpleasant things from nuclear war to asteroid impacts
会毁灭地球上的生命
could destroy life on Earth.
但是对于地球她自己呢?
But what about Earth itself?
是否有东西能毁灭这个星球
Will anything ever destroy this planet?
播放音乐
[MUSIC PLAYING]
毁灭包括行星在内的某些东西的物理条件
The physics of breaking something, including planets,
非常简单,只要增加能量
is pretty straightforward– just add enough energy
让一个物体克服引力
to the individual chunks to overcome the attractive forces
撞上去
gluing them together.
现在针对地球来说,他主体的总
Now in the case of Earth, the main glue
重量大概是6*10的24次方
is the collective gravity of almost six septillion kilograms
千克
of mass.
所以撞击物应该是有巨大能量的。(原文obscene)
So separating the chunks takes an orb scene amount of energy.
到底有多少呢
How much?
大概相当于地表在
About as much solar energy as a whole Earth
4000万年接收能量的总和
receives over 40 million years.
你如果仅仅想把地球劈成两半
Now if you just want to split Earth in half,
能给你打个折,只要1600万年
you get a bit of a discount– only 16 million years
吸收阳光的总和
worth of sunshine.
那么实际上,到底有什么我们已知的东西能对地球释放
So realistically, could anything deliver that much energy
这么多能量来终结这个星球
to Earth and end the planet as we know it?
我们来回顾下一些可能性
Let’s review some possibilities, starting
在你脑子里可能有
with one that has probably crossed your mind
一样东西-核武器
at some point– nukes.
我们能不能用核武器把这个星球炸成碎片
Could we nuke the planet to bits?
我查了下已有的最有威力核武器
I looked up the most powerful nuke ever built.
是19世纪60年代苏联的 Tsar
It was the Soviet Tsar-Bomb from the 1960s.
在实验中,他释放了相当于
When test detonated, it released the equivalent
5000万吨TNT炸药的能量
of 50 megatons of TNT, give or take.
在俄罗斯的北部,这些能量足把
That was enough energy to level everything
方圆20英里夷为平地
for more than 20 miles in every direction in northern Russia
甚至把几百英里外芬兰的一些
and even shattered windows hundreds of miles
窗户都震碎了
away in Finland.
我算了一下
So I did some arithmetic.
要破坏这颗星球,你大概需要——坐稳了哈
To wreck the planet, you’d need– are you ready
超过一千万亿颗Tsar炸弹
for this– over one quadrillion Tsar-Bombs.
地球上有那么多的铀可供开采吗
Is there even enough mineable uranium on Earth for that?
当然没有,但假设有
Almost certainly no, but even if there was,
人类也没有时间更没有兴趣
humanity has neither the time nor inclination to make
去提炼亿万分之一的铀
one quadrillion of anything.
我知道所有YouTube
I mean, all of YouTube is estimated
所有视频上传者 一共才有几亿
to host only a few hundred million videos in total.
所以我们能用核弹把地球炸成不毛之地吗
So can we nuke your Earth to a barren wasteland?
绝对可以
Absolutely.
但是能炸成碎片吗
But can we nuke it to pieces?
差的远呢
Not even close.
下面,我们研究下另一个可能性 -小行星
So let’s move on to the next obvious suspect– asteroids.
对不起,小盆友,能量也不够啊
Sorry, kids, also not enough energy.
让我给你们解释解释
Let me give you some context.
恐龙的灭绝者可能相当于
The supposed dinosaur killer was the equivalent
大概一百万Tsar核弹爆炸,那是一个巨大的能量
of about one million Tsar-Bomb detonations, which is huge
但是这对于搞定地球所需的能量来说只是其
but still only one billionth of the energy needed
十亿分之一
to blow up a planet.
甚至小行星中最最大,
Even 4-Vesta, the biggest object that’s
的4-Vesta,只有
still classified as an asteroid, would only
必须能量的0.5%
carry about half a percent of the required energy.
问题是速度
The issue is speed.
为了毁灭地球,4-Vesta得
To destroy Earth, 4-Vesta would have
按着700km/秒的速度撞来
to hurtle toward it at 700 kilometers per second–
相当于在5秒内从纽约移动到
or fast enough to get from New York to LA
洛杉矶
in under five seconds.
但小行星运动的的速度仅是他的
But asteroids orbit the sun about 35 times slower
35分之1
than that.
实际上能进入我们的轨道撞击地球的
In fact, a head-on collision between Earth
太阳系的任何物体
and any solar system object deflected into our path
最大速度顶多是70-80km/秒
will top out at a mere 70 to 80 kilometers per second.
现在,凭借这种速度,某个物体想要有足够的能量
Now with those speeds, an object could only carry enough energy
摧毁地球的话就得有巨大的质量
to destroy Earth if it had a huge mass,
没有哪个小行星拥有
which asteroids don’t.
另外,地球驮着我
Planets, on the other hand, do– which brings
跟火星打个波儿
me to colliding with Mars.
我知道你们现在的想法
Now, I know what you’re thinking.
火星和地球公转轨道不同
Mars orbit outside Earth’s orbit,
怎么才能碰一起
so how could they collide?
好吧,地球和火星的引力
Well, Earth and Mars’ field gravitational
不光靠太阳,还有其他的行星
pulls not just from the sun, but also from the other plants–
和一些大点的小行星
and from big asteroids too.
目前,那些引力很小
Now, those extra tugs are tiny.
但,如果所有东西刚刚好在一条线上,然后超过几十亿
But if everything lines up just right, then over billions
年过去,他们也许能积累出足够的效果
of years, they could have a sizable cumulative effect
来改变他们的轨道
and distort those orbits.
强调下可能性
Emphasis on could.
据一篇报道描述
In a paper linked in the description,
一些法国物理学家做了2500个差别模拟实验
some French physicists ran 2,500 distinct simulations
太阳系经过几十亿年
of the solar system’s evolution over the next few billion
变化
years.
他们把初始设定改变一下
All they changed from one initial set up to another
把水星的位置挪动一米
was Mercury’s current position by about a meter.
好,这是太阳系的立体模型
OK, you know that diorama of the solar system
回到了你的五年级了
you made back in fifth grade?
99%的模拟实验都得到和现实情况一样的结果
99% of the simulation stay faithful to that.
但1%的结果,行星轨道
But in 1%, the inner planet orbits
运行到30亿年时,地球
stretch out after about three billion years and Earth
开始被金星和火星追上
starts doing drive-bys of Venus and Mars.
在一个模拟中,大概过40亿年时
In one simulation, about four billion years from now,
地球和火星发生了膨胀,膨胀能量足够
Earth and Mars actually collide with enough energy
触发这可怕的毁灭
to do serious structural damage.
所以火星冲撞是可能发生的,但到底可能不可能
So a Martian collision is possible, but is it likely?
这是一个难题
That’s a hard question to answer.
根据天气预测,我们知道
As in weather forecasting, you have a butterfly effect
有蝴蝶效应之说
situation that’s highly unpredictable.
我们只能说目前
All we can say for now is that death
因为星际碰撞而挂掉的可能性是存在的
by interplanetary headbutt isn’t ruled out.
当然,笨蛋般的碰撞不是摧毁物体的唯一方法
Of course, hulk smash isn’t the only way to destroy something.
你也能用个白瑞特煎锅把它煎了
You can also cook it into a blinq pan
比如,地球跑到太阳上去了
For instance, if Earth enters the sun.
嗯,大概50亿年内
All right, in about five billion years,
太阳将会变成
the sun will begin its transition
一个红巨星,不停膨胀,直到
into a red giant– inflating until it
比地球目前的轨道大一点点
becomes slightly larger than Earth’s entire current orbit.
现在,如果地球位置不变,太阳不停膨胀
Now if Earth stays where it is now, during that growth spurt,
我们将被吞噬
we get swallowed up.
然后就没有然后了
And it’s game over.
好吧,然后,另一片报道说
See, another paper in the description
几百万年内一个好像是地球行星在
works out that an Earth-like planet in a solar atmosphere
太阳的大气层中被烧干净了
would vaporize after a few million years.
地球就成了烤面包,是吧
So the Earth is toast, right?
呵呵,事情没那么简单,因为
Well, it’s not that simple because there’s
有制约效应
a competing effect.
看,膨胀的太阳会造成强大的太阳风
See, the growing sun will also develop a stronger solar wind
将大量的太阳上的物质喷射向宇宙
that sprays a lot of the sun’s material out into space.
在这一过程中,太阳将会失去巨大的质量
In the process, the sun will lose a lot of mass
引力也讲减小,然后地球运行轨道
and a lot of gravitational pull, causing Earth’s orbit
也会变大
to actually grow.
几十年内,地球是否会被太阳吞噬
For decades, whether Earth will be swallowed by the sun or not
会一直争论下去
has been too close to call.
天文学家已经在孜孜不倦的寻找答案了
Astronomers have gone back and forth on the answer.
但据最新模拟实验表示
But the best recent simulations show
地球将会在太阳上烧烤而挂掉
that Earth will end up just inside the sun and fry.
目前,和原来差不多,最严谨的观点是
Now, as always, it’s prudent to see whether that answer holds
看以后模拟实验的结果
up under future simulations.
但好像被丢进去烧烤是不可避免的
But slow roasting into iron vapor seems fairly unavoidable.
说来惭愧,好像
Which is a shame, because it means
地球不太可能因为
earth is unlikely to face one final destruction
我们正在讨论的方法而毁灭
scenario that we’re going to talk about anyway
只源于最最纯粹,最最精彩的死法-
just because of the sheer awesomeness factor– death
宇宙膨胀
by expanding universe.
这是肯定的
Here’s the deal.
目前,宇宙正在膨胀
Currently, the universe is expanding
并且膨胀速度
and currently that expansion is speeding
在加速,只源于一种神秘的物质在渗透
up due to an unidentified material permeating
整个宇宙,物理学家称之为,暗物质
the cosmos that physicists have dubbed ‘dark energy’.
研究这个过程是很有意义的,它的扩展
It’s useful to think of that process– the expansion–
不像各个星系是空间距离上的远离,而是取代
not as galaxies flying apart through space, but instead
遥远星系之间的空间拉伸
as the space between distant galaxies
就像松紧带
stretching, like spandex.
注意,你我都还生存在地球上
Note that the Earth and you and I stay in one piece
是因为星系内的空间
because the space inside galaxies
至少目前还没有拉伸
is not stretching– at least not yet.
欧洲航天局的Planck卫星在其他任务之余,测量得知
See, ESA’s Planck satellite measured, among other things,
几个暗能量的性质
a few properties of this mysterious dark energy
他们能被运用到宇宙膨胀学说上
that can be used to do some space expansion forecasting.
这些测量数据,虽然不是决定性的
And those measurements, while not conclusive,
但能让物理学家想到一个可怕的场景-大撕裂
do allow for a scenario that physicists call The Big Rip.
根据Planck2014年的数据显示,自现在起1000亿年
Based on Planck’s 2014 data, sometime between 100 billion
或几万亿年后
and a few trillion years from now,
宇宙可能开始伸展,不仅速度更快
space could start to stretch– not just at faster rates,
但延伸区域越来越小
but on smaller and smaller scales.
发展到星系内部,在发展到星球级别
Inside galaxies, then inside planetary systems,
发展到行星内部,直到不能再小
inside planets themselves until littlely
所有东西都将被拉伸的空间拉扯,分离
everything in a universe is ripped apart
包括原子,原子核
by stretching space– atoms, nuclei,
甚至单个质子,一切一切
individual protons, everything.
现在我声明一下-我不是说大撕裂必然发生
Now, disclaimer– I’m not saying The Big Rip is inevitable.
未来如果按Ripley理论中发展,同样存在Planck常数的误差
A Ripley's future is also within Planck’s margin of error
大撕裂同样有问题
and The Big Rip scenario has other issues
这是包括我在内的很多物理学家所质疑的
that make a lot of physicists, including me, skeptical.
尽管如此,如果Planck最佳常数
Still, if Planck’s best-fit numbers
在未来的实验中被证实
do stand up to further experiments,
我是说,如果你全身的原子
I mean, having your atoms disassembled
被空间完全撕碎,这将是一种充满传奇色彩的方法
by space itself would be a pretty epic way to go.
就是这样
So there it is.
像勇敢的心里男猪脚那样被五马分尸
Being ripped to pieces like Braveheart
将是多么愉快的一件事啊,但地球可能
would be totally sweet, but Earth will probably
像圣女贞德一样被烧着,带着一直以来的风骚化为灰烬
burn up like Joan of Arc– which is still going out in style.
至此,你更喜欢地球按那种方式见上帝
Now, how would you prefer to have Earth meet its maker?
请在评论区留言
Let me know in the comments along
也可以写些地球毁灭的其他可能性
with any other viable scenarios for Earth destruction
我会挨个看的。不对,死星项目
that I might have overlooked– and no, the Death Star is not
是不可能的
a viable scenario.
我们在下期'宇宙时报'中将会看看大家都想到
We’ll see what you all came up with on the next episode
了什么
of ‘Space Time’.
最后,我们聊聊占领金星
Last time, we talked about occupying Venus,
这有太多东西要讲
and you guys had a lot to say.
Viridis Arborem指出金星
Viridis Arborem pointed out that Venus also
鼓舞了一种武术精神
inspired a martial art style– Venutian
合气道,前三任神秘博士的必杀技
Aikido– used by the third Doctor from Doctor Who.
我是'神秘博士'的粉丝
I’m kind of an old-school Whovian,
所以我深切怀念啊
so it cut deep that I missed that one.
再见
Good eye.
Katherine Daniel还有其他人
Katherine Daniel and lots of other people
说不管金星火星都
point out that it’s not necessarily either/or
无所谓
between Venus and Mars.
我完全同意
I fully agree.
但我们不得不先选一个
But we’re going to have to do one of them first,
这是更可行的方案
and it’s a question of which is more feasible.
Zevin X说真正的问题是行星主意
Zevin X points out that the real problem might be planetism.
也许我们该建立星际殖民地
Maybe we should be building floating colonies in space.
太伟大了,但我们应该研究基于现有科技的方法啊
That would be great, but it’s way beyond current technology.
Quite Likely说实际上我们不知道
Quite Likely points out that we don’t actually know how bad
地球人能适应火星的重力,我们确实不能
Martian gravity will be for humans, and we don’t.
真的
That’s true.
我只说过金星可能更适合
I only said that on Venus, it would be much less of an issue.
很多人争论锻炼能否
And for everyone who argued that exercise alone
恢复宇航员在太空中的骨密度
can recover the bone density astronauts
丢失-是可以恢复的
lose in space– it can recover the density,
但对于永久性的机构完整性
but the structural integrity seems
损坏是我们还
to be damaged in a permanent way that we don’t yet
不知道怎么恢复
know how to fix.
James Roach和很多人在Reddit
James Roach and a lot of people on the Reddit thread
说通过增加大气中的硫酸
bring up the sulfuric acid in the atmosphere.
看吧,大气中根本没有
Look, there’s not that much sulfuric acid
那么多硫酸
in the atmosphere.
硫酸是液态的
It’s droplets
倒是有大量的二氧化硫
There’s a lot of sulfur dioxide, but the sulfuric acid
但是硫酸只是大气中很微量的一种
is a tiny fraction of a percent of the entire Venutian
物质
atmosphere.
我是说,这些都在一个可控的水平上
All I said is that at those levels, it might be manageable.
Justin Stein,感谢你帮助其他人
And to Justin Stein, thanks for generally helping people
了解物理,了解真理
keep their physics and their facts straight.
我们感谢帮助
We appreciate the help.
嘟嘟嘟—嘟嘟嘟—-嘟嘟
[MUSIC PLAYING]

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