(单词翻译:单击)
Science fiction movies are great, but sometimes they're more fiction than actual science.
科幻电影很精彩，但有时它们比真正的科学更虚构。
Like the new movie Geostorm.
就像新电影《大地风暴》一样。
We won't spoil it for you, but the premise is that after a string of colossal natural disasters,
我们没有向你剧透，但这个故事讲得是一连串巨大的自然灾害过后，
the world works together to put a network of weather-controlling satellites into space.
全世界能共同努力将一个控制天气的卫星网送入太空。
Of course, then they go haywire, which leads to another string of now unnatural disasters.
当然，卫星网随后陷入混乱，导致另一连串非自然灾难的发生。
So, the question is could this actually happen?
所以，问题来了，这种情况真得能发生吗？
Can we control the weather with satellites?
我们真得能用卫星控制天气吗？
No. No, we can't. We cannot do this.
不不，我们做不到。
Okay, video over! Bye! Thanks for watching!
好了，节目结束，我们下期见！
Just kidding. There are actually some tiny nuggets of truth in this story.
刚刚开个玩笑。但故事中有些东西是真的。
Yes, storms are getting more frequent and more severe.
确实，风暴变得越来越频繁，也越来越猛烈了。
And yes, we do try to influence the weather! But definitely not on a planet-wide scale.
我们也尝试着影响天气！但绝对不是全球范围的。
The most widespread and successful example of us manipulating the weather is cloud seeding.
我们操控天气最广泛和成功的例子是人工降雨。
See, raindrops form on what are called nucleation sites,
看，雨滴形成于所谓的成核位置上，
which are normally particles of dust or bacteria in the atmosphere that water vapor condenses onto.
水蒸气在充满灰尘颗粒或细菌的大气中凝结。
With cloud seeding, you add nucleation sites into the atmosphere,
随着人工降雨，你在大气中增加了成核位置，
usually by spraying tiny, harmless particles of silver iodide or dry ice from a generator or plane.
通常是用发生器或飞机喷洒的微小无害的碘化银或干冰颗粒。
More nucleation sites mean more raindrops form, so you ultimately get more precipitation.
变多的成核位置意味着形成更多的雨滴，所以最终会获得更多的降水。
Typically, cloud seeding is done in either mountainous areas during the winter to increase snowfall,
通常是冬季在山区进行人工降雨来增加降雪量，
or in fairly arid areas during the summer to increase the probability it will rain over smaller areas.
或夏季在相当干旱的地区进行人工降雨以增加小范围地区降雨的可能性。
It's hard to run controlled experiments with cloud seeding, but we think it's at least somewhat effective!
用人工降雨进行控制实验是很困难的，但我们认为它至少有些作用！
It can increase precipitation in an area by as much as 15%,
它最多可以增加一个地区15%的降水，
and that can really help soften the effects of drought.
这确实有助于减轻干旱的影响。
But it's not something that can end a drought.
但它不能结束干旱。
It's limited by how much water vapor is available in the air,
它受限于空气中的水蒸气量，
and if you're in a drought, there's not a lot of vapor to go around.
如果你处于干旱期，就没有太多的水蒸气。
So cloud seeding couldn't start a global flood or any other natural disaster.
所以人工降雨不会引起全球性洪水或任何其他的自然灾害。
And it turns out it can't stop disasters, either.
不过事实证明它也不会停止灾难。
From the 1960s to 1980s, a similar cloud-seeding tactic was used not to increase precipitation,
从20世纪60年代到80年代，一个类似人工降雨的策略被应用，它不是增加降水，
but to try to stop hurricanes.
而是试图阻止飓风。
It was called Project Stormfury, which is awesome.
它被称为“Stormfury”计划，很了不起。
Pilots working for NOAA, the National Oceanic and Atmospheric Administration,
美国国家海洋和大气局（NOAA）的飞行员
would fly into a hurricane and seed it with silver iodide just outside its eyewall,
将飞进飓风里，把碘化银撒在它的风眼墙外面，
the most dangerous part of a hurricane.
风眼墙是飓风最危险的区域。
Supposedly, this would widen the eye of the storm.
据推测，此举会扩大风暴的风眼。
The idea was that water would condense outside of the existing eye,
该想法是水会凝结在现有的风眼墙之外，
which would draw moisture away from it and form a new, wider eyewall.
它会吸走水分形成一个更宽的新风眼墙。
And that would slow the hurricane's rotation rate and wind speeds, and ultimately kill the storm.
这将减缓飓风的旋转速率和风速，最终消灭风暴。
The science behind this wasn't entirely unsound, but it didn't work.
这背后的科学并非完全不可靠，但它不起作用。
It turns out hurricanes have too much ice in them,
事实证明飓风里有太多的冰晶，
and not enough water vapor to condense into a new eyewall, so seeding didn't have a big effect.
而且没有充足的水蒸气能够凝结形成新风眼墙，所以播撒碘化银没有太大的作用。
But that's something we didn't know before!
但有些事是我们之前不知道的！
And because research was always a goal of Project Stormfury,
因为研究一直是“Stormfury”计划的目标，
it yielded all kinds of other insights into hurricane formation, dynamics, and forecasting.
它为飓风的形成、动态和预测提供了各种各样的见解。
And that played a big part in how we understand hurricanes.
而且在我们理解飓风方面起了很大作用。
It also helped to develop the logistics of hurricane research,
它还帮助发展了飓风研究的后勤工作，
like, how you fly into a huge, swirling storm and make it back with good data.
比如，你如何飞进一个巨大的风暴旋涡，然后带着有价值的数据回来。
So even though it wasn't really effective at controlling the weather, Project Stormfury was still really useful!
所以，即使“Stormfury”计划在控制天气方面没多大作用，但仍很有用！
Okay, so we can't make floods or stop hurricanes and we can't stop hail, either.
我们不能制造洪水或阻止台风，也不能阻止冰雹。
But we have definitely tried using devices called hail cannons.
但我们确实尝试过使用叫冰雹炮的设备。
Modern hail cannons basically just blast a bunch of noise into the sky.
现代的冰雹炮基本上是在天空制造噪音。
The idea is that sound waves should disrupt hailstone formation before they get too big and destructive.
计划是声波应该会在冰雹变大、具有破坏性之前破坏它的形成。
And we've been trying something like this for hundreds of years.
我们已经尝试了几百年了。
In Europe, from the late Renaissance to the 1700s, people used something called weather shooting.
在欧洲，从文艺复兴到十八世纪，人们使用的是“气象炮弹”。
Basically, you'd just fire a gun into the air, because maybe the sound would do something to the hail.
基本上是向空中发射炮弹，因为声音可能会影响冰雹。
Austria actually outlawed this because people kept accidentally shooting each other.
奥地利规定此做法是违法的，因为人们会不小心互相射击。
But then in the late 1800s, the first hail cannons were produced.
但在19世纪晚期，第一架冰雹炮诞生了。
They fired big smoke rings into the atmosphere,
它们向大气中发射了大烟圈，
and people believed they saw some positive effects, although they weren't totally sure why.
人们相信自己看到了积极影响，尽管他们不完全确定原因。
They thought it may have been like weather shooting, and the sound was preventing hailstones.
他们认为它可能类似于“气象炮弹”，声音能阻止冰雹。
Or maybe the smoke provided nucleation sites, causing water to condense into rain.
或者烟雾提供了成核位置，导致水凝结成雨。
Either way, this tactic really caught on,
不管怎样，这一策略确实流行了起来，
and there were even conferences and societies of hail cannoneers!
甚至还有冰雹炮手的会议和社团！
But after about ten years, use died down, because people noticed that it still hailed.
但十年后，冰雹炮的使用渐渐少了，因为人们注意到天仍在下冰雹。
The problem with all of this is that, if sound could destroy hail,
问题在于，如果声音能破坏冰雹的话，
then the thunder that happens during storms would do the job for us.
那么风暴中的雷声就为我们做这项工作了。
Over time, people have come up with lots of ideas about how and why hail cannons should work,
随着时间的推移，人们提出了很多关于冰雹炮如何以及为什么起作用的想法，
but they're still based on a faulty idea, even if some farmers still use them today.
但它们的起点就是一个错误想法，即使今天仍有一些农民会使用它们。
One thing is for sure, though:
不过有一件事可以确定，
All of these methods are a far cry from the all-powerful weather satellites in Geostorm,
所有这些方法都与地球风暴中的全能气象卫星相去甚远，
and only one of them is actually effective.
其中只有一个方法是有效的。
I mean, we're still figuring out how rain works,
我的意思是，我们仍在研究雨的原理，
and we're definitely not capable of controlling it from space!
我们肯定没有能力从太空控制它！
So if there is a natural disaster, at least it won't have come from a satellite.
所以如果有自然灾害的话，至少不是卫星造成的。
Thanks for watching this episode of SciShow Space made possible by our awesome patrons on Patreon!
感谢您收看本期的太空科学秀，它是由伟大的Patreon赞助播出的！
Like Naiadryade and Nate and James and Patrick!
赞助商是Naiadryade、纳特、詹姆斯和帕特里克！
So many people donate money so that SciShow can be free for everyone and we really really appreciate it.
很多人都捐钱，使得太空科学秀能够对每个人免费开放，我们真得非常感激！
Thank you so much!
非常感谢您的收看！
