Blurs

Earth looks like a world overflowing with water. Around 71% of its surface is covered by oceans, while enormous quantities of water are locked away in glaciers, groundwater, lakes, rivers, soil and the atmosphere. Yet scientists have long faced a fascinating question: How much water did the young Earth actually contain—and where did it all go? The answer may involve violent impacts, a changing atmosphere, the loss of ancient oceans and enormous quantities of water hidden deep beneath our feet. And some of Earth's water may be much closer to the planet's interior than we ever imagined. A Wet Planet With a Dry Interior When viewed from space, Earth appears unmistakably blue. But compared with the size of the planet, the amount of water at the surface is surprisingly small. The oceans contain roughly 1.3 billion cubic kilometres of water. That sounds almost incomprehensibly large, yet if all of Earth's water were gathered into a single sphere, the resulting ball would be only ...