Looking for water? You'll have to dig deep. Deeper. Deeper. Yes, deeper.
Massive amounts of water appear to exist deep beneath the planet’s surface, trapped in a rocky layer of the mantle at depths between 410km to 660km. But don’t expect to quench your thirst down there.
“It’s no longer liquid water that we’re talking about at these great depths. The weight of hundreds of kilometres of rock and very high temperatures above 1,000 degrees Celsius break down water into its components. And it’s not accessible. It’s not a resource in any way,” Northwestern University geophysicist Steve Jacobsen said in a telephone interview.
Instead of flowing like rivers, frozen like ice, or vapourised like steam, the water in Earth's mantle is locked inside the molecular structure of minerals called ringwoodite and wadsleyite that possesses the remarkable ability to absorb water like a sponge.