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太阳系五大未解之谜

5 Things We Still Don't Know About the Solar System

从宏观角度来看 我们在太空探索的时间并不长
In the grand scheme of things, we haven’t been at the space-exploration game very long,
但是我们已经了解到很多关于太阳系的知识
but we’ve already learned a ton about the solar system.
我们已经发射了探测器到一些行星还有小行星和彗星上面去
We’ve sent probes to planets and asteroids and comets.
我们知道它们是什么样子 由什么组成 温度和大气组成如何
We know what they look like, what they’re made of, their temperatures, atmospheres,
等等
and so much more.
但是你知道更令人惊叹的吗?
But you know what’s even more amazing?
我们不知道的一些事
What we don’t know.
事实上 在宇宙的角落中仍然有很多我们未解之谜
The truth is, there’s still a lot we don’t understand about our little corner of the universe
那么让我们看看太阳系中几个未解之谜:
So let’s look at just a few unsolved mysteries of the solar system.
1 什么导致太阳附有磁性?
[1: What causes the Sun’s magnetism?]
第一 太阳的磁场
First off, the Sun’s magnetic field.
磁场由内部运动的微粒产生
Magnetic fields everywhere are created by the movement of charged particles.
例如 地球核心内部由一系列的微粒形成
On Earth, for example, a flow of charged particles deep inside the outer core of our planet generates
磁场让你的指南针指向北方 并让你免受
the magnetic field that makes your compass point north, and protects us from dangerous
太阳辐射的伤害
solar radiation.
现在 我们知道太阳也有磁场
Now, we know that the Sun has a magnetic field too.
也许这并不让人惊讶
Maybe that’s not surprising.
毕竟 太阳由等离子组成 ——等离子是一种气体
After all, the Sun’s made of plasma—a kind of gas in which electrons and ions have separated
并且它无条件的转 是磁场的一个特性
and are free to move around — a recipe for a magnetic field.
但我们仍然不知道它究竟是怎样运行的 或者说它是怎样构成的
But we still don’t know exactly how it works, or where it forms.
它是从太阳表面开始的吗?还是说在太阳更深处
Does it start near the solar surface, or deep inside the Sun?
不同的层面到底是怎样相互作用的呢?
How do the different layers affect each other?
弄清这些事实 能帮助我们理解
Getting to the bottom of this matters, because it’ll help us understand everything from solar
太阳耀斑 北极光
flares, to the northern lights,.
宇航员火星之旅必须处理的辐射
to the radiation that astronauts will have to deal with while on their way to mars
能帮助我们预测其他行星上的磁场情况
Plus, it could help us predict what the magnetic fields of other stars might be like.
总之 解开太阳磁场的奥秘将帮助我们弄清
But above all, unlocking the secrets of the Sun’s magnetism will help us figure out
为什么行星如此…… 变化无常
why our star is so … inconsistent.
太阳活动周期为11年
The Sun follows an 11-year cycle.
太阳活动最剧烈的时候 太阳比以往更亮 ,耀斑和黑子也更多
At the peak of this cycle, the Sun is brighter, and there are more solar flares and sunspots.
我们把这称作“太阳活动峰期”
We call this peak the solar maximum.
但有趣的是 太阳的磁场会在周期内变化
But what’s interesting is the way the Sun’s magnetic field changes during the cycle.
越接近太阳活动峰期 太阳的磁场线就更混乱
The lines of its magnetic field get more and more messy as it nears the solar maximum,
接着发生一系列的爆炸——即日冕物质抛射 之后磁场线又变得有规律了
and then a series of explosions — known as coronal mass ejections — smooth it out again.
我们不如这样描述 :和地球磁场类似 磁场线从
The best we can tell, the field lines start out running straight from pole to pole, like
一极到另一极
they do on Earth.
紧接着 由于太阳的旋转 磁场线变得 像棉花糖一样混乱
But then, because of the Sun spinning, they get wrapped around it like cotton candy.
最终 这些磁场线不断拉伸然后像橡皮绳一样 崩断——
Eventually these stretched and pulled field lines “snap” like a rubber band stretched
这就是爆炸 然后磁场再回到开始的状态
too far, producing explosions and calming the field back down to where it started.
以上推论皆基于我们对太阳表面的观察
But all of this is based on what we can observe on the surface of the Sun.
所以我们无法知道这些现象是怎么从太阳内部
What we can’t figure out is how these phenomena are created by what’s happening beneath
发生的
the surface.
也许是由太阳表面的外层对流力量引起的
Maybe they’re caused by forces between the outer layers of the Sun that are churning
就像烧热水——水开了表面会沸腾 但里面动静不大
in convection currents, like pots of hot water, and the parts below them that aren’t.
也许他们更像自我对流的模式
Maybe it’s more about the motion in the convection currents themselves.
要弄清磁场到底是怎么发生的 我们还要做长期研究
We still have a long way to go before we’ll understand where exactly the field originates.
研究得越透彻 我们给出解释才更合理
To get our answers, we’ll need to look much deeper.
2 为什么金星和地球如此不同?
[2: Why is Venus so different to Earth?]
离太阳稍远一些的行星——充满风暴的金星
Now a little further out from the Sun: the stormy planet Venus.
金星的情况还是有些复杂
Venus has always been a bit puzzling.
他常被称作地球的双胞胎兄弟
It’s been described as Earth’s twin.
——因为他们大小差不多 与太阳的距离也差不多 都处在适宜居住的范围
It’s a roughly similar size, and it’s well inside the Sun’s so-called habitable zone,
这种条件下可以存在液态水
where liquid water could be a thing.
但这种类似却不是那么回事
But it turns out … not so much.
从各方面来看 金星更像我们的反面教材的兄弟
In many ways, Venus is more like our evil twin.
金星是一个具有超强风暴的行星 风暴时速300千米每小时
It’s a planet of unrelenting storms, raging at 300 kilometers an hour, and a runaway greenhouse
同时是一个平均温度为462摄氏温度的自由温室
effect that’s given it an average temperature of 462 degrees Celsius.
这个温度足以把铅都融化!
That is hot enough to melt lead.
可 为什么它与地球如此不同?
So, why is it so different from Earth?
又是什么导致了超高温度的温室呢?
And what got that greenhouse effect started?
迄今为止 科学家们已经给出引起金星温室效应的原因
Well, we know what’s causing the greenhouse effect today.
——空气中含量为95%的高浓度二氧化碳
The atmosphere is 95% carbon dioxide.
这种温室气体的影响很大 也是导致地球气候变化的
That’s a powerful greenhouse gas, the same gas that’s the main cause of climate change
罪魁祸首
on Earth.
相比之下 地球上的空气中只有0.04%的二氧化碳
When you consider that Earth’s atmosphere only has 0.04% CO2, you can see why 95% might
这时金星上浓度高为95%的二氧化碳就成了问题
be a problem.
可 金星上为何会有如此多的二氧化碳呢?
The question is, why does Venus have so much?
科学家们认为金星曾经和地球非常相似
Scientists think Venus was once a lot like the Earth, with liquid water and not so much
那种状态下存在液态水 二氧化碳浓度也不高
CO2.
但在某一时刻金星开始变暖 水蒸发成水蒸气
But at some point, it got warm enough that the water evaporated, and since water vapor
水蒸气也是一种影响很大的温室气体 它使得金星的温度变得更高
is a powerful greenhouse gas, too, this just made the heating worse.
最终温度变得极高 高到岩石中的二氧化碳也被释放出来
Eventually it got hot enough that carbon that had been trapped in rocks was released, which
空气中充满了二氧化碳
ended up filling the atmosphere with CO2.
至关重要的问题是:一开始升温现象是怎么发生的?
The million dollar question is: What got the heating started in the first place?
是最初的时候 行星上二氧化碳就有些多吗?
Was it because the planet had a little too much CO2 to start with?
还是因为距离太阳太近了 温度就高?
Was it maybe a tad too close to the Sun?
又或者是发生了一些毁灭性的灾难?
Or could it have been because of some catastrophic event?
这个问题 仁者见仁 智者见智
It’s anybody’s guess.
虽然我们对金星疑惑甚多 但目前由于各种原因 只能计划实施三项任务
Despite all the questions we have about Venus, we’ve only sent three missions there, so we
所以未来我们有着更多的探究工作要做
have a lot more exploring to do.
未来的任务包括:第一 我们将专门研究它的空气 以便完全理解金星的气候模式
In future missions, we could study its atmosphere, to better understand the weather patterns,
和理清各层所发生的化学反应
and figure out what chemical reactions happen in each layer.
第二 我们可以关注热点来知道最近是否有活跃的火山
We could look for hotspots to see if there have been active volcanoes recently.
第三 我们甚至还可以寻找生命出现过的迹象 来了解金星的地质情况
We could even search for signs of past life, and study the planet’s geology.
现在
[3: s]
3 关注距太阳系更远的风暴场所—— 天王星
Now for another stormy place, this time on the outer reaches of the solar system: Uranus.
想象一下 你被雷雨困住时 路上泥泞让你觉得不舒服吧
When you get caught in a thunderstorm, it might be sticky and uncomfortable.
但和太阳系其他行星上的风暴比较 雷雨这点不舒服实在微不足道
But that’s nothing compared to some of the storms in the rest of our solar system.
长期以来 天王星都被看做是风暴的狂热者
And for the longest time, Uranus wasn’t seen as particularly crazy in the storm department.
直到2014 天文学家才发现一个惊喜
That is, until 2014, when astronomers got a surprise.
他们发现巨大的甲烷风暴横扫了整个星球
They found clusters of gigantic methane storms sweeping across the planet.
在这之前 其他行星上的风暴都被认为是太阳提供的能量驱动的
Before that, storms on other planets were thought to be driven by energy from the Sun.
但是太阳的能量在远距离下很弱 很难作为天王星风暴的能量来源
But the Sun’s energy just isn’t strong enough on a planet as distant as Uranus.
就我们目前知道的 没有其他能量源能够带动如此强大的风暴
And as far as we know, there isn’t any other source of energy to drive such huge storms.
但科学家们唯一非常肯定的是:天王星上的风暴
The only thing that scientists are pretty confident about is that the storms on Uranus
产生于低空 而太阳驱动的风暴产生于高空
start in its lower atmosphere, unlike Sun-driven storms, which occur higher up.
此外 其他实际性的原因仍然是谜团
Beyond that, though, the actual cause remains a mystery.
也有可能 我们对天王星上发生的一切完全搞错了!
Maybe we’re totally wrong about what’s going on in the middle of Uranus.
空气并不像我们从外部看到的那样 ——它实际上会活跃得多!
The atmosphere could be much more dynamic than it seems from the outside, generating
活跃的气体可以产生能量来驱动这些风暴
heat that’s powering these storms.
类似的 那里的温度也比我们想象的更热
And it could be a lot hotter in there than we think, too.
可能存在这样的情况:空气层的内部包围着热量
It’s possible there’s an atmospheric layer trapping heat inside the planet, making the
外部的空气就相对较冷 而仅从外部部来判断它的温度就有可能出错
upper atmosphere cooler, and masking its true inner temperature.
实际情况取决于各部分间空气交换的进行方式的不同
The secret may lie in how the different parts of the atmosphere interact.
这一点我们现在还不能确定
We just can’t say for now.
最后 天王星上的种种特殊也给我们上了一课
At the very least, these storms have taught us that there’s a lot more to Uranus than
——简单的现象背后有复杂的原因
meets the eye.
4 柯伊伯带突然出现断崖?
[4: Why does the Kuiper belt end suddenly?]
现在我们把知道和热爱的行星行星抛在脑后 来看一看柯伊伯带
Now we head out beyond the planets we know and love, to the Kuiper belt.
柯伊伯带是由冰物质 甲烷和氨组成
The Kuiper belt is a disk of frozen bits of water, methane, and ammonia.
它是从海王星轨道算起 距离太阳三十个天文单位到
It starts at the orbit of Neptune — 30 astronomical units from the Sun — and keeps going to about
50个天文单位之间的范围
50 AU from the Sun.
对于柯伊伯带 有一个大迷题:
But there’s one thing about the Kuiper belt that’s a huge mystery.
就是在50个天文单位之外 柯伊伯带突然没有了
Once we get to 50 AU, the belt just… stops.
这种天体数量的突然降为零的现象 天文学家称作做 “柯伊伯断崖”
It ends all of a sudden, something the astronomers call the “Kuiper cliff”.
这很难解释 但是我们也有一些假设
This isn’t easy to explain, but we have a few ideas.
第一种假设是: 柯伊伯带实际上更宽 而我们
It could be that the belt really does continue, but the objects become so small that we can’t
看不到是因为超出技术的可视范围
see them.
但此推断与我们已知的太阳系的构成并不相符
But this idea doesn’t fit with what we know about how the solar system formed.
如果有物质与外部行星的轨道互相产生复杂的影响
If anything — because of the complex interactions of the outer planets’ orbits — we’d actually
我们应该在这个距离会看到物体变得更大
expect objects to start getting larger again at that distance.
另外一个令人激动的假设是:本应存在的天体受到未知行星的引力作用
A more exciting idea is that the objects may have been pulled away by the gravitational
离开了原本所在的位置
attraction of an as-yet-undiscovered planet.
这个未知的行星 如果存在的话 将是太阳系的第九行星
Such a planet—which would be the ninth planet in the solar system—could be the size of
大小会和火星差不多
Earth or Mars.
遗憾的是 以我们目前的技术很难再看得更远了 因此我们也许要等上一段时间
Sadly though, it’s tough to see anything that far out, so we might be waiting a while for
才能知道答案
the answer.
5 奥特云是实体吗?
[5: Is the Oort Cloud a thing?]
柯伊伯带实际上已经非常遥远 但在柯伊伯带的外面
So the Kuiper belt is pretty far away, but there’s one part of the solar system that’s
还有奥特尔云
even more out there: the Oort Cloud.
我们都认为太阳系是一面平直的圆盘
We all have a picture in our minds of the solar system as a flat disk.
天文学家就这个问题一直有过争论 即可能有个球壳
But astronomers have hypothesized for a long time that the disk might have a spherical
包围着圆盘
shell around it.
这个球壳也就是奥特尔云 被认为是由冰冷岩石构成的 即由水 甲烷
This shell, the Oort Cloud, is thought to be made up of icy rocks — water, methane,
乙烷 二氧化碳 氰化氢和其他物质构成
ethane, carbon monoxide, hydrogen cyanide, and other nasty stuff — extending out as
从太阳向外延伸两光年的范围
far as 2 light-years from the Sun.
为什么我们会认为它是物质呢?
Why do we think it’s a thing?
有时候 我们发现周期长的彗星轨道周期一般都长于
Well, every so often, we spot long-period comets — comets whose orbits take longer
200年 当我们跟踪他们轨迹时 它们像是从各个方向
than 200 years — and when we trace back their paths, they seem to come from sources a long
很久才回归
way out in every direction.
从有关太阳系着构成方面的数学模型中 我们也可以发现
Our mathematical models for how the solar system forms tell us the cloud should be out
奥特云也可能延伸至太阳系外
there, too.
早期一团糟的太阳系演变成一个盘——也就是我们现在所知的太阳系 我们能想象小型
As the mess of the early solar system collapsed into the disk we know today, we’d expect small
冰物质由于受到木星的引力和其他大型气团影响被抛射至
icy objects to be thrown into an outer shell by the gravity of Jupiter and the other gas
更外层的壳中
giants.
尽管如此 我们并不能实际观测到奥特尔云
But even if it makes sense for it to be there, we’ve never actually observed the Oort Cloud.
奥特云距离我们遥远 本身暗淡难以通过技术观测
Being so far away, with so little light, we just don’t have the technology to see it.
这意味着目前我们还不能证实它的存在——即使他确实存在
That means for the moment we have no way of proving that it exists, or if it does, how
而且体积庞大
big it is.
正如这些谜团要表示的 不用费尽心思寻找谜团
As these mysteries show, we don’t have to go far to find puzzles-a-plenty right on our
在我们的家门口——宇宙里就有很多
own celestial doorstep.
确确实实 这五个谜团仅仅是开始
And really, these five mysteries are only the beginning.
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视频概述

1太阳磁场 2疯狂的高压世界 3神秘气候巨型风暴 4柯伊伯断崖 5奥特尔云

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收集自网络

翻译译者

Ljimnn

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赖皮

视频来源

https://www.youtube.com/watch?v=wxRHsZIHTYE

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