在地球形成的时代 它要受到成千上万个这样的彗星撞击
By the time the bombardment finished,
一旦撞击完成
it's thought they'd delivered up to half the water inour oceans.
据分析它们会将一半的水释放到我们的海洋
The amount of water inthe oceans has stayed roughly the same
自从40亿年前海洋形成开始
ever since they were formed about four billion years ago.
海洋中的水量差不多一直没变
But the oceans themselves are continually changing.
但是海洋本身不断变化着
As the continents move over millions of years,
随着大陆移动了几百万年
new oceans open up, whilst others vanish.
新的海洋会出现，有的会消失
It's hard for us to grasp because it happens over such an immense timescale.
我们很难理解 因为这些都发生在很长的时间跨度里
Vet today, in East Africa we can actually see the possible beginnings of a new ocean.
但是今天在东非 我们能看到新海洋的诞生
This long, deep fissure,
这个漫长深邃的裂缝
in an area of Ethiopia called the Afar Depression,
位于埃塞俄比亚一个叫阿法尔洼地的地方
is where the planet's next ocean may form.
这里将是地球下一个海洋形成之地
It appeared in 2005,when the Land was suddenly ripped open by a massive earthquake.
2005年出现的 陆地突然被一次巨大的地震裂开了口子
Nearby, similar tears and fractures
附近也有类似的裂缝和断层
scar the desert for many miles.
连绵沙漠几百公里
This is the Earth's crust splitting apart.
这是一个被分裂的大陆
