> 71%水的地球为什么不干燥或蒸发吗?答案很简单:因为下雨。没有这么简单的回答是:据估计,地球已经失去了大约四分之一的水,它将失去了几乎所有的水在十亿年从现在。- - - - - -因为下雨温度随高度。这递减率意味着潮湿的空气变得饱和大气中。你可以看到这一点上有点阴天。而积云蓬松的上衣,平坦的底部。这些扁平底部反映的湿度水平达到100%。目前,只有一个非常小的比例的空气中的水分使热大气层的顶端。微量的水分,使其在平流层平流层可以迁移的方法。 The top of the stratosphere is unprotected from the nastier parts of the Sun's output. Ultraviolet radiation dissociates water into hydrogen and oxygen. Some of that hydrogen escapes into space. That lost hydrogen represents lost water. The Earth is currently losing about three kilograms of hydrogen into space every second. At that rate, it would take about a trillion (1012) years for the Earth to lose all of its waters. There are signs that the escape rate was significantly higher in the distant past. This is a byproduct of solutions to the Faint Young Sun problem. The signs of this early high escape rate are written in stone (serpentine, to be specific). Very old rocks have a different deuterium ratio that is currently observed. The escape rate will inevitably become significantly higher in the distant future as the Sun gets warmer and warmer. The Earth will eventually lose all of its water.