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Hey there! Welcome to Life Noggin!
大家好！欢迎来到脑洞大开的生命奇想！
Our Earth is pretty awesome. It's basically a spinning rock flying through space, carrying humans, animals, and friendly animations with it.
我们的地球非常棒。总体来看，它是一块旋转的岩石，携带着人类、动物和可爱的动画人在太空中飞行。
And it also has a magnetic field that protects us from radiation from space and coronal mass ejections from the Sun.
它也有磁场保护我们不受空间辐射和日冕物质抛射的影响。
And the Earth has had this magnetic field for millions of years.
地球上的磁场已经有几百万年了。
You can think of the Earth as a giant bar magnet, where the magnetic field lines go from magnetic north to south.
你可以把地球想象成一个巨大的条形磁铁，磁场线从磁铁北极指向南极。
So, if your body is pointed north, a magnetic compass in your hand would be pointing north too. But it hasn't always been that way.
所以，如果你的身体指向北方，你手中的指南针也会指向北方。但也并非总是如此。
In fact, around 800,000 years ago, if you were facing north, the compass needle would point to the south.
事实上，大约80万年前，如果你面向北方，指南针就指向南方。
In other words, the magnetic field was reversed. But how?
换句话说，磁场被颠倒了。但如何颠倒的呢?
This is actually something that happens relatively often…well, often relative to the age of the universe.
这实际上是比较经常发生的…嗯，相对于宇宙的年龄来说经常发生。
See, for the past 20 million years or so, the Earth's magnetic field reverses about once every 200,000 to 300,000 years.
在过去的两千万年间，地球的磁场每20万到30万年就会发生一次翻转。
But it's been about 780,000 years since the last time the field reversed.
上次磁场逆转还是78万年前。
However, when it does happen, it doesn't just reverse instantaneously, you won't walk outside one day and Google maps will have no idea which direction is which.
然而，真的发生时，并不是瞬间反转。有一天你出门，突然发现谷歌地图也不知道哪边是哪边了吗，这样的情况不会发生的。
Instead, this reversal takes hundreds, if not thousand of years to do.
相反，这种逆转需要数百年甚至数千年的时间。
And recent research by the ESA shows that the Earth's magnetic field is weakening at a rate ten times faster than they previously thought, about 5 percent per decade, which is a sign that the magnetic field may be starting the process of reversing.
欧空局最近的研究表明，地球磁场的衰减速度是之前认为的速度的十倍，约为每十年5%，这表明磁场可能正在开始逆转。
And it's possible that this reversal may even happen within some of our lifetimes. But before you panic, don't worry, we're not all going to die because of this.
这种逆转很有可能发生在我们的有生之年。但先别恐慌，别担心，我们不会因为这个死亡。
There isn't any evidence to suggest that the magnetic field reversals in the past have led to any mass extinctions.
没有任何证据表明，过去的磁场逆转导致了大规模的物种灭绝。
And even if the magnetic field does continue to weaken, we still have the atmosphere to protect us from some harmful radiation.
即使磁场继续减弱，我们仍然有大气层保护我们免受某些有害的辐射。
The main concern is that the power grids and communications systems may be at risk.
最应该担心的是电网和通信系统，这两个可能面临风险。
And also, any animals that use the magnetic field to navigate, like pigeons, might be a little confused for a while.
而且，使用磁场导航的动物——比如鸽子——可能会困惑一段时间。
Heh...look at that poor pigeon go. But why does this reversal happen in the first place?
哈……看那只可怜的鸽子。但是为什么会发生这种逆转呢?
Well, the reason that the Earth even has a magnetic field has to do with the molten iron in the outer core.
嗯，地球有磁场的原因与外核内的熔融铁有关。
And the motion of that molten iron, along with some complicated physics, generates a magnetic field through something called the dynamo effect.
这种熔融铁的运动，再加上一些复杂的物理现象，通过一种叫做发电机效应的东西产生了磁场。
And for reasons still unknown to scientists, the molten iron's motion must somehow change to reverse the magnetic field.
虽然科学家们还不知道具体原因，但熔融铁的运动必定发生了某种改变，因而逆转了磁场。
It's not an incredibly satisfying answer, but hey, that's why we have scientists researching the topic!
这并不是一个非常令人满意的答案，但是，正因为如此我们的科学家才要研究这个话题!
But rest assured knowing that you aren't in any danger if the magnetic field reverses anytime soon.
但放心，如果磁场很快逆转，你不会有任何危险。
After all, it could be in your lifetime, or a thousand or more years from now. whichever.
毕竟，这可能发生在你有生之年，也可能是一千多年以后。都有可能。
So here is another question. Do you think you could survive 2.5 million years ago? Check out this video and find out.
另一个问题。你认为你能在250万年前生存吗？看看这个视频去寻找答案。
One of your earliest human ancestors, homo habilis.
你也可能遇到了最早的人类祖先，能人。
This species looked more like apes than humans, but were able to walk on their back legs and use their hands to make stone tools, hence its name, which means "handy man".
这个物种看起来更像猿猴而不是人类，但它们可以用它们的后腿行走，用手来制作石器，因此得名，意思是“手巧的人”。
But, luckily for you, if you encountered one of them, scientists are unsure if it would attack.
但是，幸运的是，如果你遇到一个能人，科学家们不确定它是否会攻击你。
There's a link in the description if you're on your mobile. Make sure you come back every Monday for a brand new video.
如果你是手机观看的，描述区有一个链接。每周一都要回来看新视频哦。
As always, I'm Blocko, this has been Life Noggin. Don't forget to keep on thinking!
我是宝高，这里是脑洞大开的生命奇想。思考不要停！
