A HOT layer of rock deep underground could be hiding five times as much water as is held in all Earth’s oceans.
Planetary scientists believe that when the Earth formed, about 2 per cent of its mass would have been water. Yet today’s oceans hold only a hundredth of that. No one knows if the rest escaped or is locked away under the surface.
Motohiko Murakami of the Tokyo Institute of Technology looked at the lower half of the Earth’s mantle. It was thought to contain very little water, but Murakami’s group found that defects in the rock formed by…
