Priceless imperfectionMederic PalotBy Andy CoghlanJULES VERNE’s idea of an ocean deep below the surface in Journey to the Centre of the Earth may not have been too far off. Earth’s mantle may contain many oceans’ worth of water – with the deepest 1000 kilometres down. “If it wasn’t down there, we would all be submerged,” says Steve Jacobsen at Northwestern...