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火星上的暴风雪! – 译学馆
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火星上的暴风雪!

Snowstorms on Mars!

介绍
[♪ INTRO]
九年前 美国宇航局的凤凰号火星探测器发现了某些神奇的事情
Nine years ago, NASA’s Phoenix Mars Lander saw something magical.
子夜时分 火星上下雪了
It was the middle of the night, and it was snowing on mars.
在当时 凤凰号火星探测器的任务科学家认为 这场雪看上去跟在地球上下雪很像
At the time, mission scientists believed that this snow acted a lot like it does here on
都是在几个小时内 由许多单个冰粒向下漂移造成的
Earth, with individual ice particles drifting down over the course of hours.
但是由于这周发表在自然地球科学杂志上的新研究表明
But thanks to new research published this week in the journal Nature Geoscience, we
我们现在知道那或许不是火星下雪的唯一方式
now know that might not be the only way snow falls on Mars.
正相反 就像地球上的一些风暴 大量的雪在同一时间倾泻而下
Instead, just like some storms on Earth, lots of snow might fall
这就是所谓的微暴气流
pretty much all at the same time, in what’s called a microburst.
研究人员发现 可以使用一系列计算机模拟
The researchers figured this out using a series of computer simulations that divided chunks
把火星大气层分成几百米厚的几层
of the Martian atmosphere into layers of just a couple hundred meters thick.
一颗像火星一样干燥的行星 甚至有一团团水
It might come as a shock to think that a planet as famously dry as Mars
这可能会让人大吃一惊
even has clouds of water at all.
火星大气层绝对是相当干燥的 但是它也真的非常寒冷和稀薄
And the Martian atmosphere is definitely pretty dry, but it’s also really cold and very
这为火星上的小水滴在白天形成云层
thin, which provides the right conditions for what little water Mars does have to form
提供了合适的条件
into clouds during the day.
但是 一旦夜幕降临 温度骤降 那些云层中的一些冰粒
Once night falls, though, the temperature drops and some of the ice particles from those
开始下沉
clouds start to sink down.
这一垂直运动在云层的内部和下方产生湍流
This vertical motion creates turbulence both inside and below the cloud, resulting in a
形成了叫做对流的过程 在此过程中 寒冷气流向行星表面下沉
process called convection, where cooler air falls toward the planet’s surface, taking
并带动附近的冰粒一起下沉
nearby ice particles with it.
空气流动有助于加速降雪 在几分钟内对流就会将冰粒推下来
Rushing air helps dramatically accelerate the snowfall: instead of a single flake taking
而不是需要几个小时才能降落
hours to fall, convection pushes it down in just minutes.
在大多数情况下 雪可能在到达地平面之前就会蒸发掉了
In most cases, the snow probably vaporizes before it gets to ground level.
但是 有时候 如果云层只是在地面上一公里或两公里
But, sometimes, if the clouds are just a kilometer or two above the ground, the end result might
最终的结果可能就是在火星表面形成一毯新鲜的雪
be a blanket of fresh snow on the Martian surface.
或许不是一毯雪
Maybe not a blanket of snow.
但是 这仍然是雪
But, still, It’s snow.
火星上的雪
On Mars!
这个模型又做出了另一个不祥的预测
The model makes another, more ominous prediction.
在地球上 微暴气流是飞机失事的主要原因
On Earth, microbursts are some of the most common causes for plane crashes, especially
尤其是在起飞和降落过程中
during take-off and landing.
所以 如果我们决定用无人机来研究火星 他们或许会遭受类似的命运
So if we ever decide to use drones to study Mars, they could suffer a similar fate.
嘿 但是至少一些陨石坑 他们会被大雪覆盖
But, hey, at least some of the craters they would make would be covered in snow!
火星上的暴风雪并不是本周行星科学宣布的唯一突破
Snowstorms on Mars weren’t the only breakthrough in planetary science announced this week.
我们还重现了钻石雨
We also recreated diamond rain.
用激光实现
With lasers.
这是本周在自然天文学杂志上发表的一篇新论文的关键结果
That’s the key result of a new paper out this week in the journal Nature Astronomy,
在自然天文学杂志上 研究人员对冰巨人内部的怪异现象就行预测调查
where researchers looked into a weird prediction made about the insides of ice giants like
比如天王星和海王星
Uranus and Neptune.
巨行星的内部总是额外迷人的
The interiors of the giant planets have always been extra-mysterious because they exist at
因为巨行星的内部存在于我们刚刚能够在实验室达到的温度和压力中
temperatures and pressures we’ve only started to be able to create in the lab.
在很长一段时间里 我们必须依赖理论预测来告诉我们在这些行星内部可能是什么样的
For a long time, we’ve had to rely on theoretical predictions to tell us what the insides of
有些预测可能是彻头彻尾的离奇怪异不符逻辑
these planets might be like, and some of those predictions can be downright weird.
比如 一场从天而降的钻石雨
Like, for example, a rain of diamonds falling from the sky.
天王星和海王星都包含很多甲烷 这是一种化合物
Uranus and Neptune both contain a bunch of the compound methane,
一个甲烷分子是由一个碳原子和四个氢原子组成的
which is made of a carbon atom and four hydrogens.
在这些行星内部 单个的甲烷分子开始连接在一起
Inside these planets, individual methane atoms start linking together
形成碳基分子链
to form chains of carbon-based molecules.
理论上 把这些链放置在足够的压力下
Put those chains under enough pressure and, in theory,
碳有可能变成固体钻石
that carbon might become solid diamond.
但是这是很难测试的 因为要形成这种物质需要很大压力
But that’s been hard to test, because we’re talking about a lot of pressure —
大约150个吉帕斯卡
about 150 Gigapascals.
这大约相当于在一便士上加上5000公吨的压力
That’s roughly the equivalent of stacking 5000 metric tons on top of a penny,
更不用说微小的分子了
except with tiny molecules.
这是相当困难的 而这就是使用激光进行实验的原因了
That’s pretty hard to do, which is where the lasers come in.
为了模拟这些碳基分子链 研究人员决定对一种叫做聚苯乙烯的塑料进行实验
To simulate these carbon-based molecular chains, the researchers decided to experiment on a
在聚苯乙烯中也有一堆碳连接在一起
plastic called polystyrene, which also has a bunch of carbons linked together.
当你用一束精心定时的光脉冲射击像聚苯乙烯这样的材料时
When you shoot a material like polystyrene with a carefully-timed burst of light, you
你能够通过涟漪产生一个压力冲击波
can create a shockwave of pressure that ripples through it.
为了重现海王星深处的环境 他们使用一束强大的激光创造出不止一个
To recreate the environment deep inside Neptune, they used a powerful laser to create not one,
而是两个冲击波
but two of those shockwaves.
对这两个冲击波自身来说 它们的强度都不够
On their own, neither would have been strong enough.
但是当两个冲击波相撞时 只是一瞬间 这种材料就可以达到
But when the two waves collided, for just an instant, the material reached the pressure
钻石形成所需要的压力
at which diamonds can form.
研究人员还想看到这一过程的实际现象 其中包括对一束束强大的X射线进行定时发射
The researchers also wanted to see this process in action, which involved timing a burst of
以配合冲击波相撞
powerful x-rays to coincide with the shockwave collision.
这样他们就可以用一种叫做X射线衍射的技术来观察发生了什么
That way they could see what was happening using a technique called x-ray diffraction,
这种技术根据光线如何反射其结构来识别微观材料
which identifies microscopic materials based on how light reflects off their structure.
他们观测到的正是所预测的 压力促使材料形成了纳米级别的钻石
And they saw exactly what they had predicted: the pressure formed nanometer-sized diamonds.
在海王星这样的行星上 这些钻石的体积可能比
In a planet like Neptune, those diamonds could grow thousands of times larger
我们在地球上发现的最大的钻石大几千倍
than the biggest we’ve ever found on Earth.
比如 几百万克拉
Like, millions of carats.
当它们从行星大气层坠落时 巨型钻石会聚集在海王星核心周围的区域
As they fell through the planet’s layers of gas, the giant diamonds would collect in
基本上就像用钻石涂上的一样
a region surrounding Neptune’s core, basically coating it with diamond.
同时 从原始甲烷中遗留下来的氢气
Meanwhile, the hydrogen left over from the original methane
会浮向表面
would float up towards the surface.
通过将较重的碳和较轻的氢分离 随着时间的推移
By separating the heavier carbon from the lighter hydrogen, over time the distribution
质量分布甚至行星大小都有可能发生变化
of mass and even the size of the planet could change.
这对我们来说很重要 因为很多系外行星看起来跟海王星很相似
Which is important for us to know, because a lot of exoplanets seem to be similar to
它们的体积大小是我们能够测量的物理量之一
Neptune, and their size is one of the things we can measure.
但是 让我们关注真正的奖品 激光钻石
But, let’s keep our eyes on the real prize here: Laser diamonds.
对天文学来说 这周真是太棒了
It’s been a pretty good week for astronomy!
感谢收看这一集的SciShow空间新闻 如果关于下雪的谈论
Thanks for watching this episode of SciShow Space News, and if all this talk about snow
使你想去奥林匹斯山进行一场滑雪之旅
made you want to take a ski trip to Olympus Mons,
那么当你眼巴巴的看着这 SciShow 太空滑雪海报时 你可以计划一下你的旅程
you can plan your trip while gazing longingly at this SciShow Space ski poster.
详情请见DFTBA.com/SciShow网站
Get yours at DFTBA.com/SciShow.
终曲
[♪ OUTRO]

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视频概述

本视频首先介绍了在火星上观测到的下雪的情况,对其形成原因进行探索并与地球上的暴风雪形成过程进行对比。其次介绍了巨行星钻石雨的形成,以及人造激光钻石的条件与过程。

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视频来源

https://www.youtube.com/watch?v=SESj9ANmdsA

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