Scientists say rock layer hundreds of miles down holds vast amount of water, opening up new theories on how planet formed After decades of searching scientists have discovered that a vast reservoir of water, enough to fill the Earth’s oceans three times over, may be trapped hundreds of miles beneath the surface, potentially transforming our understanding of how the planet was formed. The water is locked up in a mineral called ringwoodite about 660km (400 miles) beneath the crust of the Earth, researchers say. Geophysicist Steve Jacobsen from Northwestern University in the US co-authored the study published in the journal...