地球是一个水世界

In this view from aboard the SpaceX Crew Dragon Endeavour, a pair of the International Space Station’s main solar arrays seemingly drape across the Earth’s horizon as the orbital lab soars 271 miles above the south Atlantic in between Argentina and South Africa.

Earth is a pale, blue dot when seen from space because our home planet is 71 percent water. NASA monitors Earth’s water from space, the skies, ground stations on land, ships sailing the seas and even with apps on mobile phones.

While Earth is so wet it looks blue from space, most of that water is saltwater. Less than three percent of Earth’s water is fresh water and nearly all of that water is frozen – locked up in polar ice caps, glaciers and other ice. The small amount of fresh water that remains is all that’s available for all the ways we use water.

Learn more: When It Comes to Water, You Have to Think Global

#WorldOceanDay

Image Credit: NASA

从SpaceX载人龙飞船奋进号拍摄的这张照片来看，国际空间站的一对主太阳能电池板似乎横跨地球的地平线，轨道实验室在阿根廷和南非之间的南大西洋上空271英里处翱翔。

从太空看地球是一个淡蓝色的小点，因为我们的星球71%是水。NASA从太空、天空、陆地地面站、海上航行的船只，甚至手机上的应用程序来监测地球上的水。

虽然地球很潮湿，从太空看是蓝色的，但大部分水是盐水。地球上只有不到3%的水是淡水，而且几乎所有的水都被冻结了——锁在极地冰帽、冰川和其他冰中。剩下的少量淡水是我们所有用水方式所能得到的全部。

了解更多：当涉及到水时，您必须放眼全球

#世界海洋日

图片来源：美国宇航局