这不是实际的水是什么输给了空间,因为在高层大气水通常分离到其他分子或离子。氧离子外流经常被认为是代表行星大气层的水的流失。的全球地球外流率率从10美元不等^ {25}$ $ 10 ^ {26}s ^{1} $,根据地磁活动([引用][1])。海报的引用(作者)寄给我我们可以阅读:>如果我们假设氧气对应水损失(自律,麦克尔罗伊Hunten >和[1970]),然后一个氧损失率~ 10美元^ {25}s ^{1} >对应~ 300美元\文本{g s} ^{1} $水的损失。在太阳系的年龄>(45亿年~ \ $ 1.4 * 10 ^ {17}$ s)这一损失>率为4.2美元\ * 10 ^ {19}$ g的水。* *当前图是等价的损失~每天25920升,或9467美元\文本{m} ^ 3美元每年。* *的参考图似乎本文[逃脱O +通过遥远的尾巴等离子板)[2],使用的测量(立体量B(太阳能地面天文台的关系)飞船][3]。* *,将对应于总损失超过地球历史上的42000美元\文本{公里}^ 3美元的水,相当于海平面变化的12厘米。* *不过,这是一个简单的推断当前的利率,因为他们承认他们不知道如何模型地球的磁气圈会表现在过去当太阳是较弱的。虽然,阳光较弱是合理的期望损失小。 This value is radically different to that of [the article you pointed to][4]. In that case they use the loss of hydrogen instead of oxygen as proxy for water loss: > Knowing how much hydrogen had disappeared from the oceans over the > last four billion years enabled the researchers to calculate that the > oceans have lost about a quarter of their water since the Earth’s > early days. They the say: > Today the atmosphere is rich in oxygen, which reacts with both > hydrogen and deuterium to recreate water, which falls back to the > Earth's surface. So the vast bulk of the water on Earth is held in a > closed system that prevents the planet from gradually drying out. That suggests that the limiting factor for the existence of water is now the abundance atmospheric oxygen (although oxygen in rocks if very abundant). So it would make sense to use now Oxygen loss as proxy for water loss, but in the past, before the atmosphere was flooded with oxygen, maybe hydrogen loss was a better proxy. They suggests that methanogenesis can free hydrogen atoms and make them liable to be loss to space, but when it is part of a water molecule it is safe. Methanogenesis would have been much more common in the past when the atmosphere was rich in methane (50 to 500 richer than today). To wrap up, it seem that there is no consensus about the actual amount of water loss trough Earth's history. Different proxies give different values. Some proxies might be representative to some periods in Earth's past, but other proxies are more representative of other periods. And unfortunately we don't have yet a good reconstruction of the composition and density of the atmosphere throughout Earth's history. But we do know with some confidence, that while you where reading this answer, one or two liters of water were loss to space. [1]: https://ui.adsabs.harvard.edu//#abs/2017AGUFM.P11B2506S/abstract [2]: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2010GL045075 [3]: https://en.wikipedia.org/wiki/STEREO [4]: http://sciencenordic.com/earth-has-lost-quarter-its-water