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Nine years ago, NASA's Phoenix Mars Lander saw something magical.
九年前，美国宇航局的“凤凰号”火星探测器看到了一些神奇的东西。
It was the middle of the night, and it was snowing on mars.
火星上正在半夜下雪。
At the time, mission scientists believed that this snow acted a lot like it does here on Earth,
那时，负责此任务的科学家们相信，这次降雪和地球上的非常相似，
with individual ice particles drifting down over the course of hours.
都是单个冰粒在数小时内降落下来。
But thanks to new research published this week in the journal Nature Geoscience,
但多亏本周发表在《自然地球科学》杂志上的一项新研究，
we now know that might not be the only way snow falls on Mars.
我们现在知道那可能不是火星降雪的唯一方式。
Instead, just like some storms on Earth, lots of snow might fall pretty much all at the same time, in what's called a microburst.
相反，和地球上的暴风雨一样，大量的降雪可能同时发生，这叫做微爆流。
The researchers figured this out using a series of computer simulations that divided chunks of the Martian atmosphere into layers of just a couple hundred meters thick.
研究人员利用一系列计算机模拟，将火星大气中的大块区域分成了几百米厚的气层，才得出来的。
It might come as a shock to think that a planet as famously dry as Mars even has clouds of water at all.
火星是出名的干燥行星，它上面竟然有水云真是令人吃惊。
And the Martian atmosphere is definitely pretty dry, but it's also really cold and very thin,
火星大气层肯定很干燥，但它也很冷，很薄，
which provides the right conditions for what little water Mars does have to form into clouds during the day.
这为火星上的少量水在白天形成云层提供了合适的条件。
Once night falls, though, the temperature drops and some of the ice particles from those clouds start to sink down.
然而，一旦夜幕降临，温度就会下降，而这些云层中的一些冰粒开始下沉。
This vertical motion creates turbulence both inside and below the cloud, resulting in a process called convection,
这种垂直运动在云层内部和下方产生湍流，导致对流的发生，
where cooler air falls toward the planet's surface, taking nearby ice particles with it.
冷空气携带着周围的冰粒一起朝行星表面落去。
Rushing air helps dramatically accelerate the snowfall:
疾风对加速降雪有显著的帮助，
instead of a single flake taking hours to fall, convection pushes it down in just minutes.
对流在几分钟内就把雪花压了下来，而不是数小时内一片一片地落下。
In most cases, the snow probably vaporizes before it gets to ground level.
大多数情况下，雪可能在到达地面之前就蒸发了。
But, sometimes, if the clouds are just a kilometer or two above the ground,
但有时，如果云层离地面只有一、两公里，
the end result might be a blanket of fresh snow on the Martian surface.
最终结果可能是火星表面覆盖了一层新雪。
Maybe not a blanket of snow. But, still, It's snow. On Mars!
也许不是一层雪，但火星上仍是下雪了！
The model makes another more ominous prediction.
这个模型做出了另一个更加不祥的预测。
On Earth, microbursts are some of the most common causes for plane crashes, especially during take-off and landing.
在地球上，微爆流是导致飞机失事的最常见原因，特别是在飞机起飞和降落的时候。
So if we ever decide to use drones to study Mars, they could suffer a similar fate.
因此，如果我们决定使用无人机来研究火星，它们可能会遭受类似的命运。
But, hey, at least some of the craters they would make would be covered in snow!
但是，至少它们造成的一些陨石坑会被雪覆盖！
Snowstorms on Mars weren't the only breakthrough in planetary science announced this week.
本周，火星上的暴风雪并不是行星科学上的唯一突破。
We also recreated diamond rain. With lasers.
我们也用激光重现了钻石雨。
That's the key result of a new paper out this week in the journal Nature Astronomy,
这是本周发表在《自然天文学》杂志上一篇新论文的主要结果，
where researchers looked into a weird prediction made about the insides of ice giants like Uranus and Neptune.
研究人员对诸如天王星和海王星这样的冰巨星内部观察之后做出了不可思议的预测。
The interiors of the giant planets have always been extra-mysterious
巨大行星的内部一直以来都非常神秘，
because they exist at temperatures and pressures we've only started to be able to create in the lab.
因为我们才刚刚能在实验室里创造出它们的温度和压力。
For a long time, we've had to rely on theoretical predictions to tell us what the insides of these planets might be like,
很长一段时间内，我们只能依靠理论预测来了解这些行星的内部情况，
and some of those predictions can be downright weird.
有些预测可能非常奇怪。
Like, for example, a rain of diamonds falling from the sky.
比如，天下钻石雨。
Uranus and Neptune both contain a bunch of the compound methane, which is made of a carbon atom and four hydrogens.
天王星和海王星都包含一堆甲烷化合物，甲烷是由一个碳原子和四个氢原子构成的。
Inside these planets, individual methane atoms start linking together to form chains of carbon-based molecules.
在这些行星内部，单个甲烷原子开始连接在一起形成碳基分子链。
Put those chains under enough pressure and, in theory, that carbon might become solid diamond.
理论上，将这些碳链施加足够的压强，它们可能会变成固体钻石。
But that's been hard to test, because we're talking about a lot of pressure, about 150 Gigapascals.
但这很难测试，因为我们所说的巨大压强大约是150吉帕。
That's roughly the equivalent of stacking 5000 metric tons on top of a penny.
这大概相当于把5000公吨的物品叠加在一美分上，
Except with tiny molecules, that's pretty hard to do, which is where the lasers come in.
除了小分子，这很难做到，所以才有了激光的加入。
To simulate these carbon-based molecular chains, the researchers decided to experiment on a plastic called polystyrene,
为了模拟这些碳基分子链，研究人员决定在一种叫做聚苯乙烯的塑料上进行实验，
which also has a bunch of carbons linked together.
聚苯乙烯也有一堆碳原子相连。
When you shoot a material like polystyrene with a carefully-timed burst of light,
当你用精准定时的激光射击聚苯乙烯等材料时，
you can create a shockwave of pressure that ripples through it.
你可以制造一种压力冲击波穿透它。
To recreate the environment deep inside Neptune, they used a powerful laser to create not one, but two of those shockwaves.
为了重建海王星深处的环境，他们用一种强有力的激光制造了两束而不是一束这样的冲击波。
On their own, neither would have been strong enough.
单独一束不够强。
But when the two waves collided, for just an instant, the material reached the pressure at which diamonds can form.
但当两束冲击波相撞时，仅在一瞬间，材料就达到了钻石形成所需的压强。
The researchers also wanted to see this process in action,
研究人员也希望看到这个过程，
which involved timing a burst of powerful x-rays to coincide with the shockwave collision.
即精准定时的强力x射线与冲击波碰撞。
That way they could see what was happening using a technique called x-ray diffraction,
通过一种叫做x射线衍射的技术，他们可以看到它的发生情况，
which identifies microscopic materials based on how light reflects off their structure.
x射线衍射基于光线反射其结构的方式来鉴定微观材料。
And they saw exactly what they had predicted: the pressure formed nanometer-sized diamonds.
他们看到的和预测的一样：压力导致了纳米级钻石的形成。
In a planet like Neptune, those diamonds could grow thousands of times larger than the biggest we've ever found on Earth.
在海王星这样的行星上，这些钻石可能比我们地球上发现的最大钻石还要大上数千倍。
Like, millions of carats.
比如，上面有数以百万克拉大的钻石。
As they fell through the planet's layers of gas, the giant diamonds would collect in a region surrounding Neptune's core, basically coating it with diamond.
当它们穿过行星的大气层时，巨大的钻石将聚集到海王星核心周围的一个区域，这里基本上被钻石覆盖了。
Meanwhile, the hydrogen left over from the original methane would float up towards the surface.
与此同时，原始甲烷留下的氢会浮向地表。
By separating the heavier carbon from the lighter hydrogen, over time the distribution of mass and even the size of the planet could change.
通过将较重的碳与较轻的氢分开，质量分布甚至是行星的大小都可以随时间改变。
Which is important for us to know, because a lot of exoplanets seem to be similar to Neptune,
这对我们来说很重要，因为许多系外行星似乎与海王星相似，
and their size is one of the things we can measure.
它们的大小是我们可以测量的东西之一。
But, let's keep our eyes on the real prize here: Laser diamonds. It's been a pretty good week for astronomy!
但是，让我们聚焦到这里真正的奖品上，激光钻。对于天文学来说，这周收获颇丰！
Thanks for watching this episode of SciShow Space News,
感谢您收看本期的太空科学秀，
and if all this talk about snow made you want to take a ski trip to Olympus Mons,
如果所有这些关于雪的内容让你想去奥林匹斯山滑雪，
you can plan your trip while gazing longingly at this SciShow Space ski poster.
在看这个太空科学秀滑雪海报的同时可以计划你的旅行哦！
Get yours at DFTBA.com/SciShow.
DFTBA.com/SciShow等你哦！
