在地球形成的時(shí)代 它要受到成千上萬個(gè)這樣的彗星撞擊
By the time the bombardment finished,
一旦撞擊完成
it's thought they'd delivered up to half the water inour oceans.
據(jù)分析它們會(huì)將一半的水釋放到我們的海洋
The amount of water inthe oceans has stayed roughly the same
自從40億年前海洋形成開始
ever since they were formed about four billion years ago.
海洋中的水量差不多一直沒變
But the oceans themselves are continually changing.
但是海洋本身不斷變化著
As the continents move over millions of years,
隨著大陸移動(dòng)了幾百萬年
new oceans open up, whilst others vanish.
新的海洋會(huì)出現(xiàn),有的會(huì)消失
It's hard for us to grasp because it happens over such an immense timescale.
我們很難理解 因?yàn)檫@些都發(fā)生在很長(zhǎng)的時(shí)間跨度里
Vet today, in East Africa we can actually see the possible beginnings of a new ocean.
但是今天在東非 我們能看到新海洋的誕生
This long, deep fissure,
這個(gè)漫長(zhǎng)深邃的裂縫
in an area of Ethiopia called the Afar Depression,
位于埃塞俄比亞一個(gè)叫阿法爾洼地的地方
is where the planet's next ocean may form.
這里將是地球下一個(gè)海洋形成之地
It appeared in 2005,when the Land was suddenly ripped open by a massive earthquake.
2005年出現(xiàn)的 陸地突然被一次巨大的地震裂開了口子
Nearby, similar tears and fractures
附近也有類似的裂縫和斷層
scar the desert for many miles.
連綿沙漠幾百公里
This is the Earth's crust splitting apart.
這是一個(gè)被分裂的大陸