中文翻譯:
地球上有多少水呢？其實，非常少哦！雖然地球的海洋覆蓋了約70%的表面，但這些海洋的深度相比地球的半徑來說，其實是很淺的。如果把地球表面所有的水聚集成一個小球，這個球的半徑大約只有700公里，甚至比月球的半徑還要小，但卻比土星的衛星瑞亞(Rhea)稍大。瑞亞就像我們外太陽系中的許多衛星一樣，主要是由水冰組成的。接下來的最小一個球表示的是地球上所有的液態淡水，而最小的球則顯示了地球上所有淡水湖泊和河流的容量。水是如何來到地球的，以及地下是否有被困住的水，仍然是科學家們研究的課題哦！
原文:
How much of planet Earth is made of water? Very little, actually. Although oceans of water cover about 70 percent of Earth’s surface, these oceans are shallow compared to the Earth’s radius. The featured illustration shows what would happen if all of the water on or near the surface of the Earth were bunched up into a ball. The radius of this ball would be only about 700 kilometers, less than half the radius of the Earth’s Moon, but slightly larger than Saturn’s moon Rhea which, like many moons in our outer Solar System, is mostly water ice. The next smallest ball depicts all of Earth’s liquid fresh water, while the tiniest ball shows the volume of all of Earth’s fresh-water lakes and rivers. How any of this water came to be on the Earth and whether any significant amount is trapped far beneath Earth’s surface remain topics of research.
來源:NASA每日圖片
