Three-quarters of Earth is covered in water.

地球四分之三被水覆盖着

It's why it's called the blue planet.

所以我们称之为蓝色的星球

But imagine Earth without its oceans.

但是想象一下没有海洋的世界吧And instead, with all thewater in the world gathered together in a ball.

所有的水聚集到一起形成一个球体 就会是这个样子

There's not that much really.

其实没有这么夸张

But this water is what makes Earth different

但是水是地球区别于太阳系其它星球的一个特征

from every other planet in the solar system.

但是水是地球区别于太阳系其它星球的一个特征

The oceans have been here for almost four billion years,

海洋已经在这里存在约40亿年了

carving the coastline, driving the climate

雕刻着海岸线，改变着气候变化

and controlling the destiny of life itself

控制着生命本身的命运