If you want to find earth’s vast reservoirs of water, you may have to look beyond the obvious places like the oceans and polar ice caps. Scientists say they have found a vast reservoir of water – enough to fill the world’s oceans three times over – trapped up to 660km beneath the crust of the earth, potentially transforming our understanding of how the planet was formed.
But do not expect to quench your thirst down there. The water is not liquid – or any other familiar form like ice or vapour. It is locked inside the molecular structure of minerals called ringwoodite and wadsleyite in mantle rock that possesses the remarkable ability to absorb water like a sponge.