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Antarctica contains between 60 and 90 percent of the world’s fresh water in the form of ice.
南极洲的冰占到了全世界淡水总量的60%~90%。
It may look relatively barren, but don’t let its seemingly uniform appearance on top fool you—
这里可能看起来比较贫瘠，但请不要被它看似统一的面貌欺骗了——
a dead satellite has now given us clues that something very interesting is hiding underneath.
因为一颗废弃的卫星提供的线索表明，南极洲的冰盖下面隐藏着一些非常有趣的东西。
The satellite in question is called the Gravity Field and Steady-State Ocean Circulation Explorer,
这颗卫星名为“重力场和稳态海洋环流探测”卫星，
pronounced GOCE for short, because the European Space Agency is cosmopolitan like that.
缩写后的发音是“GOCE”，因为欧洲航天局就是这么一个国际化的机构。
This sleek little sports car of a satellite was created to measure and record fluctuations in the earth’s gravitational field and global mean sea level.
这款小巧玲珑的卫星跑车是用来测量和记录地球的重力场和全球平均海平面这两个数据的波动情况的。
We then use this data to produce a model of the earth called the geoid—
我们要用这些数据来建立一个名为“大地水准面”的地球模型，
hold that thought, we’ll come back to that in a second.
这个点我们先放一放，等下再回来讨论。
The GOCE satellite completed its mission in 2013,
GOCE卫星于2013年完成了自己的使命，
but research teams all over the world have still been piecing together the data ever since its cute little butt burned up in the earth’s atmosphere.
但它可爱的小屁屁在地球的大气层中烧毁以后，世界各地的研究团队整理该卫星获取的数据的任务到现在都还没结束。
Because here’s the thing about gravitational field data:
因为引力场数据有这样一个问题：
it tells us what the earth is like…even the parts of it we can’t see.
它能告诉我们地球是什么样子，即便是我们看不见的那些地方也不例外。
And here’s where the geoid comes back in.
这个时候，大地水准面的作用就体现出来了。
The geoid is a hypothetical ocean—no tides, no waves, no nothin’.
大地水准面是一个假想的海洋——没有潮汐，没有波浪，什么都没有。
In this model, the only things the world’s oceans are influenced by are the earth’s gravity, and the rotation of the earth.
在这个模型中，各大海洋只受地球引力和地球自转的影响。
Since objects with more mass have more gravity,
因为质量越大的物体引力也就越大，
the ‘water’ of the geoid bunches up in places on earth where there’s greater mass,
大地水准面模型中质量越大的地方聚集的“水”就会越多，
giving us a model of the earth that looks a little bit like a misshapen ball,
这么一来，这个地球模型看起来就有点像一个畸形的球，
it’s funky shape is our map to all the topographical features on earth!
它时髦而独特的形状就是我们获取地球上所有地形特征的地图!
So GOCE’s mission was really important.
所以，GOCE的任务是非常重要的。
The geoid lets us better understand ocean currents, sea level rise, and changes in ice coverage,
大地水准面能够让我们更好地了解洋流、海平面上升和冰层覆盖率的变化，
but it also lets us see inside the earth.
还能让我们看到地球内部的结构。
Using three pairs of ultra-sensitive accelerometers, mounted orthogonally to create what’s called a gradiometer,
GOCE借助三对垂直安装从而创建所谓的梯度仪的超灵敏加速度计，
GOCE took measurements that allowed one research team to calculate gravity gradients,
测量出来的数据能帮助研究小组计算出地球上的重力梯度，
which allow us to see the size and character of all of the earth’s topography—
借助这一数据，我们就能看到地球上所有地形的大小和特征——
including what’s under Antarctica, the least understood of all the continents.
包括南极洲下方这个所有大陆中最不为人知的地方的情况。
Turns out, it’s a patchwork continent, made up of at least three different cratons,
事实证明，那下面是一个拼凑起来的大陆，由至少三个不同的克拉通组成，
which are remnant rocky cores of long-lost ancient landmasses.
克拉通是失落已久的古代大陆残余的岩核。
And—get this—each craton has geologic similarities to an existing land mass we know and love today.
接下来，注意了，每一个克拉通都与我们今天所知并且喜爱的现有陆地有相似的地质构造。
One is similar to Australia, one matches up to India, and so on.
比如，其中一个克拉通的构造是与澳大利亚相似的，另一个则是与印度匹配的，诸如此类。
Now we finally know that this Antarctica is the accumulation of what was left over
现在，我们终于知道，1.6亿年前超大陆冈瓦纳分裂之后，所有的碎片分道扬镳，
after supercontinent Gondwana broke up and all the pieces went their separate ways 160 million years ago!
南极洲就是由剩下的那些碎片拼凑起来的！
This new understanding of the tectonic puzzle pieces locked together at the bottom of the globe can help us visualize the plate tectonics of earth past.
对地球底部构造之谜的这一新发现可以帮助我们直观地感受地球过去的板块构造。
How did the continental plates move around? What did they bump into?
大陆板块是如何运动的？它们究竟撞上了什么样的物体？
What mountain ranges and volcanoes and oceans did they create?
又创造了怎样的山脉、火山和海洋?
But how does knowing what’s under Antarctica’s icy face add to the science of the present?
问题是，知道南极洲冰封的表面下有什么对当今的科学又有何帮助呢?
Well, the ice is melting.
事实上，这里的冰正在融化。
Antarctica’s ice sheets and glaciers are losing just shy of 300 billion tons of ice per year.
南极洲的冰原和冰川每年都会损失近3000亿吨冰。
And that’s compared to the 1980s when the continent was losing just 44 billion tons a year.
而在20世纪80年代，这块大陆每年仅会损失440亿吨冰。
When factoring in melting from other huge ice sheets like Greenland,
如果把格陵兰岛等其他大冰原的融化也考虑进来的话，
Antarctica’s melting ice could contribute to up to six feet of sea level rise before the end of the century.
南极洲融化的冰可能会导致海平面在本世纪末上升6英尺（约合1.8米）。
Plus—we’re contending with something called post-glacial rebound.
此外，我们还要应对所谓的“冰川后反弹”。
Turns out, the earth’s crust is pretty elastic,
事实证明，地壳是很有弹性的，
and after all that heavy, heavy ice is gone off Antarctica’s back, that landmass, all that bedrock. . . is going to spring back up. Yeah.
所有这些沉重的冰层从南极洲的脊梁上消失之后，这块大陆，所有的基岩…就会弹回来。是的。
So it’d be nice to be prepared for how that might play out.
所以我们最好是做好应对准备。
This most recent study, with the help of handy dandy GOCE data,
这项最新的研究，在便捷的GOCE数据的帮助下，
gives us a detailed look at the rock composition and the configuration of land masses underneath all that ice--
详细地向我们展示了那个冰盖之下的岩石组成和所有陆地块的结构——
the nature of the rock, the way it’s all put together and the way it moves will influence how fast the ice melts, what directions that water is likely to go in,
岩石的性质，它们的组合方式和移动的方式都会影响冰盖融化的速度，水流的方向
and how the ice may shift as it melts and breaks apart.
以及冰在融化和破裂时移动的方式。
And remember, these are big freaking ice sheets,
记住了，这些都是无比巨大的冰原，
so knowing how they may move as they melt is pretty important.
所以，了解它们在融化时会怎样运动是非常重要的。
Collecting and analyzing data like this may complete our picture of how earth changed and molded itself during formative periods of geologic time,
收集并分析这类数据也许能帮助我们更加完整地了解地球在地质成形阶段是如何变化并塑造自己的，
helping us understand both its past and prepare us for its uncertain—but definitely shifting—future.
从而帮助我们了解地球的过去，并为它不确定——但肯定是在发生变化的——未来做好准备。
What else do you think is also lurking beneath our icy continent?
你觉得，在我们这片冰冷的大陆下还会潜伏着什么呢?
Tell us in the comments below and if you want even more on ancient earth discoveries,
请在下方评论中告诉我们，还有，如果你想了解更多关于古代地球的发现，
check out my other video on a secret hidden ocean here,
可以看我这期关于神秘海洋的视频，
don’t forget to subscribe, and make sure you always come back to Seeker to get your geology fix.
别忘了订阅我们的频道，经常回来，让我们帮你解决地质问题噢。
Thanks for watching!
感谢大家的收看!
